feat(surface): major work on implementing surface constraints in a presciption agnostic manner

CMakeLists.txt

@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.28)
-project(MeanField CXX)
+project(MeanField C CXX)
 
 set(CMAKE_CXX_STANDARD 23)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
@@ -138,15 +138,24 @@ target_sources(mean_field
         libmeanfield/interface/operators/kernels/rotation_displacement_force_kernels.cppm
         libmeanfield/interface/operators/prepared_rotation_displacement_force.cppm
         libmeanfield/interface/operators/prepared_displacement_operator.cppm
-        libmeanfield/interface/eos/eos_base.cppm
+        libmeanfield/interface/eos/quantities.cppm
+        libmeanfield/interface/eos/relations.cppm
+        libmeanfield/interface/eos/concepts.cppm
+        libmeanfield/interface/eos/evaluation.cppm
+        libmeanfield/interface/eos/pressure_surface.cppm
+        libmeanfield/interface/eos/runtime.cppm
         libmeanfield/interface/eos/polytropic.cppm
         libmeanfield/interface/models/structure/structure_base.cppm
         libmeanfield/interface/models/structure/polytropic.cppm
         libmeanfield/interface/models/structure_profile.cppm
-        libmeanfield/interface/surface/surface_base.cppm
+        libmeanfield/interface/surface/constant.cppm
-        libmeanfield/interface/surface/isobaric.cppm
+        libmeanfield/interface/surface/dependencies.cppm
+        libmeanfield/interface/surface/compiled.cppm
+        libmeanfield/interface/surface/compiler.cppm
         libmeanfield/interface/models/stellar_model.cppm
         libmeanfield/interface/operators/prepared_mass_normalization.cppm
+        libmeanfield/interface/operators/prepared_centering_constraint.cppm
+        libmeanfield/interface/operators/prepared_surface_constraint.cppm
         libmeanfield/interface/operators/prepared_stellar_equilibrium.cppm
 )
 
@@ -194,6 +203,12 @@ add_executable(tests
         tests/operators/contexts/gravity_field_context.cpp
         tests/physics/gravity_monopole_accuracy.cpp
         tests/physics/barotrope.cpp
+        tests/physics/polytropic_eos_characterization.cpp
+        tests/physics/equation_of_state_type_system.cpp
+        tests/physics/equation_of_state_consumer_contracts.cpp
+        tests/physics/polytropic_eos_relations.cpp
+        tests/physics/equation_of_state_runtime_view.cpp
+        tests/surface/constant_surface_compilation.cpp
         tests/operators/kernels/barotropic_closure_kernels.cpp
         tests/operators/prepared_barotropic_closure.cpp
         tests/operators/contexts/barotropic_closure_linearization_context.cpp
@@ -215,7 +230,6 @@ add_executable(tests
         tests/operators/prepared_rotation_displacement_force_analytic.cpp
         tests/operators/prepared_rotation_displacement_force_affine_deformation.cpp
         tests/operators/prepared_displacement_operator.cpp
-        tests/surface/isobaric.cpp
         tests/models/stellar_model.cpp
         tests/operators/prepared_mass_normalization.cpp
         tests/operators/prepared_stellar_equilibrium.cpp
@@ -233,6 +247,7 @@ target_sources(experiment_mod
         PUBLIC
         FILE_SET CXX_MODULES FILES
         experiments/experiment_results.cppm
+        experiments/stellar_null_space.cppm
 )
 target_link_libraries(experiment_mod
         PUBLIC
@@ -247,6 +262,21 @@ add_executable(experiments
 
 target_link_libraries(experiments PRIVATE mean_field test_mod experiment_mod Catch2::Catch2 Boost::boost)
 
+add_executable(stellar_null_space_experiments
+        experiments/experiment_main.cpp
+        experiments/rigid_motion_null_space.cpp
+        experiments/gravity_completed_rigid_motion.cpp
+)
+
+target_link_libraries(stellar_null_space_experiments
+        PRIVATE
+        mean_field
+        test_mod
+        experiment_mod
+        Catch2::Catch2
+        Boost::boost
+)
+
 include (CTest)
 include (Catch)
 catch_discover_tests(

experiments/README.md

@@ -24,6 +24,49 @@ Run only the budget and choose its output path with:
 ./mean_field_experiments --experiment-output gravity_budget.csv --catch2 "[accuracy]"
 ```
 
+## Stellar-equilibrium null-space experiments
+
+`stellar_null_space_experiments` is a dedicated diagnostic executable rather
+than an ordinary verification or validation test. It constructs the analytic
+`n = 3` Lane-Emden seed, probes the three computational translations and three
+computational rotations, and compares the Jacobian before and after the strong
+centering-row replacement. It records total and residual-block response norms,
+the isolated centering contribution, and centered finite-difference errors.
+
+The experiment prints rank-zero progress messages while it builds the seed,
+solves its gravity field, and completes each rigid-mode case. Run it with:
+
+```text
+mpirun -np 1 ./cmake-build-debug-homebrew/stellar_null_space_experiments \
+    --experiment-output stellar_null_space.csv \
+    --catch2 "[null_space][rigid_motion]"
+```
+
+The rotation sweep includes zero rotation and a spherical-state diagnostic at
+half the Keplerian angular speed. The rotating result is an operator-symmetry
+probe, not a definitive rotating-equilibrium null-space measurement.
+
+The gravity-completed probe solves the linearized mixed gravity subsystem for
+the gravity-gradient and gravity-potential variations accompanying each rigid
+displacement. It then measures the complete equilibrium response with and
+without the centering rows:
+
+```text
+mpirun -np 1 ./cmake-build-debug-homebrew/stellar_null_space_experiments \
+    --experiment-output gravity_completed_null_space.csv \
+    --catch2 "[null_space][gravity_completed]"
+```
+
+The gravity solver prints its convergence summary, while the experiment prints
+the current mode and completed-case count. This probe prepares each rotation
+state only once and does not repeat the expensive nonlinear finite-difference
+calculations from the original rigid-motion diagnostic.
+
+A whole-Jacobian dense singular-value experiment is intentionally deferred.
+The checked-in `sandbox.smesh` is too large for a useful dense SVD, and the
+current matrix-free root operator does not provide a transpose action needed by
+a scalable smallest-singular-value method.
+
 The executable needs the same dependencies, generated module mapping, and
 configuration registration as the existing Catch2 test executable. Add
 `experiment_main.cpp` and `gravity_accuracy_budget.cpp` as a second executable

experiments/gravity_completed_rigid_motion.cpp

@@ -0,0 +1,273 @@
+#include <catch2/catch_test_macros.hpp>
+
+#include <algorithm>
+#include <array>
+#include <cmath>
+#include <limits>
+#include <map>
+#include <string>
+
+#include <mfem.hpp>
+#include <mpi.h>
+
+import experiment;
+import experiment.stellar_null_space;
+import mean_field;
+import test_helpers;
+
+namespace {
+    class GravityUnknownJacobian final : public mfem::Operator {
+    public:
+        explicit GravityUnknownJacobian(
+            const mean_field::operators::PreparedStellarEquilibriumOperator &stellarOperator
+        )
+            : mfem::Operator(
+                  stellarOperator.GetLayout().size(experiment::null_space::gravityGradientValue) +
+                  stellarOperator.GetLayout().size(experiment::null_space::gravityPotentialValue)
+              ),
+              m_stellarOperator(stellarOperator),
+              m_gravityGradientSize(stellarOperator.GetLayout().size(experiment::null_space::gravityGradientValue)) {
+            MFEM_VERIFY(Width() == Height(), "The reduced gravity Jacobian must be square.");
+        }
+
+        void Mult(
+            const mfem::Vector &gravityDirection,
+            mfem::Vector &gravityAction
+        ) const override {
+            MFEM_VERIFY(gravityDirection.Size() == Width(), "The reduced gravity direction has the wrong size.");
+
+            const mfem::Vector gravityGradientDirection(
+                const_cast<mfem::real_t *>(gravityDirection.GetData()), m_gravityGradientSize
+            );
+            const mfem::Vector gravityPotentialDirection(
+                const_cast<mfem::real_t *>(gravityDirection.GetData()) + m_gravityGradientSize,
+                Width() - m_gravityGradientSize
+            );
+
+            m_stellarOperator.GetGravityOperator().ApplyGravityUnknowns(
+                gravityGradientDirection,
+                gravityPotentialDirection,
+                m_stellarOperator.GetGravityContext().GetGeometryContext(),
+                gravityAction
+            );
+        }
+
+        [[nodiscard]] int gravity_gradient_size() const noexcept {
+            return m_gravityGradientSize;
+        }
+
+    private:
+        const mean_field::operators::PreparedStellarEquilibriumOperator &m_stellarOperator;
+        int m_gravityGradientSize;
+    };
+
+    void add_block_metrics(
+        std::map<
+            std::string,
+            double> &metrics,
+        const std::string &prefix,
+        const std::array<
+            double,
+            6> &norms
+    ) {
+        for (std::size_t block = 0; block < norms.size(); ++block) {
+            metrics.emplace(prefix + experiment::null_space::residualBlockNames[block] + "_norm", norms[block]);
+        }
+    }
+
+    [[nodiscard]] mfem::Vector gravity_residual_blocks(
+        const mfem::Vector &completeAction,
+        const mean_field::operators::StellarEquilibriumLayout &layout
+    ) {
+        const mfem::Vector gradient = experiment::null_space::const_residual_view(
+            completeAction, layout, experiment::null_space::gravityGradientResidual
+        );
+        const mfem::Vector potential = experiment::null_space::const_residual_view(
+            completeAction, layout, experiment::null_space::gravityPotentialResidual
+        );
+
+        mfem::Vector result(gradient.Size() + potential.Size());
+        mfem::Vector(result.GetData(), gradient.Size())                    = gradient;
+        mfem::Vector(result.GetData() + gradient.Size(), potential.Size()) = potential;
+        return result;
+    }
+
+    void assign_gravity_completion(
+        mfem::Vector &completeDirection,
+        const mean_field::operators::StellarEquilibriumLayout &layout,
+        const mfem::Vector &gravityCompletion,
+        const int gravityGradientSize
+    ) {
+        const mfem::Vector gravityGradient(
+            const_cast<mfem::real_t *>(gravityCompletion.GetData()), gravityGradientSize
+        );
+        const mfem::Vector gravityPotential(
+            const_cast<mfem::real_t *>(gravityCompletion.GetData()) + gravityGradientSize,
+            gravityCompletion.Size() - gravityGradientSize
+        );
+        experiment::null_space::assign_value_block(
+            completeDirection, layout, experiment::null_space::gravityGradientValue, gravityGradient
+        );
+        experiment::null_space::assign_value_block(
+            completeDirection, layout, experiment::null_space::gravityPotentialValue, gravityPotential
+        );
+    }
+
+    void apply_centering_rows(
+        const mean_field::operators::PreparedStellarEquilibriumOperator &stellarOperator,
+        const mfem::Vector &direction,
+        mfem::Vector &action
+    ) {
+        const auto &layout = stellarOperator.GetLayout();
+        const mfem::Vector displacementDirection =
+            experiment::null_space::const_value_view(direction, layout, experiment::null_space::displacementValue);
+        mfem::Vector displacementAction =
+            experiment::null_space::residual_view(action, layout, experiment::null_space::displacementResidual);
+        stellarOperator.GetCenteringConstraintOperator().ApplyJacobianRows(displacementDirection, displacementAction);
+    }
+} // namespace
+
+TEST_CASE(
+    "Gravity-Completed Rigid Motion Responses Of The Stellar Equilibrium Jacobian",
+    "[null_space][gravity_completed]"
+) {
+    mean_field::utils::Args args = test_utils::setup_args();
+    args.p.rtol                  = 1.0e-11;
+    args.p.atol                  = std::min(args.p.atol, 1.0e-13);
+    args.p.max_iters             = std::max(args.p.max_iters, 2000);
+
+    experiment::null_space::N3Equilibrium fixture(std::move(args));
+    const MPI_Comm communicator = fixture.fem().mesh->GetComm();
+    int rank                    = 0;
+    MPI_Comm_rank(communicator, &rank);
+
+    const auto modes = experiment::null_space::make_rigid_modes(fixture);
+    constexpr std::array<double, 2> rotationFractions{0.0, 0.5};
+    const int totalCases = static_cast<int>(rotationFractions.size() * modes.size());
+    int completedCases   = 0;
+
+    for (const double rotationFraction : rotationFractions) {
+        const mean_field::physics::RigidRotation rotation = fixture.rotation(rotationFraction);
+        fixture.prepare(fixture.state(), rotation);
+
+        GravityUnknownJacobian gravityUnknownJacobian(fixture.stellar_operator());
+        mean_field::operators::ReducedGravityFieldPreconditioner gravityPreconditioner(
+            fixture.fem(), fixture.stellar_operator().GetGravityContext().GetGeometryContext()
+        );
+
+        mfem::MINRESSolver gravitySolver(communicator);
+        gravitySolver.SetOperator(gravityUnknownJacobian);
+        gravitySolver.SetPreconditioner(gravityPreconditioner);
+        gravitySolver.SetRelTol(1.0e-11);
+        gravitySolver.SetAbsTol(1.0e-13);
+        gravitySolver.SetMaxIter(2000);
+        gravitySolver.SetPrintLevel(1);
+
+        for (const experiment::null_space::RigidMode &mode : modes) {
+            experiment::null_space::report_progress(
+                communicator, "solving the gravity completion for " + mode.name + " at rotation fraction " +
+                                  std::to_string(rotationFraction) + " (" + std::to_string(completedCases + 1) + "/" +
+                                  std::to_string(totalCases) + ")"
+            );
+
+            const mfem::Vector displacementOnlyAction = fixture.unpinned_jacobian_action(mode.direction);
+            mfem::Vector gravityRightHandSide =
+                gravity_residual_blocks(displacementOnlyAction, fixture.stellar_operator().GetLayout());
+            gravityRightHandSide *= -1.0;
+
+            mfem::Vector gravityCompletion(gravityUnknownJacobian.Width());
+            gravityCompletion = 0.0;
+            gravitySolver.Mult(gravityRightHandSide, gravityCompletion);
+
+            REQUIRE(gravitySolver.GetConverged());
+
+            mfem::Vector gravitySolveAction;
+            gravityUnknownJacobian.Mult(gravityCompletion, gravitySolveAction);
+            mfem::Vector gravitySolveResidual(gravitySolveAction);
+            gravitySolveResidual -= gravityRightHandSide;
+
+            const double gravityRightHandSideNorm =
+                experiment::null_space::global_norm(gravityRightHandSide, communicator);
+            const double gravitySolveResidualNorm =
+                experiment::null_space::global_norm(gravitySolveResidual, communicator);
+            const double gravitySolveRelativeResidual =
+                gravitySolveResidualNorm / std::max(gravityRightHandSideNorm, std::numeric_limits<double>::epsilon());
+
+            REQUIRE(std::isfinite(gravitySolveRelativeResidual));
+
+            mfem::Vector completedDirection(mode.direction);
+            assign_gravity_completion(
+                completedDirection, fixture.stellar_operator().GetLayout(), gravityCompletion,
+                gravityUnknownJacobian.gravity_gradient_size()
+            );
+
+            const mfem::Vector completedUnpinnedAction = fixture.unpinned_jacobian_action(completedDirection);
+            mfem::Vector completedConstrainedAction(completedUnpinnedAction);
+            apply_centering_rows(fixture.stellar_operator(), completedDirection, completedConstrainedAction);
+
+            mfem::Vector centeringContribution(completedConstrainedAction);
+            centeringContribution -= completedUnpinnedAction;
+
+            std::map<std::string, double> metrics{
+                {"displacement_only_input_norm", experiment::null_space::global_norm(mode.direction, communicator)},
+                {"gravity_completion_norm", experiment::null_space::global_norm(gravityCompletion, communicator)},
+                {"completed_input_norm", experiment::null_space::global_norm(completedDirection, communicator)},
+                {"displacement_only_action_norm",
+                 experiment::null_space::global_norm(displacementOnlyAction, communicator)},
+                {"gravity_completed_unpinned_action_norm",
+                 experiment::null_space::global_norm(completedUnpinnedAction, communicator)},
+                {"gravity_completed_constrained_action_norm",
+                 experiment::null_space::global_norm(completedConstrainedAction, communicator)},
+                {"centering_contribution_norm",
+                 experiment::null_space::global_norm(centeringContribution, communicator)},
+                {"gravity_solve_rhs_norm", gravityRightHandSideNorm},
+                {"gravity_solve_residual_norm", gravitySolveResidualNorm},
+                {"gravity_solve_relative_residual", gravitySolveRelativeResidual},
+                {"gravity_solve_iterations", static_cast<double>(gravitySolver.GetNumIterations())},
+                {"gravity_solve_final_norm", gravitySolver.GetFinalNorm()}
+            };
+
+            add_block_metrics(
+                metrics, "displacement_only_",
+                experiment::null_space::residual_block_norms(
+                    displacementOnlyAction, fixture.stellar_operator().GetLayout(), communicator
+                )
+            );
+            add_block_metrics(
+                metrics, "gravity_completed_unpinned_",
+                experiment::null_space::residual_block_norms(
+                    completedUnpinnedAction, fixture.stellar_operator().GetLayout(), communicator
+                )
+            );
+            add_block_metrics(
+                metrics, "gravity_completed_constrained_",
+                experiment::null_space::residual_block_norms(
+                    completedConstrainedAction, fixture.stellar_operator().GetLayout(), communicator
+                )
+            );
+
+            if (rank == 0) {
+                experiment::record_experiment_result(
+                    "gravity_completed_stellar_rigid_motion_null_space", mode.name,
+                    {{"mode_kind",
+                      mode.kind == experiment::null_space::RigidModeKind::translation ? "translation" : "rotation"},
+                     {"axis", std::to_string(mode.axis)},
+                     {"rotation_fraction_of_keplerian", std::to_string(rotationFraction)},
+                     {"mesh_file", test_utils::setup_args().mesh_file},
+                     {"local_state_dofs", std::to_string(fixture.stellar_operator().Width())}},
+                    std::move(metrics)
+                );
+            }
+
+            ++completedCases;
+            experiment::null_space::report_progress(
+                communicator, "completed " + std::to_string(completedCases) + "/" + std::to_string(totalCases) +
+                                  " gravity-completed rigid-mode cases"
+            );
+        }
+    }
+
+    experiment::null_space::report_progress(
+        communicator, "gravity-completed rigid-motion probe complete; writing CSV output"
+    );
+}

experiments/rigid_motion_null_space.cpp

@@ -0,0 +1,174 @@
+#include <catch2/catch_test_macros.hpp>
+
+#include <algorithm>
+#include <array>
+#include <cmath>
+#include <limits>
+#include <map>
+#include <string>
+
+#include <mfem.hpp>
+#include <mpi.h>
+
+import experiment;
+import experiment.stellar_null_space;
+import mean_field;
+import test_helpers;
+
+namespace {
+    [[nodiscard]] double relative_difference(
+        const mfem::Vector &computed,
+        const mfem::Vector &reference,
+        const MPI_Comm communicator
+    ) {
+        mfem::Vector difference(computed);
+        difference -= reference;
+        const double scale = std::max(
+            {experiment::null_space::global_norm(computed, communicator),
+             experiment::null_space::global_norm(reference, communicator), std::numeric_limits<double>::epsilon()}
+        );
+        return experiment::null_space::global_norm(difference, communicator) / scale;
+    }
+
+    void add_block_metrics(
+        std::map<
+            std::string,
+            double> &metrics,
+        const std::string &prefix,
+        const std::array<
+            double,
+            6> &norms
+    ) {
+        for (std::size_t block = 0; block < norms.size(); ++block) {
+            metrics.emplace(prefix + experiment::null_space::residualBlockNames[block] + "_norm", norms[block]);
+        }
+    }
+} // namespace
+
+TEST_CASE(
+    "Rigid Motion Responses Of The Stellar Equilibrium Jacobian",
+    "[null_space][rigid_motion]"
+) {
+    mean_field::utils::Args args = test_utils::setup_args();
+    args.p.rtol                  = 1.0e-12;
+    args.p.atol                  = std::min(args.p.atol, 1.0e-14);
+    args.p.max_iters             = std::max(args.p.max_iters, 2000);
+
+    experiment::null_space::N3Equilibrium fixture(std::move(args));
+    const MPI_Comm communicator = fixture.fem().mesh->GetComm();
+    int rank                    = 0;
+    MPI_Comm_rank(communicator, &rank);
+
+    const auto modes = experiment::null_space::make_rigid_modes(fixture);
+    constexpr std::array<double, 2> rotationFractions{0.0, 0.5};
+    constexpr std::array<double, 2> finiteDifferenceSteps{1.0e-4, 1.0e-6};
+    const int totalCases = static_cast<int>(rotationFractions.size() * modes.size());
+    int completedCases   = 0;
+
+    for (const double rotationFraction : rotationFractions) {
+        const mean_field::physics::RigidRotation rotation = fixture.rotation(rotationFraction);
+        fixture.prepare(fixture.state(), rotation);
+
+        mfem::Vector constrainedResidual;
+        fixture.stellar_operator().BuildResidual(constrainedResidual);
+        const mfem::Vector unpinnedResidual = fixture.unpinned_residual();
+
+        REQUIRE(constrainedResidual.Size() == unpinnedResidual.Size());
+        REQUIRE(std::isfinite(experiment::null_space::global_norm(constrainedResidual, communicator)));
+        REQUIRE(std::isfinite(experiment::null_space::global_norm(unpinnedResidual, communicator)));
+
+        for (const experiment::null_space::RigidMode &mode : modes) {
+            experiment::null_space::report_progress(
+                communicator, "probing " + mode.name + " at rotation fraction " + std::to_string(rotationFraction) +
+                                  " (" + std::to_string(completedCases + 1) + "/" + std::to_string(totalCases) + ")"
+            );
+
+            fixture.prepare(fixture.state(), rotation);
+            const mfem::Vector unpinnedAction = fixture.unpinned_jacobian_action(mode.direction);
+            mfem::Vector constrainedAction;
+            fixture.stellar_operator().Mult(mode.direction, constrainedAction);
+
+            mfem::Vector centeringContribution(constrainedAction);
+            centeringContribution -= unpinnedAction;
+
+            const double inputNorm       = experiment::null_space::global_norm(mode.direction, communicator);
+            const double unpinnedNorm    = experiment::null_space::global_norm(unpinnedAction, communicator);
+            const double constrainedNorm = experiment::null_space::global_norm(constrainedAction, communicator);
+
+            REQUIRE(inputNorm > 0.0);
+            REQUIRE(std::isfinite(unpinnedNorm));
+            REQUIRE(std::isfinite(constrainedNorm));
+
+            std::map<std::string, double> metrics{
+                {"input_algebraic_norm", inputNorm},
+                {"unpinned_action_norm", unpinnedNorm},
+                {"unpinned_action_per_input_norm", unpinnedNorm / inputNorm},
+                {"constrained_action_norm", constrainedNorm},
+                {"constrained_action_per_input_norm", constrainedNorm / inputNorm},
+                {"centering_contribution_norm",
+                 experiment::null_space::global_norm(centeringContribution, communicator)},
+                {"unpinned_base_residual_norm", experiment::null_space::global_norm(unpinnedResidual, communicator)},
+                {"constrained_base_residual_norm",
+                 experiment::null_space::global_norm(constrainedResidual, communicator)}
+            };
+
+            add_block_metrics(
+                metrics, "unpinned_",
+                experiment::null_space::residual_block_norms(
+                    unpinnedAction, fixture.stellar_operator().GetLayout(), communicator
+                )
+            );
+            add_block_metrics(
+                metrics, "constrained_",
+                experiment::null_space::residual_block_norms(
+                    constrainedAction, fixture.stellar_operator().GetLayout(), communicator
+                )
+            );
+
+            for (const double step : finiteDifferenceSteps) {
+                mfem::Vector plusState(fixture.state());
+                plusState.Add(step, mode.direction);
+                fixture.prepare(plusState, rotation);
+                const mfem::Vector plusResidual = fixture.unpinned_residual();
+
+                mfem::Vector minusState(fixture.state());
+                minusState.Add(-step, mode.direction);
+                fixture.prepare(minusState, rotation);
+                const mfem::Vector minusResidual = fixture.unpinned_residual();
+
+                mfem::Vector finiteDifference(plusResidual);
+                finiteDifference -= minusResidual;
+                finiteDifference /= 2.0 * step;
+
+                const std::string stepName = step == finiteDifferenceSteps.front() ? "1e-4" : "1e-6";
+                metrics.emplace(
+                    "finite_difference_relative_error_" + stepName,
+                    relative_difference(unpinnedAction, finiteDifference, communicator)
+                );
+            }
+
+            fixture.prepare(fixture.state(), rotation);
+
+            if (rank == 0) {
+                experiment::record_experiment_result(
+                    "stellar_rigid_motion_null_space", mode.name,
+                    {{"mode_kind",
+                      mode.kind == experiment::null_space::RigidModeKind::translation ? "translation" : "rotation"},
+                     {"axis", std::to_string(mode.axis)},
+                     {"rotation_fraction_of_keplerian", std::to_string(rotationFraction)},
+                     {"mesh_file", test_utils::setup_args().mesh_file},
+                     {"local_state_dofs", std::to_string(fixture.stellar_operator().Width())}},
+                    std::move(metrics)
+                );
+            }
+
+            ++completedCases;
+            experiment::null_space::report_progress(
+                communicator,
+                "completed " + std::to_string(completedCases) + "/" + std::to_string(totalCases) + " rigid-mode cases"
+            );
+        }
+    }
+
+    experiment::null_space::report_progress(communicator, "rigid-motion probe complete; writing CSV output");
+}

experiments/stellar_null_space.cppm

@@ -0,0 +1,519 @@
+module;
+
+#include <algorithm>
+#include <array>
+#include <cmath>
+#include <cstdint>
+#include <iostream>
+#include <limits>
+#include <string>
+#include <utility>
+
+#include <mfem.hpp>
+#include <mpi.h>
+
+export module experiment.stellar_null_space;
+
+import mean_field;
+import test_helpers;
+
+export namespace experiment::null_space {
+    using Form         = mean_field::utils::blocks::barotropic_equilibrium_form;
+    using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
+    using Model        = mean_field::models::StellarModel<mean_field::models::structure::PolytropicStructure>;
+
+    constexpr auto densityValue =
+        mean_field::utils::blocks::get_value_block<Form>(mean_field::utils::blocks::density_field.mass_term);
+    constexpr auto displacementValue =
+        mean_field::utils::blocks::get_value_block<Form>(mean_field::utils::blocks::displacement_field.geometry_term);
+    constexpr auto gravityGradientValue =
+        mean_field::utils::blocks::get_value_block<Form>(mean_field::utils::blocks::gravity_field.gradient_term);
+    constexpr auto gravityPotentialValue =
+        mean_field::utils::blocks::get_value_block<Form>(mean_field::utils::blocks::gravity_field.poisson_term);
+    constexpr auto enthalpyValue =
+        mean_field::utils::blocks::get_value_block<Form>(mean_field::utils::blocks::enthalpy_field.specific_term);
+    constexpr auto bernoulliValue = mean_field::utils::blocks::get_value_block<Form>(
+        mean_field::utils::blocks::barotropic_constant_field.mass_normalization_term
+    );
+
+    constexpr auto gravityGradientResidual =
+        mean_field::utils::blocks::get_residual_block<Form>(mean_field::utils::blocks::gravity_field.gradient_term);
+    constexpr auto gravityPotentialResidual =
+        mean_field::utils::blocks::get_residual_block<Form>(mean_field::utils::blocks::gravity_field.poisson_term);
+    constexpr auto densityResidual =
+        mean_field::utils::blocks::get_residual_block<Form>(mean_field::utils::blocks::density_field.mass_term);
+    constexpr auto displacementResidual = mean_field::utils::blocks::get_residual_block<Form>(
+        mean_field::utils::blocks::displacement_field.geometry_term
+    );
+    constexpr auto enthalpyResidual =
+        mean_field::utils::blocks::get_residual_block<Form>(mean_field::utils::blocks::enthalpy_field.specific_term);
+    constexpr auto massResidual = mean_field::utils::blocks::get_residual_block<Form>(
+        mean_field::utils::blocks::barotropic_constant_field.mass_normalization_term
+    );
+
+    inline constexpr std::array<const char *, 6> residualBlockNames{"gravity_gradient", "gravity_potential", "closure",
+                                                                    "displacement",     "hydrostatic",       "mass"};
+
+    template <int index>
+    [[nodiscard]] mfem::Vector value_view(
+        mfem::Vector &vector,
+        const mean_field::operators::StellarEquilibriumLayout &layout,
+        const mean_field::utils::blocks::value_block<index> block
+    ) {
+        return mfem::Vector(vector.GetData() + layout.offset(block), layout.size(block));
+    }
+
+    template <int index>
+    [[nodiscard]] mfem::Vector const_value_view(
+        const mfem::Vector &vector,
+        const mean_field::operators::StellarEquilibriumLayout &layout,
+        const mean_field::utils::blocks::value_block<index> block
+    ) {
+        return mfem::Vector(const_cast<mfem::real_t *>(vector.GetData()) + layout.offset(block), layout.size(block));
+    }
+
+    template <int index>
+    [[nodiscard]] mfem::Vector residual_view(
+        mfem::Vector &vector,
+        const mean_field::operators::StellarEquilibriumLayout &layout,
+        const mean_field::utils::blocks::residual_block<index> block
+    ) {
+        return mfem::Vector(vector.GetData() + layout.offset(block), layout.size(block));
+    }
+
+    template <int index>
+    [[nodiscard]] mfem::Vector const_residual_view(
+        const mfem::Vector &vector,
+        const mean_field::operators::StellarEquilibriumLayout &layout,
+        const mean_field::utils::blocks::residual_block<index> block
+    ) {
+        return mfem::Vector(const_cast<mfem::real_t *>(vector.GetData()) + layout.offset(block), layout.size(block));
+    }
+
+    template <int index>
+    void assign_value_block(
+        mfem::Vector &vector,
+        const mean_field::operators::StellarEquilibriumLayout &layout,
+        const mean_field::utils::blocks::value_block<index> block,
+        const mfem::Vector &source
+    ) {
+        MFEM_VERIFY(source.Size() == layout.size(block), "Null-space experiment received a block with the wrong size.");
+        value_view(vector, layout, block) = source;
+    }
+
+    [[nodiscard]] inline double global_norm(
+        const mfem::Vector &vector,
+        const MPI_Comm communicator
+    ) {
+        const double localNormSquared = vector * vector;
+        double globalNormSquared      = 0.0;
+        MPI_Allreduce(&localNormSquared, &globalNormSquared, 1, MPI_DOUBLE, MPI_SUM, communicator);
+        return std::sqrt(globalNormSquared);
+    }
+
+    inline void report_progress(
+        const MPI_Comm communicator,
+        const std::string &message
+    ) {
+        int rank = 0;
+        MPI_Comm_rank(communicator, &rank);
+        if (rank == 0) {
+            std::cout << "[null-space experiment] " << message << std::endl;
+        }
+    }
+
+    [[nodiscard]] inline mean_field::operators::StellarEquilibriumDependencies make_dependencies() {
+        return {
+            .discretization    = {.identity = 2003, .revision = 1},
+            .density           = {.identity = 2011, .revision = 1},
+            .displacement      = {.identity = 2017, .revision = 1},
+            .gravityGradient   = {.identity = 2027, .revision = 1},
+            .gravityPotential  = {.identity = 2029, .revision = 1},
+            .enthalpy          = {.identity = 2039, .revision = 1},
+            .bernoulliConstant = {.identity = 2053, .revision = 1},
+            .rotation          = {.identity = 2063, .revision = 1},
+            .targetMass        = {.identity = 2069, .revision = 1}
+        };
+    }
+
+    inline void increment_state_revisions(mean_field::operators::StellarEquilibriumDependencies &dependencies) {
+        ++dependencies.density.revision;
+        ++dependencies.displacement.revision;
+        ++dependencies.gravityGradient.revision;
+        ++dependencies.gravityPotential.revision;
+        ++dependencies.enthalpy.revision;
+        ++dependencies.bernoulliConstant.revision;
+    }
+
+    [[nodiscard]] inline mfem::Vector pack_gravity_state(
+        const mfem::Vector &density,
+        const mfem::Vector &displacement,
+        const mfem::Vector &gravityGradient,
+        const mfem::Vector &gravityPotential
+    ) {
+        const std::array<int, 5> offsets{
+            0, density.Size(), density.Size() + displacement.Size(),
+            density.Size() + displacement.Size() + gravityGradient.Size(),
+            density.Size() + displacement.Size() + gravityGradient.Size() + gravityPotential.Size()
+        };
+        mfem::Vector packed(offsets.back());
+        mfem::Vector(packed.GetData() + offsets[0], density.Size())          = density;
+        mfem::Vector(packed.GetData() + offsets[1], displacement.Size())     = displacement;
+        mfem::Vector(packed.GetData() + offsets[2], gravityGradient.Size())  = gravityGradient;
+        mfem::Vector(packed.GetData() + offsets[3], gravityPotential.Size()) = gravityPotential;
+        return packed;
+    }
+
+    [[nodiscard]] inline Model make_model() {
+        const double pi                    = std::acos(-1.0);
+        const double targetMass            = mean_field::utils::MASS;
+        constexpr double dimensionlessMass = 2.0182359509662283534;
+        const double polytropicConstant =
+            pi * mean_field::utils::G * std::pow(targetMass / (4.0 * pi * dimensionlessMass), 2.0 / 3.0);
+
+        return Model{
+            mean_field::models::structure::PolytropicStructure{
+                mean_field::eos::Polytrope{3.0, polytropicConstant}, targetMass
+            },
+            mean_field::surface::ConstantPressureSurface{mean_field::eos::PressureValue{0.0}}
+        };
+    }
+
+    class N3Equilibrium final {
+    public:
+        explicit N3Equilibrium(mean_field::utils::Args args)
+            : m_args(std::move(args)),
+              m_fem(
+                  mean_field::fem::setup_fem(
+                      m_args.mesh_file,
+                      m_args,
+                      0
+                  )
+              ),
+              m_model(make_model()),
+              m_operator(
+                  m_fem,
+                  *m_fem.domainMapperStateless,
+                  m_model
+              ),
+              m_state(m_operator.GetLayout().value_offsets().Last()),
+              m_dependencies(make_dependencies()) {
+            MFEM_VERIFY(m_fem.okay(), "The null-space experiment could not construct the finite-element problem.");
+            m_state = 0.0;
+            initialize_state();
+        }
+
+        [[nodiscard]] mean_field::fem::FEM &fem() noexcept {
+            return m_fem;
+        }
+
+        [[nodiscard]] const mean_field::fem::FEM &fem() const noexcept {
+            return m_fem;
+        }
+
+        [[nodiscard]] mean_field::operators::PreparedStellarEquilibriumOperator &stellar_operator() noexcept {
+            return m_operator;
+        }
+
+        [[nodiscard]] const mean_field::operators::PreparedStellarEquilibriumOperator &
+        stellar_operator() const noexcept {
+            return m_operator;
+        }
+
+        [[nodiscard]] const mfem::Vector &state() const noexcept {
+            return m_state;
+        }
+
+        [[nodiscard]] mean_field::physics::RigidRotation rotation(const double fractionOfKeplerian) const {
+            const double radius         = mean_field::utils::RADIUS;
+            const double mass           = mean_field::utils::MASS;
+            const double keplerianSpeed = std::sqrt(mean_field::utils::G * mass / (radius * radius * radius));
+
+            mfem::Vector angularVelocity(3);
+            angularVelocity    = 0.0;
+            angularVelocity(2) = fractionOfKeplerian * keplerianSpeed;
+
+            mfem::Vector center(3);
+            center = 0.0;
+            return mean_field::physics::RigidRotation(angularVelocity, center);
+        }
+
+        void prepare(
+            const mfem::Vector &state,
+            const mean_field::physics::RigidRotation &rotation
+        ) {
+            m_currentState = state;
+            increment_state_revisions(m_dependencies);
+            ++m_dependencies.rotation.revision;
+            m_operator.Prepare(state, m_dependencies, rotation);
+        }
+
+        [[nodiscard]] mfem::Vector unpinned_residual() const {
+            const auto &layout                  = m_operator.GetLayout();
+            const mfem::Vector reducedDensity   = const_value_view(m_currentState, layout, densityValue);
+            const mfem::Vector displacement     = const_value_view(m_currentState, layout, displacementValue);
+            const mfem::Vector gravityGradient  = const_value_view(m_currentState, layout, gravityGradientValue);
+            const mfem::Vector gravityPotential = const_value_view(m_currentState, layout, gravityPotentialValue);
+            const mfem::Vector gravityState =
+                pack_gravity_state(reducedDensity, displacement, gravityGradient, gravityPotential);
+
+            mfem::Vector gravity;
+            mfem::Vector closure;
+            mfem::Vector displacementRows;
+            mfem::Vector hydrostatic;
+            mfem::Vector mass;
+            m_operator.GetGravityOperator().Mult(gravityState, gravity);
+            m_operator.GetBarotropicClosureOperator().BuildResidual(closure);
+            m_operator.GetDisplacementOperator().BuildResidual(displacementRows);
+            m_operator.GetHydrostaticOperator().BuildResidual(hydrostatic);
+            m_operator.GetSurfaceConstraintOperator().ApplyResidualRows(hydrostatic);
+            m_operator.GetMassNormalizationOperator().BuildResidual(mass);
+
+            return pack_residual(gravity, closure, displacementRows, hydrostatic, mass);
+        }
+
+        [[nodiscard]] mfem::Vector unpinned_jacobian_action(const mfem::Vector &direction) const {
+            const auto &layout                           = m_operator.GetLayout();
+            const mfem::Vector reducedDensityDirection   = const_value_view(direction, layout, densityValue);
+            const mfem::Vector displacementDirection     = const_value_view(direction, layout, displacementValue);
+            const mfem::Vector gravityGradientDirection  = const_value_view(direction, layout, gravityGradientValue);
+            const mfem::Vector gravityPotentialDirection = const_value_view(direction, layout, gravityPotentialValue);
+            const mfem::Vector reducedEnthalpyDirection  = const_value_view(direction, layout, enthalpyValue);
+            const mfem::Vector bernoulliDirection        = const_value_view(direction, layout, bernoulliValue);
+
+            const mfem::Vector gravityDirection          = pack_gravity_state(
+                reducedDensityDirection, displacementDirection, gravityGradientDirection, gravityPotentialDirection
+            );
+
+            mfem::Vector gravity;
+            mfem::Vector closure;
+            mfem::Vector displacementRows;
+            mfem::Vector hydrostatic;
+            mfem::Vector mass;
+            m_operator.GetGravityJacobianOperator().Mult(gravityDirection, gravity);
+            m_operator.GetBarotropicClosureOperator().Mult(
+                reducedDensityDirection, reducedEnthalpyDirection, displacementDirection, closure
+            );
+            m_operator.GetDisplacementOperator().ApplyCompleteJacobianAction(
+                reducedDensityDirection, displacementDirection, gravityGradientDirection, reducedEnthalpyDirection,
+                displacementRows
+            );
+            m_operator.GetHydrostaticOperator().ApplyCompleteJacobianAction(
+                reducedEnthalpyDirection, gravityPotentialDirection, bernoulliDirection(0), displacementDirection,
+                hydrostatic
+            );
+            m_operator.GetSurfaceConstraintOperator().ApplyJacobianRows(reducedEnthalpyDirection, hydrostatic);
+            m_operator.GetMassNormalizationOperator().ApplyCompleteJacobianAction(
+                reducedDensityDirection, displacementDirection, mass
+            );
+
+            return pack_residual(gravity, closure, displacementRows, hydrostatic, mass);
+        }
+
+    private:
+        void initialize_state() {
+            report_progress(m_fem.mesh->GetComm(), "constructing the analytic n=3 Lane-Emden state");
+
+            constexpr double surfaceCoordinate = 6.8968486193769603755;
+            constexpr int radialSampleCount    = 8192;
+            const double pi                    = std::acos(-1.0);
+            const double radius                = mean_field::utils::RADIUS;
+            const double targetMass            = mean_field::utils::MASS;
+            constexpr double dimensionlessMass = 2.0182359509662283534;
+            const double polytropicConstant =
+                pi * mean_field::utils::G * std::pow(targetMass / (4.0 * pi * dimensionlessMass), 2.0 / 3.0);
+            const double centralDensity =
+                std::pow(surfaceCoordinate * std::sqrt(polytropicConstant / (pi * mean_field::utils::G)) / radius, 3.0);
+
+            const mean_field::models::structure::StructureSeed seed =
+                m_model.makeInitialSeed({.centralDensity = centralDensity, .radialSampleCount = radialSampleCount});
+
+            const auto interpolate = [](const mfem::Vector &radii, const mfem::Vector &values, const double r) {
+                if (r <= radii(0)) {
+                    return values(0);
+                }
+                const int finalIndex = radii.Size() - 1;
+                if (r >= radii(finalIndex)) {
+                    return values(finalIndex);
+                }
+                int lower = 0;
+                int upper = finalIndex;
+                while (upper - lower > 1) {
+                    const int middle = lower + (upper - lower) / 2;
+                    if (radii(middle) <= r) {
+                        lower = middle;
+                    } else {
+                        upper = middle;
+                    }
+                }
+                const double fraction = (r - radii(lower)) / (radii(upper) - radii(lower));
+                return (1.0 - fraction) * values(lower) + fraction * values(upper);
+            };
+
+            mfem::FunctionCoefficient densityCoefficient([&seed, &interpolate](const mfem::Vector &position) {
+                const double r = position.Norml2();
+                return r >= seed.stellarRadius ? 0.0 : interpolate(seed.radius, seed.density, r);
+            });
+            mfem::FunctionCoefficient enthalpyCoefficient([&seed, &interpolate](const mfem::Vector &position) {
+                const double r = position.Norml2();
+                return r >= seed.stellarRadius ? 0.0 : interpolate(seed.radius, seed.enthalpy, r);
+            });
+
+            mfem::ParGridFunction densityField(m_fem.densityFes.get());
+            mfem::ParGridFunction enthalpyField(m_fem.enthalpyFes.get());
+            mfem::ParGridFunction displacementField(m_fem.displacementFes.get());
+            densityField      = 0.0;
+            enthalpyField     = 0.0;
+            displacementField = 0.0;
+            densityField.ProjectCoefficient(densityCoefficient);
+            enthalpyField.ProjectCoefficient(enthalpyCoefficient);
+            *m_fem.displacement = displacementField;
+
+            report_progress(m_fem.mesh->GetComm(), "solving the gravity field for the seed state");
+            const mean_field::physics::GravitySolution gravity =
+                mean_field::physics::solve_gravity_field(m_fem, m_args, densityField, displacementField);
+
+            mfem::Vector densityTrue;
+            mfem::Vector enthalpyTrue;
+            mfem::Vector displacementTrue;
+            mfem::Vector gravityGradientTrue;
+            mfem::Vector gravityPotentialTrue;
+            densityField.GetTrueDofs(densityTrue);
+            enthalpyField.GetTrueDofs(enthalpyTrue);
+            displacementField.GetTrueDofs(displacementTrue);
+            gravity.gradPhi.GetTrueDofs(gravityGradientTrue);
+            gravity.phi.GetTrueDofs(gravityPotentialTrue);
+
+            const auto &layout = m_operator.GetLayout();
+            const mean_field::field::FieldDofMap densityMap =
+                mean_field::field::make_field_dof_map<mean_field::field::Density, DomainSchema>(*m_fem.densityFes);
+            const mean_field::field::FieldDofMap enthalpyMap =
+                mean_field::field::make_field_dof_map<mean_field::field::Enthalpy, DomainSchema>(*m_fem.enthalpyFes);
+
+            assign_value_block(m_state, layout, densityValue, densityMap.gather(densityTrue));
+            assign_value_block(m_state, layout, displacementValue, displacementTrue);
+            assign_value_block(m_state, layout, gravityGradientValue, gravityGradientTrue);
+            assign_value_block(m_state, layout, gravityPotentialValue, gravityPotentialTrue);
+            assign_value_block(m_state, layout, enthalpyValue, enthalpyMap.gather(enthalpyTrue));
+            value_view(m_state, layout, bernoulliValue)(0) = -mean_field::utils::G * targetMass / radius;
+
+            m_currentState                                 = m_state;
+            prepare(m_state, rotation(0.0));
+            report_progress(m_fem.mesh->GetComm(), "analytic state is prepared");
+        }
+
+        [[nodiscard]] mfem::Vector pack_residual(
+            const mfem::Vector &gravity,
+            const mfem::Vector &closure,
+            const mfem::Vector &displacementRows,
+            const mfem::Vector &hydrostatic,
+            const mfem::Vector &mass
+        ) const {
+            const auto &layout = m_operator.GetLayout();
+            mfem::Vector result(layout.residual_offsets().Last());
+            result = 0.0;
+            const mfem::Vector gravityGradient(gravity.GetData(), layout.size(gravityGradientResidual));
+            const mfem::Vector gravityPotential(
+                gravity.GetData() + layout.size(gravityGradientResidual), layout.size(gravityPotentialResidual)
+            );
+            residual_view(result, layout, gravityGradientResidual)  = gravityGradient;
+            residual_view(result, layout, gravityPotentialResidual) = gravityPotential;
+            residual_view(result, layout, densityResidual)          = closure;
+            residual_view(result, layout, displacementResidual)     = displacementRows;
+            residual_view(result, layout, enthalpyResidual)         = hydrostatic;
+            residual_view(result, layout, massResidual)             = mass;
+            return result;
+        }
+
+        mean_field::utils::Args m_args;
+        mean_field::fem::FEM m_fem;
+        Model m_model;
+        mean_field::operators::PreparedStellarEquilibriumOperator m_operator;
+        mfem::Vector m_state;
+        mfem::Vector m_currentState;
+        mean_field::operators::StellarEquilibriumDependencies m_dependencies;
+    };
+
+    enum class RigidModeKind : std::uint8_t { translation, rotation };
+
+    struct RigidMode final {
+        std::string name;
+        RigidModeKind kind;
+        int axis;
+        mfem::Vector direction;
+    };
+
+    [[nodiscard]] inline std::array<
+        RigidMode,
+        6>
+    make_rigid_modes(const N3Equilibrium &fixture) {
+        const auto &fem    = fixture.fem();
+        const auto &layout = fixture.stellar_operator().GetLayout();
+        std::array<RigidMode, 6> modes;
+
+        for (int axis = 0; axis < 3; ++axis) {
+            mfem::ParGridFunction translation(fem.displacementFes.get());
+            mfem::Vector translationValue(3);
+            translationValue       = 0.0;
+            translationValue(axis) = 1.0;
+            mfem::VectorConstantCoefficient coefficient(translationValue);
+            translation.ProjectCoefficient(coefficient);
+            mfem::Vector translationTrue;
+            translation.GetTrueDofs(translationTrue);
+
+            mfem::Vector direction(layout.value_offsets().Last());
+            direction = 0.0;
+            assign_value_block(direction, layout, displacementValue, translationTrue);
+            modes[axis] = RigidMode{
+                .name      = std::string("translation_") + static_cast<char>('x' + axis),
+                .kind      = RigidModeKind::translation,
+                .axis      = axis,
+                .direction = std::move(direction)
+            };
+        }
+
+        for (int axis = 0; axis < 3; ++axis) {
+            mfem::ParGridFunction rotation(fem.displacementFes.get());
+            mfem::VectorFunctionCoefficient coefficient(3, [axis](const mfem::Vector &position, mfem::Vector &value) {
+                value.SetSize(3);
+                value            = 0.0;
+                const int first  = (axis + 1) % 3;
+                const int second = (axis + 2) % 3;
+                value(first)     = -position(second);
+                value(second)    = position(first);
+            });
+            rotation.ProjectCoefficient(coefficient);
+            mfem::Vector rotationTrue;
+            rotation.GetTrueDofs(rotationTrue);
+
+            mfem::Vector direction(layout.value_offsets().Last());
+            direction = 0.0;
+            assign_value_block(direction, layout, displacementValue, rotationTrue);
+            modes[3 + axis] = RigidMode{
+                .name      = std::string("rotation_") + static_cast<char>('x' + axis),
+                .kind      = RigidModeKind::rotation,
+                .axis      = axis,
+                .direction = std::move(direction)
+            };
+        }
+        return modes;
+    }
+
+    [[nodiscard]] inline std::array<
+        double,
+        6>
+    residual_block_norms(
+        const mfem::Vector &action,
+        const mean_field::operators::StellarEquilibriumLayout &layout,
+        const MPI_Comm communicator
+    ) {
+        return {
+            global_norm(const_residual_view(action, layout, gravityGradientResidual), communicator),
+            global_norm(const_residual_view(action, layout, gravityPotentialResidual), communicator),
+            global_norm(const_residual_view(action, layout, densityResidual), communicator),
+            global_norm(const_residual_view(action, layout, displacementResidual), communicator),
+            global_norm(const_residual_view(action, layout, enthalpyResidual), communicator),
+            global_norm(const_residual_view(action, layout, massResidual), communicator)
+        };
+    }
+} // namespace experiment::null_space

libmeanfield/impl/analysis/integral.cpp

@@ -14,20 +14,23 @@ namespace {
     ) {
         switch (domain) {
         case mean_field::utils::DOMAINS::CORE:
-            return mean_field::utils::domain::make_attribute_marker<
+            return mean_field::utils::domain::make_attribute_marker<mean_field::utils::domain::Core, DomainSchema>(
-                mean_field::utils::domain::Core, DomainSchema>(mesh);
+                mesh
+            );
         case mean_field::utils::DOMAINS::ENVELOPE:
-            return mean_field::utils::domain::make_attribute_marker<
+            return mean_field::utils::domain::make_attribute_marker<mean_field::utils::domain::Envelope, DomainSchema>(
-                mean_field::utils::domain::Envelope, DomainSchema>(mesh);
+                mesh
+            );
         case mean_field::utils::DOMAINS::ALL:
-            return mean_field::utils::domain::make_attribute_marker<
+            return mean_field::utils::domain::make_attribute_marker<mean_field::utils::domain::All, DomainSchema>(mesh);
-                mean_field::utils::domain::All, DomainSchema>(mesh);
         case mean_field::utils::DOMAINS::STELLAR:
-            return mean_field::utils::domain::make_attribute_marker<
+            return mean_field::utils::domain::make_attribute_marker<mean_field::utils::domain::Stellar, DomainSchema>(
-                mean_field::utils::domain::Stellar, DomainSchema>(mesh);
+                mesh
+            );
         case mean_field::utils::DOMAINS::VACUUM:
-            return mean_field::utils::domain::make_attribute_marker<
+            return mean_field::utils::domain::make_attribute_marker<mean_field::utils::domain::Vacuum, DomainSchema>(
-                mean_field::utils::domain::Vacuum, DomainSchema>(mesh);
+                mesh
+            );
         }
         MFEM_ABORT("Unsupported integration domain.");
     }
@@ -69,8 +72,7 @@ namespace mean_field::analysis {
 
         if (fem.has_mapping() && coord_space == mapping::COORDINATE_SPACE::PHYSICAL) {
             mapping::MappedScalarCoefficient mapped_gf_c(
-                *fem.domainMapperStateless, *fem.displacement,
+                *fem.domainMapperStateless, *fem.displacement, *fem.compactificationCoordinate, gf_c
-                *fem.compactificationCoordinate, gf_c
             );
 
             // ReSharper disable once CppDFAMemoryLeak // Disabled because MFEM
@@ -107,16 +109,14 @@ namespace mean_field::analysis {
     ) {
         const int dim = fem.mesh->Dimension();
         mapping::GridFunctionMappingEvaluator mapping_evaluator(
-            *fem.domainMapperStateless, *fem.displacement,
+            *fem.domainMapperStateless, *fem.displacement, *fem.compactificationCoordinate
-            *fem.compactificationCoordinate
         );
         mfem::Vector local_com(dim);
         local_com         = 0.0;
         double local_mass = 0.0;
 
         for (int i = 0; i < fem.mesh->GetNE(); ++i) {
-            if (!DomainSchema::template attribute_belongs_to<utils::domain::Stellar>(
+            if (!DomainSchema::template attribute_belongs_to<utils::domain::Stellar>(fem.mesh->GetAttribute(i)))
-                    fem.mesh->GetAttribute(i)))
                 continue;
             mfem::ElementTransformation *trans = fem.mesh->GetElementTransformation(i);
             const mfem::IntegrationRule &ir    = get_density_rule<field::Density::Form::CenterOfMass>(
@@ -129,8 +129,7 @@ namespace mean_field::analysis {
 
                 mapping::VolumeMappingContext mapping_context;
                 MFEM_VERIFY(
-                    mapping_evaluator.EvaluateVolume(*trans, ip, mapping_context) ==
+                    mapping_evaluator.EvaluateVolume(*trans, ip, mapping_context) == mapping::MappingStatus::valid,
-                        mapping::MappingStatus::valid,
                     "Center-of-mass integration encountered an invalid mapping."
                 );
                 const double weight            = mapping_context.quadrature.weight;
@@ -183,8 +182,7 @@ namespace mean_field::analysis {
         std::unique_ptr<mfem::Coefficient> s2_coeff;
         if (fem.has_mapping()) {
             s2_coeff = std::make_unique<mapping::PhysicalPositionFunctionCoefficient>(
-                *fem.domainMapperStateless, *fem.displacement,
+                *fem.domainMapperStateless, *fem.displacement, *fem.compactificationCoordinate, s2_func
-                *fem.compactificationCoordinate, s2_func
             );
         } else {
             s2_coeff = std::make_unique<mfem::FunctionCoefficient>(s2_func);
@@ -204,8 +202,7 @@ namespace mean_field::analysis {
         double local_I = 0.0;
         if (fem.has_mapping()) {
             mapping::MappedScalarCoefficient mapped_integrand(
-                *fem.domainMapperStateless, *fem.displacement,
+                *fem.domainMapperStateless, *fem.displacement, *fem.compactificationCoordinate, I_integrand
-                *fem.compactificationCoordinate, I_integrand
             );
             auto *integrator = new mfem::DomainLFIntegrator(mapped_integrand);
             integrator->SetIntRule(&integration_rule);
@@ -239,14 +236,12 @@ namespace mean_field::analysis {
 
         double local_volume = 0.0;
         mapping::GridFunctionMappingEvaluator mapping_evaluator(
-            *fem.domainMapperStateless, *fem.displacement,
+            *fem.domainMapperStateless, *fem.displacement, *fem.compactificationCoordinate
-            *fem.compactificationCoordinate
         );
 
         for (int e = 0; e < mesh.GetNE(); ++e) {
             const int attr      = mesh.GetAttribute(e);
-            const bool selected =
+            const bool selected = domain == utils::DOMAINS::ALL ||
-                domain == utils::DOMAINS::ALL ||
                                   (domain == utils::DOMAINS::STELLAR &&
                                    DomainSchema::template attribute_belongs_to<utils::domain::Stellar>(attr)) ||
                                   (domain == utils::DOMAINS::VACUUM &&
@@ -266,8 +261,7 @@ namespace mean_field::analysis {
                 if (physical) {
                     mapping::VolumeMappingContext context;
                     MFEM_VERIFY(
-                        mapping_evaluator.EvaluateVolume(*T, ip, context) ==
+                        mapping_evaluator.EvaluateVolume(*T, ip, context) == mapping::MappingStatus::valid,
-                            mapping::MappingStatus::valid,
                         "Mesh-volume integration encountered an invalid mapping."
                     );
                     dV = context.quadrature.weight;

libmeanfield/impl/fem.cpp

@@ -21,8 +21,11 @@ import :utils.misc;
 import :utils.user;
 
 namespace mean_field::fem {
-FEM setup_fem(const std::string &filename, const utils::Args &args,
+    FEM setup_fem(
-              const int extraRefine) {
+        const std::string &filename,
+        const utils::Args &args,
+        const int extraRefine
+    ) {
         FEM fem;
 
         using GravityPotential   = field::Gravity::Potential;
@@ -45,11 +48,9 @@ FEM setup_fem(const std::string &filename, const utils::Args &args,
         int mpiSize = 1;
         MPI_Comm_size(MPI_COMM_WORLD, &mpiSize);
 
-  const std::unique_ptr<int[]> meshPartitioning(
+        const std::unique_ptr<int[]> meshPartitioning(fem.smesh.mesh->GeneratePartitioning(mpiSize, 1));
-      fem.smesh.mesh->GeneratePartitioning(mpiSize, 1));
 
-  fem.mesh = std::make_unique<mfem::ParMesh>(MPI_COMM_WORLD, *fem.smesh.mesh,
+        fem.mesh = std::make_unique<mfem::ParMesh>(MPI_COMM_WORLD, *fem.smesh.mesh, meshPartitioning.get(), 1);
-                                             meshPartitioning.get(), 1);
 
         fem.mesh->EnsureNodes();
 
@@ -69,22 +70,22 @@ FEM setup_fem(const std::string &filename, const utils::Args &args,
             throw std::runtime_error("Values for exterior coordinate not set.");
         }
 
-  const mfem::FiniteElementSpace &serialCoordinateSpace =
+        const mfem::FiniteElementSpace &serialCoordinateSpace = *fem.smesh.exterior_coordinate->space;
-      *fem.smesh.exterior_coordinate->space;
 
-  const mfem::GridFunction &serialCoordinate =
+        const mfem::GridFunction &serialCoordinate            = *fem.smesh.exterior_coordinate->values;
-      *fem.smesh.exterior_coordinate->values;
 
         if (serialCoordinate.FESpace() != &serialCoordinateSpace) {
             throw std::runtime_error(
                 "Exterior coordinate values are not associated with the "
-        "supplied finite-element space.");
+                "supplied finite-element space."
+            );
         }
 
         if (serialCoordinateSpace.GetMesh() != fem.smesh.mesh.get()) {
             throw std::runtime_error(
                 "Exterior coordinate space is not associated with the "
-        "loaded STROID mesh.");
+                "loaded STROID mesh."
+            );
         }
 
         if (serialCoordinateSpace.GetVDim() != 1) {
@@ -94,30 +95,29 @@ FEM setup_fem(const std::string &filename, const utils::Args &args,
         if (serialCoordinate.Size() != serialCoordinateSpace.GetVSize()) {
             throw std::runtime_error(
                 "Exterior coordinate value count does not match its "
-        "finite-element space.");
+                "finite-element space."
+            );
         }
 
         const int compactificationOrder = serialCoordinateSpace.GetMaxElementOrder();
 
         const int dimension             = fem.mesh->Dimension();
 
-  fem.compactificationFec =
+        fem.compactificationFec         = std::make_unique<mfem::H1_FECollection>(compactificationOrder, dimension);
-      std::make_unique<mfem::H1_FECollection>(compactificationOrder, dimension);
 
-  fem.compactificationFes = std::make_unique<mfem::ParFiniteElementSpace>(
+        fem.compactificationFes =
-      fem.mesh.get(), fem.compactificationFec.get());
+            std::make_unique<mfem::ParFiniteElementSpace>(fem.mesh.get(), fem.compactificationFec.get());
 
-  mfem::ParGridFunction distributedCoordinate(fem.mesh.get(), &serialCoordinate,
+        mfem::ParGridFunction distributedCoordinate(fem.mesh.get(), &serialCoordinate, meshPartitioning.get());
-                                              meshPartitioning.get());
 
         if (distributedCoordinate.Size() != fem.compactificationFes->GetVSize()) {
             throw std::runtime_error(
                 "Distributed exterior coordinate does not match the "
-        "constructed parallel finite-element space.");
+                "constructed parallel finite-element space."
+            );
         }
 
-  fem.compactificationCoordinate =
+        fem.compactificationCoordinate  = std::make_unique<mfem::ParGridFunction>(fem.compactificationFes.get());
-      std::make_unique<mfem::ParGridFunction>(fem.compactificationFes.get());
 
         *fem.compactificationCoordinate = distributedCoordinate;
 
@@ -129,8 +129,7 @@ FEM setup_fem(const std::string &filename, const utils::Args &args,
             const double value = (*fem.compactificationCoordinate)(index);
 
             if (!std::isfinite(value)) {
-      throw std::runtime_error(
+                throw std::runtime_error("Exterior coordinate contains a non-finite value.");
-          "Exterior coordinate contains a non-finite value.");
             }
 
             localMinimum = std::min(localMinimum, value);
@@ -141,18 +140,17 @@ FEM setup_fem(const std::string &filename, const utils::Args &args,
         double globalMinimum = 0.0;
         double globalMaximum = 0.0;
 
-  MPI_Allreduce(&localMinimum, &globalMinimum, 1, MPI_DOUBLE, MPI_MIN,
+        MPI_Allreduce(&localMinimum, &globalMinimum, 1, MPI_DOUBLE, MPI_MIN, MPI_COMM_WORLD);
-                MPI_COMM_WORLD);
 
-  MPI_Allreduce(&localMaximum, &globalMaximum, 1, MPI_DOUBLE, MPI_MAX,
+        MPI_Allreduce(&localMaximum, &globalMaximum, 1, MPI_DOUBLE, MPI_MAX, MPI_COMM_WORLD);
-                MPI_COMM_WORLD);
 
         constexpr double coordinateTolerance = 1.0e-12;
 
-  if (globalMinimum < -coordinateTolerance ||
+        if (globalMinimum < -coordinateTolerance || globalMaximum > 1.0 + coordinateTolerance) {
-      globalMaximum > 1.0 + coordinateTolerance) {
+            throw std::runtime_error(
-    throw std::runtime_error("Exterior coordinate lies outside the expected "
+                "Exterior coordinate lies outside the expected "
-                             "interval [0, 1].");
+                "interval [0, 1]."
+            );
         }
 
         // =====================================================================
@@ -165,8 +163,7 @@ FEM setup_fem(const std::string &filename, const utils::Args &args,
 
         fem.gravityPotentialFec = GravityField::make_fec<GravityPotential>(dimension);
 
-  fem.gravityPotentialFes = GravityField::make_fespace<GravityPotential>(
+        fem.gravityPotentialFes = GravityField::make_fespace<GravityPotential>(*fem.mesh, *fem.gravityPotentialFec);
-      *fem.mesh, *fem.gravityPotentialFec);
 
         // ---------------------------------------------------------------------
         // Gravity flux: H(div)/RT. Basis choices are encoded by field.mfem.
@@ -174,21 +171,17 @@ FEM setup_fem(const std::string &filename, const utils::Args &args,
 
         fem.gravityFluxFec      = GravityField::make_fec<GravityFlux>(dimension);
 
-  fem.gravityFluxFes =
+        fem.gravityFluxFes      = GravityField::make_fespace<GravityFlux>(*fem.mesh, *fem.gravityFluxFec);
-      GravityField::make_fespace<GravityFlux>(*fem.mesh, *fem.gravityFluxFec);
 
         // ---------------------------------------------------------------------
         // Displacement: vector H1. Ordering is encoded by field.mfem.
         // ---------------------------------------------------------------------
 
-  fem.displacementFec =
+        fem.displacementFec     = DisplacementField::make_fec<DisplacementVector>(dimension);
-      DisplacementField::make_fec<DisplacementVector>(dimension);
 
-  fem.displacementFes = DisplacementField::make_fespace<DisplacementVector>(
+        fem.displacementFes     = DisplacementField::make_fespace<DisplacementVector>(*fem.mesh, *fem.displacementFec);
-      *fem.mesh, *fem.displacementFec);
 
-  fem.displacement =
+        fem.displacement        = std::make_unique<mfem::ParGridFunction>(fem.displacementFes.get());
-      std::make_unique<mfem::ParGridFunction>(fem.displacementFes.get());
 
         *fem.displacement       = 0.0;
 
@@ -198,8 +191,7 @@ FEM setup_fem(const std::string &filename, const utils::Args &args,
 
         fem.densityFec          = DensityField::make_fec<DensityScalar>(dimension);
 
-  fem.densityFes =
+        fem.densityFes          = DensityField::make_fespace<DensityScalar>(*fem.mesh, *fem.densityFec);
-      DensityField::make_fespace<DensityScalar>(*fem.mesh, *fem.densityFec);
 
         // ---------------------------------------------------------------------
         // Specific enthalpy: scalar continuous H1
@@ -207,8 +199,7 @@ FEM setup_fem(const std::string &filename, const utils::Args &args,
 
         fem.enthalpyFec         = EnthalpyField::make_fec<EnthalpyScalar>(dimension);
 
-  fem.enthalpyFes =
+        fem.enthalpyFes         = EnthalpyField::make_fespace<EnthalpyScalar>(*fem.mesh, *fem.enthalpyFec);
-      EnthalpyField::make_fespace<EnthalpyScalar>(*fem.mesh, *fem.enthalpyFec);
 
         // =====================================================================
         // Section 4: Multipole data
@@ -233,12 +224,9 @@ FEM setup_fem(const std::string &filename, const utils::Args &args,
         fem.boundaryContext.inf_bounds                                                                  = 0;
         fem.boundaryContext.stellar_bounds                                                              = 0;
 
-  fem.boundaryContext
+        fem.boundaryContext.inf_bounds[static_cast<int>(boundary::Boundaries::INF_SURFACE) - 1]         = 1;
-      .inf_bounds[static_cast<int>(boundary::Boundaries::INF_SURFACE) - 1] = 1;
 
-  fem.boundaryContext
+        fem.boundaryContext.stellar_bounds[static_cast<int>(boundary::Boundaries::STELLAR_SURFACE) - 1] = 1;
-      .stellar_bounds[static_cast<int>(boundary::Boundaries::STELLAR_SURFACE) -
-                      1] = 1;
 
         // =====================================================================
         // Section 7: Quadrature policy
@@ -246,34 +234,30 @@ FEM setup_fem(const std::string &filename, const utils::Args &args,
 
         const quadrature::QuadratureOptions &quadratureOptions = args.quadrature;
 
-  if (quadratureOptions.validation.reject_negative_boosts &&
+        if (quadratureOptions.validation.reject_negative_boosts && quadratureOptions.global_boost < 0) {
-      quadratureOptions.global_boost < 0) {
             throw std::invalid_argument("Global quadrature boost cannot be negative.");
         }
 
-  quadrature::RuleSet quadratureRuleSet = quadrature::make_rule_set(
+        quadrature::RuleSet quadratureRuleSet =
-      quadratureOptions.mode, quadratureOptions.global_boost);
+            quadrature::make_rule_set(quadratureOptions.mode, quadratureOptions.global_boost);
 
         if (quadratureOptions.fallback_fixed_order.has_value()) {
             if (*quadratureOptions.fallback_fixed_order < 0) {
-      throw std::invalid_argument(
+                throw std::invalid_argument("Fallback quadrature order cannot be negative.");
-          "Fallback quadrature order cannot be negative.");
             }
 
-    quadratureRuleSet.fallback.fixed_order =
+            quadratureRuleSet.fallback.fixed_order = quadratureOptions.fallback_fixed_order;
-        quadratureOptions.fallback_fixed_order;
         }
 
         auto apply_quadrature_options = [&quadratureOptions](
                                             quadrature::RuleControl &ruleControl,
-                                      const quadrature::QuadratureTermOptions
+                                            const quadrature::QuadratureTermOptions &termOptions
-                                          &termOptions) {
+                                        ) {
             if (termOptions.fixed_order.has_value() && *termOptions.fixed_order < 0) {
                 throw std::invalid_argument("Fixed quadrature order cannot be negative.");
             }
 
-    if (quadratureOptions.validation.reject_negative_boosts &&
+            if (quadratureOptions.validation.reject_negative_boosts && termOptions.additional_boost < 0) {
-        termOptions.additional_boost < 0) {
                 throw std::invalid_argument("Term quadrature boost cannot be negative.");
             }
 
@@ -284,98 +268,75 @@ FEM setup_fem(const std::string &filename, const utils::Args &args,
             }
         };
 
-  apply_quadrature_options(quadratureRuleSet.gravity_hdiv_mass,
+        apply_quadrature_options(quadratureRuleSet.gravity_hdiv_mass, quadratureOptions.gravity_hdiv_mass);
-                           quadratureOptions.gravity_hdiv_mass);
 
-  apply_quadrature_options(quadratureRuleSet.gravity_divergence,
+        apply_quadrature_options(quadratureRuleSet.gravity_divergence, quadratureOptions.gravity_divergence);
-                           quadratureOptions.gravity_divergence);
 
-  apply_quadrature_options(quadratureRuleSet.gravity_source,
+        apply_quadrature_options(quadratureRuleSet.gravity_source, quadratureOptions.gravity_source);
-                           quadratureOptions.gravity_source);
 
-  apply_quadrature_options(quadratureRuleSet.gravity_force,
+        apply_quadrature_options(quadratureRuleSet.gravity_force, quadratureOptions.gravity_force);
-                           quadratureOptions.gravity_force);
 
-  apply_quadrature_options(quadratureRuleSet.gravity_boundary,
+        apply_quadrature_options(quadratureRuleSet.gravity_boundary, quadratureOptions.gravity_boundary);
-                           quadratureOptions.gravity_boundary);
 
-  apply_quadrature_options(quadratureRuleSet.centrifugal,
+        apply_quadrature_options(quadratureRuleSet.centrifugal, quadratureOptions.centrifugal);
-                           quadratureOptions.centrifugal);
 
-  apply_quadrature_options(quadratureRuleSet.density_projection,
+        apply_quadrature_options(quadratureRuleSet.density_projection, quadratureOptions.density_projection);
-                           quadratureOptions.density_projection);
 
-  apply_quadrature_options(quadratureRuleSet.eos_closure,
+        apply_quadrature_options(quadratureRuleSet.eos_closure, quadratureOptions.eos_closure);
-                           quadratureOptions.eos_closure);
 
-  apply_quadrature_options(quadratureRuleSet.hydrostatic_equilibrium,
+        apply_quadrature_options(quadratureRuleSet.hydrostatic_equilibrium, quadratureOptions.hydrostatic_equilibrium);
-                           quadratureOptions.hydrostatic_equilibrium);
 
-  apply_quadrature_options(quadratureRuleSet.isobaric_surface,
+        apply_quadrature_options(quadratureRuleSet.isobaric_surface, quadratureOptions.isobaric_surface);
-                           quadratureOptions.isobaric_surface);
 
-  apply_quadrature_options(quadratureRuleSet.mesh_extension,
+        apply_quadrature_options(quadratureRuleSet.mesh_extension, quadratureOptions.mesh_extension);
-                           quadratureOptions.mesh_extension);
 
-  apply_quadrature_options(quadratureRuleSet.mass_conservation,
+        apply_quadrature_options(quadratureRuleSet.mass_conservation, quadratureOptions.mass_conservation);
-                           quadratureOptions.mass_conservation);
 
-  apply_quadrature_options(quadratureRuleSet.mass_normalization,
+        apply_quadrature_options(quadratureRuleSet.mass_normalization, quadratureOptions.mass_normalization);
-                           quadratureOptions.mass_normalization);
 
-  apply_quadrature_options(quadratureRuleSet.center_of_mass,
+        apply_quadrature_options(quadratureRuleSet.center_of_mass, quadratureOptions.center_of_mass);
-                           quadratureOptions.center_of_mass);
 
-  apply_quadrature_options(quadratureRuleSet.quadrupole,
+        apply_quadrature_options(quadratureRuleSet.quadrupole, quadratureOptions.quadrupole);
-                           quadratureOptions.quadrupole);
 
-  apply_quadrature_options(quadratureRuleSet.gravitational_energy,
+        apply_quadrature_options(quadratureRuleSet.gravitational_energy, quadratureOptions.gravitational_energy);
-                           quadratureOptions.gravitational_energy);
 
-  apply_quadrature_options(quadratureRuleSet.pressure_integral,
+        apply_quadrature_options(quadratureRuleSet.pressure_integral, quadratureOptions.pressure_integral);
-                           quadratureOptions.pressure_integral);
 
-  apply_quadrature_options(quadratureRuleSet.pressure_force,
+        apply_quadrature_options(quadratureRuleSet.pressure_force, quadratureOptions.pressure_force);
-                           quadratureOptions.pressure_force);
 
         apply_quadrature_options(quadratureRuleSet.virial, quadratureOptions.virial);
 
-  apply_quadrature_options(quadratureRuleSet.error_norm,
+        apply_quadrature_options(quadratureRuleSet.error_norm, quadratureOptions.error_norm);
-                           quadratureOptions.error_norm);
 
-  apply_quadrature_options(quadratureRuleSet.roles.discretization,
+        apply_quadrature_options(quadratureRuleSet.roles.discretization, quadratureOptions.roles.discretization);
-                           quadratureOptions.roles.discretization);
 
-  apply_quadrature_options(quadratureRuleSet.roles.preconditioner,
+        apply_quadrature_options(quadratureRuleSet.roles.preconditioner, quadratureOptions.roles.preconditioner);
-                           quadratureOptions.roles.preconditioner);
 
-  apply_quadrature_options(quadratureRuleSet.roles.diagnostic,
+        apply_quadrature_options(quadratureRuleSet.roles.diagnostic, quadratureOptions.roles.diagnostic);
-                           quadratureOptions.roles.diagnostic);
 
-  apply_quadrature_options(quadratureRuleSet.roles.projection,
+        apply_quadrature_options(quadratureRuleSet.roles.projection, quadratureOptions.roles.projection);
-                           quadratureOptions.roles.projection);
 
-  fem.quadratureFactory = std::make_unique<quadrature::RuleFactory>(
+        fem.quadratureFactory =
-      quadrature::Policy(std::move(quadratureRuleSet)));
+            std::make_unique<quadrature::RuleFactory>(quadrature::Policy(std::move(quadratureRuleSet)));
 
         // =====================================================================
         // Section 11: Stateless domain mapper
         // =====================================================================
 
         auto exteriorDomain =
-      std::make_unique<const mapping::compactification::KelvinCompactification>(
+            std::make_unique<const mapping::compactification::KelvinCompactification>(args.kelvin_options);
-          args.kelvin_options);
 
         MFEM_VERIFY(
             args.domain_mapper_options.vacuum_element_attribute ==
                 DomainSchema::template material_attribute<utils::domain::Vacuum>(),
             "The domain-mapper compactification attribute must match the vacuum "
             "material registered by the "
-      "production domain schema.");
+            "production domain schema."
+        );
 
-  fem.domainMapperStateless = std::make_unique<mapping::DomainMapper>(
+        fem.domainMapperStateless =
-      args.domain_mapper_options, std::move(exteriorDomain));
+            std::make_unique<mapping::DomainMapper>(args.domain_mapper_options, std::move(exteriorDomain));
 
         return fem;
-}
+    }
 } // namespace mean_field::fem

libmeanfield/impl/integrators/advection.cpp

@@ -9,7 +9,11 @@ namespace mean_field::integrators {
         const mfem::GridFunction &displacement,
         const mfem::GridFunction &compactification_coordinate
     )
-        : m_mapping(mapper, displacement, compactification_coordinate) {
+        : m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ) {
     }
 
     void AdvectionIntegrator::AssembleElementVector(

libmeanfield/impl/integrators/centrifugal.cpp

@@ -9,7 +9,11 @@ namespace mean_field::integrators {
         const mfem::GridFunction &compactification_coordinate,
         const mfem::Vector &omega
     )
-        : m_mapping(mapper, displacement, compactification_coordinate),
+        : m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ),
           m_omega(3) {
         MFEM_ASSERT(omega.Size() == 3, "Omega vector must be 3D");
         m_omega = omega;

libmeanfield/impl/integrators/coriolis.cpp

@@ -10,7 +10,11 @@ namespace mean_field::integrators {
         const mfem::GridFunction &compactification_coordinate,
         const mfem::Vector &omega
     )
-        : m_mapping(mapper, displacement, compactification_coordinate),
+        : m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ),
           m_omega(omega) {
         m_omega_mat.SetSize(3, 3);
         m_omega_mat       = 0.0;

libmeanfield/impl/integrators/gravity.cpp

@@ -19,7 +19,11 @@ namespace mean_field::integrators {
         const mfem::GridFunction &compactification_coordinate,
         const GravityForceJacobianMode jacobian_mode
     )
-        : m_mapping(mapper, displacement, compactification_coordinate),
+        : m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ),
           m_jacobian_mode(jacobian_mode) {
     }
 

libmeanfield/impl/integrators/mass_continuity.cpp

@@ -9,7 +9,11 @@ namespace mean_field::integrators {
         const mfem::GridFunction &displacement,
         const mfem::GridFunction &compactification_coordinate
     )
-        : m_mapping(mapper, displacement, compactification_coordinate) { };
+        : m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ) { };
 
     void ContinuityVolumeIntegrator::AssembleElementVector(
         const mfem::Array<const mfem::FiniteElement *> &el,
@@ -174,7 +178,11 @@ namespace mean_field::integrators {
         const mfem::GridFunction &displacement,
         const mfem::GridFunction &compactification_coordinate
     )
-        : m_mapping(mapper, displacement, compactification_coordinate) {
+        : m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ) {
     }
 
     void ContinuityFaceIntegrator::AssembleFaceVector(

libmeanfield/impl/integrators/viscosity.cpp

@@ -10,7 +10,11 @@ namespace mean_field::integrators {
         const double mu,
         const int quad_boost
     )
-        : m_mapping(mapper, displacement, compactification_coordinate),
+        : m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ),
           m_mu(mu),
           m_quad_boost(quad_boost) {
     }

libmeanfield/impl/mapping/coefficients.cpp

@@ -15,7 +15,11 @@ namespace mean_field::mapping {
         Coefficient &coeff,
         const COORDINATE_SPACE coord_space
     )
-        : m_mapping(mapper, displacement, compactification_coordinate),
+        : m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ),
           m_coeff(coeff),
           m_coord_space(coord_space) { };
 
@@ -63,7 +67,11 @@ namespace mean_field::mapping {
         const int dim
     )
         : MatrixCoefficient(dim),
-          m_mapping(mapper, displacement, compactification_coordinate),
+          m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ),
           m_scalar(&sigma),
           m_tensor(nullptr) { };
 
@@ -74,7 +82,11 @@ namespace mean_field::mapping {
         MatrixCoefficient &sigma
     )
         : MatrixCoefficient(sigma.GetHeight()),
-          m_mapping(mapper, displacement, compactification_coordinate),
+          m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ),
           m_scalar(nullptr),
           m_tensor(&sigma) { };
 
@@ -120,7 +132,11 @@ namespace mean_field::mapping {
         VectorCoefficient &coeff
     )
         : VectorCoefficient(coeff.GetVDim()),
-          m_mapping(mapper, displacement, compactification_coordinate),
+          m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ),
           m_coeff(coeff) { };
 
     void MappedVectorCoefficient::Eval(
@@ -157,7 +173,11 @@ namespace mean_field::mapping {
         Func f // std::function<double(const mfem::Vector&)>
     )
         : m_f(std::move(f)),
-          m_mapping(mapper, displacement, compactification_coordinate) { };
+          m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ) { };
 
     double PhysicalPositionFunctionCoefficient::Eval(
         mfem::ElementTransformation &T,
@@ -179,7 +199,11 @@ namespace mean_field::mapping {
         const int dim
     )
         : MatrixCoefficient(dim),
-          m_mapping(mapper, displacement, compactification_coordinate) {
+          m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ) {
     }
 
     void MappedHDivMassCoefficient::Eval(

libmeanfield/impl/models/polytropic.cpp

@@ -15,7 +15,7 @@ namespace mean_field::models::structure {
         validate();
     }
 
-    const eos::EquationOfState &PolytropicStructure::equationOfState() const noexcept {
+    const eos::Polytrope &PolytropicStructure::equationOfState() const noexcept {
         return m_equationOfState;
     }
 
@@ -29,7 +29,9 @@ namespace mean_field::models::structure {
         const double polytropicIndex                        = m_equationOfState.polytropic_index();
         const std::vector<LaneEmdenPoint> laneEmdenSolution = solveLaneEmden(polytropicIndex);
         const double surfaceCoordinate                      = laneEmdenSolution.back().coordinate;
-        const double centralEnthalpy = m_equationOfState.enthalpy_from_density(request.centralDensity);
+        const double centralEnthalpy =
+            eos::evaluate<eos::quantity::SpecificEnthalpy>(m_equationOfState, eos::DensityValue{request.centralDensity})
+                .value();
         const double radialScaleSquared =
             centralEnthalpy / (4.0 * std::numbers::pi_v<double> * mean_field::utils::G * request.centralDensity);
 
@@ -65,7 +67,8 @@ namespace mean_field::models::structure {
 
             seed.radius(sampleIndex)  = radialScale * dimensionlessRadius;
             seed.density(sampleIndex) = density;
-            seed.enthalpy(sampleIndex) = m_equationOfState.enthalpy_from_density(density);
+            seed.enthalpy(sampleIndex) =
+                eos::evaluate<eos::quantity::SpecificEnthalpy>(m_equationOfState, eos::DensityValue{density}).value();
         }
 
         seed.radius(0)              = 0.0;

libmeanfield/impl/operators/contexts/hydrostatic_equilibrium_context.cpp

@@ -80,13 +80,19 @@ namespace mean_field::operators::context::hydrostatic {
         : m_f(f),
           m_domainMapper(domainMapper),
           m_enthalpyMap(
-              field::make_field_dof_map<field::Enthalpy, DomainSchema>(*f.enthalpyFes)
+              field::make_field_dof_map<
+                  field::Enthalpy,
+                  DomainSchema>(*f.enthalpyFes)
           ),
           m_gravityPotentialMap(
-              field::make_field_dof_map<field::Gravity, DomainSchema>(*f.gravityPotentialFes)
+              field::make_field_dof_map<
+                  field::Gravity,
+                  DomainSchema>(*f.gravityPotentialFes)
           ),
           m_displacementMap(
-              field::make_field_dof_map<field::Displacement, DomainSchema>(*f.displacementFes)
+              field::make_field_dof_map<
+                  field::Displacement,
+                  DomainSchema>(*f.displacementFes)
           ) {
         MFEM_VERIFY(m_f.mesh != nullptr, "HydrostaticEquilibriumContext requires a mesh.");
 

libmeanfield/impl/operators/kernels/barotropic_closure_kernels.cpp

@@ -12,6 +12,8 @@ import :field.registry;
 import :utils.domain;
 
 namespace {
+    namespace eos       = mean_field::eos;
+
     using DomainSchema  = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
     using ClosureDomain = mean_field::field::FieldDomainT<mean_field::field::Density>;
 
@@ -336,11 +338,21 @@ namespace {
                     if (closureAction == ClosureAction::residual) {
                         const double density = elementDensityInput * densityShape;
 
-                        integrand            = density - barotrope.density_from_enthalpy(baseEnthalpy);
+                        const double equationOfStateDensity =
+                            eos::evaluate<eos::quantity::Density>(barotrope, eos::SpecificEnthalpyValue{baseEnthalpy})
+                                .value();
+
+                        integrand = density - equationOfStateDensity;
                     } else {
                         const double enthalpyVariation = elementEnthalpyVariation * enthalpyShape;
 
-                        integrand = -barotrope.density_derivative_from_enthalpy(baseEnthalpy) * enthalpyVariation;
+                        const double densityDerivative =
+                            eos::partialDerivative<eos::quantity::Density, eos::quantity::SpecificEnthalpy>(
+                                barotrope, eos::SpecificEnthalpyValue{baseEnthalpy}
+                            )
+                                .value();
+
+                        integrand = -densityDerivative * enthalpyVariation;
                     }
                 }
 
@@ -632,7 +644,10 @@ namespace mean_field::operators::kernels {
 
                 const double enthalpyValue = elementBaseEnthalpy * enthalpyShape;
 
-                const double closureValue        = densityValue - barotrope.density_from_enthalpy(enthalpyValue);
+                const double equationOfStateDensity =
+                    eos::evaluate<eos::quantity::Density>(barotrope, eos::SpecificEnthalpyValue{enthalpyValue}).value();
+
+                const double closureValue        = densityValue - equationOfStateDensity;
 
                 const double geometryActionValue = closureValue * mappingVariation.weight_variation;
 

libmeanfield/impl/operators/kernels/gravity_displacement_force_kernels.cpp

@@ -11,61 +11,64 @@ module mean_field;
 import :operators.kernels.gravity_displacement_force;
 
 namespace {
-using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
+    using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
 
-[[nodiscard]] bool is_vacuum_attribute(const int attribute) {
+    [[nodiscard]] bool is_vacuum_attribute(const int attribute) {
-  return DomainSchema::template attribute_belongs_to<
+        return DomainSchema::template attribute_belongs_to<mean_field::utils::domain::Vacuum>(attribute);
-      mean_field::utils::domain::Vacuum>(attribute);
+    }
-}
 
-enum class GravityDisplacementForceAction {
+    enum class GravityDisplacementForceAction { residual, density, gravityGradient, displacement, complete };
-  residual,
-  density,
-  gravityGradient,
-  displacement,
-  complete
-};
 
-void true_to_local(const mfem::ParFiniteElementSpace &finiteElementSpace,
+    void true_to_local(
-                   const mfem::Vector &trueVector, mfem::Vector &localVector) {
+        const mfem::ParFiniteElementSpace &finiteElementSpace,
-  MFEM_VERIFY(trueVector.Size() == finiteElementSpace.GetTrueVSize(),
+        const mfem::Vector &trueVector,
-              "The gravity-displacement-force true vector has the wrong size.");
+        mfem::Vector &localVector
+    ) {
+        MFEM_VERIFY(
+            trueVector.Size() == finiteElementSpace.GetTrueVSize(),
+            "The gravity-displacement-force true vector has the wrong size."
+        );
 
         localVector.SetSize(finiteElementSpace.GetVSize());
 
-  const mfem::Operator *prolongation =
+        const mfem::Operator *prolongation = finiteElementSpace.GetProlongationMatrix();
-      finiteElementSpace.GetProlongationMatrix();
 
         if (prolongation != nullptr) {
             prolongation->Mult(trueVector, localVector);
         } else {
             localVector = trueVector;
         }
-}
+    }
 
-void local_to_true(const mfem::ParFiniteElementSpace &finiteElementSpace,
+    void local_to_true(
-                   const mfem::Vector &localVector, mfem::Vector &trueVector) {
+        const mfem::ParFiniteElementSpace &finiteElementSpace,
+        const mfem::Vector &localVector,
+        mfem::Vector &trueVector
+    ) {
         MFEM_VERIFY(
             localVector.Size() == finiteElementSpace.GetVSize(),
-      "The gravity-displacement-force local vector has the wrong size.");
+            "The gravity-displacement-force local vector has the wrong size."
+        );
 
         trueVector.SetSize(finiteElementSpace.GetTrueVSize());
         trueVector                         = 0.0;
 
-  const mfem::Operator *prolongation =
+        const mfem::Operator *prolongation = finiteElementSpace.GetProlongationMatrix();
-      finiteElementSpace.GetProlongationMatrix();
 
         if (prolongation != nullptr) {
             prolongation->MultTranspose(localVector, trueVector);
         } else {
             trueVector = localVector;
         }
-}
+    }
 
-[[nodiscard]] int vector_dof_index(const mfem::Ordering::Type ordering,
+    [[nodiscard]] int vector_dof_index(
-                                   const int scalarDof, const int component,
+        const mfem::Ordering::Type ordering,
+        const int scalarDof,
+        const int component,
         const int scalarDofCount,
-                                   const int dimension) {
+        const int dimension
+    ) {
         if (ordering == mfem::Ordering::byNODES) {
             return scalarDof + component * scalarDofCount;
         }
@@ -74,120 +77,143 @@ void local_to_true(const mfem::ParFiniteElementSpace &finiteElementSpace,
             return scalarDof * dimension + component;
         }
 
-  MFEM_ABORT("The gravity-displacement-force test space uses an unsupported "
+        MFEM_ABORT(
-             "ordering.");
+            "The gravity-displacement-force test space uses an unsupported "
+            "ordering."
+        );
 
         return -1;
-}
+    }
 
-[[nodiscard]] const mfem::IntegrationRule &
+    [[nodiscard]] const mfem::IntegrationRule &get_gravity_force_rule(
-get_gravity_force_rule(const mean_field::fem::FEM &f,
+        const mean_field::fem::FEM &f,
         const mfem::FiniteElement &densityElement,
         const mfem::FiniteElement &gravityGradientElement,
         const mfem::FiniteElement &displacementElement,
-                       const mfem::ElementTransformation &transformation) {
+        const mfem::ElementTransformation &transformation
-  using DisplacementField =
+    ) {
-      mean_field::field::Field<mean_field::field::Displacement>;
+        using DisplacementField = mean_field::field::Field<mean_field::field::Displacement>;
 
-  MFEM_VERIFY(densityElement.GetOrder() ==
+        MFEM_VERIFY(
-                  mean_field::field::Density::Scalar::familyOrder,
+            densityElement.GetOrder() == mean_field::field::Density::Scalar::familyOrder,
             "The gravity-displacement-force density element does not match "
-              "the registered density field.");
+            "the registered density field."
+        );
 
-  MFEM_VERIFY(gravityGradientElement.GetOrder() ==
+        MFEM_VERIFY(
-                  mean_field::field::Gravity::Flux::familyOrder + 1,
+            gravityGradientElement.GetOrder() == mean_field::field::Gravity::Flux::familyOrder + 1,
             "The gravity-displacement-force RT element does not match the "
-              "registered gravity-gradient field.");
+            "registered gravity-gradient field."
+        );
 
-  MFEM_VERIFY(displacementElement.GetOrder() ==
+        MFEM_VERIFY(
-                  mean_field::field::Displacement::Vector::familyOrder,
+            displacementElement.GetOrder() == mean_field::field::Displacement::Vector::familyOrder,
             "The gravity-displacement-force test element does not match the "
-              "registered displacement field.");
+            "registered displacement field."
+        );
 
-  const mean_field::quadrature::Query query = DisplacementField::make_query<
+        const mean_field::quadrature::Query query =
-      mean_field::field::Displacement::Form::GravityForce>(
+            DisplacementField::make_query<mean_field::field::Displacement::Form::GravityForce>(
-      mean_field::quadrature::QuadratureRole::discretization,
+                mean_field::quadrature::QuadratureRole::discretization, transformation.OrderW(), {},
-      transformation.OrderW(), {}, mean_field::utils::DOMAINS::STELLAR,
+                mean_field::utils::DOMAINS::STELLAR, mean_field::quadrature::MappingKind::general
-      mean_field::quadrature::MappingKind::general);
+            );
 
-  const mean_field::quadrature::MfemRule rule =
+        const mean_field::quadrature::MfemRule rule = f.quadratureFactory->get(query, transformation.GetGeometryType());
-      f.quadratureFactory->get(query, transformation.GetGeometryType());
 
-  MFEM_VERIFY(rule.integration_rule != nullptr,
+        MFEM_VERIFY(
-              "The quadrature policy did not return a gravity-displacement-"
+            rule.integration_rule != nullptr, "The quadrature policy did not return a gravity-displacement-"
-              "force integration rule.");
+                                              "force integration rule."
+        );
 
         return *rule.integration_rule;
-}
+    }
 
-void validate_finite_vector(const mfem::Vector &vector, const char *message) {
+    void validate_finite_vector(
+        const mfem::Vector &vector,
+        const char *message
+    ) {
         for (int index = 0; index < vector.Size(); ++index) {
             MFEM_VERIFY(std::isfinite(vector(index)), message);
         }
-}
+    }
 
-void validate_common_inputs(
+    void validate_common_inputs(
         const mean_field::fem::FEM &f,
         const mean_field::mapping::DomainMapper &domainMapper,
-    const mfem::Vector &displacementTrue) {
+        const mfem::Vector &displacementTrue
-  MFEM_VERIFY(f.mesh != nullptr,
+    ) {
-              "The gravity-displacement-force kernel requires a mesh.");
+        MFEM_VERIFY(f.mesh != nullptr, "The gravity-displacement-force kernel requires a mesh.");
 
-  MFEM_VERIFY(f.densityFes != nullptr,
+        MFEM_VERIFY(
-              "The gravity-displacement-force kernel requires the density "
+            f.densityFes != nullptr, "The gravity-displacement-force kernel requires the density "
-              "finite-element space.");
+                                     "finite-element space."
+        );
 
-  MFEM_VERIFY(f.gravityFluxFes != nullptr,
+        MFEM_VERIFY(
-              "The gravity-displacement-force kernel requires the gravity-"
+            f.gravityFluxFes != nullptr, "The gravity-displacement-force kernel requires the gravity-"
-              "gradient finite-element space.");
+                                         "gradient finite-element space."
+        );
 
-  MFEM_VERIFY(f.displacementFes != nullptr,
+        MFEM_VERIFY(
-              "The gravity-displacement-force kernel requires the displacement "
+            f.displacementFes != nullptr, "The gravity-displacement-force kernel requires the displacement "
-              "finite-element space.");
+                                          "finite-element space."
+        );
 
-  MFEM_VERIFY(f.compactificationFes != nullptr &&
+        MFEM_VERIFY(
-                  f.compactificationCoordinate != nullptr,
+            f.compactificationFes != nullptr && f.compactificationCoordinate != nullptr,
             "The gravity-displacement-force kernel requires the "
-              "compactification coordinate.");
+            "compactification coordinate."
+        );
 
-  MFEM_VERIFY(f.quadratureFactory != nullptr,
+        MFEM_VERIFY(
-              "The gravity-displacement-force kernel requires the quadrature "
+            f.quadratureFactory != nullptr, "The gravity-displacement-force kernel requires the quadrature "
-              "rule factory.");
+                                            "rule factory."
+        );
 
-  MFEM_VERIFY(displacementTrue.Size() == f.displacementFes->GetTrueVSize(),
+        MFEM_VERIFY(
+            displacementTrue.Size() == f.displacementFes->GetTrueVSize(),
             "The gravity-displacement-force displacement vector has the "
-              "wrong size.");
+            "wrong size."
+        );
 
-  MFEM_VERIFY(domainMapper.GetDimension() == f.mesh->Dimension(),
+        MFEM_VERIFY(
+            domainMapper.GetDimension() == f.mesh->Dimension(),
             "The gravity-displacement-force mapper dimension does not match "
-              "the mesh dimension.");
+            "the mesh dimension."
+        );
 
-  MFEM_VERIFY(f.displacementFes->GetVDim() == f.mesh->Dimension(),
+        MFEM_VERIFY(
+            f.displacementFes->GetVDim() == f.mesh->Dimension(),
             "The gravity-displacement-force displacement dimension does not "
-              "match the mesh dimension.");
+            "match the mesh dimension."
+        );
 
         validate_finite_vector(
-      displacementTrue,
+            displacementTrue, "The gravity-displacement-force displacement contains a "
-      "The gravity-displacement-force displacement contains a "
+                              "non-finite value."
-      "non-finite value.");
+        );
-}
+    }
 
-void validate_density(const mean_field::fem::FEM &f,
+    void validate_density(
-                      const mfem::Vector &density, const char *message) {
+        const mean_field::fem::FEM &f,
+        const mfem::Vector &density,
+        const char *message
+    ) {
         MFEM_VERIFY(density.Size() == f.densityFes->GetTrueVSize(), message);
         validate_finite_vector(density, message);
-}
+    }
 
-void validate_gravity_gradient(const mean_field::fem::FEM &f,
+    void validate_gravity_gradient(
+        const mean_field::fem::FEM &f,
         const mfem::Vector &gravityGradient,
-                               const char *message) {
+        const char *message
-  MFEM_VERIFY(gravityGradient.Size() == f.gravityFluxFes->GetTrueVSize(),
+    ) {
-              message);
+        MFEM_VERIFY(gravityGradient.Size() == f.gravityFluxFes->GetTrueVSize(), message);
 
         validate_finite_vector(gravityGradient, message);
-}
+    }
 
-void apply_gravity_displacement_force_action(
+    void apply_gravity_displacement_force_action(
         const mean_field::fem::FEM &f,
         const mean_field::mapping::DomainMapper &domainMapper,
         const GravityDisplacementForceAction requestedAction,
@@ -196,85 +222,90 @@ void apply_gravity_displacement_force_action(
         const mfem::Vector *baseGravityGradientTrue,
         const mfem::Vector *gravityGradientVariationTrue,
         const mfem::Vector *displacementVariationTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &actionTrue) {
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &actionTrue
+    ) {
         validate_common_inputs(f, domainMapper, displacementTrue);
 
-  const bool needsBaseDensity =
+        const bool needsBaseDensity              = requestedAction == GravityDisplacementForceAction::residual ||
-      requestedAction == GravityDisplacementForceAction::residual ||
                                                    requestedAction == GravityDisplacementForceAction::gravityGradient ||
                                                    requestedAction == GravityDisplacementForceAction::displacement ||
                                                    requestedAction == GravityDisplacementForceAction::complete;
 
-  const bool needsDensityVariation =
+        const bool needsDensityVariation         = requestedAction == GravityDisplacementForceAction::density ||
-      requestedAction == GravityDisplacementForceAction::density ||
                                                    requestedAction == GravityDisplacementForceAction::complete;
 
-  const bool needsBaseGravityGradient =
+        const bool needsBaseGravityGradient      = requestedAction == GravityDisplacementForceAction::residual ||
-      requestedAction == GravityDisplacementForceAction::residual ||
                                                    requestedAction == GravityDisplacementForceAction::density ||
                                                    requestedAction == GravityDisplacementForceAction::displacement ||
                                                    requestedAction == GravityDisplacementForceAction::complete;
 
-  const bool needsGravityGradientVariation =
+        const bool needsGravityGradientVariation = requestedAction == GravityDisplacementForceAction::gravityGradient ||
-      requestedAction == GravityDisplacementForceAction::gravityGradient ||
                                                    requestedAction == GravityDisplacementForceAction::complete;
 
-  const bool needsDisplacementVariation =
+        const bool needsDisplacementVariation    = requestedAction == GravityDisplacementForceAction::displacement ||
-      requestedAction == GravityDisplacementForceAction::displacement ||
                                                    requestedAction == GravityDisplacementForceAction::complete;
 
         if (needsBaseDensity) {
-    MFEM_VERIFY(baseDensityTrue != nullptr,
+            MFEM_VERIFY(
-                "The gravity-displacement-force action requires a base "
+                baseDensityTrue != nullptr, "The gravity-displacement-force action requires a base "
-                "density.");
+                                            "density."
+            );
 
-    validate_density(f, *baseDensityTrue,
+            validate_density(f, *baseDensityTrue, "The gravity-displacement-force base density is invalid.");
-                     "The gravity-displacement-force base density is invalid.");
         }
 
         if (needsDensityVariation) {
-    MFEM_VERIFY(densityVariationTrue != nullptr,
+            MFEM_VERIFY(
-                "The gravity-displacement-force action requires a density "
+                densityVariationTrue != nullptr, "The gravity-displacement-force action requires a density "
-                "variation.");
+                                                 "variation."
+            );
 
-    validate_density(f, *densityVariationTrue,
+            validate_density(
+                f, *densityVariationTrue,
                 "The gravity-displacement-force density variation is "
-                     "invalid.");
+                "invalid."
+            );
         }
 
         if (needsBaseGravityGradient) {
-    MFEM_VERIFY(baseGravityGradientTrue != nullptr,
+            MFEM_VERIFY(
-                "The gravity-displacement-force action requires a base "
+                baseGravityGradientTrue != nullptr, "The gravity-displacement-force action requires a base "
-                "gravity gradient.");
+                                                    "gravity gradient."
+            );
 
             validate_gravity_gradient(
                 f, *baseGravityGradientTrue,
                 "The gravity-displacement-force base gravity gradient is "
-        "invalid.");
+                "invalid."
+            );
         }
 
         if (needsGravityGradientVariation) {
-    MFEM_VERIFY(gravityGradientVariationTrue != nullptr,
+            MFEM_VERIFY(
-                "The gravity-displacement-force action requires a gravity-"
+                gravityGradientVariationTrue != nullptr, "The gravity-displacement-force action requires a gravity-"
-                "gradient variation.");
+                                                         "gradient variation."
+            );
 
             validate_gravity_gradient(
                 f, *gravityGradientVariationTrue,
                 "The gravity-displacement-force gravity-gradient variation "
-        "is invalid.");
+                "is invalid."
+            );
         }
 
         if (needsDisplacementVariation) {
-    MFEM_VERIFY(displacementVariationTrue != nullptr &&
+            MFEM_VERIFY(
-                    displacementVariationTrue->Size() ==
+                displacementVariationTrue != nullptr &&
-                        f.displacementFes->GetTrueVSize(),
+                    displacementVariationTrue->Size() == f.displacementFes->GetTrueVSize(),
                 "The gravity-displacement-force displacement variation is "
-                "invalid.");
+                "invalid."
+            );
 
             validate_finite_vector(
-        *displacementVariationTrue,
+                *displacementVariationTrue, "The gravity-displacement-force displacement variation "
-        "The gravity-displacement-force displacement variation "
+                                            "contains a non-finite value."
-        "contains a non-finite value.");
+            );
         }
 
         mfem::Vector baseDensityLocal;
@@ -293,27 +324,23 @@ void apply_gravity_displacement_force_action(
         }
 
         if (needsBaseGravityGradient) {
-    true_to_local(*f.gravityFluxFes, *baseGravityGradientTrue,
+            true_to_local(*f.gravityFluxFes, *baseGravityGradientTrue, baseGravityGradientLocal);
-                  baseGravityGradientLocal);
         }
 
         if (needsGravityGradientVariation) {
-    true_to_local(*f.gravityFluxFes, *gravityGradientVariationTrue,
+            true_to_local(*f.gravityFluxFes, *gravityGradientVariationTrue, gravityGradientVariationLocal);
-                  gravityGradientVariationLocal);
         }
 
         true_to_local(*f.displacementFes, displacementTrue, displacementLocal);
 
         if (needsDisplacementVariation) {
-    true_to_local(*f.displacementFes, *displacementVariationTrue,
+            true_to_local(*f.displacementFes, *displacementVariationTrue, displacementVariationLocal);
-                  displacementVariationLocal);
         }
 
         mfem::Vector localAction(f.displacementFes->GetVSize());
         localAction = 0.0;
 
-  mean_field::mapping::DomainMapper::Workspace workspace(
+        mean_field::mapping::DomainMapper::Workspace workspace(f.mesh->Dimension());
-      f.mesh->Dimension());
 
         mfem::Array<int> densityDofs;
         mfem::Array<int> gravityGradientDofs;
@@ -345,16 +372,15 @@ void apply_gravity_displacement_force_action(
 
         const int dimension                             = f.mesh->Dimension();
 
-  const mfem::Ordering::Type displacementOrdering =
+        const mfem::Ordering::Type displacementOrdering = f.displacementFes->GetOrdering();
-      f.displacementFes->GetOrdering();
 
         for (int elementId = 0; elementId < f.mesh->GetNE(); ++elementId) {
-    mfem::ElementTransformation *transformation =
+            mfem::ElementTransformation *transformation = f.mesh->GetElementTransformation(elementId);
-        f.mesh->GetElementTransformation(elementId);
 
-    MFEM_VERIFY(transformation != nullptr,
+            MFEM_VERIFY(
-                "The gravity-displacement-force kernel received a null "
+                transformation != nullptr, "The gravity-displacement-force kernel received a null "
-                "element transformation.");
+                                           "element transformation."
+            );
 
             if (is_vacuum_attribute(transformation->Attribute)) {
                 continue;
@@ -362,17 +388,13 @@ void apply_gravity_displacement_force_action(
 
             const mfem::FiniteElement &densityElement          = *f.densityFes->GetFE(elementId);
 
-    const mfem::FiniteElement &gravityGradientElement =
+            const mfem::FiniteElement &gravityGradientElement  = *f.gravityFluxFes->GetFE(elementId);
-        *f.gravityFluxFes->GetFE(elementId);
 
-    const mfem::FiniteElement &displacementElement =
+            const mfem::FiniteElement &displacementElement     = *f.displacementFes->GetFE(elementId);
-        *f.displacementFes->GetFE(elementId);
 
-    const mfem::FiniteElement &compactificationElement =
+            const mfem::FiniteElement &compactificationElement = *f.compactificationFes->GetFE(elementId);
-        *f.compactificationFes->GetFE(elementId);
 
-    mfem::DofTransformation *densityDofTransformation =
+            mfem::DofTransformation *densityDofTransformation  = f.densityFes->GetElementDofs(elementId, densityDofs);
-        f.densityFes->GetElementDofs(elementId, densityDofs);
 
             mfem::DofTransformation *gravityGradientDofTransformation =
                 f.gravityFluxFes->GetElementVDofs(elementId, gravityGradientDofs);
@@ -392,24 +414,20 @@ void apply_gravity_displacement_force_action(
             }
 
             if (needsBaseGravityGradient) {
-      baseGravityGradientLocal.GetSubVector(gravityGradientDofs,
+                baseGravityGradientLocal.GetSubVector(gravityGradientDofs, elementBaseGravityGradient);
-                                            elementBaseGravityGradient);
             }
 
             if (needsGravityGradientVariation) {
-      gravityGradientVariationLocal.GetSubVector(
+                gravityGradientVariationLocal.GetSubVector(gravityGradientDofs, elementGravityGradientVariation);
-          gravityGradientDofs, elementGravityGradientVariation);
             }
 
             displacementLocal.GetSubVector(displacementDofs, elementDisplacement);
 
             if (needsDisplacementVariation) {
-      displacementVariationLocal.GetSubVector(displacementDofs,
+                displacementVariationLocal.GetSubVector(displacementDofs, elementDisplacementVariation);
-                                              elementDisplacementVariation);
             }
 
-    f.compactificationCoordinate->GetSubVector(compactificationDofs,
+            f.compactificationCoordinate->GetSubVector(compactificationDofs, elementCompactification);
-                                               elementCompactification);
 
             if (densityDofTransformation != nullptr) {
                 if (needsBaseDensity) {
@@ -423,13 +441,11 @@ void apply_gravity_displacement_force_action(
 
             if (gravityGradientDofTransformation != nullptr) {
                 if (needsBaseGravityGradient) {
-        gravityGradientDofTransformation->InvTransformPrimal(
+                    gravityGradientDofTransformation->InvTransformPrimal(elementBaseGravityGradient);
-            elementBaseGravityGradient);
                 }
 
                 if (needsGravityGradientVariation) {
-        gravityGradientDofTransformation->InvTransformPrimal(
+                    gravityGradientDofTransformation->InvTransformPrimal(elementGravityGradientVariation);
-            elementGravityGradientVariation);
                 }
             }
 
@@ -437,42 +453,42 @@ void apply_gravity_displacement_force_action(
                 displacementDofTransformation->InvTransformPrimal(elementDisplacement);
 
                 if (needsDisplacementVariation) {
-        displacementDofTransformation->InvTransformPrimal(
+                    displacementDofTransformation->InvTransformPrimal(elementDisplacementVariation);
-            elementDisplacementVariation);
                 }
             }
 
             if (compactificationDofTransformation != nullptr) {
-      compactificationDofTransformation->InvTransformPrimal(
+                compactificationDofTransformation->InvTransformPrimal(elementCompactification);
-          elementCompactification);
             }
 
             const mean_field::mapping::ElementDisplacementData displacementData =
-        mean_field::mapping::ElementDisplacementDataFromElementVDofs(
+                mean_field::mapping::ElementDisplacementDataFromElementVDofs(displacementElement, elementDisplacement);
-            displacementElement, elementDisplacement);
 
             const mean_field::mapping::ElementCompactificationData compactificationData(
-        compactificationElement, elementCompactification);
+                compactificationElement, elementCompactification
+            );
 
             const mean_field::mapping::ElementMappingData mappingData{
-        .displacement = displacementData,
+                .displacement = displacementData, .compactification = compactificationData
-        .compactification = compactificationData};
+            };
 
-    std::optional<mean_field::mapping::ElementDisplacementData>
+            std::optional<mean_field::mapping::ElementDisplacementData> displacementVariationData;
-        displacementVariationData;
 
             if (needsDisplacementVariation) {
                 displacementVariationData.emplace(
                     mean_field::mapping::ElementDisplacementDataFromElementVDofs(
-              displacementElement, elementDisplacementVariation));
+                        displacementElement, elementDisplacementVariation
+                    )
+                );
             }
 
             const int scalarDisplacementDofCount = displacementElement.GetDof();
 
-    MFEM_VERIFY(displacementDofs.Size() ==
+            MFEM_VERIFY(
-                    scalarDisplacementDofCount * dimension,
+                displacementDofs.Size() == scalarDisplacementDofCount * dimension,
                 "The gravity-displacement-force element displacement vector "
-                "has the wrong size.");
+                "has the wrong size."
+            );
 
             densityShape.SetSize(densityElement.GetDof());
             displacementShape.SetSize(scalarDisplacementDofCount);
@@ -489,42 +505,38 @@ void apply_gravity_displacement_force_action(
             elementAction = 0.0;
 
             const mfem::IntegrationRule &integrationRule =
-        get_gravity_force_rule(f, densityElement, gravityGradientElement,
+                get_gravity_force_rule(f, densityElement, gravityGradientElement, displacementElement, *transformation);
-                               displacementElement, *transformation);
 
-    for (int quadratureIndex = 0;
+            for (int quadratureIndex = 0; quadratureIndex < integrationRule.GetNPoints(); ++quadratureIndex) {
-         quadratureIndex < integrationRule.GetNPoints(); ++quadratureIndex) {
+                const mfem::IntegrationPoint &integrationPoint = integrationRule.IntPoint(quadratureIndex);
-      const mfem::IntegrationPoint &integrationPoint =
-          integrationRule.IntPoint(quadratureIndex);
 
                 transformation->SetIntPoint(&integrationPoint);
 
-      const mean_field::mapping::MappingStatus mappingStatus =
+                const mean_field::mapping::MappingStatus mappingStatus = domainMapper.EvaluateVolume(
-          domainMapper.EvaluateVolume(mappingData, *transformation,
+                    mappingData, *transformation, integrationPoint, workspace, mappingContext
-                                      integrationPoint, workspace,
+                );
-                                      mappingContext);
 
-      MFEM_VERIFY(mappingStatus == mean_field::mapping::MappingStatus::valid,
+                MFEM_VERIFY(
+                    mappingStatus == mean_field::mapping::MappingStatus::valid,
                     "Stateless mapping failed in the gravity-displacement-"
                     "force kernel. Element: "
-                      << elementId
+                        << elementId << ", attribute: " << transformation->Attribute
-                      << ", attribute: " << transformation->Attribute
+                        << ", quadrature point: " << quadratureIndex << ", status: " << static_cast<int>(mappingStatus)
-                      << ", quadrature point: " << quadratureIndex
+                );
-                      << ", status: " << static_cast<int>(mappingStatus));
 
                 if (needsDisplacementVariation) {
-        const mean_field::mapping::MappingStatus variationStatus =
+                    const mean_field::mapping::MappingStatus variationStatus = domainMapper.EvaluateVolumeVariation(
-            domainMapper.EvaluateVolumeVariation(
+                        mappingData, *displacementVariationData, *transformation, integrationPoint, mappingContext,
-                mappingData, *displacementVariationData, *transformation,
+                        workspace, mappingVariation
-                integrationPoint, mappingContext, workspace, mappingVariation);
+                    );
 
                     MFEM_VERIFY(
                         variationStatus == mean_field::mapping::MappingStatus::valid,
                         "Stateless mapping variation failed in the gravity-"
                         "displacement-force kernel. Element: "
-                << elementId << ", attribute: " << transformation->Attribute
+                            << elementId << ", attribute: " << transformation->Attribute << ", quadrature point: "
-                << ", quadrature point: " << quadratureIndex
+                            << quadratureIndex << ", status: " << static_cast<int>(variationStatus)
-                << ", status: " << static_cast<int>(variationStatus));
+                    );
                 }
 
                 densityElement.CalcShape(integrationPoint, densityShape);
@@ -545,28 +557,27 @@ void apply_gravity_displacement_force_action(
                 }
 
                 if (needsBaseGravityGradient) {
-        gravityGradientShape.MultTranspose(elementBaseGravityGradient,
+                    gravityGradientShape.MultTranspose(elementBaseGravityGradient, baseGravityReferenceValue);
-                                           baseGravityReferenceValue);
 
-        mappingContext.mapping.mapping_jacobian.Mult(baseGravityReferenceValue,
+                    mappingContext.mapping.mapping_jacobian.Mult(baseGravityReferenceValue, mappedBaseGravity);
-                                                     mappedBaseGravity);
                 } else {
                     mappedBaseGravity = 0.0;
                 }
 
                 if (needsGravityGradientVariation) {
-        gravityGradientShape.MultTranspose(elementGravityGradientVariation,
+                    gravityGradientShape.MultTranspose(elementGravityGradientVariation, gravityVariationReferenceValue);
-                                           gravityVariationReferenceValue);
 
                     mappingContext.mapping.mapping_jacobian.Mult(
-            gravityVariationReferenceValue, mappedGravityVariation);
+                        gravityVariationReferenceValue, mappedGravityVariation
+                    );
                 } else {
                     mappedGravityVariation = 0.0;
                 }
 
                 if (needsDisplacementVariation) {
                     mappingVariation.mapping.mapping_jacobian_variation.Mult(
-            baseGravityReferenceValue, mappedGeometryVariation);
+                        baseGravityReferenceValue, mappedGeometryVariation
+                    );
                 } else {
                     mappedGeometryVariation = 0.0;
                 }
@@ -601,24 +612,22 @@ void apply_gravity_displacement_force_action(
                  * differentiating the Piola map and physical volume weight,
                  * but avoids a numerically pointless cancellation.
                  */
-      const double referenceWeight =
+                const double referenceWeight = integrationPoint.weight * transformation->Weight();
-          integrationPoint.weight * transformation->Weight();
 
                 forceValue *= referenceWeight;
 
-      for (int scalarDof = 0; scalarDof < scalarDisplacementDofCount;
+                for (int scalarDof = 0; scalarDof < scalarDisplacementDofCount; ++scalarDof) {
-           ++scalarDof) {
                     for (int component = 0; component < dimension; ++component) {
-          const int vectorDof =
+                        const int vectorDof = vector_dof_index(
-              vector_dof_index(displacementOrdering, scalarDof, component,
+                            displacementOrdering, scalarDof, component, scalarDisplacementDofCount, dimension
-                               scalarDisplacementDofCount, dimension);
+                        );
 
-          const double contribution =
+                        const double contribution = displacementShape(scalarDof) * forceValue(component);
-              displacementShape(scalarDof) * forceValue(component);
 
-          MFEM_VERIFY(std::isfinite(contribution),
+                        MFEM_VERIFY(
-                      "The gravity-displacement-force kernel "
+                            std::isfinite(contribution), "The gravity-displacement-force kernel "
-                      "encountered a non-finite contribution.");
+                                                         "encountered a non-finite contribution."
+                        );
 
                         elementAction(vectorDof) += contribution;
                     }
@@ -633,66 +642,82 @@ void apply_gravity_displacement_force_action(
         }
 
         local_to_true(*f.displacementFes, localAction, actionTrue);
-}
+    }
 } // namespace
 
 namespace mean_field::operators::kernels {
-void apply_gravity_displacement_force_residual(
+    void apply_gravity_displacement_force_residual(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
-    const mfem::Vector &densityTrue, const mfem::Vector &gravityGradientTrue,
+        const mapping::DomainMapper &domainMapper,
-    const mfem::Vector &displacementTrue, mfem::Vector &residualTrue) {
+        const mfem::Vector &densityTrue,
+        const mfem::Vector &gravityGradientTrue,
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &residualTrue
+    ) {
         apply_gravity_displacement_force_action(
-      f, domainMapper, GravityDisplacementForceAction::residual, &densityTrue,
+            f, domainMapper, GravityDisplacementForceAction::residual, &densityTrue, nullptr, &gravityGradientTrue,
-      nullptr, &gravityGradientTrue, nullptr, nullptr, displacementTrue,
+            nullptr, nullptr, displacementTrue, residualTrue
-      residualTrue);
+        );
-}
+    }
 
-void apply_gravity_displacement_force_density_action(
+    void apply_gravity_displacement_force_density_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
+        const mapping::DomainMapper &domainMapper,
         const mfem::Vector &densityVariationTrue,
         const mfem::Vector &baseGravityGradientTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &actionTrue) {
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &actionTrue
+    ) {
         apply_gravity_displacement_force_action(
-      f, domainMapper, GravityDisplacementForceAction::density, nullptr,
+            f, domainMapper, GravityDisplacementForceAction::density, nullptr, &densityVariationTrue,
-      &densityVariationTrue, &baseGravityGradientTrue, nullptr, nullptr,
+            &baseGravityGradientTrue, nullptr, nullptr, displacementTrue, actionTrue
-      displacementTrue, actionTrue);
+        );
-}
+    }
 
-void apply_gravity_displacement_force_gradient_action(
+    void apply_gravity_displacement_force_gradient_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
+        const mapping::DomainMapper &domainMapper,
         const mfem::Vector &baseDensityTrue,
         const mfem::Vector &gravityGradientVariationTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &actionTrue) {
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &actionTrue
+    ) {
         apply_gravity_displacement_force_action(
-      f, domainMapper, GravityDisplacementForceAction::gravityGradient,
+            f, domainMapper, GravityDisplacementForceAction::gravityGradient, &baseDensityTrue, nullptr, nullptr,
-      &baseDensityTrue, nullptr, nullptr, &gravityGradientVariationTrue,
+            &gravityGradientVariationTrue, nullptr, displacementTrue, actionTrue
-      nullptr, displacementTrue, actionTrue);
+        );
-}
+    }
 
-void apply_gravity_displacement_force_displacement_action(
+    void apply_gravity_displacement_force_displacement_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
+        const mapping::DomainMapper &domainMapper,
         const mfem::Vector &baseDensityTrue,
         const mfem::Vector &baseGravityGradientTrue,
         const mfem::Vector &displacementVariationTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &actionTrue) {
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &actionTrue
+    ) {
         apply_gravity_displacement_force_action(
-      f, domainMapper, GravityDisplacementForceAction::displacement,
+            f, domainMapper, GravityDisplacementForceAction::displacement, &baseDensityTrue, nullptr,
-      &baseDensityTrue, nullptr, &baseGravityGradientTrue, nullptr,
+            &baseGravityGradientTrue, nullptr, &displacementVariationTrue, displacementTrue, actionTrue
-      &displacementVariationTrue, displacementTrue, actionTrue);
+        );
-}
+    }
 
-void apply_gravity_displacement_force_complete_action(
+    void apply_gravity_displacement_force_complete_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
+        const mapping::DomainMapper &domainMapper,
         const mfem::Vector &baseDensityTrue,
         const mfem::Vector &densityVariationTrue,
         const mfem::Vector &baseGravityGradientTrue,
         const mfem::Vector &gravityGradientVariationTrue,
         const mfem::Vector &displacementVariationTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &actionTrue) {
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &actionTrue
+    ) {
         apply_gravity_displacement_force_action(
-      f, domainMapper, GravityDisplacementForceAction::complete,
+            f, domainMapper, GravityDisplacementForceAction::complete, &baseDensityTrue, &densityVariationTrue,
-      &baseDensityTrue, &densityVariationTrue, &baseGravityGradientTrue,
+            &baseGravityGradientTrue, &gravityGradientVariationTrue, &displacementVariationTrue, displacementTrue,
-      &gravityGradientVariationTrue, &displacementVariationTrue,
+            actionTrue
-      displacementTrue, actionTrue);
+        );
-}
+    }
 } // namespace mean_field::operators::kernels

libmeanfield/impl/operators/kernels/hydrostatic_equilibrium_kernels.cpp

@@ -11,138 +11,146 @@ module mean_field;
 import :operators.kernels.hydrostatic_equilibrium;
 
 namespace {
-using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
+    using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
 
-[[nodiscard]] bool is_vacuum_attribute(const int attribute) {
+    [[nodiscard]] bool is_vacuum_attribute(const int attribute) {
-  return DomainSchema::template attribute_belongs_to<
+        return DomainSchema::template attribute_belongs_to<mean_field::utils::domain::Vacuum>(attribute);
-      mean_field::utils::domain::Vacuum>(attribute);
+    }
-}
 
-void true_to_local(const mfem::ParFiniteElementSpace &finiteElementSpace,
+    void true_to_local(
-                   const mfem::Vector &trueVector, mfem::Vector &localVector) {
+        const mfem::ParFiniteElementSpace &finiteElementSpace,
-  MFEM_VERIFY(trueVector.Size() == finiteElementSpace.GetTrueVSize(),
+        const mfem::Vector &trueVector,
-              "True vector has the wrong size.");
+        mfem::Vector &localVector
+    ) {
+        MFEM_VERIFY(trueVector.Size() == finiteElementSpace.GetTrueVSize(), "True vector has the wrong size.");
 
         localVector.SetSize(finiteElementSpace.GetVSize());
 
-  const mfem::Operator *prolongation =
+        const mfem::Operator *prolongation = finiteElementSpace.GetProlongationMatrix();
-      finiteElementSpace.GetProlongationMatrix();
 
         if (prolongation != nullptr) {
             prolongation->Mult(trueVector, localVector);
         } else {
             localVector = trueVector;
         }
-}
+    }
 
-void local_to_true(const mfem::ParFiniteElementSpace &finiteElementSpace,
+    void local_to_true(
-                   const mfem::Vector &localVector, mfem::Vector &trueVector) {
+        const mfem::ParFiniteElementSpace &finiteElementSpace,
-  MFEM_VERIFY(localVector.Size() == finiteElementSpace.GetVSize(),
+        const mfem::Vector &localVector,
-              "Local vector has the wrong size.");
+        mfem::Vector &trueVector
+    ) {
+        MFEM_VERIFY(localVector.Size() == finiteElementSpace.GetVSize(), "Local vector has the wrong size.");
 
         trueVector.SetSize(finiteElementSpace.GetTrueVSize());
 
         trueVector                         = 0.0;
 
-  const mfem::Operator *prolongation =
+        const mfem::Operator *prolongation = finiteElementSpace.GetProlongationMatrix();
-      finiteElementSpace.GetProlongationMatrix();
 
         if (prolongation != nullptr) {
             prolongation->MultTranspose(localVector, trueVector);
         } else {
             trueVector = localVector;
         }
-}
+    }
 
-void validate_fem(
+    void validate_fem(
         const mean_field::fem::FEM &f,
-    const mean_field::mapping::DomainMapper &domainMapper) {
+        const mean_field::mapping::DomainMapper &domainMapper
+    ) {
         MFEM_VERIFY(f.mesh != nullptr, "The hydrostatic kernel requires a mesh.");
 
-  MFEM_VERIFY(f.enthalpyFes != nullptr, "The hydrostatic kernel requires the "
+        MFEM_VERIFY(
-                                        "enthalpy finite-element space.");
+            f.enthalpyFes != nullptr, "The hydrostatic kernel requires the "
+                                      "enthalpy finite-element space."
+        );
 
-  MFEM_VERIFY(f.gravityPotentialFes != nullptr,
+        MFEM_VERIFY(
-              "The hydrostatic kernel requires the "
+            f.gravityPotentialFes != nullptr, "The hydrostatic kernel requires the "
-              "gravity-potential finite-element space.");
+                                              "gravity-potential finite-element space."
+        );
 
-  MFEM_VERIFY(f.displacementFes != nullptr,
+        MFEM_VERIFY(
-              "The hydrostatic kernel requires the "
+            f.displacementFes != nullptr, "The hydrostatic kernel requires the "
-              "displacement finite-element space.");
+                                          "displacement finite-element space."
+        );
 
-  MFEM_VERIFY(f.compactificationFes != nullptr,
+        MFEM_VERIFY(
-              "The hydrostatic kernel requires the "
+            f.compactificationFes != nullptr, "The hydrostatic kernel requires the "
-              "compactification finite-element space.");
+                                              "compactification finite-element space."
+        );
 
-  MFEM_VERIFY(f.compactificationCoordinate != nullptr,
+        MFEM_VERIFY(
-              "The hydrostatic kernel requires the "
+            f.compactificationCoordinate != nullptr, "The hydrostatic kernel requires the "
-              "compactification coordinate.");
+                                                     "compactification coordinate."
+        );
 
-  MFEM_VERIFY(f.quadratureFactory != nullptr,
+        MFEM_VERIFY(
-              "The hydrostatic kernel requires the "
+            f.quadratureFactory != nullptr, "The hydrostatic kernel requires the "
-              "quadrature-rule factory.");
+                                            "quadrature-rule factory."
+        );
 
-  MFEM_VERIFY(f.mesh->Dimension() == 3,
+        MFEM_VERIFY(
-              "The rigid-rotation hydrostatic kernel "
+            f.mesh->Dimension() == 3, "The rigid-rotation hydrostatic kernel "
-              "currently requires a three-dimensional mesh.");
+                                      "currently requires a three-dimensional mesh."
+        );
 
-  MFEM_VERIFY(domainMapper.GetDimension() == f.mesh->Dimension(),
+        MFEM_VERIFY(
-              "The domain-mapper dimension does not match "
+            domainMapper.GetDimension() == f.mesh->Dimension(), "The domain-mapper dimension does not match "
-              "the mesh dimension.");
+                                                                "the mesh dimension."
-}
+        );
+    }
 
-const mfem::IntegrationRule &
+    const mfem::IntegrationRule &get_hydrostatic_rule(
-get_hydrostatic_rule(const mean_field::fem::FEM &f,
+        const mean_field::fem::FEM &f,
         const mfem::FiniteElement &enthalpyElement,
         const mfem::FiniteElement &potentialElement,
-                     const mfem::ElementTransformation &transformation) {
+        const mfem::ElementTransformation &transformation
+    ) {
         using EnthalpyField = mean_field::field::Field<mean_field::field::Enthalpy>;
 
-  MFEM_VERIFY(enthalpyElement.GetOrder() ==
+        MFEM_VERIFY(
-                  mean_field::field::Enthalpy::Scalar::familyOrder,
+            enthalpyElement.GetOrder() == mean_field::field::Enthalpy::Scalar::familyOrder,
             "The hydrostatic test element does not match "
-              "the registered enthalpy field.");
+            "the registered enthalpy field."
+        );
 
-  MFEM_VERIFY(potentialElement.GetOrder() ==
+        MFEM_VERIFY(
-                  mean_field::field::Gravity::Potential::familyOrder,
+            potentialElement.GetOrder() == mean_field::field::Gravity::Potential::familyOrder,
             "The hydrostatic potential element does not "
-              "match the registered gravity-potential field.");
+            "match the registered gravity-potential field."
+        );
 
-  const auto enthalpyQuery = EnthalpyField::make_query<
+        const auto enthalpyQuery = EnthalpyField::make_query<mean_field::field::Enthalpy::Form::EquilibriumEnthalpy>(
-      mean_field::field::Enthalpy::Form::EquilibriumEnthalpy>(
+            mean_field::quadrature::QuadratureRole::discretization, transformation.OrderW(), {},
-      mean_field::quadrature::QuadratureRole::discretization,
+            mean_field::utils::DOMAINS::STELLAR, mean_field::quadrature::MappingKind::general
-      transformation.OrderW(), {}, mean_field::utils::DOMAINS::STELLAR,
+        );
-      mean_field::quadrature::MappingKind::general);
 
-  const auto gravityQuery = EnthalpyField::make_query<
+        const auto gravityQuery = EnthalpyField::make_query<mean_field::field::Enthalpy::Form::EquilibriumGravity>(
-      mean_field::field::Enthalpy::Form::EquilibriumGravity>(
+            mean_field::quadrature::QuadratureRole::discretization, transformation.OrderW(), {},
-      mean_field::quadrature::QuadratureRole::discretization,
+            mean_field::utils::DOMAINS::STELLAR, mean_field::quadrature::MappingKind::general
-      transformation.OrderW(), {}, mean_field::utils::DOMAINS::STELLAR,
+        );
-      mean_field::quadrature::MappingKind::general);
 
-  const auto rotationQuery = EnthalpyField::make_query<
+        const auto rotationQuery = EnthalpyField::make_query<mean_field::field::Enthalpy::Form::EquilibriumRotation>(
-      mean_field::field::Enthalpy::Form::EquilibriumRotation>(
+            mean_field::quadrature::QuadratureRole::discretization, transformation.OrderW(), std::array<int, 1>{2},
-      mean_field::quadrature::QuadratureRole::discretization,
+            mean_field::utils::DOMAINS::STELLAR, mean_field::quadrature::MappingKind::general
-      transformation.OrderW(), std::array<int, 1>{2},
+        );
-      mean_field::utils::DOMAINS::STELLAR,
-      mean_field::quadrature::MappingKind::general);
 
-  const auto constantQuery = EnthalpyField::make_query<
+        const auto constantQuery = EnthalpyField::make_query<mean_field::field::Enthalpy::Form::EquilibriumConstant>(
-      mean_field::field::Enthalpy::Form::EquilibriumConstant>(
+            mean_field::quadrature::QuadratureRole::discretization, transformation.OrderW(), {},
-      mean_field::quadrature::QuadratureRole::discretization,
+            mean_field::utils::DOMAINS::STELLAR, mean_field::quadrature::MappingKind::general
-      transformation.OrderW(), {}, mean_field::utils::DOMAINS::STELLAR,
+        );
-      mean_field::quadrature::MappingKind::general);
 
         int integrationOrder    = 0;
 
-  const auto update_order = [&f, &transformation, &integrationOrder](
+        const auto update_order = [&f, &transformation, &integrationOrder](const mean_field::quadrature::Query &query) {
-                                const mean_field::quadrature::Query &query) {
+            const auto rule = f.quadratureFactory->get(query, transformation.GetGeometryType());
-    const auto rule =
-        f.quadratureFactory->get(query, transformation.GetGeometryType());
 
-    MFEM_VERIFY(rule.integration_rule != nullptr,
+            MFEM_VERIFY(
-                "The quadrature policy did not return "
+                rule.integration_rule != nullptr, "The quadrature policy did not return "
-                "a hydrostatic-equilibrium rule.");
+                                                  "a hydrostatic-equilibrium rule."
+            );
 
             integrationOrder = std::max(integrationOrder, rule.resolution.order);
         };
@@ -153,9 +161,9 @@ get_hydrostatic_rule(const mean_field::fem::FEM &f,
         update_order(constantQuery);
 
         return mfem::IntRules.Get(transformation.GetGeometryType(), integrationOrder);
-}
+    }
 
-struct HydrostaticAssemblyRequest {
+    struct HydrostaticAssemblyRequest {
         const mean_field::physics::RigidRotation *rotation{nullptr};
 
         const mfem::Vector *baseEnthalpyTrue{nullptr};
@@ -169,70 +177,78 @@ struct HydrostaticAssemblyRequest {
         double constantVariation{0.0};
 
         bool buildResidual{false};
-};
+    };
 
-void assemble_hydrostatic_form(
+    void assemble_hydrostatic_form(
         const mean_field::fem::FEM &f,
         const mean_field::mapping::DomainMapper &domainMapper,
         const mfem::Vector &displacementTrue,
-    const HydrostaticAssemblyRequest &request, mfem::Vector &result) {
+        const HydrostaticAssemblyRequest &request,
+        mfem::Vector &result
+    ) {
         validate_fem(f, domainMapper);
 
-  MFEM_VERIFY(displacementTrue.Size() == f.displacementFes->GetTrueVSize(),
+        MFEM_VERIFY(
-              "The hydrostatic displacement vector has "
+            displacementTrue.Size() == f.displacementFes->GetTrueVSize(), "The hydrostatic displacement vector has "
-              "the wrong size.");
+                                                                          "the wrong size."
+        );
 
-  MFEM_VERIFY(std::isfinite(request.bernoulliConstant),
+        MFEM_VERIFY(std::isfinite(request.bernoulliConstant), "The Bernoulli constant is non-finite.");
-              "The Bernoulli constant is non-finite.");
 
-  MFEM_VERIFY(std::isfinite(request.constantVariation),
+        MFEM_VERIFY(std::isfinite(request.constantVariation), "The Bernoulli-constant variation is non-finite.");
-              "The Bernoulli-constant variation is non-finite.");
 
-  const bool requiresBaseState =
+        const bool requiresBaseState = request.buildResidual || request.displacementVariationTrue != nullptr;
-      request.buildResidual || request.displacementVariationTrue != nullptr;
 
         if (requiresBaseState) {
-    MFEM_VERIFY(request.rotation != nullptr,
+            MFEM_VERIFY(
-                "The hydrostatic residual or geometry "
+                request.rotation != nullptr, "The hydrostatic residual or geometry "
-                "action requires the rotation model.");
+                                             "action requires the rotation model."
+            );
 
-    MFEM_VERIFY(request.baseEnthalpyTrue != nullptr,
+            MFEM_VERIFY(
-                "The hydrostatic residual or geometry "
+                request.baseEnthalpyTrue != nullptr, "The hydrostatic residual or geometry "
-                "action requires the base enthalpy.");
+                                                     "action requires the base enthalpy."
+            );
 
-    MFEM_VERIFY(request.basePotentialTrue != nullptr,
+            MFEM_VERIFY(
-                "The hydrostatic residual or geometry "
+                request.basePotentialTrue != nullptr, "The hydrostatic residual or geometry "
-                "action requires the base potential.");
+                                                      "action requires the base potential."
+            );
         }
 
         if (request.baseEnthalpyTrue != nullptr) {
-    MFEM_VERIFY(request.baseEnthalpyTrue->Size() ==
+            MFEM_VERIFY(
-                    f.enthalpyFes->GetTrueVSize(),
+                request.baseEnthalpyTrue->Size() == f.enthalpyFes->GetTrueVSize(),
-                "The base enthalpy vector has the wrong size.");
+                "The base enthalpy vector has the wrong size."
+            );
         }
 
         if (request.basePotentialTrue != nullptr) {
-    MFEM_VERIFY(request.basePotentialTrue->Size() ==
+            MFEM_VERIFY(
-                    f.gravityPotentialFes->GetTrueVSize(),
+                request.basePotentialTrue->Size() == f.gravityPotentialFes->GetTrueVSize(),
-                "The base potential vector has the wrong size.");
+                "The base potential vector has the wrong size."
+            );
         }
 
         if (request.enthalpyVariationTrue != nullptr) {
-    MFEM_VERIFY(request.enthalpyVariationTrue->Size() ==
+            MFEM_VERIFY(
-                    f.enthalpyFes->GetTrueVSize(),
+                request.enthalpyVariationTrue->Size() == f.enthalpyFes->GetTrueVSize(),
-                "The enthalpy variation has the wrong size.");
+                "The enthalpy variation has the wrong size."
+            );
         }
 
         if (request.potentialVariationTrue != nullptr) {
-    MFEM_VERIFY(request.potentialVariationTrue->Size() ==
+            MFEM_VERIFY(
-                    f.gravityPotentialFes->GetTrueVSize(),
+                request.potentialVariationTrue->Size() == f.gravityPotentialFes->GetTrueVSize(),
-                "The potential variation has the wrong size.");
+                "The potential variation has the wrong size."
+            );
         }
 
         if (request.displacementVariationTrue != nullptr) {
-    MFEM_VERIFY(request.displacementVariationTrue->Size() ==
+            MFEM_VERIFY(
-                    f.displacementFes->GetTrueVSize(),
+                request.displacementVariationTrue->Size() == f.displacementFes->GetTrueVSize(),
-                "The displacement variation has the wrong size.");
+                "The displacement variation has the wrong size."
+            );
         }
 
         mfem::Vector displacementLocal;
@@ -249,31 +265,26 @@ void assemble_hydrostatic_form(
         }
 
         if (request.basePotentialTrue != nullptr) {
-    true_to_local(*f.gravityPotentialFes, *request.basePotentialTrue,
+            true_to_local(*f.gravityPotentialFes, *request.basePotentialTrue, basePotentialLocal);
-                  basePotentialLocal);
         }
 
         if (request.enthalpyVariationTrue != nullptr) {
-    true_to_local(*f.enthalpyFes, *request.enthalpyVariationTrue,
+            true_to_local(*f.enthalpyFes, *request.enthalpyVariationTrue, enthalpyVariationLocal);
-                  enthalpyVariationLocal);
         }
 
         if (request.potentialVariationTrue != nullptr) {
-    true_to_local(*f.gravityPotentialFes, *request.potentialVariationTrue,
+            true_to_local(*f.gravityPotentialFes, *request.potentialVariationTrue, potentialVariationLocal);
-                  potentialVariationLocal);
         }
 
         if (request.displacementVariationTrue != nullptr) {
-    true_to_local(*f.displacementFes, *request.displacementVariationTrue,
+            true_to_local(*f.displacementFes, *request.displacementVariationTrue, displacementVariationLocal);
-                  displacementVariationLocal);
         }
 
         mfem::Vector localResult(f.enthalpyFes->GetVSize());
 
         localResult = 0.0;
 
-  mean_field::mapping::DomainMapper::Workspace workspace(
+        mean_field::mapping::DomainMapper::Workspace workspace(f.mesh->Dimension());
-      f.mesh->Dimension());
 
         mfem::Array<int> enthalpyDofs;
         mfem::Array<int> potentialDofs;
@@ -293,31 +304,26 @@ void assemble_hydrostatic_form(
         mfem::Vector potentialShape;
 
         for (int elementId = 0; elementId < f.mesh->GetNE(); ++elementId) {
-    mfem::ElementTransformation *transformation =
+            mfem::ElementTransformation *transformation = f.mesh->GetElementTransformation(elementId);
-        f.mesh->GetElementTransformation(elementId);
 
-    MFEM_VERIFY(transformation != nullptr,
+            MFEM_VERIFY(
-                "The hydrostatic kernel received a null "
+                transformation != nullptr, "The hydrostatic kernel received a null "
-                "element transformation.");
+                                           "element transformation."
+            );
 
             if (is_vacuum_attribute(transformation->Attribute)) {
                 continue;
             }
 
-    const mfem::FiniteElement &enthalpyElement =
+            const mfem::FiniteElement &enthalpyElement         = *f.enthalpyFes->GetFE(elementId);
-        *f.enthalpyFes->GetFE(elementId);
 
-    const mfem::FiniteElement &potentialElement =
+            const mfem::FiniteElement &potentialElement        = *f.gravityPotentialFes->GetFE(elementId);
-        *f.gravityPotentialFes->GetFE(elementId);
 
-    const mfem::FiniteElement &displacementElement =
+            const mfem::FiniteElement &displacementElement     = *f.displacementFes->GetFE(elementId);
-        *f.displacementFes->GetFE(elementId);
 
-    const mfem::FiniteElement &compactificationElement =
+            const mfem::FiniteElement &compactificationElement = *f.compactificationFes->GetFE(elementId);
-        *f.compactificationFes->GetFE(elementId);
 
-    mfem::DofTransformation *enthalpyDofTransformation =
+            mfem::DofTransformation *enthalpyDofTransformation = f.enthalpyFes->GetElementDofs(elementId, enthalpyDofs);
-        f.enthalpyFes->GetElementDofs(elementId, enthalpyDofs);
 
             mfem::DofTransformation *potentialDofTransformation =
                 f.gravityPotentialFes->GetElementDofs(elementId, potentialDofs);
@@ -330,8 +336,7 @@ void assemble_hydrostatic_form(
 
             displacementLocal.GetSubVector(displacementDofs, elementDisplacement);
 
-    f.compactificationCoordinate->GetSubVector(compactificationDofs,
+            f.compactificationCoordinate->GetSubVector(compactificationDofs, elementCompactification);
-                                               elementCompactification);
 
             if (request.baseEnthalpyTrue != nullptr) {
                 baseEnthalpyLocal.GetSubVector(enthalpyDofs, elementBaseEnthalpy);
@@ -342,18 +347,15 @@ void assemble_hydrostatic_form(
             }
 
             if (request.enthalpyVariationTrue != nullptr) {
-      enthalpyVariationLocal.GetSubVector(enthalpyDofs,
+                enthalpyVariationLocal.GetSubVector(enthalpyDofs, elementEnthalpyVariation);
-                                          elementEnthalpyVariation);
             }
 
             if (request.potentialVariationTrue != nullptr) {
-      potentialVariationLocal.GetSubVector(potentialDofs,
+                potentialVariationLocal.GetSubVector(potentialDofs, elementPotentialVariation);
-                                           elementPotentialVariation);
             }
 
             if (request.displacementVariationTrue != nullptr) {
-      displacementVariationLocal.GetSubVector(displacementDofs,
+                displacementVariationLocal.GetSubVector(displacementDofs, elementDisplacementVariation);
-                                              elementDisplacementVariation);
             }
 
             if (enthalpyDofTransformation != nullptr) {
@@ -372,8 +374,7 @@ void assemble_hydrostatic_form(
                 }
 
                 if (request.potentialVariationTrue != nullptr) {
-        potentialDofTransformation->InvTransformPrimal(
+                    potentialDofTransformation->InvTransformPrimal(elementPotentialVariation);
-            elementPotentialVariation);
                 }
             }
 
@@ -381,34 +382,33 @@ void assemble_hydrostatic_form(
                 displacementDofTransformation->InvTransformPrimal(elementDisplacement);
 
                 if (request.displacementVariationTrue != nullptr) {
-        displacementDofTransformation->InvTransformPrimal(
+                    displacementDofTransformation->InvTransformPrimal(elementDisplacementVariation);
-            elementDisplacementVariation);
                 }
             }
 
             if (compactificationDofTransformation != nullptr) {
-      compactificationDofTransformation->InvTransformPrimal(
+                compactificationDofTransformation->InvTransformPrimal(elementCompactification);
-          elementCompactification);
             }
 
             const mean_field::mapping::ElementDisplacementData displacementData =
-        mean_field::mapping::ElementDisplacementDataFromElementVDofs(
+                mean_field::mapping::ElementDisplacementDataFromElementVDofs(displacementElement, elementDisplacement);
-            displacementElement, elementDisplacement);
 
             const mean_field::mapping::ElementCompactificationData compactificationData(
-        compactificationElement, elementCompactification);
+                compactificationElement, elementCompactification
+            );
 
             const mean_field::mapping::ElementMappingData mappingData{
-        .displacement = displacementData,
+                .displacement = displacementData, .compactification = compactificationData
-        .compactification = compactificationData};
+            };
 
-    std::optional<mean_field::mapping::ElementDisplacementData>
+            std::optional<mean_field::mapping::ElementDisplacementData> displacementVariationData;
-        displacementVariationData;
 
             if (request.displacementVariationTrue != nullptr) {
                 displacementVariationData.emplace(
                     mean_field::mapping::ElementDisplacementDataFromElementVDofs(
-              displacementElement, elementDisplacementVariation));
+                        displacementElement, elementDisplacementVariation
+                    )
+                );
             }
 
             elementResult.SetSize(enthalpyElement.GetDof());
@@ -419,28 +419,27 @@ void assemble_hydrostatic_form(
 
             potentialShape.SetSize(potentialElement.GetDof());
 
-    const mfem::IntegrationRule &integrationRule = get_hydrostatic_rule(
+            const mfem::IntegrationRule &integrationRule =
-        f, enthalpyElement, potentialElement, *transformation);
+                get_hydrostatic_rule(f, enthalpyElement, potentialElement, *transformation);
 
-    for (int quadraturePoint = 0;
+            for (int quadraturePoint = 0; quadraturePoint < integrationRule.GetNPoints(); ++quadraturePoint) {
-         quadraturePoint < integrationRule.GetNPoints(); ++quadraturePoint) {
+                const mfem::IntegrationPoint &integrationPoint = integrationRule.IntPoint(quadraturePoint);
-      const mfem::IntegrationPoint &integrationPoint =
-          integrationRule.IntPoint(quadraturePoint);
 
                 transformation->SetIntPoint(&integrationPoint);
 
                 mean_field::mapping::VolumeMappingContext mappingContext;
 
-      const mean_field::mapping::MappingStatus mappingStatus =
+                const mean_field::mapping::MappingStatus mappingStatus = domainMapper.EvaluateVolume(
-          domainMapper.EvaluateVolume(mappingData, *transformation,
+                    mappingData, *transformation, integrationPoint, workspace, mappingContext
-                                      integrationPoint, workspace,
+                );
-                                      mappingContext);
 
-      MFEM_VERIFY(mappingStatus == mean_field::mapping::MappingStatus::valid,
+                MFEM_VERIFY(
+                    mappingStatus == mean_field::mapping::MappingStatus::valid,
                     "The base mapping is invalid in the "
                     "hydrostatic kernel. Element: "
                         << elementId << ", quadrature point: " << quadraturePoint
-                      << ", status: " << static_cast<int>(mappingStatus));
+                        << ", status: " << static_cast<int>(mappingStatus)
+                );
 
                 enthalpyElement.CalcShape(integrationPoint, enthalpyShape);
 
@@ -453,16 +452,14 @@ void assemble_hydrostatic_form(
 
                     const double potentialValue = elementBasePotential * potentialShape;
 
-        const double rotationPotential = request.rotation->potential(
+                    const double rotationPotential =
-            mappingContext.mapping.physical_position);
+                        request.rotation->potential(mappingContext.mapping.physical_position);
 
-        baseIntegrand = enthalpyValue + potentialValue - rotationPotential -
+                    baseIntegrand = enthalpyValue + potentialValue - rotationPotential - request.bernoulliConstant;
-                        request.bernoulliConstant;
                 }
 
                 if (request.buildResidual) {
-        elementResult.Add(mappingContext.quadrature.weight * baseIntegrand,
+                    elementResult.Add(mappingContext.quadrature.weight * baseIntegrand, enthalpyShape);
-                          enthalpyShape);
 
                     continue;
                 }
@@ -477,29 +474,27 @@ void assemble_hydrostatic_form(
                     materialVariation += elementPotentialVariation * potentialShape;
                 }
 
-      double weightedVariation =
+                double weightedVariation = mappingContext.quadrature.weight * materialVariation;
-          mappingContext.quadrature.weight * materialVariation;
 
                 if (request.displacementVariationTrue != nullptr) {
                     mean_field::mapping::VolumeMappingVariation mappingVariation;
 
-        const mean_field::mapping::MappingStatus variationStatus =
+                    const mean_field::mapping::MappingStatus variationStatus = domainMapper.EvaluateVolumeVariation(
-            domainMapper.EvaluateVolumeVariation(
+                        mappingData, *displacementVariationData, *transformation, integrationPoint, mappingContext,
-                mappingData, *displacementVariationData, *transformation,
+                        workspace, mappingVariation
-                integrationPoint, mappingContext, workspace, mappingVariation);
+                    );
 
-        MFEM_VERIFY(variationStatus ==
+                    MFEM_VERIFY(
-                        mean_field::mapping::MappingStatus::valid,
+                        variationStatus == mean_field::mapping::MappingStatus::valid,
                         "The mapping variation is invalid "
-                    "in the hydrostatic kernel.");
+                        "in the hydrostatic kernel."
+                    );
 
-        const double rotationVariation =
+                    const double rotationVariation = request.rotation->potential_directional_derivative(
-            request.rotation->potential_directional_derivative(
+                        mappingContext.mapping.physical_position, mappingVariation.mapping.physical_position_variation
-                mappingContext.mapping.physical_position,
+                    );
-                mappingVariation.mapping.physical_position_variation);
 
-        weightedVariation +=
+                    weightedVariation += baseIntegrand * mappingVariation.weight_variation -
-            baseIntegrand * mappingVariation.weight_variation -
                                          rotationVariation * mappingContext.quadrature.weight;
                 }
 
@@ -514,15 +509,20 @@ void assemble_hydrostatic_form(
         }
 
         local_to_true(*f.enthalpyFes, localResult, result);
-}
+    }
 } // namespace
 
 namespace mean_field::operators::kernels {
-void apply_hydrostatic_equilibrium(
+    void apply_hydrostatic_equilibrium(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
-    const physics::RigidRotation &rotation, const mfem::Vector &enthalpyTrue,
+        const mapping::DomainMapper &domainMapper,
-    const mfem::Vector &potentialTrue, const mfem::Vector &displacementTrue,
+        const physics::RigidRotation &rotation,
-    const double bernoulliConstant, mfem::Vector &residual) {
+        const mfem::Vector &enthalpyTrue,
+        const mfem::Vector &potentialTrue,
+        const mfem::Vector &displacementTrue,
+        const double bernoulliConstant,
+        mfem::Vector &residual
+    ) {
         HydrostaticAssemblyRequest request;
 
         request.rotation          = &rotation;
@@ -531,50 +531,62 @@ void apply_hydrostatic_equilibrium(
         request.bernoulliConstant = bernoulliConstant;
         request.buildResidual     = true;
 
-  assemble_hydrostatic_form(f, domainMapper, displacementTrue, request,
+        assemble_hydrostatic_form(f, domainMapper, displacementTrue, request, residual);
-                            residual);
+    }
-}
 
-void apply_hydrostatic_equilibrium_enthalpy_action(
+    void apply_hydrostatic_equilibrium_enthalpy_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
+        const mapping::DomainMapper &domainMapper,
         const mfem::Vector &enthalpyVariationTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &action) {
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &action
+    ) {
         HydrostaticAssemblyRequest request;
 
         request.enthalpyVariationTrue = &enthalpyVariationTrue;
 
         assemble_hydrostatic_form(f, domainMapper, displacementTrue, request, action);
-}
+    }
 
-void apply_hydrostatic_equilibrium_potential_action(
+    void apply_hydrostatic_equilibrium_potential_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
+        const mapping::DomainMapper &domainMapper,
         const mfem::Vector &potentialVariationTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &action) {
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &action
+    ) {
         HydrostaticAssemblyRequest request;
 
         request.potentialVariationTrue = &potentialVariationTrue;
 
         assemble_hydrostatic_form(f, domainMapper, displacementTrue, request, action);
-}
+    }
 
-void apply_hydrostatic_equilibrium_constant_action(
+    void apply_hydrostatic_equilibrium_constant_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
-    const double constantVariation, const mfem::Vector &displacementTrue,
+        const mapping::DomainMapper &domainMapper,
-    mfem::Vector &action) {
+        const double constantVariation,
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &action
+    ) {
         HydrostaticAssemblyRequest request;
 
         request.constantVariation = constantVariation;
 
         assemble_hydrostatic_form(f, domainMapper, displacementTrue, request, action);
-}
+    }
 
-void apply_hydrostatic_equilibrium_displacement_action(
+    void apply_hydrostatic_equilibrium_displacement_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
+        const mapping::DomainMapper &domainMapper,
         const physics::RigidRotation &rotation,
-    const mfem::Vector &baseEnthalpyTrue, const mfem::Vector &basePotentialTrue,
+        const mfem::Vector &baseEnthalpyTrue,
+        const mfem::Vector &basePotentialTrue,
         const mfem::Vector &baseDisplacementTrue,
         const double baseBernoulliConstant,
-    const mfem::Vector &displacementVariationTrue, mfem::Vector &action) {
+        const mfem::Vector &displacementVariationTrue,
+        mfem::Vector &action
+    ) {
         HydrostaticAssemblyRequest request;
 
         request.rotation                  = &rotation;
@@ -583,19 +595,23 @@ void apply_hydrostatic_equilibrium_displacement_action(
         request.displacementVariationTrue = &displacementVariationTrue;
         request.bernoulliConstant         = baseBernoulliConstant;
 
-  assemble_hydrostatic_form(f, domainMapper, baseDisplacementTrue, request,
+        assemble_hydrostatic_form(f, domainMapper, baseDisplacementTrue, request, action);
-                            action);
+    }
-}
 
-void apply_hydrostatic_equilibrium_action(
+    void apply_hydrostatic_equilibrium_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
+        const mapping::DomainMapper &domainMapper,
         const physics::RigidRotation &rotation,
-    const mfem::Vector &baseEnthalpyTrue, const mfem::Vector &basePotentialTrue,
+        const mfem::Vector &baseEnthalpyTrue,
+        const mfem::Vector &basePotentialTrue,
         const mfem::Vector &baseDisplacementTrue,
         const double baseBernoulliConstant,
         const mfem::Vector &enthalpyVariationTrue,
-    const mfem::Vector &potentialVariationTrue, const double constantVariation,
+        const mfem::Vector &potentialVariationTrue,
-    const mfem::Vector &displacementVariationTrue, mfem::Vector &action) {
+        const double constantVariation,
+        const mfem::Vector &displacementVariationTrue,
+        mfem::Vector &action
+    ) {
         HydrostaticAssemblyRequest request;
 
         request.rotation                  = &rotation;
@@ -607,7 +623,6 @@ void apply_hydrostatic_equilibrium_action(
         request.bernoulliConstant         = baseBernoulliConstant;
         request.constantVariation         = constantVariation;
 
-  assemble_hydrostatic_form(f, domainMapper, baseDisplacementTrue, request,
+        assemble_hydrostatic_form(f, domainMapper, baseDisplacementTrue, request, action);
-                            action);
+    }
-}
 } // namespace mean_field::operators::kernels

libmeanfield/impl/operators/kernels/pressure_force_kernels.cpp

@@ -12,54 +12,64 @@ module mean_field;
 import :operators.kernels.pressure_force;
 
 namespace {
-using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
+    namespace eos      = mean_field::eos;
 
-[[nodiscard]] bool is_vacuum_attribute(const int attribute) {
+    using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
-  return DomainSchema::template attribute_belongs_to<
-      mean_field::utils::domain::Vacuum>(attribute);
-}
 
-enum class PressureForceAction { residual, enthalpy, displacement };
+    [[nodiscard]] bool is_vacuum_attribute(const int attribute) {
+        return DomainSchema::template attribute_belongs_to<mean_field::utils::domain::Vacuum>(attribute);
+    }
 
-void true_to_local(const mfem::ParFiniteElementSpace &finiteElementSpace,
+    enum class PressureForceAction { residual, enthalpy, displacement };
-                   const mfem::Vector &trueVector, mfem::Vector &localVector) {
+
-  MFEM_VERIFY(trueVector.Size() == finiteElementSpace.GetTrueVSize(),
+    void true_to_local(
-              "The pressure-force true vector has the wrong size.");
+        const mfem::ParFiniteElementSpace &finiteElementSpace,
+        const mfem::Vector &trueVector,
+        mfem::Vector &localVector
+    ) {
+        MFEM_VERIFY(
+            trueVector.Size() == finiteElementSpace.GetTrueVSize(), "The pressure-force true vector has the wrong size."
+        );
 
         localVector.SetSize(finiteElementSpace.GetVSize());
 
-  const mfem::Operator *prolongation =
+        const mfem::Operator *prolongation = finiteElementSpace.GetProlongationMatrix();
-      finiteElementSpace.GetProlongationMatrix();
 
         if (prolongation != nullptr) {
             prolongation->Mult(trueVector, localVector);
         } else {
             localVector = trueVector;
         }
-}
+    }
 
-void local_to_true(const mfem::ParFiniteElementSpace &finiteElementSpace,
+    void local_to_true(
-                   const mfem::Vector &localVector, mfem::Vector &trueVector) {
+        const mfem::ParFiniteElementSpace &finiteElementSpace,
-  MFEM_VERIFY(localVector.Size() == finiteElementSpace.GetVSize(),
+        const mfem::Vector &localVector,
-              "The pressure-force local vector has the wrong size.");
+        mfem::Vector &trueVector
+    ) {
+        MFEM_VERIFY(
+            localVector.Size() == finiteElementSpace.GetVSize(), "The pressure-force local vector has the wrong size."
+        );
 
         trueVector.SetSize(finiteElementSpace.GetTrueVSize());
         trueVector                         = 0.0;
 
-  const mfem::Operator *prolongation =
+        const mfem::Operator *prolongation = finiteElementSpace.GetProlongationMatrix();
-      finiteElementSpace.GetProlongationMatrix();
 
         if (prolongation != nullptr) {
             prolongation->MultTranspose(localVector, trueVector);
         } else {
             trueVector = localVector;
         }
-}
+    }
 
-[[nodiscard]] int vector_dof_index(const mfem::Ordering::Type ordering,
+    [[nodiscard]] int vector_dof_index(
-                                   const int scalarDof, const int component,
+        const mfem::Ordering::Type ordering,
+        const int scalarDof,
+        const int component,
         const int scalarDofCount,
-                                   const int dimension) {
+        const int dimension
+    ) {
         if (ordering == mfem::Ordering::byNODES) {
             return scalarDof + component * scalarDofCount;
         }
@@ -70,10 +80,9 @@ void local_to_true(const mfem::ParFiniteElementSpace &finiteElementSpace,
 
         MFEM_ABORT("The displacement space uses an unsupported ordering.");
         return -1;
-}
+    }
 
-[[nodiscard]] int
+    [[nodiscard]] int get_pressure_extra_order(const mean_field::eos::Polytrope &barotrope) {
-get_pressure_extra_order(const mean_field::eos::Polytrope &barotrope) {
         /*
          * Pressure has the enthalpy dependence
          *
@@ -84,92 +93,108 @@ get_pressure_extra_order(const mean_field::eos::Polytrope &barotrope) {
          * contribution is therefore n times that order.
          */
         const double extraOrder =
-      barotrope.polytropic_index() *
+            barotrope.polytropic_index() * static_cast<double>(mean_field::field::Enthalpy::Scalar::familyOrder);
-      static_cast<double>(mean_field::field::Enthalpy::Scalar::familyOrder);
 
-  MFEM_VERIFY(std::isfinite(extraOrder) && extraOrder >= 0.0 &&
+        MFEM_VERIFY(
-                  extraOrder <=
+            std::isfinite(extraOrder) && extraOrder >= 0.0 &&
-                      static_cast<double>(std::numeric_limits<int>::max()),
+                extraOrder <= static_cast<double>(std::numeric_limits<int>::max()),
-              "The pressure EOS effective polynomial order is invalid.");
+            "The pressure EOS effective polynomial order is invalid."
+        );
 
         return static_cast<int>(std::ceil(extraOrder));
-}
+    }
 
-[[nodiscard]] const mfem::IntegrationRule &
+    [[nodiscard]] const mfem::IntegrationRule &get_pressure_force_rule(
-get_pressure_force_rule(const mean_field::fem::FEM &f,
+        const mean_field::fem::FEM &f,
         const mean_field::eos::Polytrope &barotrope,
         const mfem::FiniteElement &enthalpyElement,
         const mfem::FiniteElement &displacementElement,
-                        const mfem::ElementTransformation &transformation) {
+        const mfem::ElementTransformation &transformation
+    ) {
         using EnthalpyField = mean_field::field::Field<mean_field::field::Enthalpy>;
 
-  MFEM_VERIFY(enthalpyElement.GetOrder() ==
+        MFEM_VERIFY(
-                  mean_field::field::Enthalpy::Scalar::familyOrder,
+            enthalpyElement.GetOrder() == mean_field::field::Enthalpy::Scalar::familyOrder,
             "The pressure-force enthalpy element does not match the "
-              "registered enthalpy field.");
+            "registered enthalpy field."
+        );
 
-  MFEM_VERIFY(displacementElement.GetOrder() ==
+        MFEM_VERIFY(
-                  mean_field::field::Displacement::Vector::familyOrder,
+            displacementElement.GetOrder() == mean_field::field::Displacement::Vector::familyOrder,
             "The pressure-force test element does not match the "
-              "registered displacement field.");
+            "registered displacement field."
+        );
 
-  const mean_field::quadrature::Query query = EnthalpyField::make_query<
+        const mean_field::quadrature::Query query =
-      mean_field::field::Enthalpy::Form::PressureForce>(
+            EnthalpyField::make_query<mean_field::field::Enthalpy::Form::PressureForce>(
-      mean_field::quadrature::QuadratureRole::discretization,
+                mean_field::quadrature::QuadratureRole::discretization, transformation.OrderW(),
-      transformation.OrderW(),
+                std::array<int, 1>{get_pressure_extra_order(barotrope)}, mean_field::utils::DOMAINS::STELLAR,
-      std::array<int, 1>{get_pressure_extra_order(barotrope)},
+                mean_field::quadrature::MappingKind::general
-      mean_field::utils::DOMAINS::STELLAR,
+            );
-      mean_field::quadrature::MappingKind::general);
 
-  const mean_field::quadrature::MfemRule rule =
+        const mean_field::quadrature::MfemRule rule = f.quadratureFactory->get(query, transformation.GetGeometryType());
-      f.quadratureFactory->get(query, transformation.GetGeometryType());
 
-  MFEM_VERIFY(rule.integration_rule != nullptr,
+        MFEM_VERIFY(
-              "The quadrature policy did not return a pressure-force "
+            rule.integration_rule != nullptr, "The quadrature policy did not return a pressure-force "
-              "integration rule.");
+                                              "integration rule."
+        );
 
         return *rule.integration_rule;
-}
+    }
 
-void validate_inputs(
+    void validate_inputs(
         const mean_field::fem::FEM &f,
         const mean_field::mapping::DomainMapper &domainMapper,
-    const mfem::Vector &enthalpyTrue, const mfem::Vector &displacementTrue) {
+        const mfem::Vector &enthalpyTrue,
+        const mfem::Vector &displacementTrue
+    ) {
         MFEM_VERIFY(f.mesh != nullptr, "The pressure-force kernel requires a mesh.");
 
-  MFEM_VERIFY(f.enthalpyFes != nullptr,
+        MFEM_VERIFY(
-              "The pressure-force kernel requires the enthalpy "
+            f.enthalpyFes != nullptr, "The pressure-force kernel requires the enthalpy "
-              "finite-element space.");
+                                      "finite-element space."
+        );
 
-  MFEM_VERIFY(f.displacementFes != nullptr,
+        MFEM_VERIFY(
-              "The pressure-force kernel requires the displacement "
+            f.displacementFes != nullptr, "The pressure-force kernel requires the displacement "
-              "finite-element space.");
+                                          "finite-element space."
+        );
 
-  MFEM_VERIFY(f.compactificationFes != nullptr,
+        MFEM_VERIFY(
-              "The pressure-force kernel requires the compactification "
+            f.compactificationFes != nullptr, "The pressure-force kernel requires the compactification "
-              "finite-element space.");
+                                              "finite-element space."
+        );
 
-  MFEM_VERIFY(f.compactificationCoordinate != nullptr,
+        MFEM_VERIFY(
-              "The pressure-force kernel requires the compactification "
+            f.compactificationCoordinate != nullptr, "The pressure-force kernel requires the compactification "
-              "coordinate.");
+                                                     "coordinate."
+        );
 
-  MFEM_VERIFY(f.quadratureFactory != nullptr,
+        MFEM_VERIFY(
-              "The pressure-force kernel requires the quadrature "
+            f.quadratureFactory != nullptr, "The pressure-force kernel requires the quadrature "
-              "rule factory.");
+                                            "rule factory."
+        );
 
-  MFEM_VERIFY(enthalpyTrue.Size() == f.enthalpyFes->GetTrueVSize(),
+        MFEM_VERIFY(
-              "The pressure-force enthalpy vector has the wrong size.");
+            enthalpyTrue.Size() == f.enthalpyFes->GetTrueVSize(),
+            "The pressure-force enthalpy vector has the wrong size."
+        );
 
-  MFEM_VERIFY(displacementTrue.Size() == f.displacementFes->GetTrueVSize(),
+        MFEM_VERIFY(
-              "The pressure-force displacement vector has the wrong size.");
+            displacementTrue.Size() == f.displacementFes->GetTrueVSize(),
+            "The pressure-force displacement vector has the wrong size."
+        );
 
-  MFEM_VERIFY(domainMapper.GetDimension() == f.mesh->Dimension(),
+        MFEM_VERIFY(
+            domainMapper.GetDimension() == f.mesh->Dimension(),
             "The pressure-force domain-mapper dimension does not match "
-              "the mesh dimension.");
+            "the mesh dimension."
+        );
 
-  MFEM_VERIFY(f.displacementFes->GetVDim() == f.mesh->Dimension(),
+        MFEM_VERIFY(
-              "The displacement vector dimension does not match the "
+            f.displacementFes->GetVDim() == f.mesh->Dimension(), "The displacement vector dimension does not match the "
-              "mesh dimension.");
+                                                                 "mesh dimension."
+        );
 
         /*
          * ElementDisplacementDataFromElementVDofs currently consumes the
@@ -177,12 +202,14 @@ void validate_inputs(
          * registry change fails immediately rather than silently
          * corrupting the geometry.
          */
-  MFEM_VERIFY(f.displacementFes->GetOrdering() == mfem::Ordering::byNODES,
+        MFEM_VERIFY(
+            f.displacementFes->GetOrdering() == mfem::Ordering::byNODES,
             "The pressure-force kernel requires the registered byNODES "
-              "displacement ordering.");
+            "displacement ordering."
-}
+        );
+    }
 
-void apply_pressure_force_action(
+    void apply_pressure_force_action(
         const mean_field::fem::FEM &f,
         const mean_field::mapping::DomainMapper &domainMapper,
         const mean_field::eos::Polytrope &barotrope,
@@ -190,22 +217,25 @@ void apply_pressure_force_action(
         const mfem::Vector &baseEnthalpyTrue,
         const mfem::Vector *enthalpyVariationTrue,
         const mfem::Vector *displacementVariationTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &actionTrue) {
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &actionTrue
+    ) {
         validate_inputs(f, domainMapper, baseEnthalpyTrue, displacementTrue);
 
         if (pressureForceAction == PressureForceAction::enthalpy) {
-    MFEM_VERIFY(enthalpyVariationTrue != nullptr &&
+            MFEM_VERIFY(
-                    enthalpyVariationTrue->Size() ==
+                enthalpyVariationTrue != nullptr && enthalpyVariationTrue->Size() == f.enthalpyFes->GetTrueVSize(),
-                        f.enthalpyFes->GetTrueVSize(),
+                "The pressure-force enthalpy variation has the wrong size."
-                "The pressure-force enthalpy variation has the wrong size.");
+            );
         }
 
         if (pressureForceAction == PressureForceAction::displacement) {
-    MFEM_VERIFY(displacementVariationTrue != nullptr &&
+            MFEM_VERIFY(
-                    displacementVariationTrue->Size() ==
+                displacementVariationTrue != nullptr &&
-                        f.displacementFes->GetTrueVSize(),
+                    displacementVariationTrue->Size() == f.displacementFes->GetTrueVSize(),
                 "The pressure-force displacement variation has the wrong "
-                "size.");
+                "size."
+            );
         }
 
         mfem::Vector baseEnthalpyLocal;
@@ -216,22 +246,19 @@ void apply_pressure_force_action(
         true_to_local(*f.enthalpyFes, baseEnthalpyTrue, baseEnthalpyLocal);
 
         if (enthalpyVariationTrue != nullptr) {
-    true_to_local(*f.enthalpyFes, *enthalpyVariationTrue,
+            true_to_local(*f.enthalpyFes, *enthalpyVariationTrue, enthalpyVariationLocal);
-                  enthalpyVariationLocal);
         }
 
         true_to_local(*f.displacementFes, displacementTrue, displacementLocal);
 
         if (displacementVariationTrue != nullptr) {
-    true_to_local(*f.displacementFes, *displacementVariationTrue,
+            true_to_local(*f.displacementFes, *displacementVariationTrue, displacementVariationLocal);
-                  displacementVariationLocal);
         }
 
         mfem::Vector localAction(f.displacementFes->GetVSize());
         localAction = 0.0;
 
-  mean_field::mapping::DomainMapper::Workspace workspace(
+        mean_field::mapping::DomainMapper::Workspace workspace(f.mesh->Dimension());
-      f.mesh->Dimension());
 
         mfem::Array<int> enthalpyDofsofs;
         mfem::Array<int> displacementDofs;
@@ -255,16 +282,15 @@ void apply_pressure_force_action(
 
         const int dimension                             = f.mesh->Dimension();
 
-  const mfem::Ordering::Type displacementOrdering =
+        const mfem::Ordering::Type displacementOrdering = f.displacementFes->GetOrdering();
-      f.displacementFes->GetOrdering();
 
         for (int elementId = 0; elementId < f.mesh->GetNE(); ++elementId) {
-    mfem::ElementTransformation *transformation =
+            mfem::ElementTransformation *transformation = f.mesh->GetElementTransformation(elementId);
-        f.mesh->GetElementTransformation(elementId);
 
-    MFEM_VERIFY(transformation != nullptr,
+            MFEM_VERIFY(
-                "The pressure-force kernel received a null element "
+                transformation != nullptr, "The pressure-force kernel received a null element "
-                "transformation.");
+                                           "transformation."
+            );
 
             /*
              * Skip vacuum before constructing or evaluating any mapping
@@ -274,17 +300,13 @@ void apply_pressure_force_action(
                 continue;
             }
 
-    const mfem::FiniteElement &enthalpyElement =
+            const mfem::FiniteElement &enthalpyElement         = *f.enthalpyFes->GetFE(elementId);
-        *f.enthalpyFes->GetFE(elementId);
 
-    const mfem::FiniteElement &displacementElement =
+            const mfem::FiniteElement &displacementElement     = *f.displacementFes->GetFE(elementId);
-        *f.displacementFes->GetFE(elementId);
 
-    const mfem::FiniteElement &compactificationElement =
+            const mfem::FiniteElement &compactificationElement = *f.compactificationFes->GetFE(elementId);
-        *f.compactificationFes->GetFE(elementId);
 
-    mfem::DofTransformation *enthalpyDofTransformation =
+            mfem::DofTransformation *enthalpyDofTransformation = f.enthalpyFes->GetElementDofs(elementId, enthalpyDofs);
-        f.enthalpyFes->GetElementDofs(elementId, enthalpyDofs);
 
             mfem::DofTransformation *displacementDofTransformation =
                 f.displacementFes->GetElementVDofs(elementId, displacementDofs);
@@ -295,19 +317,16 @@ void apply_pressure_force_action(
             baseEnthalpyLocal.GetSubVector(enthalpyDofs, elementBaseEnthalpy);
 
             if (enthalpyVariationTrue != nullptr) {
-      enthalpyVariationLocal.GetSubVector(enthalpyDofs,
+                enthalpyVariationLocal.GetSubVector(enthalpyDofs, elementEnthalpyVariation);
-                                          elementEnthalpyVariation);
             }
 
             displacementLocal.GetSubVector(displacementDofs, elementDisplacement);
 
             if (displacementVariationTrue != nullptr) {
-      displacementVariationLocal.GetSubVector(displacementDofs,
+                displacementVariationLocal.GetSubVector(displacementDofs, elementDisplacementVariation);
-                                              elementDisplacementVariation);
             }
 
-    f.compactificationCoordinate->GetSubVector(compactificationDofs,
+            f.compactificationCoordinate->GetSubVector(compactificationDofs, elementCompactification);
-                                               elementCompactification);
 
             if (enthalpyDofTransformation != nullptr) {
                 enthalpyDofTransformation->InvTransformPrimal(elementBaseEnthalpy);
@@ -321,42 +340,42 @@ void apply_pressure_force_action(
                 displacementDofTransformation->InvTransformPrimal(elementDisplacement);
 
                 if (displacementVariationTrue != nullptr) {
-        displacementDofTransformation->InvTransformPrimal(
+                    displacementDofTransformation->InvTransformPrimal(elementDisplacementVariation);
-            elementDisplacementVariation);
                 }
             }
 
             if (compactificationDofTransformation != nullptr) {
-      compactificationDofTransformation->InvTransformPrimal(
+                compactificationDofTransformation->InvTransformPrimal(elementCompactification);
-          elementCompactification);
             }
 
             const mean_field::mapping::ElementDisplacementData displacementData =
-        mean_field::mapping::ElementDisplacementDataFromElementVDofs(
+                mean_field::mapping::ElementDisplacementDataFromElementVDofs(displacementElement, elementDisplacement);
-            displacementElement, elementDisplacement);
 
             const mean_field::mapping::ElementCompactificationData compactificationData(
-        compactificationElement, elementCompactification);
+                compactificationElement, elementCompactification
+            );
 
             const mean_field::mapping::ElementMappingData mappingData{
-        .displacement = displacementData,
+                .displacement = displacementData, .compactification = compactificationData
-        .compactification = compactificationData};
+            };
 
-    std::optional<mean_field::mapping::ElementDisplacementData>
+            std::optional<mean_field::mapping::ElementDisplacementData> displacementVariationData;
-        displacementVariationData;
 
             if (displacementVariationTrue != nullptr) {
                 displacementVariationData.emplace(
                     mean_field::mapping::ElementDisplacementDataFromElementVDofs(
-              displacementElement, elementDisplacementVariation));
+                        displacementElement, elementDisplacementVariation
+                    )
+                );
             }
 
             const int scalarDisplacementDofCount = displacementElement.GetDof();
 
-    MFEM_VERIFY(displacementDofs.Size() ==
+            MFEM_VERIFY(
-                    scalarDisplacementDofCount * dimension,
+                displacementDofs.Size() == scalarDisplacementDofCount * dimension,
                 "The pressure-force element displacement vector has "
-                "the wrong size.");
+                "the wrong size."
+            );
 
             enthalpyShape.SetSize(enthalpyElement.GetDof());
 
@@ -364,34 +383,30 @@ void apply_pressure_force_action(
 
             displacementDShapePhysical.SetSize(scalarDisplacementDofCount, dimension);
 
-    displacementDShapePhysicalVariation.SetSize(scalarDisplacementDofCount,
+            displacementDShapePhysicalVariation.SetSize(scalarDisplacementDofCount, dimension);
-                                                dimension);
 
             elementAction.SetSize(displacementDofs.Size());
             elementAction = 0.0;
 
-    const mfem::IntegrationRule &integrationRule = get_pressure_force_rule(
+            const mfem::IntegrationRule &integrationRule =
-        f, barotrope, enthalpyElement, displacementElement, *transformation);
+                get_pressure_force_rule(f, barotrope, enthalpyElement, displacementElement, *transformation);
 
-    for (int quadratureIndex = 0;
+            for (int quadratureIndex = 0; quadratureIndex < integrationRule.GetNPoints(); ++quadratureIndex) {
-         quadratureIndex < integrationRule.GetNPoints(); ++quadratureIndex) {
+                const mfem::IntegrationPoint &integrationPoint = integrationRule.IntPoint(quadratureIndex);
-      const mfem::IntegrationPoint &integrationPoint =
-          integrationRule.IntPoint(quadratureIndex);
 
                 transformation->SetIntPoint(&integrationPoint);
 
-      const mean_field::mapping::MappingStatus mappingStatus =
+                const mean_field::mapping::MappingStatus mappingStatus = domainMapper.EvaluateVolume(
-          domainMapper.EvaluateVolume(mappingData, *transformation,
+                    mappingData, *transformation, integrationPoint, workspace, mappingContext
-                                      integrationPoint, workspace,
+                );
-                                      mappingContext);
 
-      MFEM_VERIFY(mappingStatus == mean_field::mapping::MappingStatus::valid,
+                MFEM_VERIFY(
+                    mappingStatus == mean_field::mapping::MappingStatus::valid,
                     "Stateless mapping failed in the pressure-force "
                     "kernel. Element: "
-                      << elementId
+                        << elementId << ", attribute: " << transformation->Attribute
-                      << ", attribute: " << transformation->Attribute
+                        << ", quadrature point: " << quadratureIndex << ", status: " << static_cast<int>(mappingStatus)
-                      << ", quadrature point: " << quadratureIndex
+                );
-                      << ", status: " << static_cast<int>(mappingStatus));
 
                 enthalpyElement.CalcShape(integrationPoint, enthalpyShape);
 
@@ -401,18 +416,20 @@ void apply_pressure_force_action(
 
                 if (pressureForceAction == PressureForceAction::residual ||
                     pressureForceAction == PressureForceAction::displacement) {
-        pressureFactor = barotrope.pressure_from_enthalpy(enthalpyValue);
-      } else {
-        const double enthalpyVariationValue =
-            elementEnthalpyVariation * enthalpyShape;
-
                     pressureFactor =
-            barotrope.pressure_derivative_from_enthalpy(enthalpyValue) *
+                        eos::evaluate<eos::quantity::Pressure>(barotrope, eos::SpecificEnthalpyValue{enthalpyValue})
+                            .value();
+                } else {
+                    const double enthalpyVariationValue = elementEnthalpyVariation * enthalpyShape;
+
+                    pressureFactor = eos::partialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>(
+                                         barotrope, eos::SpecificEnthalpyValue{enthalpyValue}
+                                     )
+                                         .value() *
                                      enthalpyVariationValue;
                 }
 
-      displacementElement.CalcDShape(integrationPoint,
+                displacementElement.CalcDShape(integrationPoint, displacementDShapeReference);
-                                     displacementDShapeReference);
 
                 /*
                  * Row i of DShape is grad_reference(N_i). Multiplication
@@ -421,27 +438,25 @@ void apply_pressure_force_action(
                  *     grad_physical(N_i)
                  *       = grad_reference(N_i) J^{-1}.
                  */
-      mfem::Mult(displacementDShapeReference, mappingContext.quadrature.J_inv,
+                mfem::Mult(displacementDShapeReference, mappingContext.quadrature.J_inv, displacementDShapePhysical);
-                 displacementDShapePhysical);
 
-      std::optional<mean_field::mapping::VolumeMappingVariation>
+                std::optional<mean_field::mapping::VolumeMappingVariation> mappingVariation;
-          mappingVariation;
 
                 if (pressureForceAction == PressureForceAction::displacement) {
                     mappingVariation.emplace();
 
-        const mean_field::mapping::MappingStatus variationStatus =
+                    const mean_field::mapping::MappingStatus variationStatus = domainMapper.EvaluateVolumeVariation(
-            domainMapper.EvaluateVolumeVariation(
+                        mappingData, *displacementVariationData, *transformation, integrationPoint, mappingContext,
-                mappingData, *displacementVariationData, *transformation,
+                        workspace, *mappingVariation
-                integrationPoint, mappingContext, workspace, *mappingVariation);
+                    );
 
                     MFEM_VERIFY(
                         variationStatus == mean_field::mapping::MappingStatus::valid,
                         "Stateless mapping variation failed in the "
                         "pressure-force kernel. Element: "
-                << elementId << ", attribute: " << transformation->Attribute
+                            << elementId << ", attribute: " << transformation->Attribute << ", quadrature point: "
-                << ", quadrature point: " << quadratureIndex
+                            << quadratureIndex << ", status: " << static_cast<int>(variationStatus)
-                << ", status: " << static_cast<int>(variationStatus));
+                    );
 
                     /*
                      * Differentiating
@@ -452,18 +467,19 @@ void apply_pressure_force_action(
                      * test-gradient variation used by the geometric
                      * pressure block.
                      */
-        mfem::Mult(displacementDShapeReference,
+                    mfem::Mult(
-                   mappingVariation->inverse_element_jacobian_variation,
+                        displacementDShapeReference, mappingVariation->inverse_element_jacobian_variation,
-                   displacementDShapePhysicalVariation);
+                        displacementDShapePhysicalVariation
+                    );
                 }
 
-      const double weightedPressureFactor =
+                const double weightedPressureFactor = pressureFactor * mappingContext.quadrature.weight;
-          pressureFactor * mappingContext.quadrature.weight;
 
-      MFEM_VERIFY(std::isfinite(pressureFactor) &&
+                MFEM_VERIFY(
-                      std::isfinite(weightedPressureFactor),
+                    std::isfinite(pressureFactor) && std::isfinite(weightedPressureFactor),
                     "The pressure-force kernel encountered a non-finite "
-                  "quadrature value.");
+                    "quadrature value."
+                );
 
                 /*
                  * For the vector basis N_i e_c,
@@ -475,12 +491,11 @@ void apply_pressure_force_action(
                  *     R_(i,c)
                  *       = -integral P partial_c N_i dV.
                  */
-      for (int scalarDof = 0; scalarDof < scalarDisplacementDofCount;
+                for (int scalarDof = 0; scalarDof < scalarDisplacementDofCount; ++scalarDof) {
-           ++scalarDof) {
                     for (int component = 0; component < dimension; ++component) {
-          const int vectorDof =
+                        const int vectorDof = vector_dof_index(
-              vector_dof_index(displacementOrdering, scalarDof, component,
+                            displacementOrdering, scalarDof, component, scalarDisplacementDofCount, dimension
-                               scalarDisplacementDofCount, dimension);
+                        );
 
                         if (pressureForceAction == PressureForceAction::displacement) {
                             /*
@@ -494,22 +509,20 @@ void apply_pressure_force_action(
                             const double gradientWeightVariation =
                                 mappingContext.quadrature.weight *
                                     displacementDShapePhysicalVariation(scalarDof, component) +
-                mappingVariation->weight_variation *
+                                mappingVariation->weight_variation * displacementDShapePhysical(scalarDof, component);
-                    displacementDShapePhysical(scalarDof, component);
 
-            const double contribution =
+                            const double contribution = pressureFactor * gradientWeightVariation;
-                pressureFactor * gradientWeightVariation;
 
-            MFEM_VERIFY(std::isfinite(gradientWeightVariation) &&
+                            MFEM_VERIFY(
-                            std::isfinite(contribution),
+                                std::isfinite(gradientWeightVariation) && std::isfinite(contribution),
                                 "The pressure-force geometry action "
-                        "encountered a non-finite contribution.");
+                                "encountered a non-finite contribution."
+                            );
 
                             elementAction(vectorDof) -= contribution;
                         } else {
                             elementAction(vectorDof) -=
-                weightedPressureFactor *
+                                weightedPressureFactor * displacementDShapePhysical(scalarDof, component);
-                displacementDShapePhysical(scalarDof, component);
                         }
                     }
                 }
@@ -523,38 +536,51 @@ void apply_pressure_force_action(
         }
 
         local_to_true(*f.displacementFes, localAction, actionTrue);
-}
+    }
 } // namespace
 
 namespace mean_field::operators::kernels {
-void apply_pressure_force_residual(
+    void apply_pressure_force_residual(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
-    const eos::Polytrope &barotrope, const mfem::Vector &enthalpyTrue,
+        const mapping::DomainMapper &domainMapper,
-    const mfem::Vector &displacementTrue, mfem::Vector &residualTrue) {
+        const eos::Polytrope &barotrope,
-  apply_pressure_force_action(f, domainMapper, barotrope,
+        const mfem::Vector &enthalpyTrue,
-                              PressureForceAction::residual, enthalpyTrue,
+        const mfem::Vector &displacementTrue,
-                              nullptr, nullptr, displacementTrue, residualTrue);
+        mfem::Vector &residualTrue
-}
+    ) {
-
-void apply_pressure_force_enthalpy_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
-    const eos::Polytrope &barotrope, const mfem::Vector &baseEnthalpyTrue,
-    const mfem::Vector &enthalpyVariationTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &actionTrue) {
-  apply_pressure_force_action(f, domainMapper, barotrope,
-                              PressureForceAction::enthalpy, baseEnthalpyTrue,
-                              &enthalpyVariationTrue, nullptr, displacementTrue,
-                              actionTrue);
-}
-
-void apply_pressure_force_displacement_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
-    const eos::Polytrope &barotrope, const mfem::Vector &baseEnthalpyTrue,
-    const mfem::Vector &displacementVariationTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &actionTrue) {
         apply_pressure_force_action(
-      f, domainMapper, barotrope, PressureForceAction::displacement,
+            f, domainMapper, barotrope, PressureForceAction::residual, enthalpyTrue, nullptr, nullptr, displacementTrue,
-      baseEnthalpyTrue, nullptr, &displacementVariationTrue, displacementTrue,
+            residualTrue
-      actionTrue);
+        );
-}
+    }
+
+    void apply_pressure_force_enthalpy_action(
+        const fem::FEM &f,
+        const mapping::DomainMapper &domainMapper,
+        const eos::Polytrope &barotrope,
+        const mfem::Vector &baseEnthalpyTrue,
+        const mfem::Vector &enthalpyVariationTrue,
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &actionTrue
+    ) {
+        apply_pressure_force_action(
+            f, domainMapper, barotrope, PressureForceAction::enthalpy, baseEnthalpyTrue, &enthalpyVariationTrue,
+            nullptr, displacementTrue, actionTrue
+        );
+    }
+
+    void apply_pressure_force_displacement_action(
+        const fem::FEM &f,
+        const mapping::DomainMapper &domainMapper,
+        const eos::Polytrope &barotrope,
+        const mfem::Vector &baseEnthalpyTrue,
+        const mfem::Vector &displacementVariationTrue,
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &actionTrue
+    ) {
+        apply_pressure_force_action(
+            f, domainMapper, barotrope, PressureForceAction::displacement, baseEnthalpyTrue, nullptr,
+            &displacementVariationTrue, displacementTrue, actionTrue
+        );
+    }
 } // namespace mean_field::operators::kernels

libmeanfield/impl/operators/kernels/rotation_displacement_force_kernels.cpp

@@ -11,61 +11,66 @@ module mean_field;
 import :operators.kernels.rotational_displacement_force;
 
 namespace {
-using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
+    using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
 
-[[nodiscard]] bool is_vacuum_attribute(const int attribute) {
+    [[nodiscard]] bool is_vacuum_attribute(const int attribute) {
-  return DomainSchema::template attribute_belongs_to<
+        return DomainSchema::template attribute_belongs_to<mean_field::utils::domain::Vacuum>(attribute);
-      mean_field::utils::domain::Vacuum>(attribute);
+    }
-}
 
-enum class RotationalDisplacementForceAction {
+    enum class RotationalDisplacementForceAction { residual, density, displacement, complete };
-  residual,
-  density,
-  displacement,
-  complete
-};
 
-void true_to_local(const mfem::ParFiniteElementSpace &finiteElementSpace,
+    void true_to_local(
-                   const mfem::Vector &trueVector, mfem::Vector &localVector) {
+        const mfem::ParFiniteElementSpace &finiteElementSpace,
-  MFEM_VERIFY(trueVector.Size() == finiteElementSpace.GetTrueVSize(),
+        const mfem::Vector &trueVector,
+        mfem::Vector &localVector
+    ) {
+        MFEM_VERIFY(
+            trueVector.Size() == finiteElementSpace.GetTrueVSize(),
             "The rotational-displacement-force true vector has the wrong "
-              "size.");
+            "size."
+        );
 
         localVector.SetSize(finiteElementSpace.GetVSize());
 
-  const mfem::Operator *prolongation =
+        const mfem::Operator *prolongation = finiteElementSpace.GetProlongationMatrix();
-      finiteElementSpace.GetProlongationMatrix();
 
         if (prolongation != nullptr) {
             prolongation->Mult(trueVector, localVector);
         } else {
             localVector = trueVector;
         }
-}
+    }
 
-void local_to_true(const mfem::ParFiniteElementSpace &finiteElementSpace,
+    void local_to_true(
-                   const mfem::Vector &localVector, mfem::Vector &trueVector) {
+        const mfem::ParFiniteElementSpace &finiteElementSpace,
-  MFEM_VERIFY(localVector.Size() == finiteElementSpace.GetVSize(),
+        const mfem::Vector &localVector,
+        mfem::Vector &trueVector
+    ) {
+        MFEM_VERIFY(
+            localVector.Size() == finiteElementSpace.GetVSize(),
             "The rotational-displacement-force local vector has the wrong "
-              "size.");
+            "size."
+        );
 
         trueVector.SetSize(finiteElementSpace.GetTrueVSize());
         trueVector                         = 0.0;
 
-  const mfem::Operator *prolongation =
+        const mfem::Operator *prolongation = finiteElementSpace.GetProlongationMatrix();
-      finiteElementSpace.GetProlongationMatrix();
 
         if (prolongation != nullptr) {
             prolongation->MultTranspose(localVector, trueVector);
         } else {
             trueVector = localVector;
         }
-}
+    }
 
-[[nodiscard]] int vector_dof_index(const mfem::Ordering::Type ordering,
+    [[nodiscard]] int vector_dof_index(
-                                   const int scalarDof, const int component,
+        const mfem::Ordering::Type ordering,
+        const int scalarDof,
+        const int component,
         const int scalarDofCount,
-                                   const int dimension) {
+        const int dimension
+    ) {
         if (ordering == mfem::Ordering::byNODES) {
             return scalarDof + component * scalarDofCount;
         }
@@ -74,110 +79,130 @@ void local_to_true(const mfem::ParFiniteElementSpace &finiteElementSpace,
             return scalarDof * dimension + component;
         }
 
-  MFEM_ABORT("The rotational-displacement-force test space uses an "
+        MFEM_ABORT(
-             "unsupported ordering.");
+            "The rotational-displacement-force test space uses an "
+            "unsupported ordering."
+        );
 
         return -1;
-}
+    }
 
-[[nodiscard]] const mfem::IntegrationRule &
+    [[nodiscard]] const mfem::IntegrationRule &get_rotation_force_rule(
-get_rotation_force_rule(const mean_field::fem::FEM &f,
+        const mean_field::fem::FEM &f,
         const mfem::FiniteElement &densityElement,
         const mfem::FiniteElement &displacementElement,
-                        const mfem::ElementTransformation &transformation) {
+        const mfem::ElementTransformation &transformation
-  using DisplacementField =
+    ) {
-      mean_field::field::Field<mean_field::field::Displacement>;
+        using DisplacementField = mean_field::field::Field<mean_field::field::Displacement>;
 
-  MFEM_VERIFY(densityElement.GetOrder() ==
+        MFEM_VERIFY(
-                  mean_field::field::Density::Scalar::familyOrder,
+            densityElement.GetOrder() == mean_field::field::Density::Scalar::familyOrder,
             "The rotational-displacement-force density element does not "
-              "match the registered density field.");
+            "match the registered density field."
+        );
 
-  MFEM_VERIFY(displacementElement.GetOrder() ==
+        MFEM_VERIFY(
-                  mean_field::field::Displacement::Vector::familyOrder,
+            displacementElement.GetOrder() == mean_field::field::Displacement::Vector::familyOrder,
             "The rotational-displacement-force test element does not match "
-              "the registered displacement field.");
+            "the registered displacement field."
+        );
 
         /*
          * grad(Psi_rotation) is linear in physical position, so it adds one
          * dynamic polynomial-order contribution.
          */
-  const mean_field::quadrature::Query query = DisplacementField::make_query<
+        const mean_field::quadrature::Query query =
-      mean_field::field::Displacement::Form::CentrifugalForce>(
+            DisplacementField::make_query<mean_field::field::Displacement::Form::CentrifugalForce>(
-      mean_field::quadrature::QuadratureRole::discretization,
+                mean_field::quadrature::QuadratureRole::discretization, transformation.OrderW(), std::array<int, 1>{1},
-      transformation.OrderW(), std::array<int, 1>{1},
+                mean_field::utils::DOMAINS::STELLAR, mean_field::quadrature::MappingKind::general
-      mean_field::utils::DOMAINS::STELLAR,
+            );
-      mean_field::quadrature::MappingKind::general);
 
-  const mean_field::quadrature::MfemRule rule =
+        const mean_field::quadrature::MfemRule rule = f.quadratureFactory->get(query, transformation.GetGeometryType());
-      f.quadratureFactory->get(query, transformation.GetGeometryType());
 
-  MFEM_VERIFY(rule.integration_rule != nullptr,
+        MFEM_VERIFY(
-              "The quadrature policy did not return a rotational-"
+            rule.integration_rule != nullptr, "The quadrature policy did not return a rotational-"
-              "displacement-force integration rule.");
+                                              "displacement-force integration rule."
+        );
 
         return *rule.integration_rule;
-}
+    }
 
-void validate_finite_vector(const mfem::Vector &vector, const char *message) {
+    void validate_finite_vector(
+        const mfem::Vector &vector,
+        const char *message
+    ) {
         for (int index = 0; index < vector.Size(); ++index) {
             MFEM_VERIFY(std::isfinite(vector(index)), message);
         }
-}
+    }
 
-void validate_common_inputs(
+    void validate_common_inputs(
         const mean_field::fem::FEM &f,
         const mean_field::mapping::DomainMapper &domainMapper,
-    const mfem::Vector &displacementTrue) {
+        const mfem::Vector &displacementTrue
-  MFEM_VERIFY(f.mesh != nullptr,
+    ) {
-              "The rotational-displacement-force kernel requires a mesh.");
+        MFEM_VERIFY(f.mesh != nullptr, "The rotational-displacement-force kernel requires a mesh.");
 
-  MFEM_VERIFY(f.mesh->Dimension() == 3,
+        MFEM_VERIFY(
-              "The rotational-displacement-force kernel requires a "
+            f.mesh->Dimension() == 3, "The rotational-displacement-force kernel requires a "
-              "three-dimensional mesh.");
+                                      "three-dimensional mesh."
+        );
 
-  MFEM_VERIFY(f.densityFes != nullptr,
+        MFEM_VERIFY(
-              "The rotational-displacement-force kernel requires the density "
+            f.densityFes != nullptr, "The rotational-displacement-force kernel requires the density "
-              "finite-element space.");
+                                     "finite-element space."
+        );
 
-  MFEM_VERIFY(f.displacementFes != nullptr,
+        MFEM_VERIFY(
+            f.displacementFes != nullptr, "The rotational-displacement-force kernel requires the "
+                                          "displacement finite-element space."
+        );
+
+        MFEM_VERIFY(
+            f.compactificationFes != nullptr && f.compactificationCoordinate != nullptr,
             "The rotational-displacement-force kernel requires the "
-              "displacement finite-element space.");
+            "compactification coordinate."
+        );
 
-  MFEM_VERIFY(f.compactificationFes != nullptr &&
+        MFEM_VERIFY(
-                  f.compactificationCoordinate != nullptr,
+            f.quadratureFactory != nullptr, "The rotational-displacement-force kernel requires the "
-              "The rotational-displacement-force kernel requires the "
+                                            "quadrature-rule factory."
-              "compactification coordinate.");
+        );
 
-  MFEM_VERIFY(f.quadratureFactory != nullptr,
+        MFEM_VERIFY(
-              "The rotational-displacement-force kernel requires the "
+            displacementTrue.Size() == f.displacementFes->GetTrueVSize(),
-              "quadrature-rule factory.");
-
-  MFEM_VERIFY(displacementTrue.Size() == f.displacementFes->GetTrueVSize(),
             "The rotational-displacement-force displacement vector has the "
-              "wrong size.");
+            "wrong size."
+        );
 
-  MFEM_VERIFY(domainMapper.GetDimension() == f.mesh->Dimension(),
+        MFEM_VERIFY(
+            domainMapper.GetDimension() == f.mesh->Dimension(),
             "The rotational-displacement-force mapper dimension does not "
-              "match the mesh dimension.");
+            "match the mesh dimension."
+        );
 
-  MFEM_VERIFY(f.displacementFes->GetVDim() == f.mesh->Dimension(),
+        MFEM_VERIFY(
+            f.displacementFes->GetVDim() == f.mesh->Dimension(),
             "The rotational-displacement-force displacement dimension does "
-              "not match the mesh dimension.");
+            "not match the mesh dimension."
+        );
 
         validate_finite_vector(
-      displacementTrue,
+            displacementTrue, "The rotational-displacement-force displacement contains a "
-      "The rotational-displacement-force displacement contains a "
+                              "non-finite value."
-      "non-finite value.");
+        );
-}
+    }
 
-void validate_density(const mean_field::fem::FEM &f,
+    void validate_density(
-                      const mfem::Vector &density, const char *message) {
+        const mean_field::fem::FEM &f,
+        const mfem::Vector &density,
+        const char *message
+    ) {
         MFEM_VERIFY(density.Size() == f.densityFes->GetTrueVSize(), message);
         validate_finite_vector(density, message);
-}
+    }
 
-void apply_rotational_displacement_force_action(
+    void apply_rotational_displacement_force_action(
         const mean_field::fem::FEM &f,
         const mean_field::mapping::DomainMapper &domainMapper,
         const mean_field::physics::RigidRotation &rotation,
@@ -185,53 +210,55 @@ void apply_rotational_displacement_force_action(
         const mfem::Vector *baseDensityTrue,
         const mfem::Vector *densityVariationTrue,
         const mfem::Vector *displacementVariationTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &actionTrue) {
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &actionTrue
+    ) {
         validate_common_inputs(f, domainMapper, displacementTrue);
 
-  const bool needsBaseDensity =
+        const bool needsBaseDensity           = requestedAction == RotationalDisplacementForceAction::residual ||
-      requestedAction == RotationalDisplacementForceAction::residual ||
                                                 requestedAction == RotationalDisplacementForceAction::displacement ||
                                                 requestedAction == RotationalDisplacementForceAction::complete;
 
-  const bool needsDensityVariation =
+        const bool needsDensityVariation      = requestedAction == RotationalDisplacementForceAction::density ||
-      requestedAction == RotationalDisplacementForceAction::density ||
                                                 requestedAction == RotationalDisplacementForceAction::complete;
 
-  const bool needsDisplacementVariation =
+        const bool needsDisplacementVariation = requestedAction == RotationalDisplacementForceAction::displacement ||
-      requestedAction == RotationalDisplacementForceAction::displacement ||
                                                 requestedAction == RotationalDisplacementForceAction::complete;
 
         if (needsBaseDensity) {
-    MFEM_VERIFY(baseDensityTrue != nullptr,
+            MFEM_VERIFY(
-                "The rotational-displacement-force action requires a base "
+                baseDensityTrue != nullptr, "The rotational-displacement-force action requires a base "
-                "density.");
+                                            "density."
+            );
 
-    validate_density(
+            validate_density(f, *baseDensityTrue, "The rotational-displacement-force base density is invalid.");
-        f, *baseDensityTrue,
-        "The rotational-displacement-force base density is invalid.");
         }
 
         if (needsDensityVariation) {
-    MFEM_VERIFY(densityVariationTrue != nullptr,
+            MFEM_VERIFY(
-                "The rotational-displacement-force action requires a "
+                densityVariationTrue != nullptr, "The rotational-displacement-force action requires a "
-                "density variation.");
+                                                 "density variation."
+            );
 
-    validate_density(f, *densityVariationTrue,
+            validate_density(
+                f, *densityVariationTrue,
                 "The rotational-displacement-force density variation is "
-                     "invalid.");
+                "invalid."
+            );
         }
 
         if (needsDisplacementVariation) {
-    MFEM_VERIFY(displacementVariationTrue != nullptr &&
+            MFEM_VERIFY(
-                    displacementVariationTrue->Size() ==
+                displacementVariationTrue != nullptr &&
-                        f.displacementFes->GetTrueVSize(),
+                    displacementVariationTrue->Size() == f.displacementFes->GetTrueVSize(),
                 "The rotational-displacement-force displacement variation "
-                "is invalid.");
+                "is invalid."
+            );
 
             validate_finite_vector(
-        *displacementVariationTrue,
+                *displacementVariationTrue, "The rotational-displacement-force displacement variation "
-        "The rotational-displacement-force displacement variation "
+                                            "contains a non-finite value."
-        "contains a non-finite value.");
+            );
         }
 
         mfem::Vector baseDensityLocal;
@@ -250,15 +277,13 @@ void apply_rotational_displacement_force_action(
         true_to_local(*f.displacementFes, displacementTrue, displacementLocal);
 
         if (needsDisplacementVariation) {
-    true_to_local(*f.displacementFes, *displacementVariationTrue,
+            true_to_local(*f.displacementFes, *displacementVariationTrue, displacementVariationLocal);
-                  displacementVariationLocal);
         }
 
         mfem::Vector localAction(f.displacementFes->GetVSize());
         localAction = 0.0;
 
-  mean_field::mapping::DomainMapper::Workspace workspace(
+        mean_field::mapping::DomainMapper::Workspace workspace(f.mesh->Dimension());
-      f.mesh->Dimension());
 
         mfem::Array<int> densityDofs;
         mfem::Array<int> displacementDofs;
@@ -284,16 +309,15 @@ void apply_rotational_displacement_force_action(
 
         const int dimension                             = f.mesh->Dimension();
 
-  const mfem::Ordering::Type displacementOrdering =
+        const mfem::Ordering::Type displacementOrdering = f.displacementFes->GetOrdering();
-      f.displacementFes->GetOrdering();
 
         for (int elementId = 0; elementId < f.mesh->GetNE(); ++elementId) {
-    mfem::ElementTransformation *transformation =
+            mfem::ElementTransformation *transformation = f.mesh->GetElementTransformation(elementId);
-        f.mesh->GetElementTransformation(elementId);
 
-    MFEM_VERIFY(transformation != nullptr,
+            MFEM_VERIFY(
-                "The rotational-displacement-force kernel received a null "
+                transformation != nullptr, "The rotational-displacement-force kernel received a null "
-                "element transformation.");
+                                           "element transformation."
+            );
 
             if (is_vacuum_attribute(transformation->Attribute)) {
                 continue;
@@ -301,14 +325,11 @@ void apply_rotational_displacement_force_action(
 
             const mfem::FiniteElement &densityElement          = *f.densityFes->GetFE(elementId);
 
-    const mfem::FiniteElement &displacementElement =
+            const mfem::FiniteElement &displacementElement     = *f.displacementFes->GetFE(elementId);
-        *f.displacementFes->GetFE(elementId);
 
-    const mfem::FiniteElement &compactificationElement =
+            const mfem::FiniteElement &compactificationElement = *f.compactificationFes->GetFE(elementId);
-        *f.compactificationFes->GetFE(elementId);
 
-    mfem::DofTransformation *densityDofTransformation =
+            mfem::DofTransformation *densityDofTransformation  = f.densityFes->GetElementDofs(elementId, densityDofs);
-        f.densityFes->GetElementDofs(elementId, densityDofs);
 
             mfem::DofTransformation *displacementDofTransformation =
                 f.displacementFes->GetElementVDofs(elementId, displacementDofs);
@@ -327,12 +348,10 @@ void apply_rotational_displacement_force_action(
             displacementLocal.GetSubVector(displacementDofs, elementDisplacement);
 
             if (needsDisplacementVariation) {
-      displacementVariationLocal.GetSubVector(displacementDofs,
+                displacementVariationLocal.GetSubVector(displacementDofs, elementDisplacementVariation);
-                                              elementDisplacementVariation);
             }
 
-    f.compactificationCoordinate->GetSubVector(compactificationDofs,
+            f.compactificationCoordinate->GetSubVector(compactificationDofs, elementCompactification);
-                                               elementCompactification);
 
             if (densityDofTransformation != nullptr) {
                 if (needsBaseDensity) {
@@ -348,42 +367,42 @@ void apply_rotational_displacement_force_action(
                 displacementDofTransformation->InvTransformPrimal(elementDisplacement);
 
                 if (needsDisplacementVariation) {
-        displacementDofTransformation->InvTransformPrimal(
+                    displacementDofTransformation->InvTransformPrimal(elementDisplacementVariation);
-            elementDisplacementVariation);
                 }
             }
 
             if (compactificationDofTransformation != nullptr) {
-      compactificationDofTransformation->InvTransformPrimal(
+                compactificationDofTransformation->InvTransformPrimal(elementCompactification);
-          elementCompactification);
             }
 
             const mean_field::mapping::ElementDisplacementData displacementData =
-        mean_field::mapping::ElementDisplacementDataFromElementVDofs(
+                mean_field::mapping::ElementDisplacementDataFromElementVDofs(displacementElement, elementDisplacement);
-            displacementElement, elementDisplacement);
 
             const mean_field::mapping::ElementCompactificationData compactificationData(
-        compactificationElement, elementCompactification);
+                compactificationElement, elementCompactification
+            );
 
             const mean_field::mapping::ElementMappingData mappingData{
-        .displacement = displacementData,
+                .displacement = displacementData, .compactification = compactificationData
-        .compactification = compactificationData};
+            };
 
-    std::optional<mean_field::mapping::ElementDisplacementData>
+            std::optional<mean_field::mapping::ElementDisplacementData> displacementVariationData;
-        displacementVariationData;
 
             if (needsDisplacementVariation) {
                 displacementVariationData.emplace(
                     mean_field::mapping::ElementDisplacementDataFromElementVDofs(
-              displacementElement, elementDisplacementVariation));
+                        displacementElement, elementDisplacementVariation
+                    )
+                );
             }
 
             const int scalarDisplacementDofCount = displacementElement.GetDof();
 
-    MFEM_VERIFY(displacementDofs.Size() ==
+            MFEM_VERIFY(
-                    scalarDisplacementDofCount * dimension,
+                displacementDofs.Size() == scalarDisplacementDofCount * dimension,
                 "The rotational-displacement-force element displacement "
-                "vector has the wrong size.");
+                "vector has the wrong size."
+            );
 
             densityShape.SetSize(densityElement.GetDof());
             displacementShape.SetSize(scalarDisplacementDofCount);
@@ -396,42 +415,39 @@ void apply_rotational_displacement_force_action(
             elementAction.SetSize(displacementDofs.Size());
             elementAction = 0.0;
 
-    const mfem::IntegrationRule &integrationRule = get_rotation_force_rule(
+            const mfem::IntegrationRule &integrationRule =
-        f, densityElement, displacementElement, *transformation);
+                get_rotation_force_rule(f, densityElement, displacementElement, *transformation);
 
-    for (int quadratureIndex = 0;
+            for (int quadratureIndex = 0; quadratureIndex < integrationRule.GetNPoints(); ++quadratureIndex) {
-         quadratureIndex < integrationRule.GetNPoints(); ++quadratureIndex) {
+                const mfem::IntegrationPoint &integrationPoint = integrationRule.IntPoint(quadratureIndex);
-      const mfem::IntegrationPoint &integrationPoint =
-          integrationRule.IntPoint(quadratureIndex);
 
                 transformation->SetIntPoint(&integrationPoint);
 
-      const mean_field::mapping::MappingStatus mappingStatus =
+                const mean_field::mapping::MappingStatus mappingStatus = domainMapper.EvaluateVolume(
-          domainMapper.EvaluateVolume(mappingData, *transformation,
+                    mappingData, *transformation, integrationPoint, workspace, mappingContext
-                                      integrationPoint, workspace,
+                );
-                                      mappingContext);
 
-      MFEM_VERIFY(mappingStatus == mean_field::mapping::MappingStatus::valid,
+                MFEM_VERIFY(
+                    mappingStatus == mean_field::mapping::MappingStatus::valid,
                     "Stateless mapping failed in the rotational-"
                     "displacement-force kernel. Element: "
-                      << elementId
+                        << elementId << ", attribute: " << transformation->Attribute
-                      << ", attribute: " << transformation->Attribute
+                        << ", quadrature point: " << quadratureIndex << ", status: " << static_cast<int>(mappingStatus)
-                      << ", quadrature point: " << quadratureIndex
+                );
-                      << ", status: " << static_cast<int>(mappingStatus));
 
                 if (needsDisplacementVariation) {
-        const mean_field::mapping::MappingStatus variationStatus =
+                    const mean_field::mapping::MappingStatus variationStatus = domainMapper.EvaluateVolumeVariation(
-            domainMapper.EvaluateVolumeVariation(
+                        mappingData, *displacementVariationData, *transformation, integrationPoint, mappingContext,
-                mappingData, *displacementVariationData, *transformation,
+                        workspace, mappingVariation
-                integrationPoint, mappingContext, workspace, mappingVariation);
+                    );
 
                     MFEM_VERIFY(
                         variationStatus == mean_field::mapping::MappingStatus::valid,
                         "Stateless mapping variation failed in the "
                         "rotational-displacement-force kernel. Element: "
-                << elementId << ", attribute: " << transformation->Attribute
+                            << elementId << ", attribute: " << transformation->Attribute << ", quadrature point: "
-                << ", quadrature point: " << quadratureIndex
+                            << quadratureIndex << ", status: " << static_cast<int>(variationStatus)
-                << ", status: " << static_cast<int>(variationStatus));
+                    );
                 }
 
                 densityElement.CalcShape(integrationPoint, densityShape);
@@ -449,16 +465,15 @@ void apply_rotational_displacement_force_action(
                     densityVariationValue = elementDensityVariation * densityShape;
                 }
 
-      rotation.potential_gradient(mappingContext.mapping.physical_position,
+                rotation.potential_gradient(mappingContext.mapping.physical_position, potentialGradient);
-                                  potentialGradient);
 
                 centrifugalAcceleration = potentialGradient;
                 centrifugalAcceleration *= -1.0;
 
                 if (needsDisplacementVariation) {
                     rotation.potential_gradient_directional_derivative(
-            mappingVariation.mapping.physical_position_variation,
+                        mappingVariation.mapping.physical_position_variation, potentialGradientVariation
-            potentialGradientVariation);
+                    );
 
                     centrifugalAccelerationVariation = potentialGradientVariation;
 
@@ -470,38 +485,37 @@ void apply_rotational_displacement_force_action(
                 weightedForce = 0.0;
 
                 if (requestedAction == RotationalDisplacementForceAction::residual) {
-        weightedForce.Add(baseDensityValue * mappingContext.quadrature.weight,
+                    weightedForce.Add(baseDensityValue * mappingContext.quadrature.weight, centrifugalAcceleration);
-                          centrifugalAcceleration);
                 } else {
                     if (needsDensityVariation) {
-          weightedForce.Add(densityVariationValue *
+                        weightedForce.Add(
-                                mappingContext.quadrature.weight,
+                            densityVariationValue * mappingContext.quadrature.weight, centrifugalAcceleration
-                            centrifugalAcceleration);
+                        );
                     }
 
                     if (needsDisplacementVariation) {
-          weightedForce.Add(baseDensityValue * mappingContext.quadrature.weight,
+                        weightedForce.Add(
-                            centrifugalAccelerationVariation);
+                            baseDensityValue * mappingContext.quadrature.weight, centrifugalAccelerationVariation
+                        );
 
-          weightedForce.Add(baseDensityValue *
+                        weightedForce.Add(
-                                mappingVariation.weight_variation,
+                            baseDensityValue * mappingVariation.weight_variation, centrifugalAcceleration
-                            centrifugalAcceleration);
+                        );
                     }
                 }
 
-      for (int scalarDof = 0; scalarDof < scalarDisplacementDofCount;
+                for (int scalarDof = 0; scalarDof < scalarDisplacementDofCount; ++scalarDof) {
-           ++scalarDof) {
                     for (int component = 0; component < dimension; ++component) {
-          const int vectorDof =
+                        const int vectorDof = vector_dof_index(
-              vector_dof_index(displacementOrdering, scalarDof, component,
+                            displacementOrdering, scalarDof, component, scalarDisplacementDofCount, dimension
-                               scalarDisplacementDofCount, dimension);
+                        );
 
-          const double contribution =
+                        const double contribution = displacementShape(scalarDof) * weightedForce(component);
-              displacementShape(scalarDof) * weightedForce(component);
 
-          MFEM_VERIFY(std::isfinite(contribution),
+                        MFEM_VERIFY(
-                      "The rotational-displacement-force kernel "
+                            std::isfinite(contribution), "The rotational-displacement-force kernel "
-                      "encountered a non-finite contribution.");
+                                                         "encountered a non-finite contribution."
+                        );
 
                         elementAction(vectorDof) += contribution;
                     }
@@ -516,49 +530,66 @@ void apply_rotational_displacement_force_action(
         }
 
         local_to_true(*f.displacementFes, localAction, actionTrue);
-}
+    }
 } // namespace
 
 namespace mean_field::operators::kernels {
-void apply_rotational_displacement_force_residual(
+    void apply_rotational_displacement_force_residual(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
-    const physics::RigidRotation &rotation, const mfem::Vector &densityTrue,
+        const mapping::DomainMapper &domainMapper,
-    const mfem::Vector &displacementTrue, mfem::Vector &residualTrue) {
+        const physics::RigidRotation &rotation,
+        const mfem::Vector &densityTrue,
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &residualTrue
+    ) {
         apply_rotational_displacement_force_action(
-      f, domainMapper, rotation, RotationalDisplacementForceAction::residual,
+            f, domainMapper, rotation, RotationalDisplacementForceAction::residual, &densityTrue, nullptr, nullptr,
-      &densityTrue, nullptr, nullptr, displacementTrue, residualTrue);
+            displacementTrue, residualTrue
-}
+        );
+    }
 
-void apply_rotational_displacement_force_density_action(
+    void apply_rotational_displacement_force_density_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
+        const mapping::DomainMapper &domainMapper,
         const physics::RigidRotation &rotation,
         const mfem::Vector &densityVariationTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &actionTrue) {
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &actionTrue
+    ) {
         apply_rotational_displacement_force_action(
-      f, domainMapper, rotation, RotationalDisplacementForceAction::density,
+            f, domainMapper, rotation, RotationalDisplacementForceAction::density, nullptr, &densityVariationTrue,
-      nullptr, &densityVariationTrue, nullptr, displacementTrue, actionTrue);
+            nullptr, displacementTrue, actionTrue
-}
+        );
+    }
 
-void apply_rotational_displacement_force_displacement_action(
+    void apply_rotational_displacement_force_displacement_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
-    const physics::RigidRotation &rotation, const mfem::Vector &baseDensityTrue,
+        const mapping::DomainMapper &domainMapper,
+        const physics::RigidRotation &rotation,
+        const mfem::Vector &baseDensityTrue,
         const mfem::Vector &displacementVariationTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &actionTrue) {
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &actionTrue
+    ) {
         apply_rotational_displacement_force_action(
-      f, domainMapper, rotation,
+            f, domainMapper, rotation, RotationalDisplacementForceAction::displacement, &baseDensityTrue, nullptr,
-      RotationalDisplacementForceAction::displacement, &baseDensityTrue,
+            &displacementVariationTrue, displacementTrue, actionTrue
-      nullptr, &displacementVariationTrue, displacementTrue, actionTrue);
+        );
-}
+    }
 
-void apply_rotational_displacement_force_complete_action(
+    void apply_rotational_displacement_force_complete_action(
-    const fem::FEM &f, const mapping::DomainMapper &domainMapper,
+        const fem::FEM &f,
-    const physics::RigidRotation &rotation, const mfem::Vector &baseDensityTrue,
+        const mapping::DomainMapper &domainMapper,
+        const physics::RigidRotation &rotation,
+        const mfem::Vector &baseDensityTrue,
         const mfem::Vector &densityVariationTrue,
         const mfem::Vector &displacementVariationTrue,
-    const mfem::Vector &displacementTrue, mfem::Vector &actionTrue) {
+        const mfem::Vector &displacementTrue,
+        mfem::Vector &actionTrue
+    ) {
         apply_rotational_displacement_force_action(
-      f, domainMapper, rotation, RotationalDisplacementForceAction::complete,
+            f, domainMapper, rotation, RotationalDisplacementForceAction::complete, &baseDensityTrue,
-      &baseDensityTrue, &densityVariationTrue, &displacementVariationTrue,
+            &densityVariationTrue, &displacementVariationTrue, displacementTrue, actionTrue
-      displacementTrue, actionTrue);
+        );
-}
+    }
 } // namespace mean_field::operators::kernels

libmeanfield/impl/operators/prepared_barotropic_closure.cpp

@@ -401,8 +401,14 @@ namespace mean_field::operators {
                 const double density          = elementBaseDensity * densityShape;
                 const double enthalpy         = elementBaseEnthalpy * enthalpyShape;
                 const double quadratureWeight = mappingContext.quadrature.weight;
-                const double eosDensity         = m_equationOfState.density_from_enthalpy(enthalpy);
+                const eos::SpecificEnthalpyValue specificEnthalpy{enthalpy};
-                const double enthalpyDerivative = m_equationOfState.density_derivative_from_enthalpy(enthalpy);
+                const double eosDensity =
+                    eos::evaluate<eos::quantity::Density>(m_equationOfState, specificEnthalpy).value();
+                const double enthalpyDerivative =
+                    eos::partialDerivative<eos::quantity::Density, eos::quantity::SpecificEnthalpy>(
+                        m_equationOfState, specificEnthalpy
+                    )
+                        .value();
 
                 MFEM_VERIFY(
                     std::isfinite(quadratureWeight) && quadratureWeight > 0.0 && std::isfinite(eosDensity) &&

libmeanfield/impl/operators/prepared_gravity_source.cpp

@@ -9,128 +9,133 @@ module mean_field;
 import :operators.prepared_gravity_source;
 
 namespace {
-using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
+    using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
 
-int get_operator_height(const mean_field::fem::FEM &f) {
+    int get_operator_height(const mean_field::fem::FEM &f) {
-  MFEM_VERIFY(f.gravityPotentialFes != nullptr,
+        MFEM_VERIFY(
-              "PreparedMappedGravitySourceOperator requires the "
+            f.gravityPotentialFes != nullptr, "PreparedMappedGravitySourceOperator requires the "
                                               "gravity-potential "
-              "finite-element space.");
+                                              "finite-element space."
-  return mean_field::field::make_field_dof_map<mean_field::field::Gravity,
+        );
-                                               DomainSchema>(
+        return mean_field::field::make_field_dof_map<mean_field::field::Gravity, DomainSchema>(*f.gravityPotentialFes)
-             *f.gravityPotentialFes)
             .reduced_size();
-}
+    }
 
-int get_operator_width(const mean_field::fem::FEM &f) {
+    int get_operator_width(const mean_field::fem::FEM &f) {
-  MFEM_VERIFY(f.densityFes != nullptr,
+        MFEM_VERIFY(
-              "PreparedMappedGravitySourceOperator requires the density "
+            f.densityFes != nullptr, "PreparedMappedGravitySourceOperator requires the density "
-              "finite-element space.");
+                                     "finite-element space."
-  return mean_field::field::make_field_dof_map<mean_field::field::Density,
+        );
-                                               DomainSchema>(*f.densityFes)
+        return mean_field::field::make_field_dof_map<mean_field::field::Density, DomainSchema>(*f.densityFes)
             .reduced_size();
-}
+    }
 
-void true_to_local(const mfem::ParFiniteElementSpace &finite_element_space,
+    void true_to_local(
+        const mfem::ParFiniteElementSpace &finite_element_space,
         const mfem::Vector &true_vector,
-                   mfem::Vector &local_vector) {
+        mfem::Vector &local_vector
+    ) {
         local_vector.SetSize(finite_element_space.GetVSize());
 
-  const mfem::Operator *prolongation =
+        const mfem::Operator *prolongation = finite_element_space.GetProlongationMatrix();
-      finite_element_space.GetProlongationMatrix();
 
         if (prolongation != nullptr) {
             prolongation->Mult(true_vector, local_vector);
         } else {
             local_vector = true_vector;
         }
-}
+    }
 
-void local_to_true(const mfem::ParFiniteElementSpace &finite_element_space,
+    void local_to_true(
+        const mfem::ParFiniteElementSpace &finite_element_space,
         const mfem::Vector &local_vector,
-                   mfem::Vector &true_vector) {
+        mfem::Vector &true_vector
-  MFEM_VERIFY(local_vector.Size() == finite_element_space.GetVSize(),
+    ) {
-              "Local vector has the wrong size.");
+        MFEM_VERIFY(local_vector.Size() == finite_element_space.GetVSize(), "Local vector has the wrong size.");
 
         true_vector.SetSize(finite_element_space.GetTrueVSize());
         true_vector                        = 0.0;
 
-  const mfem::Operator *prolongation =
+        const mfem::Operator *prolongation = finite_element_space.GetProlongationMatrix();
-      finite_element_space.GetProlongationMatrix();
 
         if (prolongation != nullptr) {
             prolongation->MultTranspose(local_vector, true_vector);
         } else {
             true_vector = local_vector;
         }
-}
+    }
 
-const mfem::IntegrationRule &
+    const mfem::IntegrationRule &get_source_rule(
-get_source_rule(const mean_field::fem::FEM &f,
+        const mean_field::fem::FEM &f,
         const mfem::FiniteElement &density_element,
         const mfem::FiniteElement &potential_element,
-                const mfem::ElementTransformation &transformation) {
+        const mfem::ElementTransformation &transformation
+    ) {
         using GravityField = mean_field::field::Field<mean_field::field::Gravity>;
-  MFEM_VERIFY(density_element.GetOrder() ==
+        MFEM_VERIFY(
-                  mean_field::field::Density::Scalar::familyOrder,
+            density_element.GetOrder() == mean_field::field::Density::Scalar::familyOrder,
             "The prepared source trial element does not match the registered "
-              "density field.");
+            "density field."
-  MFEM_VERIFY(potential_element.GetOrder() ==
+        );
-                  mean_field::field::Gravity::Potential::familyOrder,
+        MFEM_VERIFY(
+            potential_element.GetOrder() == mean_field::field::Gravity::Potential::familyOrder,
             "The prepared source test element does not match the registered "
-              "gravity potential.");
+            "gravity potential."
-  const mean_field::quadrature::Query query = GravityField::make_query<
+        );
-      mean_field::field::Gravity::Form::SourceProjection>(
+        const mean_field::quadrature::Query query =
-      mean_field::quadrature::QuadratureRole::discretization,
+            GravityField::make_query<mean_field::field::Gravity::Form::SourceProjection>(
-      transformation.OrderW(), {}, mean_field::utils::DOMAINS::STELLAR,
+                mean_field::quadrature::QuadratureRole::discretization, transformation.OrderW(), {},
-      mean_field::quadrature::MappingKind::general);
+                mean_field::utils::DOMAINS::STELLAR, mean_field::quadrature::MappingKind::general
+            );
 
-  return *f.quadratureFactory->get(query, transformation.GetGeometryType())
+        return *f.quadratureFactory->get(query, transformation.GetGeometryType()).integration_rule;
-              .integration_rule;
+    }
-}
 
-class FrozenMappedGravitySourceCoefficient final : public mfem::Coefficient {
+    class FrozenMappedGravitySourceCoefficient final : public mfem::Coefficient {
-public:
+    public:
         FrozenMappedGravitySourceCoefficient(
             const mean_field::fem::FEM &f,
             const mean_field::mapping::DomainMapper &domain_mapper,
-      const mfem::Vector &displacement_true)
+            const mfem::Vector &displacement_true
-      : m_fem(f), m_domain_mapper(domain_mapper),
+        )
+            : m_fem(f),
+              m_domain_mapper(domain_mapper),
               m_workspace(domain_mapper.GetDimension()) {
-    true_to_local(*m_fem.displacementFes, displacement_true,
+            true_to_local(*m_fem.displacementFes, displacement_true, m_displacement_local);
-                  m_displacement_local);
         }
 
-  double Eval(mfem::ElementTransformation &transformation,
+        double Eval(
-              const mfem::IntegrationPoint &integration_point) override {
+            mfem::ElementTransformation &transformation,
+            const mfem::IntegrationPoint &integration_point
+        ) override {
             transformation.SetIntPoint(&integration_point);
 
             const int element_id = transformation.ElementNo;
-    MFEM_VERIFY(element_id >= 0 && element_id < m_fem.mesh->GetNE(),
+            MFEM_VERIFY(
+                element_id >= 0 && element_id < m_fem.mesh->GetNE(),
                 "Mapped gravity source coefficient received an invalid element "
-                "ID.");
+                "ID."
-    if (DomainSchema::template attribute_belongs_to<
+            );
-            mean_field::utils::domain::Vacuum>(transformation.Attribute)) {
+            if (DomainSchema::template attribute_belongs_to<mean_field::utils::domain::Vacuum>(
+                    transformation.Attribute
+                )) {
                 return 0.0;
             }
 
             LoadElement(element_id);
             const mean_field::mapping::ElementMappingData mapping_data{
-        .displacement = *m_displacement_data,
+                .displacement = *m_displacement_data, .compactification = *m_compactification_data
-        .compactification = *m_compactification_data};
+            };
 
             mean_field::mapping::VolumeMappingContext mapping_context;
 
-    const mean_field::mapping::MappingStatus status =
+            const mean_field::mapping::MappingStatus status = m_domain_mapper.EvaluateVolume(
-        m_domain_mapper.EvaluateVolume(mapping_data, transformation,
+                mapping_data, transformation, integration_point, m_workspace, mapping_context
-                                       integration_point, m_workspace,
+            );
-                                       mapping_context);
 
             if (status != mean_field::mapping::MappingStatus::valid) {
-      const mfem::FiniteElement &displacement_element =
+                const mfem::FiniteElement &displacement_element     = *m_fem.displacementFes->GetFE(element_id);
-          *m_fem.displacementFes->GetFE(element_id);
+                const mfem::FiniteElement &compactification_element = *m_fem.compactificationFes->GetFE(element_id);
-      const mfem::FiniteElement &compactification_element =
-          *m_fem.compactificationFes->GetFE(element_id);
 
                 mfem::Vector displacement_shape(displacement_element.GetDof());
                 mfem::Vector compactification_shape(compactification_element.GetDof());
@@ -138,85 +143,74 @@ public:
                 mfem::Vector displacement_value(m_domain_mapper.GetDimension());
 
                 displacement_element.CalcShape(integration_point, displacement_shape);
-      compactification_element.CalcShape(integration_point,
+                compactification_element.CalcShape(integration_point, compactification_shape);
-                                         compactification_shape);
                 transformation.Transform(integration_point, reference_position);
-      m_displacement_data->GetDofMatrix().MultTranspose(displacement_shape,
+                m_displacement_data->GetDofMatrix().MultTranspose(displacement_shape, displacement_value);
-                                                        displacement_value);
 
-      const double compactification_coordinate =
+                const double compactification_coordinate = m_compactification_data->GetDofs() * compactification_shape;
-          m_compactification_data->GetDofs() * compactification_shape;
 
                 MFEM_ABORT(
                     "Stateless domain mapping failed while preparing the "
                     "gravity "
                     "source operator."
-          << "\nMapping status = " << static_cast<int>(status)
+                    << "\nMapping status = " << static_cast<int>(status) << "\nElement ID = " << element_id
-          << "\nElement ID = " << element_id
                     << "\nElement attribute = " << transformation.Attribute
-          << "\nIntegration-point index = " << integration_point.index
+                    << "\nIntegration-point index = " << integration_point.index << "\nIntegration point = <"
-          << "\nIntegration point = <" << integration_point.x << ", "
+                    << integration_point.x << ", " << integration_point.y << ", " << integration_point.z << ">"
-          << integration_point.y << ", " << integration_point.z << ">"
+                    << "\nReference position = <" << reference_position(0) << ", " << reference_position(1) << ", "
-          << "\nReference position = <" << reference_position(0) << ", "
+                    << reference_position(2) << ">"
-          << reference_position(1) << ", " << reference_position(2) << ">"
+                    << "\nReference radius = " << reference_position.Norml2() << "\nDisplacement value = <"
-          << "\nReference radius = " << reference_position.Norml2()
+                    << displacement_value(0) << ", " << displacement_value(1) << ", " << displacement_value(2) << ">"
-          << "\nDisplacement value = <" << displacement_value(0) << ", "
-          << displacement_value(1) << ", " << displacement_value(2) << ">"
                     << "\nDisplacement magnitude = " << displacement_value.Norml2()
                     << "\nCompactification coordinate = " << compactification_coordinate
-          << "\nDisplacement ordering = "
+                    << "\nDisplacement ordering = " << static_cast<int>(m_fem.displacementFes->GetOrdering())
-          << static_cast<int>(m_fem.displacementFes->GetOrdering()));
+                );
             }
-    const double mapping_determinant =
+            const double mapping_determinant = mapping_context.mapping.mapping_determinant;
-        mapping_context.mapping.mapping_determinant;
+            MFEM_VERIFY(
-    MFEM_VERIFY(std::isfinite(mapping_determinant) && mapping_determinant > 0.0,
+                std::isfinite(mapping_determinant) && mapping_determinant > 0.0,
                 "Prepared gravity source operator encountered a non-positive "
                 "or "
-                "non-finite mapping determinant.");
+                "non-finite mapping determinant."
+            );
 
             return 4.0 * std::numbers::pi * mean_field::utils::G * mapping_determinant;
         }
 
-private:
+    private:
         void LoadElement(const int element_id) {
             if (element_id == m_cached_element_id) {
                 return;
             }
 
-    const mfem::FiniteElement &displacement_element =
+            const mfem::FiniteElement &displacement_element     = *m_fem.displacementFes->GetFE(element_id);
-        *m_fem.displacementFes->GetFE(element_id);
+            const mfem::FiniteElement &compactification_element = *m_fem.compactificationFes->GetFE(element_id);
-    const mfem::FiniteElement &compactification_element =
-        *m_fem.compactificationFes->GetFE(element_id);
 
             mfem::DofTransformation *displacement_dof_transformation =
                 m_fem.displacementFes->GetElementVDofs(element_id, m_displacement_dofs);
             mfem::DofTransformation *compactification_dof_transformation =
-        m_fem.compactificationFes->GetElementDofs(element_id,
+                m_fem.compactificationFes->GetElementDofs(element_id, m_compactification_dofs);
-                                                  m_compactification_dofs);
 
-    m_displacement_local.GetSubVector(m_displacement_dofs,
+            m_displacement_local.GetSubVector(m_displacement_dofs, m_element_displacement);
-                                      m_element_displacement);
+            m_fem.compactificationCoordinate->GetSubVector(m_compactification_dofs, m_element_compactification);
-    m_fem.compactificationCoordinate->GetSubVector(m_compactification_dofs,
-                                                   m_element_compactification);
 
             if (displacement_dof_transformation != nullptr) {
-      displacement_dof_transformation->InvTransformPrimal(
+                displacement_dof_transformation->InvTransformPrimal(m_element_displacement);
-          m_element_displacement);
             }
 
             if (compactification_dof_transformation != nullptr) {
-      compactification_dof_transformation->InvTransformPrimal(
+                compactification_dof_transformation->InvTransformPrimal(m_element_compactification);
-          m_element_compactification);
             }
 
-    m_displacement_data =
+            m_displacement_data = std::make_unique<mean_field::mapping::ElementDisplacementData>(
-        std::make_unique<mean_field::mapping::ElementDisplacementData>(
                 mean_field::mapping::ElementDisplacementDataFromElementVDofs(
-                displacement_element, m_element_displacement));
+                    displacement_element, m_element_displacement
+                )
+            );
 
-    m_compactification_data =
+            m_compactification_data = std::make_unique<mean_field::mapping::ElementCompactificationData>(
-        std::make_unique<mean_field::mapping::ElementCompactificationData>(
+                compactification_element, m_element_compactification
-            compactification_element, m_element_compactification);
+            );
 
             m_cached_element_id = element_id;
         }
@@ -232,71 +226,89 @@ private:
         mfem::Vector m_element_displacement;
         mfem::Vector m_element_compactification;
 
-  std::unique_ptr<mean_field::mapping::ElementDisplacementData>
+        std::unique_ptr<mean_field::mapping::ElementDisplacementData> m_displacement_data;
-      m_displacement_data;
+        std::unique_ptr<mean_field::mapping::ElementCompactificationData> m_compactification_data;
-  std::unique_ptr<mean_field::mapping::ElementCompactificationData>
-      m_compactification_data;
 
         mean_field::mapping::DomainMapper::Workspace m_workspace;
         int m_cached_element_id{-1};
-};
+    };
 } // namespace
 
 namespace mean_field::operators {
-PreparedMappedGravitySourceOperator::PreparedMappedGravitySourceOperator(
+    PreparedMappedGravitySourceOperator::PreparedMappedGravitySourceOperator(
-    const fem::FEM &f, const mapping::DomainMapper &domain_mapper)
+        const fem::FEM &f,
-    : Operator(get_operator_height(f), get_operator_width(f)), m_fem(f),
+        const mapping::DomainMapper &domain_mapper
+    )
+        : Operator(
+              get_operator_height(f),
+              get_operator_width(f)
+          ),
+          m_fem(f),
           m_domain_mapper(domain_mapper),
-      m_density_map(field::make_field_dof_map<field::Density, DomainSchema>(
+          m_density_map(
-          *f.densityFes)),
+              field::make_field_dof_map<
-      m_potential_map(field::make_field_dof_map<field::Gravity, DomainSchema>(
+                  field::Density,
-          *f.gravityPotentialFes)),
+                  DomainSchema>(*f.densityFes)
+          ),
+          m_potential_map(
+              field::make_field_dof_map<
+                  field::Gravity,
+                  DomainSchema>(*f.gravityPotentialFes)
+          ),
           m_displacement_map(
-          field::make_field_dof_map<field::Displacement, DomainSchema>(
+              field::make_field_dof_map<
-              *f.displacementFes)) {
+                  field::Displacement,
-  MFEM_VERIFY(f.mesh != nullptr,
+                  DomainSchema>(*f.displacementFes)
-              "PreparedMappedGravitySourceOperator requires a mesh.");
+          ) {
-  MFEM_VERIFY(f.densityFes != nullptr,
+        MFEM_VERIFY(f.mesh != nullptr, "PreparedMappedGravitySourceOperator requires a mesh.");
-              "PreparedMappedGravitySourceOperator requires the density "
-              "finite-element space.");
-  MFEM_VERIFY(f.gravityPotentialFes != nullptr,
-              "PreparedMappedGravitySourceOperator requires the "
-              "gravity-potential "
-              "finite-element space.");
-  MFEM_VERIFY(f.displacementFes != nullptr,
-              "PreparedMappedGravitySourceOperator requires "
-              "the displacement finite-element space.");
         MFEM_VERIFY(
-      f.compactificationFes != nullptr,
+            f.densityFes != nullptr, "PreparedMappedGravitySourceOperator requires the density "
-      "PreparedMappedGravitySourceOperator requires the compactification "
+                                     "finite-element space."
-      "finite-element space.");
+        );
+        MFEM_VERIFY(
+            f.gravityPotentialFes != nullptr, "PreparedMappedGravitySourceOperator requires the "
+                                              "gravity-potential "
+                                              "finite-element space."
+        );
+        MFEM_VERIFY(
+            f.displacementFes != nullptr, "PreparedMappedGravitySourceOperator requires "
+                                          "the displacement finite-element space."
+        );
+        MFEM_VERIFY(
+            f.compactificationFes != nullptr, "PreparedMappedGravitySourceOperator requires the compactification "
+                                              "finite-element space."
+        );
         MFEM_VERIFY(
             f.compactificationCoordinate != nullptr,
             "PreparedMappedGravitySourceOperator requires the compactification "
-      "coordinate.");
+            "coordinate."
-  MFEM_VERIFY(f.quadratureFactory != nullptr,
+        );
-              "PreparedMappedGravitySourceOperator "
+        MFEM_VERIFY(
-              "requires the quadrature-rule factory.");
+            f.quadratureFactory != nullptr, "PreparedMappedGravitySourceOperator "
-  MFEM_VERIFY(domain_mapper.GetDimension() == f.mesh->Dimension(),
+                                            "requires the quadrature-rule factory."
+        );
+        MFEM_VERIFY(
+            domain_mapper.GetDimension() == f.mesh->Dimension(),
             "The stateless domain-mapper dimension does not match the mesh "
-              "dimension.");
+            "dimension."
+        );
 
-  m_stellar_marker =
+        m_stellar_marker = utils::domain::make_attribute_marker<utils::domain::Stellar, DomainSchema>(*f.mesh);
-      utils::domain::make_attribute_marker<utils::domain::Stellar,
+    }
-                                           DomainSchema>(*f.mesh);
-}
 
-void PreparedMappedGravitySourceOperator::Prepare(
+    void PreparedMappedGravitySourceOperator::Prepare(const mfem::Vector &displacement) {
-    const mfem::Vector &displacement) {
+        MFEM_VERIFY(
-  MFEM_VERIFY(displacement.Size() == m_displacement_map.reduced_size(),
+            displacement.Size() == m_displacement_map.reduced_size(),
             "PreparedMappedGravitySourceOperator received a displacement "
             "vector "
-              "with the wrong size.");
+            "with the wrong size."
+        );
 
         for (int i = 0; i < displacement.Size(); ++i) {
-    MFEM_VERIFY(std::isfinite(displacement(i)),
+            MFEM_VERIFY(
-                "PreparedMappedGravitySourceOperator received a non-finite "
+                std::isfinite(displacement(i)), "PreparedMappedGravitySourceOperator received a non-finite "
-                "displacement value.");
+                                                "displacement value."
+            );
         }
 
         m_is_prepared = false;
@@ -305,14 +317,12 @@ void PreparedMappedGravitySourceOperator::Prepare(
         m_elements.clear();
         m_elements.reserve(m_fem.mesh->GetNE());
 
-  FrozenMappedGravitySourceCoefficient source_coefficient(
+        FrozenMappedGravitySourceCoefficient source_coefficient(m_fem, m_domain_mapper, m_displacement_true);
-      m_fem, m_domain_mapper, m_displacement_true);
 
         for (int element_id = 0; element_id < m_fem.mesh->GetNE(); ++element_id) {
             const int attribute = m_fem.mesh->GetAttribute(element_id);
 
-    if (attribute <= 0 || attribute > m_stellar_marker.Size() ||
+            if (attribute <= 0 || attribute > m_stellar_marker.Size() || m_stellar_marker[attribute - 1] == 0) {
-        m_stellar_marker[attribute - 1] == 0) {
                 continue;
             }
 
@@ -321,24 +331,19 @@ void PreparedMappedGravitySourceOperator::Prepare(
 
             data.element_id                 = element_id;
 
-    data.density_dof_transformation =
+            data.density_dof_transformation = m_fem.densityFes->GetElementDofs(element_id, data.density_dofs);
-        m_fem.densityFes->GetElementDofs(element_id, data.density_dofs);
 
             data.potential_dof_transformation =
-        m_fem.gravityPotentialFes->GetElementDofs(element_id,
+                m_fem.gravityPotentialFes->GetElementDofs(element_id, data.potential_dofs);
-                                                  data.potential_dofs);
 
-    const mfem::FiniteElement &density_element =
+            const mfem::FiniteElement &density_element   = *m_fem.densityFes->GetFE(element_id);
-        *m_fem.densityFes->GetFE(element_id);
 
-    const mfem::FiniteElement &potential_element =
+            const mfem::FiniteElement &potential_element = *m_fem.gravityPotentialFes->GetFE(element_id);
-        *m_fem.gravityPotentialFes->GetFE(element_id);
 
-    mfem::ElementTransformation &transformation =
+            mfem::ElementTransformation &transformation  = *m_fem.mesh->GetElementTransformation(element_id);
-        *m_fem.mesh->GetElementTransformation(element_id);
 
-    const mfem::IntegrationRule &integration_rule = get_source_rule(
+            const mfem::IntegrationRule &integration_rule =
-        m_fem, density_element, potential_element, transformation);
+                get_source_rule(m_fem, density_element, potential_element, transformation);
 
             const int quadrature_point_count = integration_rule.GetNPoints();
 
@@ -355,10 +360,8 @@ void PreparedMappedGravitySourceOperator::Prepare(
             mfem::Vector density_shape(density_dof_count);
             mfem::Vector potential_shape(potential_dof_count);
 
-    for (int quadrature_point = 0; quadrature_point < quadrature_point_count;
+            for (int quadrature_point = 0; quadrature_point < quadrature_point_count; ++quadrature_point) {
-         ++quadrature_point) {
+                const mfem::IntegrationPoint &integration_point = integration_rule.IntPoint(quadrature_point);
-      const mfem::IntegrationPoint &integration_point =
-          integration_rule.IntPoint(quadrature_point);
 
                 transformation.SetIntPoint(&integration_point);
 
@@ -376,40 +379,41 @@ void PreparedMappedGravitySourceOperator::Prepare(
                     data.potential_basis(quadrature_point, i) = potential_shape(i);
                 }
 
-      const double coefficient_value =
+                const double coefficient_value = source_coefficient.Eval(transformation, integration_point);
-          source_coefficient.Eval(transformation, integration_point);
 
                 transformation.SetIntPoint(&integration_point);
 
-      const double quadrature_value = integration_point.weight *
+                const double quadrature_value = integration_point.weight * transformation.Weight() * coefficient_value;
-                                      transformation.Weight() *
-                                      coefficient_value;
 
-      MFEM_VERIFY(std::isfinite(quadrature_value) && quadrature_value > 0.0,
+                MFEM_VERIFY(
+                    std::isfinite(quadrature_value) && quadrature_value > 0.0,
                     "Prepared gravity source operator encountered invalid "
                     "quadrature data on element "
-                      << element_id << ", quadrature point " << quadrature_point
+                        << element_id << ", quadrature point " << quadrature_point << "."
-                      << ".");
+                );
 
                 data.quadrature_data(quadrature_point) = quadrature_value;
             }
         }
 
-  MFEM_VERIFY(!m_elements.empty(),
+        MFEM_VERIFY(!m_elements.empty(), "PreparedMappedGravitySourceOperator found no stellar elements.");
-              "PreparedMappedGravitySourceOperator found no stellar elements.");
 
         m_is_prepared = true;
         ++m_preparation_count;
-}
+    }
-void PreparedMappedGravitySourceOperator::Mult(const mfem::Vector &density,
+    void PreparedMappedGravitySourceOperator::Mult(
-                                               mfem::Vector &action) const {
+        const mfem::Vector &density,
-  MFEM_VERIFY(m_is_prepared,
+        mfem::Vector &action
-              "PreparedMappedGravitySourceOperator must be prepared before "
+    ) const {
-              "Mult is called.");
+        MFEM_VERIFY(
+            m_is_prepared, "PreparedMappedGravitySourceOperator must be prepared before "
+                           "Mult is called."
+        );
 
-  MFEM_VERIFY(density.Size() == Width(),
+        MFEM_VERIFY(
-              "PreparedMappedGravitySourceOperator received a density vector "
+            density.Size() == Width(), "PreparedMappedGravitySourceOperator received a density vector "
-              "with the wrong size.");
+                                       "with the wrong size."
+        );
 
         m_density_true.SetSize(m_density_map.full_size());
         m_density_map.scatter(density, m_density_true);
@@ -457,17 +461,21 @@ void PreparedMappedGravitySourceOperator::Mult(const mfem::Vector &density,
         local_to_true(*m_fem.gravityPotentialFes, local_action, m_action_true);
         action.SetSize(Height());
         m_potential_map.gather(m_action_true, action);
-}
+    }
 
-void PreparedMappedGravitySourceOperator::MultTranspose(
+    void PreparedMappedGravitySourceOperator::MultTranspose(
-    const mfem::Vector &potential, mfem::Vector &action) const {
+        const mfem::Vector &potential,
-  MFEM_VERIFY(m_is_prepared,
+        mfem::Vector &action
-              "PreparedMappedGravitySourceOperator must be prepared before "
+    ) const {
-              "MultTranspose is called.");
+        MFEM_VERIFY(
+            m_is_prepared, "PreparedMappedGravitySourceOperator must be prepared before "
+                           "MultTranspose is called."
+        );
 
-  MFEM_VERIFY(potential.Size() == Height(),
+        MFEM_VERIFY(
-              "PreparedMappedGravitySourceOperator received a potential vector "
+            potential.Size() == Height(), "PreparedMappedGravitySourceOperator received a potential vector "
-              "with the wrong size.");
+                                          "with the wrong size."
+        );
 
         m_potential_true.SetSize(m_potential_map.full_size());
         m_potential_map.scatter(potential, m_potential_true);
@@ -512,28 +520,24 @@ void PreparedMappedGravitySourceOperator::MultTranspose(
         local_to_true(*m_fem.densityFes, local_action, m_action_true);
         action.SetSize(Width());
         m_density_map.gather(m_action_true, action);
-}
+    }
-bool PreparedMappedGravitySourceOperator::IsPrepared() const noexcept {
+    bool PreparedMappedGravitySourceOperator::IsPrepared() const noexcept {
         return m_is_prepared;
-}
+    }
 
-std::uint64_t
+    std::uint64_t PreparedMappedGravitySourceOperator::GetPreparationCount() const noexcept {
-PreparedMappedGravitySourceOperator::GetPreparationCount() const noexcept {
         return m_preparation_count;
-}
+    }
 
-const field::FieldDofMap &
+    const field::FieldDofMap &PreparedMappedGravitySourceOperator::GetDensityMap() const noexcept {
-PreparedMappedGravitySourceOperator::GetDensityMap() const noexcept {
         return m_density_map;
-}
+    }
 
-const field::FieldDofMap &
+    const field::FieldDofMap &PreparedMappedGravitySourceOperator::GetPotentialMap() const noexcept {
-PreparedMappedGravitySourceOperator::GetPotentialMap() const noexcept {
         return m_potential_map;
-}
+    }
 
-const field::FieldDofMap &
+    const field::FieldDofMap &PreparedMappedGravitySourceOperator::GetDisplacementMap() const noexcept {
-PreparedMappedGravitySourceOperator::GetDisplacementMap() const noexcept {
         return m_displacement_map;
-}
+    }
 } // namespace mean_field::operators

libmeanfield/impl/operators/prepared_hdiv_mass.cpp

@@ -8,106 +8,119 @@ module mean_field;
 import :operators.prepared_hdiv_mass;
 
 namespace {
-using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
+    using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
 
-int get_operator_size(const mean_field::fem::FEM &f) {
+    int get_operator_size(const mean_field::fem::FEM &f) {
-  MFEM_VERIFY(f.gravityFluxFes != nullptr,
+        MFEM_VERIFY(
-              "PreparedMappedHDivMassOperator requires the "
+            f.gravityFluxFes != nullptr, "PreparedMappedHDivMassOperator requires the "
-              "gravity-gradient finite-element space.");
+                                         "gravity-gradient finite-element space."
-  return mean_field::field::make_field_dof_map<mean_field::field::Gravity,
+        );
-                                               DomainSchema>(*f.gravityFluxFes)
+        return mean_field::field::make_field_dof_map<mean_field::field::Gravity, DomainSchema>(*f.gravityFluxFes)
             .reduced_size();
-}
+    }
 
-void true_to_local(const mfem::ParFiniteElementSpace &finite_element_space,
+    void true_to_local(
+        const mfem::ParFiniteElementSpace &finite_element_space,
         const mfem::Vector &true_vector,
-                   mfem::Vector &local_vector) {
+        mfem::Vector &local_vector
+    ) {
         local_vector.SetSize(finite_element_space.GetVSize());
 
-  const mfem::Operator *prolongation =
+        const mfem::Operator *prolongation = finite_element_space.GetProlongationMatrix();
-      finite_element_space.GetProlongationMatrix();
 
         if (prolongation != nullptr) {
             prolongation->Mult(true_vector, local_vector);
         } else {
             local_vector = true_vector;
         }
-}
+    }
 
-int find_representative_element(const mean_field::fem::FEM &f,
+    int find_representative_element(
-                                const mfem::Array<int> &marker) {
+        const mean_field::fem::FEM &f,
+        const mfem::Array<int> &marker
+    ) {
         for (int element_id = 0; element_id < f.mesh->GetNE(); ++element_id) {
             const int attribute = f.mesh->GetAttribute(element_id);
 
-    if (attribute > 0 && attribute <= marker.Size() &&
+            if (attribute > 0 && attribute <= marker.Size() && marker[attribute - 1] != 0) {
-        marker[attribute - 1] != 0) {
                 return element_id;
             }
         }
 
         return -1;
-}
+    }
 
-void validate_uniform_domain_discretization(
+    void validate_uniform_domain_discretization(
-    const mean_field::fem::FEM &f, const mfem::Array<int> &marker,
+        const mean_field::fem::FEM &f,
-    const int representative_element_id) {
+        const mfem::Array<int> &marker,
-  const mfem::FiniteElement &representative_element =
+        const int representative_element_id
-      *f.gravityFluxFes->GetFE(representative_element_id);
+    ) {
+        const mfem::FiniteElement &representative_element = *f.gravityFluxFes->GetFE(representative_element_id);
         const mfem::ElementTransformation &representative_transformation =
             *f.mesh->GetElementTransformation(representative_element_id);
 
         for (int element_id = 0; element_id < f.mesh->GetNE(); ++element_id) {
             const int attribute = f.mesh->GetAttribute(element_id);
 
-    if (attribute <= 0 || attribute > marker.Size() ||
+            if (attribute <= 0 || attribute > marker.Size() || marker[attribute - 1] == 0) {
-        marker[attribute - 1] == 0) {
                 continue;
             }
 
             const mfem::FiniteElement &element                = *f.gravityFluxFes->GetFE(element_id);
-    const mfem::ElementTransformation &transformation =
+            const mfem::ElementTransformation &transformation = *f.mesh->GetElementTransformation(element_id);
-        *f.mesh->GetElementTransformation(element_id);
 
-    MFEM_VERIFY(element.GetGeomType() == representative_element.GetGeomType(),
+            MFEM_VERIFY(
+                element.GetGeomType() == representative_element.GetGeomType(),
                 "Prepared H(div) mass domains currently require a uniform "
                 "element "
-                "geometry.");
+                "geometry."
-    MFEM_VERIFY(element.GetOrder() == representative_element.GetOrder(),
+            );
+            MFEM_VERIFY(
+                element.GetOrder() == representative_element.GetOrder(),
                 "Prepared H(div) mass domains currently require a uniform "
-                "finite-element order.");
+                "finite-element order."
-    MFEM_VERIFY(transformation.OrderW() ==
+            );
-                    representative_transformation.OrderW(),
+            MFEM_VERIFY(
+                transformation.OrderW() == representative_transformation.OrderW(),
                 "Prepared H(div) mass domains currently require a uniform "
-                "geometry-weight order.");
+                "geometry-weight order."
+            );
+        }
     }
-}
 
-class FrozenMappedHDivMassCoefficient final : public mfem::MatrixCoefficient {
+    class FrozenMappedHDivMassCoefficient final : public mfem::MatrixCoefficient {
-public:
+    public:
         FrozenMappedHDivMassCoefficient(
             const mean_field::fem::FEM &f,
             const mean_field::mapping::DomainMapper &domain_mapper,
-      const mfem::Vector &displacement_true, bool elevates_vacuum)
+            const mfem::Vector &displacement_true,
-      : MatrixCoefficient(domain_mapper.GetDimension()), m_fem(f),
+            bool elevates_vacuum
+        )
+            : MatrixCoefficient(domain_mapper.GetDimension()),
+              m_fem(f),
               m_domain_mapper(domain_mapper),
               m_workspace(domain_mapper.GetDimension()),
               m_elevates_vacuum(elevates_vacuum) {
-    true_to_local(*m_fem.displacementFes, displacement_true,
+            true_to_local(*m_fem.displacementFes, displacement_true, m_displacement_local);
-                  m_displacement_local);
         }
 
-  void Eval(mfem::DenseMatrix &mass_tensor,
+        void Eval(
+            mfem::DenseMatrix &mass_tensor,
             mfem::ElementTransformation &transformation,
-            const mfem::IntegrationPoint &integration_point) override {
+            const mfem::IntegrationPoint &integration_point
+        ) override {
             transformation.SetIntPoint(&integration_point);
 
             const int element_id = transformation.ElementNo;
             MFEM_VERIFY(
                 element_id >= 0 && element_id < m_fem.mesh->GetNE(),
-        "Mapped H(div) mass coefficient received an invalid element ID.");
+                "Mapped H(div) mass coefficient received an invalid element ID."
+            );
 
-    const bool element_is_vacuum = DomainSchema::template attribute_belongs_to<
+            const bool element_is_vacuum =
-        mean_field::utils::domain::Vacuum>(transformation.Attribute);
+                DomainSchema::template attribute_belongs_to<mean_field::utils::domain::Vacuum>(
+                    transformation.Attribute
+                );
 
             if (element_is_vacuum != m_elevates_vacuum) {
                 mass_tensor.SetSize(m_domain_mapper.GetDimension());
@@ -118,79 +131,72 @@ public:
             LoadElement(element_id);
 
             const mean_field::mapping::ElementMappingData mapping_data{
-        .displacement = *m_displacement_data,
+                .displacement = *m_displacement_data, .compactification = *m_compactification_data
-        .compactification = *m_compactification_data};
+            };
 
             mean_field::mapping::VolumeMappingContext mapping_context;
 
-    const mean_field::mapping::MappingStatus status =
+            const mean_field::mapping::MappingStatus status = m_domain_mapper.EvaluateVolume(
-        m_domain_mapper.EvaluateVolume(mapping_data, transformation,
+                mapping_data, transformation, integration_point, m_workspace, mapping_context
-                                       integration_point, m_workspace,
+            );
-                                       mapping_context);
 
-    MFEM_VERIFY(status == mean_field::mapping::MappingStatus::valid,
+            MFEM_VERIFY(
+                status == mean_field::mapping::MappingStatus::valid,
                 "Stateless domain mapping failed while preparing the H(div) "
                 "mass "
                 "operator. Mapping status = "
-                    << static_cast<int>(status)
+                    << static_cast<int>(status) << ", element ID = " << element_id
-                    << ", element ID = " << element_id
                     << ", element attribute = " << transformation.Attribute
-                    << ", coefficient domain = "
+                    << ", coefficient domain = " << (m_elevates_vacuum ? "vacuum" : "stellar")
-                    << (m_elevates_vacuum ? "vacuum" : "stellar"));
+            );
 
-    const mfem::DenseMatrix &mapping_jacobian =
+            const mfem::DenseMatrix &mapping_jacobian = mapping_context.mapping.mapping_jacobian;
-        mapping_context.mapping.mapping_jacobian;
+            const double mapping_determinant          = mapping_context.mapping.mapping_determinant;
-    const double mapping_determinant =
-        mapping_context.mapping.mapping_determinant;
 
-    MFEM_VERIFY(std::isfinite(mapping_determinant) && mapping_determinant > 0.0,
+            MFEM_VERIFY(
+                std::isfinite(mapping_determinant) && mapping_determinant > 0.0,
                 "Prepared H(div) mass operator encountered a non-positive or "
-                "non-finite mapping determinant.");
+                "non-finite mapping determinant."
+            );
 
             mfem::MultAtB(mapping_jacobian, mapping_jacobian, mass_tensor);
             mass_tensor *= 1.0 / mapping_determinant;
         }
 
-private:
+    private:
         void LoadElement(const int element_id) {
             if (element_id == m_cached_element_id) {
                 return;
             }
 
-    const mfem::FiniteElement &displacement_element =
+            const mfem::FiniteElement &displacement_element     = *m_fem.displacementFes->GetFE(element_id);
-        *m_fem.displacementFes->GetFE(element_id);
+            const mfem::FiniteElement &compactification_element = *m_fem.compactificationFes->GetFE(element_id);
-    const mfem::FiniteElement &compactification_element =
-        *m_fem.compactificationFes->GetFE(element_id);
 
             mfem::DofTransformation *displacement_dof_transformation =
                 m_fem.displacementFes->GetElementVDofs(element_id, m_displacement_dofs);
             mfem::DofTransformation *compactification_dof_transformation =
-        m_fem.compactificationFes->GetElementDofs(element_id,
+                m_fem.compactificationFes->GetElementDofs(element_id, m_compactification_dofs);
-                                                  m_compactification_dofs);
 
-    m_displacement_local.GetSubVector(m_displacement_dofs,
+            m_displacement_local.GetSubVector(m_displacement_dofs, m_element_displacement);
-                                      m_element_displacement);
+            m_fem.compactificationCoordinate->GetSubVector(m_compactification_dofs, m_element_compactification);
-    m_fem.compactificationCoordinate->GetSubVector(m_compactification_dofs,
-                                                   m_element_compactification);
 
             if (displacement_dof_transformation != nullptr) {
-      displacement_dof_transformation->InvTransformPrimal(
+                displacement_dof_transformation->InvTransformPrimal(m_element_displacement);
-          m_element_displacement);
             }
 
             if (compactification_dof_transformation != nullptr) {
-      compactification_dof_transformation->InvTransformPrimal(
+                compactification_dof_transformation->InvTransformPrimal(m_element_compactification);
-          m_element_compactification);
             }
 
-    m_displacement_data =
+            m_displacement_data = std::make_unique<mean_field::mapping::ElementDisplacementData>(
-        std::make_unique<mean_field::mapping::ElementDisplacementData>(
                 mean_field::mapping::ElementDisplacementDataFromElementVDofs(
-                displacement_element, m_element_displacement));
+                    displacement_element, m_element_displacement
+                )
+            );
 
-    m_compactification_data =
+            m_compactification_data = std::make_unique<mean_field::mapping::ElementCompactificationData>(
-        std::make_unique<mean_field::mapping::ElementCompactificationData>(
+                compactification_element, m_element_compactification
-            compactification_element, m_element_compactification);
+            );
 
             m_cached_element_id = element_id;
         }
@@ -206,100 +212,106 @@ private:
         mfem::Vector m_element_displacement;
         mfem::Vector m_element_compactification;
 
-  std::unique_ptr<mean_field::mapping::ElementDisplacementData>
+        std::unique_ptr<mean_field::mapping::ElementDisplacementData> m_displacement_data;
-      m_displacement_data;
+        std::unique_ptr<mean_field::mapping::ElementCompactificationData> m_compactification_data;
-  std::unique_ptr<mean_field::mapping::ElementCompactificationData>
-      m_compactification_data;
 
         mean_field::mapping::DomainMapper::Workspace m_workspace;
         int m_cached_element_id{-1};
         bool m_elevates_vacuum;
-};
+    };
 } // namespace
 
 namespace mean_field::operators {
-PreparedMappedHDivMassOperator::PreparedMappedHDivMassOperator(
+    PreparedMappedHDivMassOperator::PreparedMappedHDivMassOperator(
-    const fem::FEM &f, const mapping::DomainMapper &domain_mapper)
+        const fem::FEM &f,
-    : Operator(get_operator_size(f)), m_fem(f), m_domain_mapper(domain_mapper),
+        const mapping::DomainMapper &domain_mapper
-      m_flux_map(field::make_field_dof_map<field::Gravity, DomainSchema>(
+    )
-          *f.gravityFluxFes)),
+        : Operator(get_operator_size(f)),
+          m_fem(f),
+          m_domain_mapper(domain_mapper),
+          m_flux_map(
+              field::make_field_dof_map<
+                  field::Gravity,
+                  DomainSchema>(*f.gravityFluxFes)
+          ),
           m_displacement_map(
-          field::make_field_dof_map<field::Displacement, DomainSchema>(
+              field::make_field_dof_map<
-              *f.displacementFes)) {
+                  field::Displacement,
-  MFEM_VERIFY(f.mesh != nullptr,
+                  DomainSchema>(*f.displacementFes)
-              "PreparedMappedHDivMassOperator requires a mesh.");
+          ) {
-  MFEM_VERIFY(f.gravityFluxFes != nullptr,
+        MFEM_VERIFY(f.mesh != nullptr, "PreparedMappedHDivMassOperator requires a mesh.");
-              "PreparedMappedHDivMassOperator requires the "
+        MFEM_VERIFY(
-              "gravity-gradient finite-element space.");
+            f.gravityFluxFes != nullptr, "PreparedMappedHDivMassOperator requires the "
-  MFEM_VERIFY(f.displacementFes != nullptr,
+                                         "gravity-gradient finite-element space."
-              "PreparedMappedHDivMassOperator requires the "
+        );
-              "displacement finite-element space.");
+        MFEM_VERIFY(
-  MFEM_VERIFY(f.compactificationFes != nullptr,
+            f.displacementFes != nullptr, "PreparedMappedHDivMassOperator requires the "
-              "PreparedMappedHDivMassOperator requires the compactification "
+                                          "displacement finite-element space."
-              "finite-element space.");
+        );
-  MFEM_VERIFY(f.compactificationCoordinate != nullptr,
+        MFEM_VERIFY(
-              "PreparedMappedHDivMassOperator requires the compactification "
+            f.compactificationFes != nullptr, "PreparedMappedHDivMassOperator requires the compactification "
-              "coordinate.");
+                                              "finite-element space."
-  MFEM_VERIFY(f.quadratureFactory != nullptr,
+        );
-              "PreparedMappedHDivMassOperator requires the quadrature-rule "
+        MFEM_VERIFY(
-              "factory.");
+            f.compactificationCoordinate != nullptr, "PreparedMappedHDivMassOperator requires the compactification "
-  MFEM_VERIFY(domain_mapper.GetDimension() == f.mesh->Dimension(),
+                                                     "coordinate."
+        );
+        MFEM_VERIFY(
+            f.quadratureFactory != nullptr, "PreparedMappedHDivMassOperator requires the quadrature-rule "
+                                            "factory."
+        );
+        MFEM_VERIFY(
+            domain_mapper.GetDimension() == f.mesh->Dimension(),
             "The stateless domain-mapper dimension does not match the mesh "
-              "dimension.");
+            "dimension."
+        );
 
-  m_stellar_marker =
+        m_stellar_marker = utils::domain::make_attribute_marker<utils::domain::Stellar, DomainSchema>(*f.mesh);
-      utils::domain::make_attribute_marker<utils::domain::Stellar,
+        m_vacuum_marker  = utils::domain::make_attribute_marker<utils::domain::Vacuum, DomainSchema>(*f.mesh);
-                                           DomainSchema>(*f.mesh);
-  m_vacuum_marker =
-      utils::domain::make_attribute_marker<utils::domain::Vacuum, DomainSchema>(
-          *f.mesh);
 
-  const int stellar_element_id =
+        const int stellar_element_id = find_representative_element(f, m_stellar_marker);
-      find_representative_element(f, m_stellar_marker);
         const int vacuum_element_id  = find_representative_element(f, m_vacuum_marker);
 
-  MFEM_VERIFY(stellar_element_id >= 0,
+        MFEM_VERIFY(
-              "PreparedMappedHDivMassOperator requires "
+            stellar_element_id >= 0, "PreparedMappedHDivMassOperator requires "
-              "at least one stellar element.");
+                                     "at least one stellar element."
-  MFEM_VERIFY(vacuum_element_id >= 0,
+        );
-              "PreparedMappedHDivMassOperator requires at "
+        MFEM_VERIFY(
-              "least one compactified vacuum element.");
+            vacuum_element_id >= 0, "PreparedMappedHDivMassOperator requires at "
+                                    "least one compactified vacuum element."
+        );
 
-  validate_uniform_domain_discretization(f, m_stellar_marker,
+        validate_uniform_domain_discretization(f, m_stellar_marker, stellar_element_id);
-                                         stellar_element_id);
         validate_uniform_domain_discretization(f, m_vacuum_marker, vacuum_element_id);
-}
+    }
 
-void PreparedMappedHDivMassOperator::Prepare(const mfem::Vector &displacement) {
+    void PreparedMappedHDivMassOperator::Prepare(const mfem::Vector &displacement) {
-  MFEM_VERIFY(displacement.Size() == m_displacement_map.reduced_size(),
+        MFEM_VERIFY(
+            displacement.Size() == m_displacement_map.reduced_size(),
             "PreparedMappedHDivMassOperator received a displacement vector "
             "with "
-              "the wrong size.");
+            "the wrong size."
+        );
 
         for (int i = 0; i < displacement.Size(); ++i) {
-    MFEM_VERIFY(std::isfinite(displacement(i)),
+            MFEM_VERIFY(
-                "PreparedMappedHDivMassOperator received a non-finite "
+                std::isfinite(displacement(i)), "PreparedMappedHDivMassOperator received a non-finite "
                                                 "displacement "
-                "value.");
+                                                "value."
+            );
         }
 
         m_displacement_true.SetSize(m_displacement_map.full_size());
         m_displacement_map.scatter(displacement, m_displacement_true);
 
-  const int stellar_element_id =
+        const int stellar_element_id                        = find_representative_element(m_fem, m_stellar_marker);
-      find_representative_element(m_fem, m_stellar_marker);
+        const int vacuum_element_id                         = find_representative_element(m_fem, m_vacuum_marker);
-  const int vacuum_element_id =
-      find_representative_element(m_fem, m_vacuum_marker);
 
-  const mfem::FiniteElement &stellar_element =
+        const mfem::FiniteElement &stellar_element          = *m_fem.gravityFluxFes->GetFE(stellar_element_id);
-      *m_fem.gravityFluxFes->GetFE(stellar_element_id);
+        const mfem::FiniteElement &vacuum_element           = *m_fem.gravityFluxFes->GetFE(vacuum_element_id);
-  const mfem::FiniteElement &vacuum_element =
-      *m_fem.gravityFluxFes->GetFE(vacuum_element_id);
 
-  mfem::ElementTransformation &stellar_transformation =
+        mfem::ElementTransformation &stellar_transformation = *m_fem.mesh->GetElementTransformation(stellar_element_id);
-      *m_fem.mesh->GetElementTransformation(stellar_element_id);
+        mfem::ElementTransformation &vacuum_transformation  = *m_fem.mesh->GetElementTransformation(vacuum_element_id);
-  mfem::ElementTransformation &vacuum_transformation =
-      *m_fem.mesh->GetElementTransformation(vacuum_element_id);
 
         m_stellar_mass_form.reset();
         m_vacuum_mass_form.reset();
@@ -307,55 +319,53 @@ void PreparedMappedHDivMassOperator::Prepare(const mfem::Vector &displacement) {
         m_vacuum_mass_coefficient.reset();
 
         m_stellar_mass_coefficient =
-      std::make_unique<FrozenMappedHDivMassCoefficient>(
+            std::make_unique<FrozenMappedHDivMassCoefficient>(m_fem, m_domain_mapper, m_displacement_true, false);
-          m_fem, m_domain_mapper, m_displacement_true, false);
+        m_vacuum_mass_coefficient =
-  m_vacuum_mass_coefficient = std::make_unique<FrozenMappedHDivMassCoefficient>(
+            std::make_unique<FrozenMappedHDivMassCoefficient>(m_fem, m_domain_mapper, m_displacement_true, true);
-      m_fem, m_domain_mapper, m_displacement_true, true);
 
-  m_stellar_mass_form =
+        m_stellar_mass_form = std::make_unique<mfem::ParBilinearForm>(m_fem.gravityFluxFes.get());
-      std::make_unique<mfem::ParBilinearForm>(m_fem.gravityFluxFes.get());
+        m_vacuum_mass_form  = std::make_unique<mfem::ParBilinearForm>(m_fem.gravityFluxFes.get());
-  m_vacuum_mass_form =
-      std::make_unique<mfem::ParBilinearForm>(m_fem.gravityFluxFes.get());
         m_stellar_mass_form->SetAssemblyLevel(mfem::AssemblyLevel::PARTIAL);
         m_vacuum_mass_form->SetAssemblyLevel(mfem::AssemblyLevel::PARTIAL);
 
-  auto stellar_integrator = std::make_unique<mfem::VectorFEMassIntegrator>(
+        auto stellar_integrator = std::make_unique<mfem::VectorFEMassIntegrator>(*m_stellar_mass_coefficient);
-      *m_stellar_mass_coefficient);
+        auto vacuum_integrator  = std::make_unique<mfem::VectorFEMassIntegrator>(*m_vacuum_mass_coefficient);
-  auto vacuum_integrator = std::make_unique<mfem::VectorFEMassIntegrator>(
-      *m_vacuum_mass_coefficient);
 
         m_fem.quadratureFactory->configure_gravity_hdiv_mass(
-      *stellar_integrator, quadrature::QuadratureRole::discretization,
+            *stellar_integrator, quadrature::QuadratureRole::discretization, stellar_element, stellar_transformation,
-      stellar_element, stellar_transformation, utils::DOMAINS::STELLAR,
+            utils::DOMAINS::STELLAR, quadrature::MappingKind::general
-      quadrature::MappingKind::general);
+        );
 
         m_fem.quadratureFactory->configure_gravity_hdiv_mass(
-      *vacuum_integrator, quadrature::QuadratureRole::discretization,
+            *vacuum_integrator, quadrature::QuadratureRole::discretization, vacuum_element, vacuum_transformation,
-      vacuum_element, vacuum_transformation, utils::DOMAINS::VACUUM,
+            utils::DOMAINS::VACUUM, quadrature::MappingKind::kelvin
-      quadrature::MappingKind::kelvin);
+        );
 
-  m_stellar_mass_form->AddDomainIntegrator(stellar_integrator.release(),
+        m_stellar_mass_form->AddDomainIntegrator(stellar_integrator.release(), m_stellar_marker);
-                                           m_stellar_marker);
+        m_vacuum_mass_form->AddDomainIntegrator(vacuum_integrator.release(), m_vacuum_marker);
-  m_vacuum_mass_form->AddDomainIntegrator(vacuum_integrator.release(),
-                                          m_vacuum_marker);
         m_stellar_mass_form->Assemble();
         m_vacuum_mass_form->Assemble();
 
         m_is_prepared = true;
         ++m_preparation_count;
-}
+    }
 
-void PreparedMappedHDivMassOperator::Mult(const mfem::Vector &gravity_gradient,
+    void PreparedMappedHDivMassOperator::Mult(
-                                          mfem::Vector &action) const {
+        const mfem::Vector &gravity_gradient,
-  MFEM_VERIFY(m_is_prepared, "PreparedMappedHDivMassOperator must be prepared "
+        mfem::Vector &action
-                             "before Mult is called.");
+    ) const {
+        MFEM_VERIFY(
+            m_is_prepared, "PreparedMappedHDivMassOperator must be prepared "
+                           "before Mult is called."
+        );
         MFEM_VERIFY(
             m_stellar_mass_form != nullptr && m_vacuum_mass_form != nullptr,
-      "PreparedMappedHDivMassOperator has incomplete domain mass forms.");
+            "PreparedMappedHDivMassOperator has incomplete domain mass forms."
+        );
         MFEM_VERIFY(
-      gravity_gradient.Size() == Width(),
+            gravity_gradient.Size() == Width(), "PreparedMappedHDivMassOperator received a gravity-gradient vector "
-      "PreparedMappedHDivMassOperator received a gravity-gradient vector "
+                                                "with the wrong size."
-      "with the wrong size.");
+        );
 
         m_flux_true.SetSize(m_flux_map.full_size());
         m_action_true.SetSize(m_flux_map.full_size());
@@ -366,47 +376,45 @@ void PreparedMappedHDivMassOperator::Mult(const mfem::Vector &gravity_gradient,
         m_action_true += m_domain_action_true;
         action.SetSize(Height());
         m_flux_map.gather(m_action_true, action);
-}
+    }
 
-void PreparedMappedHDivMassOperator::AssembleDiagonal(
+    void PreparedMappedHDivMassOperator::AssembleDiagonal(mfem::Vector &diagonal) const {
-    mfem::Vector &diagonal) const {
         mfem::Vector true_diagonal;
         AssembleTrueDiagonal(true_diagonal);
         diagonal.SetSize(Height());
         m_flux_map.gather(true_diagonal, diagonal);
-}
+    }
 
-void PreparedMappedHDivMassOperator::AssembleTrueDiagonal(
+    void PreparedMappedHDivMassOperator::AssembleTrueDiagonal(mfem::Vector &diagonal) const {
-    mfem::Vector &diagonal) const {
+        MFEM_VERIFY(
-  MFEM_VERIFY(m_is_prepared, "PreparedMappedHDivMassOperator must be prepared "
+            m_is_prepared, "PreparedMappedHDivMassOperator must be prepared "
-                             "before assembling its diagonal.");
+                           "before assembling its diagonal."
+        );
         MFEM_VERIFY(
             m_stellar_mass_form != nullptr && m_vacuum_mass_form != nullptr,
-      "PreparedMappedHDivMassOperator has incomplete domain mass forms.");
+            "PreparedMappedHDivMassOperator has incomplete domain mass forms."
+        );
 
         diagonal.SetSize(m_flux_map.full_size());
         mfem::Vector domain_diagonal(m_flux_map.full_size());
         m_stellar_mass_form->AssembleDiagonal(diagonal);
         m_vacuum_mass_form->AssembleDiagonal(domain_diagonal);
         diagonal += domain_diagonal;
-}
+    }
 
-bool PreparedMappedHDivMassOperator::IsPrepared() const noexcept {
+    bool PreparedMappedHDivMassOperator::IsPrepared() const noexcept {
         return m_is_prepared;
-}
+    }
 
-std::uint64_t
+    std::uint64_t PreparedMappedHDivMassOperator::GetPreparationCount() const noexcept {
-PreparedMappedHDivMassOperator::GetPreparationCount() const noexcept {
         return m_preparation_count;
-}
+    }
 
-const field::FieldDofMap &
+    const field::FieldDofMap &PreparedMappedHDivMassOperator::GetFluxMap() const noexcept {
-PreparedMappedHDivMassOperator::GetFluxMap() const noexcept {
         return m_flux_map;
-}
+    }
 
-const field::FieldDofMap &
+    const field::FieldDofMap &PreparedMappedHDivMassOperator::GetDisplacementMap() const noexcept {
-PreparedMappedHDivMassOperator::GetDisplacementMap() const noexcept {
         return m_displacement_map;
-}
+    }
 } // namespace mean_field::operators

libmeanfield/impl/operators/prepared_pressure_force.cpp

@@ -619,9 +619,15 @@ namespace mean_field::operators {
             for (int quadraturePoint = 0; quadraturePoint < quadraturePointCount; ++quadraturePoint) {
                 const double enthalpy = quadratureEnthalpy(quadraturePoint);
 
-                const double pressure           = m_equationOfState.pressure_from_enthalpy(enthalpy);
+                const eos::SpecificEnthalpyValue specificEnthalpy{enthalpy};
+                const double pressure =
+                    eos::evaluate<eos::quantity::Pressure>(m_equationOfState, specificEnthalpy).value();
 
-                const double pressureDerivative = m_equationOfState.pressure_derivative_from_enthalpy(enthalpy);
+                const double pressureDerivative =
+                    eos::partialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>(
+                        m_equationOfState, specificEnthalpy
+                    )
+                        .value();
 
                 const double quadratureWeight = data.quadratureWeights(quadraturePoint);
 

libmeanfield/impl/operators/prepared_stellar_equilibrium.cpp

@@ -21,6 +21,12 @@ namespace {
         );
     }
 
+    [[nodiscard]] mfem::Vector make_computational_origin(const mfem::ParMesh &mesh) {
+        mfem::Vector origin(mesh.SpaceDimension());
+        origin = 0.0;
+        return origin;
+    }
+
     [[nodiscard]] mean_field::operators::StellarEquilibriumLayout make_layout(
         const mean_field::field::FieldDofMap &densityMap,
         const mean_field::field::FieldDofMap &displacementMap,
@@ -253,6 +259,8 @@ namespace mean_field::operators {
         field::FieldDofMap gravityFluxMap;
         field::FieldDofMap gravityPotentialMap;
         field::FieldDofMap enthalpyMap;
+        field::FieldBoundaryDofMap pressureSurfaceRows;
+        field::FieldPointDofMap centerDisplacementRows;
 
         StellarEquilibriumLayout layout;
         mfem::Array<int> gravityStateOffsets;
@@ -284,6 +292,23 @@ namespace mean_field::operators {
                       field::Enthalpy,
                       DomainSchema>(*f.enthalpyFes)
               ),
+              pressureSurfaceRows(
+                  field::make_field_boundary_dof_map<
+                      field::Enthalpy,
+                      utils::domain::StellarSurface,
+                      DomainSchema>(
+                      *f.enthalpyFes,
+                      enthalpyMap
+                  )
+              ),
+              centerDisplacementRows(
+                  field::make_field_point_dof_map<field::Displacement>(
+                      *f.displacementFes,
+                      displacementMap,
+                      make_computational_origin(*f.mesh),
+                      1.0e-12
+                  )
+              ),
               layout(make_layout(
                   densityMap,
                   displacementMap,
@@ -314,27 +339,15 @@ namespace mean_field::operators {
         fem::FEM &f,
         const mapping::DomainMapper &domainMapper,
         const eos::Polytrope &equationOfState,
-        const models::StellarModel &stellarModel
+        const double targetMass,
-    )
+        const PressureSurfaceConstraintView surfaceConstraint
-        : PreparedStellarEquilibriumOperator(
-              f,
-              domainMapper,
-              equationOfState,
-              stellarModel.targetMass()
-          ) {
-    }
-
-    PreparedStellarEquilibriumOperator::PreparedStellarEquilibriumOperator(
-        fem::FEM &f,
-        const mapping::DomainMapper &domainMapper,
-        const eos::Polytrope &equationOfState,
-        const double targetMass
     )
         : PreparedStellarEquilibriumOperator(
               f,
               domainMapper,
               equationOfState,
               targetMass,
+              surfaceConstraint,
               MakeConstructionData(f)
           ) {
     }
@@ -344,6 +357,7 @@ namespace mean_field::operators {
         const mapping::DomainMapper &domainMapper,
         const eos::Polytrope &equationOfState,
         const double targetMass,
+        const PressureSurfaceConstraintView surfaceConstraint,
         ConstructionData constructionData
     )
         : mfem::Operator(
@@ -390,6 +404,11 @@ namespace mean_field::operators {
               domainMapper,
               m_gravityContext
           ),
+          m_surfaceConstraintOperator(
+              constructionData.pressureSurfaceRows,
+              surfaceConstraint
+          ),
+          m_centeringConstraintOperator(constructionData.centerDisplacementRows),
           m_targetMass(targetMass) {
         MFEM_VERIFY(
             std::isfinite(m_targetMass) && m_targetMass > 0.0,
@@ -506,6 +525,14 @@ namespace mean_field::operators {
         report.massNormalization =
             m_massNormalizationOperator.Prepare({.targetMass = m_targetMass}, make_mass_dependencies(dependencies));
 
+        report.surfaceConstraint = m_surfaceConstraintOperator.Prepare(
+            reducedEnthalpy, !wasPrepared || dependencies.enthalpy != m_preparedDependencies.enthalpy
+        );
+
+        report.centeringConstraint = m_centeringConstraintOperator.Prepare(
+            displacement, !wasPrepared || dependencies.displacement != m_preparedDependencies.displacement
+        );
+
         const bool dependenciesChanged = !wasPrepared || dependencies != m_preparedDependencies;
         if (dependenciesChanged || report.DidAnyChildWork()) {
             AssembleResidual();
@@ -542,7 +569,9 @@ namespace mean_field::operators {
         m_gravityOperator.Mult(m_gravityState, gravity);
         m_barotropicClosureOperator.BuildResidual(closure);
         m_displacementOperator.BuildResidual(displacement);
+        m_centeringConstraintOperator.ApplyResidualRows(displacement);
         m_hydrostaticOperator.BuildResidual(hydrostatic);
+        m_surfaceConstraintOperator.ApplyResidualRows(hydrostatic);
         m_massNormalizationOperator.BuildResidual(mass);
 
         m_cachedResidual.SetSize(Height());
@@ -659,11 +688,13 @@ namespace mean_field::operators {
             reducedDensityDirection, displacementDirection, gravityGradientDirection, reducedEnthalpyDirection,
             displacementAction
         );
+        m_centeringConstraintOperator.ApplyJacobianRows(displacementDirection, displacementAction);
 
         m_hydrostaticOperator.ApplyCompleteJacobianAction(
             reducedEnthalpyDirection, gravityPotentialDirection, bernoulliDirection(0), displacementDirection,
             hydrostaticAction
         );
+        m_surfaceConstraintOperator.ApplyJacobianRows(reducedEnthalpyDirection, hydrostaticAction);
 
         m_massNormalizationOperator.ApplyCompleteJacobianAction(
             reducedDensityDirection, displacementDirection, massAction
@@ -712,7 +743,8 @@ namespace mean_field::operators {
     bool PreparedStellarEquilibriumOperator::IsPrepared() const noexcept {
         return m_isPrepared && m_gravityContext.IsPrepared() && m_barotropicClosureOperator.IsPrepared() &&
                m_hydrostaticOperator.IsPrepared() && m_displacementOperator.IsPrepared() &&
-               m_massNormalizationOperator.IsPrepared();
+               m_massNormalizationOperator.IsPrepared() && m_surfaceConstraintOperator.IsPrepared() &&
+               m_centeringConstraintOperator.IsPrepared();
     }
 
     double PreparedStellarEquilibriumOperator::GetTargetMass() const noexcept {
@@ -771,6 +803,16 @@ namespace mean_field::operators {
         return m_massNormalizationOperator;
     }
 
+    const PreparedPressureSurfaceConstraint &
+    PreparedStellarEquilibriumOperator::GetSurfaceConstraintOperator() const noexcept {
+        return m_surfaceConstraintOperator;
+    }
+
+    const PreparedCenteringConstraint &
+    PreparedStellarEquilibriumOperator::GetCenteringConstraintOperator() const noexcept {
+        return m_centeringConstraintOperator;
+    }
+
     void PreparedStellarEquilibriumOperator::VerifyPrepared() const {
         MFEM_VERIFY(
             IsPrepared(), "PreparedStellarEquilibriumOperator must be prepared before residual or Jacobian application."

libmeanfield/impl/physics/gravity.cpp

@@ -16,13 +16,11 @@ namespace mean_field::physics {
         local_Q            = 0.0;
         using DomainSchema = utils::domain::CoreEnvelopeVacuumDomainSchema;
         mapping::GridFunctionMappingEvaluator mapping_evaluator(
-            *fem.domainMapperStateless, *fem.displacement,
+            *fem.domainMapperStateless, *fem.displacement, *fem.compactificationCoordinate
-            *fem.compactificationCoordinate
         );
 
         for (int i = 0; i < fem.mesh->GetNE(); ++i) {
-            if (!DomainSchema::template attribute_belongs_to<utils::domain::Stellar>(
+            if (!DomainSchema::template attribute_belongs_to<utils::domain::Stellar>(fem.mesh->GetAttribute(i)))
-                    fem.mesh->GetAttribute(i)))
                 continue;
 
             mfem::ElementTransformation *trans = fem.mesh->GetElementTransformation(i);
@@ -40,8 +38,7 @@ namespace mean_field::physics {
 
                 mapping::VolumeMappingContext mapping_context;
                 MFEM_VERIFY(
-                    mapping_evaluator.EvaluateVolume(*trans, ip, mapping_context) ==
+                    mapping_evaluator.EvaluateVolume(*trans, ip, mapping_context) == mapping::MappingStatus::valid,
-                        mapping::MappingStatus::valid,
                     "Quadrupole integration encountered an invalid mapping."
                 );
                 const double weight            = mapping_context.quadrature.weight;
@@ -220,12 +217,8 @@ namespace mean_field::physics {
 
         GravitySolution solution(f);
 
-        gravity_flux_adapter.scatter(
+        gravity_flux_adapter.scatter(gravity_state.GetBlock(gravity_gradient_residual_block), solution.gradPhi);
-            gravity_state.GetBlock(gravity_gradient_residual_block), solution.gradPhi
+        gravity_potential_adapter.scatter(gravity_state.GetBlock(gravity_poisson_residual_block), solution.phi);
-        );
-        gravity_potential_adapter.scatter(
-            gravity_state.GetBlock(gravity_poisson_residual_block), solution.phi
-        );
 
         return solution;
     }

libmeanfield/impl/physics/solid.cpp

@@ -12,13 +12,11 @@ namespace mean_field::physics {
         double local_I     = 0.0;
         using DomainSchema = utils::domain::CoreEnvelopeVacuumDomainSchema;
         mapping::GridFunctionMappingEvaluator mapping_evaluator(
-            *fem.domainMapperStateless, *fem.displacement,
+            *fem.domainMapperStateless, *fem.displacement, *fem.compactificationCoordinate
-            *fem.compactificationCoordinate
         );
 
         for (int i = 0; i < fem.mesh->GetNE(); i++) {
-            if (!DomainSchema::template attribute_belongs_to<utils::domain::Stellar>(
+            if (!DomainSchema::template attribute_belongs_to<utils::domain::Stellar>(fem.mesh->GetAttribute(i)))
-                    fem.mesh->GetAttribute(i)))
                 continue;
 
             mfem::ElementTransformation *T = fem.mesh->GetElementTransformation(i);
@@ -37,8 +35,7 @@ namespace mean_field::physics {
 
                 mapping::VolumeMappingContext mapping_context;
                 MFEM_VERIFY(
-                    mapping_evaluator.EvaluateVolume(*T, ip, mapping_context) ==
+                    mapping_evaluator.EvaluateVolume(*T, ip, mapping_context) == mapping::MappingStatus::valid,
-                        mapping::MappingStatus::valid,
                     "Moment-of-inertia integration encountered an invalid mapping."
                 );
                 const mfem::Vector &x_phys = mapping_context.mapping.physical_position;

libmeanfield/impl/utils/domain.cpp

@@ -13,8 +13,7 @@ namespace mean_field::utils {
         const int dim = fem.mesh->Dimension();
         x_ref         = x_phys_target;
         mapping::GridFunctionMappingEvaluator mapping_evaluator(
-            *fem.domainMapperStateless, *fem.displacement,
+            *fem.domainMapperStateless, *fem.displacement, *fem.compactificationCoordinate
-            *fem.compactificationCoordinate
         );
 
         mfem::Array<int> init_elem;
@@ -39,8 +38,7 @@ namespace mean_field::utils {
 
                 mapping::MappingPointContext context;
                 MFEM_VERIFY(
-                    mapping_evaluator.EvaluatePoint(*T0, origin_ip[0], context) ==
+                    mapping_evaluator.EvaluatePoint(*T0, origin_ip[0], context) == mapping::MappingStatus::valid,
-                        mapping::MappingStatus::valid,
                     "Reference-point initialization encountered an invalid mapping."
                 );
 
@@ -104,8 +102,7 @@ namespace mean_field::utils {
             T->SetIntPoint(&ip);
 
             mapping::MappingPointContext context;
-            if (mapping_evaluator.EvaluatePoint(*T, ip, context) !=
+            if (mapping_evaluator.EvaluatePoint(*T, ip, context) != mapping::MappingStatus::valid) {
-                mapping::MappingStatus::valid) {
                 return false;
             }
             const mfem::Vector &current_x_phys = context.physical_position;

libmeanfield/impl/utils/misc.cpp

@@ -4,21 +4,25 @@ module;
 module mean_field;
 
 namespace mean_field::utils {
-DOMAINS operator|(DOMAINS lhs, DOMAINS rhs) {
+    DOMAINS operator|(
-  return static_cast<DOMAINS>(static_cast<uint8_t>(lhs) |
+        DOMAINS lhs,
-                              static_cast<uint8_t>(rhs));
+        DOMAINS rhs
-}
+    ) {
+        return static_cast<DOMAINS>(static_cast<uint8_t>(lhs) | static_cast<uint8_t>(rhs));
+    }
 
-DOMAINS operator&(DOMAINS lhs, DOMAINS rhs) {
+    DOMAINS operator&(
-  return static_cast<DOMAINS>(static_cast<uint8_t>(lhs) &
+        DOMAINS lhs,
-                              static_cast<uint8_t>(rhs));
+        DOMAINS rhs
-}
+    ) {
+        return static_cast<DOMAINS>(static_cast<uint8_t>(lhs) & static_cast<uint8_t>(rhs));
+    }
 
-int get_mesh_order(const mfem::Mesh &mesh) {
+    int get_mesh_order(const mfem::Mesh &mesh) {
         if (mesh.GetNodes() != nullptr) {
             return mesh.GetNodes()->FESpace()->GetMaxElementOrder();
         }
         return 1;
-}
+    }
 
 } // namespace mean_field::utils

libmeanfield/interface/eos/concepts.cppm

@@ -0,0 +1,100 @@
+module;
+
+#include <concepts>
+#include <type_traits>
+
+export module mean_field:eos.concepts;
+export import :eos.relations;
+
+export namespace mean_field::eos {
+    namespace detail {
+        template <typename EquationOfState, typename RelationType> struct ImplementsRelation : std::false_type { };
+
+        template <
+            typename EquationOfState,
+            typename Output,
+            typename... Inputs>
+            struct ImplementsRelation<
+                EquationOfState,
+                Relation<
+                    Output,
+                    Inputs...>> : std::bool_constant <
+                                  requires(
+                                      const std::remove_cvref_t<EquationOfState> &equationOfState,
+                                      QuantityValue<Inputs>... inputValues
+                                  ) {
+            {equationOfState.evaluate(Relation<Output, Inputs...>{}, inputValues...)}
+                ->std::same_as<QuantityValue<Output>>;
+        }>{};
+
+        template <typename EquationOfState, typename Catalog> struct ImplementsRelationCatalog : std::false_type { };
+
+        template <typename EquationOfState, typename... Relations>
+        struct ImplementsRelationCatalog<EquationOfState, RelationCatalog<Relations...>>
+            : std::bool_constant<(ImplementsRelation<EquationOfState, Relations>::value && ...)> { };
+
+        template <typename Candidate, typename = void> struct IsEquationOfStateModel : std::false_type { };
+
+        template <typename Candidate>
+        struct IsEquationOfStateModel<Candidate, std::void_t<typename std::remove_cvref_t<Candidate>::Relations>>
+            : std::bool_constant<
+                  ValidRelationCatalog<typename std::remove_cvref_t<Candidate>::Relations> &&
+                  ImplementsRelationCatalog<
+                      std::remove_cvref_t<Candidate>,
+                      typename std::remove_cvref_t<Candidate>::Relations>::value> { };
+
+        template <typename EquationOfState, typename RelationType, typename InputQuantity>
+        struct ImplementsPartialDerivative : std::false_type { };
+
+        template <
+            typename EquationOfState,
+            typename Output,
+            typename... Inputs,
+            typename InputQuantity>
+                struct ImplementsPartialDerivative<
+                    EquationOfState,
+                    Relation<
+                        Output,
+                        Inputs...>,
+                    InputQuantity> : std::bool_constant <
+                                     (std::same_as<
+                                          InputQuantity,
+                                          Inputs> ||
+                                      ...) &&
+            requires(
+                const std::remove_cvref_t<EquationOfState> &equationOfState,
+                QuantityValue<Inputs>... inputValues
+            ) {
+            {equationOfState
+                 .partialDerivative(Relation<Output, Inputs...>{}, WithRespectTo<InputQuantity>{}, inputValues...)}
+                ->std::same_as<PartialDerivative<Output, InputQuantity>>;
+        }>{};
+    } // namespace detail
+
+    template <typename Candidate>
+    concept EquationOfStateModel = detail::IsEquationOfStateModel<Candidate>::value;
+
+    template <typename EquationOfState, typename RelationType>
+    concept SupportsRelation =
+        EquationOfStateModel<EquationOfState> && ThermodynamicRelationType<RelationType> &&
+        relationCatalogContains<typename std::remove_cvref_t<EquationOfState>::Relations, RelationType>;
+
+    template <typename EquationOfState, typename RelationType, typename InputQuantity>
+    concept SupportsPartialDerivative =
+        SupportsRelation<EquationOfState, RelationType> && ThermodynamicQuantityType<InputQuantity> &&
+        detail::ImplementsPartialDerivative<EquationOfState, RelationType, InputQuantity>::value;
+
+    template <typename Candidate>
+    concept StructureSeedEquationOfState =
+        EquationOfStateModel<Candidate> && SupportsRelation<Candidate, SpecificEnthalpyFromDensity>;
+
+    template <typename Candidate>
+    concept BarotropicClosureEquationOfState =
+        EquationOfStateModel<Candidate> && SupportsRelation<Candidate, DensityFromSpecificEnthalpy> &&
+        SupportsPartialDerivative<Candidate, DensityFromSpecificEnthalpy, quantity::SpecificEnthalpy>;
+
+    template <typename Candidate>
+    concept PressureForceEquationOfState =
+        EquationOfStateModel<Candidate> && SupportsRelation<Candidate, PressureFromSpecificEnthalpy> &&
+        SupportsPartialDerivative<Candidate, PressureFromSpecificEnthalpy, quantity::SpecificEnthalpy>;
+} // namespace mean_field::eos

libmeanfield/interface/eos/eos_base.cppm

@@ -1,16 +0,0 @@
-export module mean_field:eos.base;
-
-export namespace mean_field::eos {
-    class EquationOfState {
-    public:
-        virtual ~EquationOfState()                                                            = default;
-        [[nodiscard]] virtual double pressure_from_density(double density) const              = 0;
-        [[nodiscard]] virtual double pressure_from_enthalpy(double enthalpy) const            = 0;
-        [[nodiscard]] virtual double enthalpy_from_density(double density) const              = 0;
-        [[nodiscard]] virtual double enthalpy_from_pressure(double pressure) const            = 0;
-        [[nodiscard]] virtual double density_from_enthalpy(double enthalpy) const             = 0;
-        [[nodiscard]] virtual double density_derivative_from_enthalpy(double enthalpy) const  = 0;
-        [[nodiscard]] virtual double pressure_derivative_from_enthalpy(double enthalpy) const = 0;
-        [[nodiscard]] virtual double pressure_derivative_from_density(double density) const   = 0;
-    };
-} // namespace mean_field::eos

libmeanfield/interface/eos/evaluation.cppm

@@ -0,0 +1,90 @@
+module;
+
+#include <stdexcept>
+#include <string>
+#include <utility>
+
+export module mean_field:eos.evaluation;
+export import :eos.concepts;
+
+export namespace mean_field::eos {
+    enum class EvaluationErrorCode {
+        unsupported_relation,
+        unsupported_derivative,
+        wrong_input_count,
+        wrong_input_quantity,
+        nonfinite_input,
+        outside_domain,
+        nonfinite_result
+    };
+
+    class EvaluationError final : public std::domain_error {
+    public:
+        explicit EvaluationError(
+            const EvaluationErrorCode code,
+            std::string message
+        )
+            : std::domain_error(std::move(message)),
+              m_code(code) {
+        }
+
+        [[nodiscard]] EvaluationErrorCode code() const noexcept {
+            return m_code;
+        }
+
+    private:
+        EvaluationErrorCode m_code;
+    };
+
+    template <
+        ThermodynamicQuantityType OutputQuantity,
+        EquationOfStateModel EquationOfState,
+        QuantityValueType... InputValues>
+        requires SupportsRelation<
+            EquationOfState,
+            Relation<
+                OutputQuantity,
+                QuantityOfT<InputValues>...>>
+    [[nodiscard]] constexpr QuantityValue<OutputQuantity> evaluate(
+        const EquationOfState &equationOfState,
+        const InputValues... inputValues
+    ) noexcept(noexcept(equationOfState
+                            .evaluate(
+                                Relation<
+                                    OutputQuantity,
+                                    QuantityOfT<InputValues>...>{},
+                                inputValues...
+                            ))) {
+        return equationOfState.evaluate(Relation<OutputQuantity, QuantityOfT<InputValues>...>{}, inputValues...);
+    }
+
+    template <
+        ThermodynamicQuantityType OutputQuantity,
+        ThermodynamicQuantityType InputQuantity,
+        EquationOfStateModel EquationOfState,
+        QuantityValueType... InputValues>
+        requires SupportsPartialDerivative<
+            EquationOfState,
+            Relation<
+                OutputQuantity,
+                QuantityOfT<InputValues>...>,
+            InputQuantity>
+    [[nodiscard]] constexpr PartialDerivative<
+        OutputQuantity,
+        InputQuantity>
+    partialDerivative(
+        const EquationOfState &equationOfState,
+        const InputValues... inputValues
+    ) noexcept(noexcept(equationOfState
+                            .partialDerivative(
+                                Relation<
+                                    OutputQuantity,
+                                    QuantityOfT<InputValues>...>{},
+                                WithRespectTo<InputQuantity>{},
+                                inputValues...
+                            ))) {
+        return equationOfState.partialDerivative(
+            Relation<OutputQuantity, QuantityOfT<InputValues>...>{}, WithRespectTo<InputQuantity>{}, inputValues...
+        );
+    }
+} // namespace mean_field::eos

libmeanfield/interface/eos/polytropic.cppm

@@ -3,11 +3,18 @@ module;
 #include <format>
 #include <stdexcept>
 export module mean_field:eos.polytrope;
-export import :eos.base;
+export import :eos.evaluation;
 
 export namespace mean_field::eos {
-    class Polytrope final : public EquationOfState {
+    class Polytrope final {
     public:
+        using Relations = RelationCatalog<
+            PressureFromDensity,
+            PressureFromSpecificEnthalpy,
+            SpecificEnthalpyFromDensity,
+            SpecificEnthalpyFromPressure,
+            DensityFromSpecificEnthalpy>;
+
         Polytrope(
             const double polytropic_index,
             const double polytropic_constant
@@ -49,82 +56,128 @@ export namespace mean_field::eos {
             return m_enthalpy_scale;
         }
 
-        [[nodiscard]] double pressure_from_density(const double density) const override {
+        [[nodiscard]] PressureValue evaluate(
-            validate_nonnegativity(density, "density");
+            PressureFromDensity,
-            if (density == 0.0) {
+            const DensityValue density
-                return 0.0;
+        ) const {
+            validate_nonnegativity(density.value(), "density");
+            if (density.value() == 0.0) {
+                return PressureValue{0.0};
             }
 
-            return m_polytropic_constant * std::pow(density, 1.0 + 1.0 / m_polytropic_index);
+            return PressureValue{m_polytropic_constant * std::pow(density.value(), 1.0 + 1.0 / m_polytropic_index)};
         }
 
-        [[nodiscard]] double enthalpy_from_density(const double density) const override {
+        [[nodiscard]] SpecificEnthalpyValue evaluate(
-            validate_nonnegativity(density, "density");
+            SpecificEnthalpyFromDensity,
-            if (density == 0.0) {
+            const DensityValue density
-                return 0.0;
+        ) const {
+            validate_nonnegativity(density.value(), "density");
+            if (density.value() == 0.0) {
+                return SpecificEnthalpyValue{0.0};
             }
 
-            return m_enthalpy_scale * std::pow(density, 1.0 / m_polytropic_index);
+            return SpecificEnthalpyValue{m_enthalpy_scale * std::pow(density.value(), 1.0 / m_polytropic_index)};
         }
 
-        [[nodiscard]] double density_from_enthalpy(const double enthalpy) const override {
+        [[nodiscard]] DensityValue evaluate(
-            validate_finite(enthalpy, "enthalpy");
+            DensityFromSpecificEnthalpy,
+            const SpecificEnthalpyValue specificEnthalpy
+        ) const {
+            validate_finite(specificEnthalpy.value(), "specific enthalpy");
 
-            if (enthalpy <= 0.0) {
+            if (specificEnthalpy.value() <= 0.0) {
-                return 0.0;
+                return DensityValue{0.0};
             }
 
-            return std::pow(enthalpy / m_enthalpy_scale, m_polytropic_index);
+            return DensityValue{std::pow(specificEnthalpy.value() / m_enthalpy_scale, m_polytropic_index)};
         }
 
-        [[nodiscard]] double pressure_from_enthalpy(const double enthalpy) const override {
+        [[nodiscard]] PressureValue evaluate(
-            validate_finite(enthalpy, "enthalpy");
+            PressureFromSpecificEnthalpy,
+            const SpecificEnthalpyValue specificEnthalpy
+        ) const {
+            const DensityValue density = evaluate(DensityFromSpecificEnthalpy{}, specificEnthalpy);
 
-            if (enthalpy <= 0.0) {
+            if (specificEnthalpy.value() <= 0.0) {
-                return 0.0;
+                return PressureValue{0.0};
             }
 
-            return density_from_enthalpy(enthalpy) * enthalpy / (m_polytropic_index + 1.0);
+            return PressureValue{density.value() * specificEnthalpy.value() / (m_polytropic_index + 1.0)};
         }
 
-        [[nodiscard]] double density_derivative_from_enthalpy(const double enthalpy) const override {
+        [[nodiscard]] SpecificEnthalpyValue evaluate(
-            validate_finite(enthalpy, "enthalpy");
+            SpecificEnthalpyFromPressure,
-            if (enthalpy < 0.0) {
+            const PressureValue pressure
-                return 0.0;
+        ) const {
+            validate_nonnegativity(pressure.value(), "pressure");
+            if (pressure.value() == 0.0) {
+                return SpecificEnthalpyValue{0.0};
             }
 
-            if (enthalpy == 0.0) {
+            const double indexPlusOne = m_polytropic_index + 1.0;
-                return m_polytropic_index == 1.0 ? 1.0 / m_enthalpy_scale : 0.0;
+
+            return SpecificEnthalpyValue{
+                indexPlusOne * std::pow(m_polytropic_constant, m_polytropic_index / indexPlusOne) *
+                std::pow(pressure.value(), 1.0 / indexPlusOne)
+            };
         }
 
-            return m_polytropic_index / m_enthalpy_scale *
+        [[nodiscard]] PartialDerivative<
-                   std::pow(enthalpy / m_enthalpy_scale, m_polytropic_index - 1.0);
+            quantity::Density,
+            quantity::SpecificEnthalpy>
+        partialDerivative(
+            DensityFromSpecificEnthalpy,
+            WithRespectTo<quantity::SpecificEnthalpy>,
+            const SpecificEnthalpyValue specificEnthalpy
+        ) const {
+            validate_finite(specificEnthalpy.value(), "specific enthalpy");
+            if (specificEnthalpy.value() < 0.0) {
+                return PartialDerivative<quantity::Density, quantity::SpecificEnthalpy>{0.0};
             }
 
-        [[nodiscard]] double pressure_derivative_from_enthalpy(const double enthalpy) const override {
+            if (specificEnthalpy.value() == 0.0) {
-            validate_finite(enthalpy, "enthalpy");
+                return PartialDerivative<quantity::Density, quantity::SpecificEnthalpy>{
-
+                    m_polytropic_index == 1.0 ? 1.0 / m_enthalpy_scale : 0.0
-            if (enthalpy <= 0.0) {
+                };
-                return 0.0;
             }
 
-            return density_from_enthalpy(enthalpy);
+            return PartialDerivative<quantity::Density, quantity::SpecificEnthalpy>{
+                m_polytropic_index / m_enthalpy_scale *
+                std::pow(specificEnthalpy.value() / m_enthalpy_scale, m_polytropic_index - 1.0)
+            };
         }
 
-        [[nodiscard]] double pressure_derivative_from_density(const double density) const override {
+        [[nodiscard]] PartialDerivative<
-            validate_nonnegativity(density, "density");
+            quantity::Pressure,
-            if (density == 0.0) {
+            quantity::SpecificEnthalpy>
-                return 0.0;
+        partialDerivative(
+            PressureFromSpecificEnthalpy,
+            WithRespectTo<quantity::SpecificEnthalpy>,
+            const SpecificEnthalpyValue specificEnthalpy
+        ) const {
+            const DensityValue density = evaluate(DensityFromSpecificEnthalpy{}, specificEnthalpy);
+
+            return PartialDerivative<quantity::Pressure, quantity::SpecificEnthalpy>{density.value()};
         }
 
-            return m_polytropic_constant * (1.0 + 1.0 / m_polytropic_index) *
+        [[nodiscard]] PartialDerivative<
-                   std::pow(density, 1.0 / m_polytropic_index);
+            quantity::Pressure,
+            quantity::Density>
+        partialDerivative(
+            PressureFromDensity,
+            WithRespectTo<quantity::Density>,
+            const DensityValue density
+        ) const {
+            validate_nonnegativity(density.value(), "density");
+            if (density.value() == 0.0) {
+                return PartialDerivative<quantity::Pressure, quantity::Density>{0.0};
             }
 
-        [[nodiscard]] double enthalpy_from_pressure(const double pressure) const override {
+            return PartialDerivative<quantity::Pressure, quantity::Density>{
-            validate_nonnegativity(pressure, "pressure");
+                m_polytropic_constant * (1.0 + 1.0 / m_polytropic_index) *
-            const double np1 = m_polytropic_index + 1;
+                std::pow(density.value(), 1.0 / m_polytropic_index)
-            return np1 * std::pow(m_polytropic_constant, m_polytropic_index / np1) * std::pow(pressure, 1.0 / np1);
+            };
         }
 
     private:
@@ -133,8 +186,8 @@ export namespace mean_field::eos {
             const char *quantity
         ) {
             if (!std::isfinite(value)) {
-                throw std::domain_error(
+                throw EvaluationError(
-                    std::format(
+                    EvaluationErrorCode::nonfinite_input, std::format(
                                                               "The {} must be finite. Instead a value of {} has been "
                                                               "provided",
                                                               quantity, value
@@ -149,8 +202,8 @@ export namespace mean_field::eos {
         ) {
             validate_finite(value, quantity);
             if (value < 0.0) {
-                throw std::domain_error(
+                throw EvaluationError(
-                    std::format(
+                    EvaluationErrorCode::outside_domain, std::format(
                                                              "The {} must be non-negative. Instead a value of {} "
                                                              "has been "
                                                              "provided",

libmeanfield/interface/eos/pressure_surface.cppm

@@ -0,0 +1,128 @@
+module;
+
+#include <memory>
+#include <type_traits>
+
+export module mean_field:eos.pressure_surface;
+
+export import :eos.evaluation;
+
+export namespace mean_field::eos {
+    namespace detail {
+        template <
+            ThermodynamicQuantityType InputQuantity,
+            typename SurfaceState>
+        [[nodiscard]] constexpr auto pressureSurfaceRelationInput(
+            const PressureValue targetPressure,
+            const SurfaceState &state
+        ) {
+            if constexpr (std::same_as<InputQuantity, quantity::Pressure>) {
+                return targetPressure;
+            } else {
+                return state.value(InputQuantity{});
+            }
+        }
+
+        template <typename RelationType> struct PressureSurfaceRelationOperations;
+
+        template <typename CarrierQuantity, typename... InputQuantities>
+        struct PressureSurfaceRelationOperations<Relation<CarrierQuantity, InputQuantities...>> {
+            template <
+                typename EquationOfState,
+                typename SurfaceState>
+            [[nodiscard]] static QuantityValue<CarrierQuantity> requiredCarrierValue(
+                const EquationOfState &equationOfState,
+                const PressureValue targetPressure,
+                const SurfaceState &state
+            ) {
+                return evaluate<CarrierQuantity>(
+                    equationOfState, pressureSurfaceRelationInput<InputQuantities>(targetPressure, state)...
+                );
+            }
+
+            template <
+                typename InputQuantity,
+                typename EquationOfState,
+                typename SurfaceState,
+                typename SurfaceVariation>
+            [[nodiscard]] static double inputJacobianContribution(
+                const EquationOfState &equationOfState,
+                const PressureValue targetPressure,
+                const SurfaceState &state,
+                const SurfaceVariation &variation
+            ) {
+                if constexpr (std::same_as<InputQuantity, quantity::Pressure>) {
+                    return 0.0;
+                } else {
+                    const auto derivative = partialDerivative<CarrierQuantity, InputQuantity>(
+                        equationOfState, pressureSurfaceRelationInput<InputQuantities>(targetPressure, state)...
+                    );
+                    return derivative.value() * variation.value(InputQuantity{}).value();
+                }
+            }
+
+            template <
+                typename EquationOfState,
+                typename SurfaceState,
+                typename SurfaceVariation>
+            [[nodiscard]] static double carrierCorrectionJacobianAction(
+                const EquationOfState &equationOfState,
+                const PressureValue targetPressure,
+                const SurfaceState &state,
+                const SurfaceVariation &variation
+            ) {
+                return (
+                    0.0 + ... +
+                    inputJacobianContribution<InputQuantities>(equationOfState, targetPressure, state, variation)
+                );
+            }
+        };
+    } // namespace detail
+
+    /*
+     * EOS-owned resolution of a constant-pressure condition into the carrier
+     * quantity used by an equation formulation. No field or solver concepts
+     * enter this type.
+     */
+    template <EquationOfStateModel EquationOfState, ThermodynamicRelationType SelectedRelation>
+    class ResolvedPressureSurfaceRelation final {
+    public:
+        using RelationType    = SelectedRelation;
+        using CarrierQuantity = RelationOutputT<RelationType>;
+
+        ResolvedPressureSurfaceRelation(
+            const EquationOfState &equationOfState,
+            const PressureValue targetPressure
+        ) noexcept
+            : m_equationOfState(std::addressof(equationOfState)),
+              m_targetPressure(targetPressure) {
+        }
+
+        [[nodiscard]] PressureValue targetPressure() const noexcept {
+            return m_targetPressure;
+        }
+
+        template <typename SurfaceState>
+        [[nodiscard]] QuantityValue<CarrierQuantity> requiredCarrierValue(const SurfaceState &state) const {
+            return detail::PressureSurfaceRelationOperations<RelationType>::requiredCarrierValue(
+                *m_equationOfState, m_targetPressure, state
+            );
+        }
+
+        template <
+            typename SurfaceState,
+            typename SurfaceVariation>
+        [[nodiscard]] double carrierCorrectionJacobianAction(
+            const SurfaceState &state,
+            const SurfaceVariation &variation
+        ) const {
+            return detail::PressureSurfaceRelationOperations<RelationType>::carrierCorrectionJacobianAction(
+                *m_equationOfState, m_targetPressure, state, variation
+            );
+        }
+
+    private:
+        const EquationOfState *m_equationOfState;
+        PressureValue m_targetPressure;
+    };
+} // namespace mean_field::eos

libmeanfield/interface/eos/quantities.cppm

@@ -0,0 +1,235 @@
+module;
+
+#include <compare>
+#include <concepts>
+#include <string_view>
+#include <type_traits>
+
+export module mean_field:eos.quantities;
+
+export namespace mean_field::eos {
+    struct ThermodynamicQuantity { };
+
+    template <typename Candidate>
+    concept ThermodynamicQuantityType =
+        std::same_as<Candidate, std::remove_cv_t<Candidate>> && std::derived_from<Candidate, ThermodynamicQuantity>;
+
+    namespace quantity {
+        struct Density final : ThermodynamicQuantity {
+            static constexpr std::string_view identifier = "density";
+        };
+
+        struct Pressure final : ThermodynamicQuantity {
+            static constexpr std::string_view identifier = "pressure";
+        };
+
+        struct SpecificEnthalpy final : ThermodynamicQuantity {
+            static constexpr std::string_view identifier = "specific_enthalpy";
+        };
+    } // namespace quantity
+
+    template <typename T>
+    concept Numeric = std::integral<T> || std::floating_point<T>;
+
+    template <ThermodynamicQuantityType Quantity> class QuantityValue final {
+    public:
+        explicit constexpr QuantityValue(const double value) noexcept : m_value(value) {
+        }
+
+        [[nodiscard]] constexpr double value() const noexcept {
+            return m_value;
+        }
+
+        [[nodiscard]] friend constexpr bool operator==(
+            const QuantityValue &,
+            const QuantityValue &
+        ) noexcept = default;
+
+        friend constexpr QuantityValue<Quantity> operator+(
+            const QuantityValue<Quantity> &lhs,
+            const QuantityValue<Quantity> &rhs
+        ) noexcept {
+            return QuantityValue<Quantity>{lhs.m_value + rhs.m_value};
+        }
+
+        friend constexpr QuantityValue<Quantity> operator-(
+            const QuantityValue<Quantity> &lhs,
+            const QuantityValue<Quantity> &rhs
+        ) noexcept {
+            return QuantityValue<Quantity>{lhs.m_value - rhs.m_value};
+        }
+
+        template <Numeric rhsT>
+        friend constexpr QuantityValue<Quantity> operator*(
+            const QuantityValue<Quantity> &lhs,
+            rhsT rhs
+        ) noexcept {
+            return QuantityValue<Quantity>{lhs.m_value * static_cast<double>(rhs)};
+        }
+
+        template <Numeric lhsT>
+        friend constexpr QuantityValue<Quantity> operator*(
+            lhsT lhs,
+            const QuantityValue<Quantity> &rhs
+        ) noexcept {
+            return QuantityValue<Quantity>{static_cast<double>(lhs) * rhs.m_value};
+        }
+
+        template <Numeric rhsT>
+        friend constexpr QuantityValue<Quantity> operator/(
+            const QuantityValue<Quantity> &lhs,
+            rhsT rhs
+        ) noexcept {
+            return QuantityValue<Quantity>{lhs.m_value / static_cast<double>(rhs)};
+        }
+
+        template <Numeric compT>
+        friend constexpr std::partial_ordering operator<=>(
+            const QuantityValue<Quantity> &lhs,
+            compT rhs
+        ) noexcept {
+            return lhs.m_value <=> static_cast<double>(rhs);
+        }
+
+        template <Numeric compT>
+        friend constexpr std::partial_ordering operator<=>(
+            compT lhs,
+            const QuantityValue<Quantity> &rhs
+        ) noexcept {
+            return static_cast<double>(lhs) <=> rhs.m_value;
+        }
+
+        friend constexpr std::partial_ordering operator<=>(
+            const QuantityValue<Quantity> &lhs,
+            const QuantityValue<Quantity> &rhs
+        ) noexcept {
+            return lhs.m_value <=> rhs.m_value;
+        }
+
+    private:
+        double m_value;
+    };
+
+    using DensityValue          = QuantityValue<quantity::Density>;
+    using PressureValue         = QuantityValue<quantity::Pressure>;
+    using SpecificEnthalpyValue = QuantityValue<quantity::SpecificEnthalpy>;
+
+    template <typename Candidate> struct IsQuantityValue : std::false_type { };
+
+    template <ThermodynamicQuantityType Quantity> struct IsQuantityValue<QuantityValue<Quantity>> : std::true_type { };
+
+    template <typename Candidate>
+    concept QuantityValueType = IsQuantityValue<std::remove_cvref_t<Candidate>>::value;
+
+    template <typename Candidate> struct QuantityOf;
+
+    template <ThermodynamicQuantityType Quantity> struct QuantityOf<QuantityValue<Quantity>> {
+        using Type = Quantity;
+    };
+
+    template <QuantityValueType Value> using QuantityOfT = typename QuantityOf<std::remove_cvref_t<Value>>::Type;
+
+    template <ThermodynamicQuantityType OutputQuantity, ThermodynamicQuantityType InputQuantity>
+    class PartialDerivative final {
+    public:
+        explicit constexpr PartialDerivative(const double value) noexcept : m_value(value) {
+        }
+
+        [[nodiscard]] constexpr double value() const noexcept {
+            return m_value;
+        }
+
+        friend constexpr PartialDerivative<
+            OutputQuantity,
+            InputQuantity>
+        operator+(
+            const PartialDerivative<
+                OutputQuantity,
+                InputQuantity> &lhs,
+            const PartialDerivative<
+                OutputQuantity,
+                InputQuantity> &rhs
+        ) noexcept;
+
+        friend constexpr PartialDerivative<
+            OutputQuantity,
+            InputQuantity>
+        operator-(
+            const PartialDerivative<
+                OutputQuantity,
+                InputQuantity> &lhs,
+            const PartialDerivative<
+                OutputQuantity,
+                InputQuantity> &rhs
+        ) noexcept;
+
+        template <Numeric rhsT>
+        friend constexpr PartialDerivative<
+            OutputQuantity,
+            InputQuantity>
+        operator*(
+            const PartialDerivative<
+                OutputQuantity,
+                InputQuantity> &,
+            rhsT
+        ) noexcept;
+
+        template <Numeric lhsT>
+        friend constexpr PartialDerivative<
+            OutputQuantity,
+            InputQuantity>
+        operator*(
+            lhsT,
+            const PartialDerivative<
+                OutputQuantity,
+                InputQuantity> &
+        ) noexcept;
+
+        template <Numeric rhsT>
+        friend constexpr PartialDerivative<
+            OutputQuantity,
+            InputQuantity>
+        operator/(
+            const PartialDerivative<
+                OutputQuantity,
+                InputQuantity> &,
+            rhsT
+        ) noexcept;
+
+        template <Numeric cmpT>
+        friend constexpr std::partial_ordering operator<=>(
+            const PartialDerivative<
+                OutputQuantity,
+                InputQuantity> &lhs,
+            cmpT rhs
+        ) noexcept {
+            return lhs.m_value <=> static_cast<double>(rhs);
+        }
+
+        template <Numeric cmpT>
+        friend constexpr std::partial_ordering operator<=>(
+            cmpT lhs,
+            const PartialDerivative<
+                OutputQuantity,
+                InputQuantity> &rhs
+        ) noexcept {
+            return static_cast<double>(lhs) <=> rhs.m_value;
+        }
+
+        friend constexpr std::partial_ordering operator<=>(
+            const PartialDerivative<
+                OutputQuantity,
+                InputQuantity> &lhs,
+            const PartialDerivative<
+                OutputQuantity,
+                InputQuantity> &rhs
+        ) noexcept {
+            return lhs.m_value <=> rhs.m_value;
+        }
+
+    private:
+        double m_value;
+    };
+
+    template <ThermodynamicQuantityType Quantity> struct WithRespectTo final { };
+} // namespace mean_field::eos

libmeanfield/interface/eos/relations.cppm

@@ -0,0 +1,93 @@
+module;
+
+#include <concepts>
+#include <cstddef>
+#include <tuple>
+#include <type_traits>
+
+export module mean_field:eos.relations;
+export import :eos.quantities;
+
+export namespace mean_field::eos {
+    template <typename... Quantities> struct QuantityList final { };
+
+    template <typename Output, typename... Inputs> struct Relation final {
+        using OutputQuantity                    = Output;
+        using InputQuantities                   = QuantityList<Inputs...>;
+
+        static constexpr std::size_t inputCount = sizeof...(Inputs);
+    };
+
+    template <typename... Relations> struct RelationCatalog final {
+        static constexpr std::size_t size = sizeof...(Relations);
+    };
+
+    namespace detail {
+        template <typename... Types> struct TypesAreUnique;
+
+        template <typename Candidate> struct IsThermodynamicRelation : std::false_type { };
+
+        template <typename Output, typename... Inputs>
+        struct IsThermodynamicRelation<Relation<Output, Inputs...>>
+            : std::bool_constant<
+                  ThermodynamicQuantityType<Output> && (ThermodynamicQuantityType<Inputs> && ...) &&
+                  TypesAreUnique<Inputs...>::value> { };
+
+        template <typename... Types> struct TypesAreUnique : std::true_type { };
+
+        template <typename First, typename... Remaining>
+        struct TypesAreUnique<First, Remaining...>
+            : std::bool_constant<(!std::same_as<First, Remaining> && ...) && TypesAreUnique<Remaining...>::value> { };
+
+        template <typename Candidate> struct IsValidRelationCatalog : std::false_type { };
+
+        template <typename... Relations>
+        struct IsValidRelationCatalog<RelationCatalog<Relations...>>
+            : std::bool_constant<
+                  (sizeof...(Relations) > 0) && (IsThermodynamicRelation<Relations>::value && ...) &&
+                  TypesAreUnique<Relations...>::value> { };
+
+        template <typename Catalog, typename RelationType> struct CatalogContainsRelation : std::false_type { };
+
+        template <typename... Relations, typename RelationType>
+        struct CatalogContainsRelation<RelationCatalog<Relations...>, RelationType>
+            : std::bool_constant<(std::same_as<RelationType, Relations> || ...)> { };
+
+        template <typename RelationType, typename Quantity> struct RelationContainsInput : std::false_type { };
+
+        template <typename Output, typename... Inputs, typename Quantity>
+        struct RelationContainsInput<Relation<Output, Inputs...>, Quantity>
+            : std::bool_constant<(std::same_as<Quantity, Inputs> || ...)> { };
+
+        template <std::size_t Index, typename Quantities> struct QuantityAt;
+
+        template <std::size_t Index, typename... Quantities> struct QuantityAt<Index, QuantityList<Quantities...>> {
+            using Type = std::tuple_element_t<Index, std::tuple<Quantities...>>;
+        };
+    } // namespace detail
+
+    template <typename Candidate>
+    concept ThermodynamicRelationType = detail::IsThermodynamicRelation<std::remove_cv_t<Candidate>>::value;
+
+    template <typename Candidate>
+    concept ValidRelationCatalog = detail::IsValidRelationCatalog<std::remove_cv_t<Candidate>>::value;
+
+    template <typename Catalog, typename RelationType>
+    inline constexpr bool relationCatalogContains =
+        detail::CatalogContainsRelation<std::remove_cv_t<Catalog>, std::remove_cv_t<RelationType>>::value;
+
+    template <typename RelationType, typename Quantity>
+    inline constexpr bool relationContainsInput =
+        detail::RelationContainsInput<std::remove_cv_t<RelationType>, std::remove_cv_t<Quantity>>::value;
+
+    template <ThermodynamicRelationType RelationType> using RelationOutputT = typename RelationType::OutputQuantity;
+
+    template <std::size_t Index, ThermodynamicRelationType RelationType>
+    using RelationInputT      = typename detail::QuantityAt<Index, typename RelationType::InputQuantities>::Type;
+
+    using PressureFromDensity = Relation<quantity::Pressure, quantity::Density>;
+    using PressureFromSpecificEnthalpy = Relation<quantity::Pressure, quantity::SpecificEnthalpy>;
+    using SpecificEnthalpyFromDensity  = Relation<quantity::SpecificEnthalpy, quantity::Density>;
+    using SpecificEnthalpyFromPressure = Relation<quantity::SpecificEnthalpy, quantity::Pressure>;
+    using DensityFromSpecificEnthalpy  = Relation<quantity::Density, quantity::SpecificEnthalpy>;
+} // namespace mean_field::eos

libmeanfield/interface/eos/runtime.cppm

@@ -0,0 +1,645 @@
+module;
+
+#include <array>
+#include <concepts>
+#include <cstddef>
+#include <cstdint>
+#include <expected>
+#include <memory>
+#include <span>
+#include <string>
+#include <string_view>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+
+export module mean_field:eos.runtime;
+export import :eos.evaluation;
+
+export namespace mean_field::eos {
+    class ThermodynamicQuantityId final {
+    public:
+        explicit constexpr ThermodynamicQuantityId(const std::string_view name) noexcept : m_name(name) {
+        }
+
+        [[nodiscard]] constexpr std::string_view name() const noexcept {
+            return m_name;
+        }
+
+        [[nodiscard]] friend constexpr bool operator==(
+            const ThermodynamicQuantityId &,
+            const ThermodynamicQuantityId &
+        ) noexcept = default;
+
+    private:
+        std::string_view m_name;
+    };
+
+    template <typename Quantity>
+    concept RuntimeIdentifiedThermodynamicQuantity = ThermodynamicQuantityType<Quantity> && requires {
+        { Quantity::identifier } -> std::convertible_to<std::string_view>;
+    } && (std::string_view{Quantity::identifier}.size() > 0);
+
+    template <RuntimeIdentifiedThermodynamicQuantity Quantity>
+    inline constexpr ThermodynamicQuantityId thermodynamicQuantityId{std::string_view{Quantity::identifier}};
+
+    struct RuntimeQuantityValue final {
+        ThermodynamicQuantityId quantity;
+        double value;
+    };
+
+    struct RuntimeRelationDescriptor final {
+        ThermodynamicQuantityId outputQuantity;
+        std::span<const ThermodynamicQuantityId> inputQuantities;
+        std::uint64_t partialDerivativeMask;
+
+        [[nodiscard]] constexpr bool hasPartialDerivative(const std::size_t inputIndex) const noexcept {
+            return inputIndex < inputQuantities.size() &&
+                   (partialDerivativeMask & (std::uint64_t{1} << inputIndex)) != 0;
+        }
+    };
+
+    namespace detail {
+        template <typename RelationType> struct HasRuntimeQuantityIdentifiers : std::false_type { };
+
+        template <typename Output, typename... Inputs>
+        struct HasRuntimeQuantityIdentifiers<Relation<Output, Inputs...>>
+            : std::bool_constant<
+                  RuntimeIdentifiedThermodynamicQuantity<Output> &&
+                  (RuntimeIdentifiedThermodynamicQuantity<Inputs> && ...)> { };
+
+        template <typename RelationType> struct RuntimeRelationQuantities;
+
+        template <typename Output, typename... Inputs> struct RuntimeRelationQuantities<Relation<Output, Inputs...>> {
+            using Type = std::tuple<Output, Inputs...>;
+        };
+
+        template <typename... Relations>
+        using RuntimeCatalogQuantityTuple =
+            decltype(std::tuple_cat(std::declval<typename RuntimeRelationQuantities<Relations>::Type>()...));
+
+        template <
+            typename FirstQuantity,
+            typename SecondQuantity>
+        [[nodiscard]] consteval bool runtimeQuantityIdentifiersAreCompatible() {
+            if constexpr (std::same_as<FirstQuantity, SecondQuantity>) {
+                return true;
+            } else {
+                return thermodynamicQuantityId<FirstQuantity> != thermodynamicQuantityId<SecondQuantity>;
+            }
+        }
+
+        template <
+            typename QuantityTuple,
+            std::size_t First,
+            std::size_t... Offsets>
+        [[nodiscard]] consteval bool runtimeQuantityIdentifierIsUnambiguous(std::index_sequence<Offsets...>) {
+            return (
+                runtimeQuantityIdentifiersAreCompatible<
+                    std::tuple_element_t<First, QuantityTuple>,
+                    std::tuple_element_t<First + 1 + Offsets, QuantityTuple>>() &&
+                ...
+            );
+        }
+
+        template <
+            typename QuantityTuple,
+            std::size_t... Indices>
+        [[nodiscard]] consteval bool runtimeQuantityIdentifiersAreUnambiguous(std::index_sequence<Indices...>) {
+            return (
+                runtimeQuantityIdentifierIsUnambiguous<QuantityTuple, Indices>(
+                    std::make_index_sequence<std::tuple_size_v<QuantityTuple> - Indices - 1>{}
+                ) &&
+                ...
+            );
+        }
+
+        template <bool QuantitiesAreIdentified, typename... Relations>
+        struct RuntimeRelationsAreSupported : std::false_type { };
+
+        template <typename... Relations>
+        struct RuntimeRelationsAreSupported<true, Relations...>
+            : std::bool_constant<runtimeQuantityIdentifiersAreUnambiguous<RuntimeCatalogQuantityTuple<Relations...>>(
+                  std::make_index_sequence<std::tuple_size_v<RuntimeCatalogQuantityTuple<Relations...>>>{}
+              )> { };
+
+        template <typename Catalog> struct RuntimeCatalogIsSupported : std::false_type { };
+
+        template <typename... Relations>
+        struct RuntimeCatalogIsSupported<RelationCatalog<Relations...>>
+            : RuntimeRelationsAreSupported<(HasRuntimeQuantityIdentifiers<Relations>::value && ...), Relations...> { };
+    } // namespace detail
+
+    template <typename Candidate>
+    concept RuntimeEquationOfStateModel =
+        EquationOfStateModel<Candidate> &&
+        detail::RuntimeCatalogIsSupported<typename std::remove_cvref_t<Candidate>::Relations>::value;
+
+    namespace detail {
+        template <typename EquationOfState, typename RelationType> struct RuntimeRelationStorage;
+
+        template <typename EquationOfState, typename Output, typename... Inputs>
+        struct RuntimeRelationStorage<EquationOfState, Relation<Output, Inputs...>> {
+            using RelationType = Relation<Output, Inputs...>;
+
+            static_assert(
+                sizeof...(Inputs) <= 64,
+                "Runtime EOS relation descriptors support at most 64 inputs."
+            );
+
+            inline static constexpr std::array<ThermodynamicQuantityId, sizeof...(Inputs)> inputQuantityIds{
+                thermodynamicQuantityId<Inputs>...
+            };
+
+            template <std::size_t... Indices>
+            [[nodiscard]] static consteval std::uint64_t makePartialDerivativeMask(std::index_sequence<Indices...>) {
+                using InputTuple = std::tuple<Inputs...>;
+
+                return (
+                    std::uint64_t{0} | ... |
+                    (SupportsPartialDerivative<EquationOfState, RelationType, std::tuple_element_t<Indices, InputTuple>>
+                         ? (std::uint64_t{1} << Indices)
+                         : std::uint64_t{0})
+                );
+            }
+
+            inline static constexpr std::uint64_t partialDerivativeMask =
+                makePartialDerivativeMask(std::index_sequence_for<Inputs...>{});
+
+            inline static constexpr RuntimeRelationDescriptor descriptor{
+                thermodynamicQuantityId<Output>, std::span<const ThermodynamicQuantityId>{inputQuantityIds},
+                partialDerivativeMask
+            };
+        };
+
+        template <typename EquationOfState, typename Catalog> struct RuntimeCatalogStorage;
+
+        template <typename EquationOfState, typename... Relations>
+        struct RuntimeCatalogStorage<EquationOfState, RelationCatalog<Relations...>> {
+            inline static constexpr std::array descriptors{
+                RuntimeRelationStorage<EquationOfState, Relations>::descriptor...
+            };
+        };
+
+        [[nodiscard]] inline std::expected<
+            double,
+            EvaluationError>
+        runtimeEvaluationFailure(
+            const EvaluationErrorCode code,
+            std::string message
+        ) {
+            return std::unexpected<EvaluationError>{EvaluationError{code, std::move(message)}};
+        }
+
+        template <
+            typename EquationOfState,
+            typename Output,
+            typename... Inputs>
+        [[nodiscard]] std::expected<
+            double,
+            EvaluationError>
+        evaluateRuntimeRelation(
+            const EquationOfState &equationOfState,
+            Relation<
+                Output,
+                Inputs...>,
+            const std::span<const RuntimeQuantityValue> inputValues
+        ) {
+            const auto invoke = [&]<std::size_t... Indices>(std::index_sequence<Indices...>) {
+                return eos::evaluate<Output>(equationOfState, QuantityValue<Inputs>{inputValues[Indices].value}...)
+                    .value();
+            };
+
+            try {
+                return invoke(std::index_sequence_for<Inputs...>{});
+            } catch (const EvaluationError &error) {
+                return std::unexpected<EvaluationError>{error};
+            }
+        }
+
+        template <
+            typename InputQuantity,
+            typename EquationOfState,
+            typename Output,
+            typename... Inputs>
+        [[nodiscard]] bool tryRuntimePartialDerivative(
+            const EquationOfState &equationOfState,
+            Relation<
+                Output,
+                Inputs...> relation,
+            const ThermodynamicQuantityId withRespectTo,
+            const std::span<const RuntimeQuantityValue> inputValues,
+            std::expected<
+                double,
+                EvaluationError> &result
+        ) {
+            if (withRespectTo != thermodynamicQuantityId<InputQuantity>) {
+                return false;
+            }
+
+            if constexpr (SupportsPartialDerivative<EquationOfState, Relation<Output, Inputs...>, InputQuantity>) {
+                const auto invoke = [&]<std::size_t... Indices>(std::index_sequence<Indices...>) {
+                    return eos::partialDerivative<Output, InputQuantity>(
+                               equationOfState, QuantityValue<Inputs>{inputValues[Indices].value}...
+                    )
+                        .value();
+                };
+
+                try {
+                    result = invoke(std::index_sequence_for<Inputs...>{});
+                } catch (const EvaluationError &error) {
+                    result = std::unexpected<EvaluationError>{error};
+                }
+            } else {
+                result = runtimeEvaluationFailure(
+                    EvaluationErrorCode::unsupported_derivative,
+                    "The requested EOS partial derivative is not available."
+                );
+            }
+
+            return true;
+        }
+
+        template <
+            typename EquationOfState,
+            typename Output,
+            typename... Inputs>
+        [[nodiscard]] std::expected<
+            double,
+            EvaluationError>
+        evaluateRuntimePartialDerivative(
+            const EquationOfState &equationOfState,
+            Relation<
+                Output,
+                Inputs...> relation,
+            const ThermodynamicQuantityId withRespectTo,
+            const std::span<const RuntimeQuantityValue> inputValues
+        ) {
+            std::expected<double, EvaluationError> result = runtimeEvaluationFailure(
+                EvaluationErrorCode::unsupported_derivative,
+                "The requested quantity is not an input to the EOS relation."
+            );
+
+            const bool matched =
+                (tryRuntimePartialDerivative<Inputs>(equationOfState, relation, withRespectTo, inputValues, result) ||
+                 ...);
+
+            static_cast<void>(matched);
+            return result;
+        }
+
+        template <
+            typename EquationOfState,
+            typename RelationType>
+        [[nodiscard]] bool runtimeRelationMatches(
+            const ThermodynamicQuantityId outputQuantity,
+            const std::span<const RuntimeQuantityValue> inputValues
+        ) {
+            const RuntimeRelationDescriptor &descriptor =
+                RuntimeRelationStorage<EquationOfState, RelationType>::descriptor;
+
+            if (descriptor.outputQuantity != outputQuantity ||
+                descriptor.inputQuantities.size() != inputValues.size()) {
+                return false;
+            }
+
+            for (std::size_t index = 0; index < inputValues.size(); ++index) {
+                if (descriptor.inputQuantities[index] != inputValues[index].quantity) {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        template <typename EquationOfState, typename Catalog> struct RuntimeCatalogDispatch;
+
+        template <typename EquationOfState, typename... Relations>
+        struct RuntimeCatalogDispatch<EquationOfState, RelationCatalog<Relations...>> {
+            [[nodiscard]] static std::expected<
+                double,
+                EvaluationError>
+            evaluate(
+                const void *object,
+                const ThermodynamicQuantityId outputQuantity,
+                const std::span<const RuntimeQuantityValue> inputValues
+            ) {
+                const auto &equationOfState                   = *static_cast<const EquationOfState *>(object);
+
+                std::expected<double, EvaluationError> result = runtimeEvaluationFailure(
+                    EvaluationErrorCode::unsupported_relation, "The requested EOS relation is not available."
+                );
+
+                const bool matched =
+                    ((runtimeRelationMatches<EquationOfState, Relations>(outputQuantity, inputValues)
+                          ? (result = evaluateRuntimeRelation(equationOfState, Relations{}, inputValues), true)
+                          : false) ||
+                     ...);
+
+                static_cast<void>(matched);
+                return result;
+            }
+
+            [[nodiscard]] static std::expected<
+                double,
+                EvaluationError>
+            partialDerivative(
+                const void *object,
+                const ThermodynamicQuantityId outputQuantity,
+                const ThermodynamicQuantityId withRespectTo,
+                const std::span<const RuntimeQuantityValue> inputValues
+            ) {
+                const auto &equationOfState                   = *static_cast<const EquationOfState *>(object);
+
+                std::expected<double, EvaluationError> result = runtimeEvaluationFailure(
+                    EvaluationErrorCode::unsupported_relation, "The requested EOS relation is not available."
+                );
+
+                const bool matched =
+                    ((runtimeRelationMatches<EquationOfState, Relations>(outputQuantity, inputValues)
+                          ? (result = evaluateRuntimePartialDerivative(
+                                 equationOfState, Relations{}, withRespectTo, inputValues
+                             ),
+                             true)
+                          : false) ||
+                     ...);
+
+                static_cast<void>(matched);
+                return result;
+            }
+        };
+
+        template <RuntimeEquationOfStateModel EquationOfState>
+        using RuntimeAdapter = RuntimeCatalogDispatch<EquationOfState, typename EquationOfState::Relations>;
+
+        template <RuntimeEquationOfStateModel EquationOfState>
+        [[nodiscard]] constexpr std::span<const RuntimeRelationDescriptor> runtimeRelationDescriptors() noexcept {
+            return RuntimeCatalogStorage<EquationOfState, typename EquationOfState::Relations>::descriptors;
+        }
+    } // namespace detail
+
+    class EquationOfStateView final {
+    public:
+        template <RuntimeEquationOfStateModel EquationOfState>
+        explicit EquationOfStateView(EquationOfState &equationOfState) noexcept
+            : m_object(std::addressof(equationOfState)),
+              m_relations(detail::runtimeRelationDescriptors<std::remove_cv_t<EquationOfState>>()),
+              m_evaluate(&detail::RuntimeAdapter<std::remove_cv_t<EquationOfState>>::evaluate),
+              m_partialDerivative(&detail::RuntimeAdapter<std::remove_cv_t<EquationOfState>>::partialDerivative) {
+        }
+
+        [[nodiscard]] std::span<const RuntimeRelationDescriptor> relations() const noexcept {
+            return m_relations;
+        }
+
+        [[nodiscard]] bool supports(
+            const ThermodynamicQuantityId outputQuantity,
+            const std::span<const ThermodynamicQuantityId> inputQuantities
+        ) const noexcept {
+            return findRelation(outputQuantity, inputQuantities) != nullptr;
+        }
+
+        template <
+            RuntimeIdentifiedThermodynamicQuantity OutputQuantity,
+            RuntimeIdentifiedThermodynamicQuantity... InputQuantities>
+        [[nodiscard]] bool supports() const noexcept {
+            constexpr std::array<ThermodynamicQuantityId, sizeof...(InputQuantities)> inputs{
+                thermodynamicQuantityId<InputQuantities>...
+            };
+
+            return supports(thermodynamicQuantityId<OutputQuantity>, std::span<const ThermodynamicQuantityId>{inputs});
+        }
+
+        [[nodiscard]] std::expected<
+            RuntimeQuantityValue,
+            EvaluationError>
+        tryEvaluate(
+            const ThermodynamicQuantityId outputQuantity,
+            const std::span<const RuntimeQuantityValue> inputValues
+        ) const {
+            const auto validation = validateRelationRequest(outputQuantity, inputValues);
+
+            if (!validation.has_value()) {
+                return std::unexpected<EvaluationError>{validation.error()};
+            }
+
+            auto result = m_evaluate(m_object, outputQuantity, inputValues);
+            if (!result.has_value()) {
+                return std::unexpected<EvaluationError>{result.error()};
+            }
+
+            return RuntimeQuantityValue{outputQuantity, *result};
+        }
+
+        template <
+            RuntimeIdentifiedThermodynamicQuantity OutputQuantity,
+            QuantityValueType... InputValues>
+        [[nodiscard]] std::expected<
+            QuantityValue<OutputQuantity>,
+            EvaluationError>
+        tryEvaluate(const InputValues... inputValues) const {
+            constexpr bool inputsHaveRuntimeIdentifiers =
+                (RuntimeIdentifiedThermodynamicQuantity<QuantityOfT<InputValues>> && ...);
+
+            static_assert(inputsHaveRuntimeIdentifiers, "Every runtime EOS input quantity needs a stable identifier.");
+
+            const std::array<RuntimeQuantityValue, sizeof...(InputValues)> runtimeInputs{
+                RuntimeQuantityValue{thermodynamicQuantityId<QuantityOfT<InputValues>>, inputValues.value()}...
+            };
+
+            auto result = tryEvaluate(
+                thermodynamicQuantityId<OutputQuantity>, std::span<const RuntimeQuantityValue>{runtimeInputs}
+            );
+
+            if (!result.has_value()) {
+                return std::unexpected<EvaluationError>{result.error()};
+            }
+
+            return QuantityValue<OutputQuantity>{result->value};
+        }
+
+        [[nodiscard]] std::expected<
+            double,
+            EvaluationError>
+        tryPartialDerivative(
+            const ThermodynamicQuantityId outputQuantity,
+            const ThermodynamicQuantityId withRespectTo,
+            const std::span<const RuntimeQuantityValue> inputValues
+        ) const {
+            const auto validation = validateRelationRequest(outputQuantity, inputValues);
+
+            if (!validation.has_value()) {
+                return std::unexpected<EvaluationError>{validation.error()};
+            }
+
+            const RuntimeRelationDescriptor &descriptor = **validation;
+            bool derivativeAvailable                    = false;
+
+            for (std::size_t index = 0; index < descriptor.inputQuantities.size(); ++index) {
+                if (descriptor.inputQuantities[index] == withRespectTo) {
+                    derivativeAvailable = descriptor.hasPartialDerivative(index);
+                    break;
+                }
+            }
+
+            if (!derivativeAvailable) {
+                return runtimeFailure<double>(
+                    EvaluationErrorCode::unsupported_derivative,
+                    "The requested EOS partial derivative is not available."
+                );
+            }
+
+            return m_partialDerivative(m_object, outputQuantity, withRespectTo, inputValues);
+        }
+
+        template <
+            RuntimeIdentifiedThermodynamicQuantity OutputQuantity,
+            RuntimeIdentifiedThermodynamicQuantity InputQuantity,
+            QuantityValueType... InputValues>
+        [[nodiscard]] std::expected<
+            PartialDerivative<
+                OutputQuantity,
+                InputQuantity>,
+            EvaluationError>
+        tryPartialDerivative(const InputValues... inputValues) const {
+            constexpr bool inputsHaveRuntimeIdentifiers =
+                (RuntimeIdentifiedThermodynamicQuantity<QuantityOfT<InputValues>> && ...);
+
+            static_assert(inputsHaveRuntimeIdentifiers, "Every runtime EOS input quantity needs a stable identifier.");
+
+            const std::array<RuntimeQuantityValue, sizeof...(InputValues)> runtimeInputs{
+                RuntimeQuantityValue{thermodynamicQuantityId<QuantityOfT<InputValues>>, inputValues.value()}...
+            };
+
+            auto result = tryPartialDerivative(
+                thermodynamicQuantityId<OutputQuantity>, thermodynamicQuantityId<InputQuantity>,
+                std::span<const RuntimeQuantityValue>{runtimeInputs}
+            );
+
+            if (!result.has_value()) {
+                return std::unexpected<EvaluationError>{result.error()};
+            }
+
+            return PartialDerivative<OutputQuantity, InputQuantity>{*result};
+        }
+
+    private:
+        using RuntimeEvaluateFunction = std::expected<
+            double,
+            EvaluationError> (*)(
+            const void *,
+            ThermodynamicQuantityId,
+            std::span<const RuntimeQuantityValue>
+        );
+
+        using RuntimePartialDerivativeFunction = std::expected<
+            double,
+            EvaluationError> (*)(
+            const void *,
+            ThermodynamicQuantityId,
+            ThermodynamicQuantityId,
+            std::span<const RuntimeQuantityValue>
+        );
+
+        [[nodiscard]] const RuntimeRelationDescriptor *findRelation(
+            const ThermodynamicQuantityId outputQuantity,
+            const std::span<const ThermodynamicQuantityId> inputQuantities
+        ) const noexcept {
+            for (const RuntimeRelationDescriptor &descriptor : m_relations) {
+                if (descriptor.outputQuantity != outputQuantity ||
+                    descriptor.inputQuantities.size() != inputQuantities.size()) {
+                    continue;
+                }
+
+                bool matches = true;
+                for (std::size_t index = 0; index < inputQuantities.size(); ++index) {
+                    if (descriptor.inputQuantities[index] != inputQuantities[index]) {
+                        matches = false;
+                        break;
+                    }
+                }
+
+                if (matches) {
+                    return std::addressof(descriptor);
+                }
+            }
+
+            return nullptr;
+        }
+
+        [[nodiscard]] std::expected<
+            const RuntimeRelationDescriptor *,
+            EvaluationError>
+        validateRelationRequest(
+            const ThermodynamicQuantityId outputQuantity,
+            const std::span<const RuntimeQuantityValue> inputValues
+        ) const {
+            bool outputAvailable     = false;
+            bool inputCountAvailable = false;
+
+            for (const RuntimeRelationDescriptor &descriptor : m_relations) {
+                if (descriptor.outputQuantity != outputQuantity) {
+                    continue;
+                }
+
+                outputAvailable = true;
+
+                if (descriptor.inputQuantities.size() != inputValues.size()) {
+                    continue;
+                }
+
+                inputCountAvailable = true;
+                bool matches        = true;
+
+                for (std::size_t index = 0; index < inputValues.size(); ++index) {
+                    if (descriptor.inputQuantities[index] != inputValues[index].quantity) {
+                        matches = false;
+                        break;
+                    }
+                }
+
+                if (matches) {
+                    return std::addressof(descriptor);
+                }
+            }
+
+            if (!outputAvailable) {
+                return runtimeFailure<const RuntimeRelationDescriptor *>(
+                    EvaluationErrorCode::unsupported_relation,
+                    "The EOS does not provide a relation for output quantity '" + std::string{outputQuantity.name()} +
+                        "'."
+                );
+            }
+
+            if (!inputCountAvailable) {
+                return runtimeFailure<const RuntimeRelationDescriptor *>(
+                    EvaluationErrorCode::wrong_input_count, "No EOS relation for output quantity '" +
+                                                                std::string{outputQuantity.name()} +
+                                                                "' accepts the supplied number of inputs."
+                );
+            }
+
+            return runtimeFailure<const RuntimeRelationDescriptor *>(
+                EvaluationErrorCode::wrong_input_quantity, "No EOS relation for output quantity '" +
+                                                               std::string{outputQuantity.name()} +
+                                                               "' accepts the supplied input quantities."
+            );
+        }
+
+        template <typename Value>
+        [[nodiscard]] static std::expected<
+            Value,
+            EvaluationError>
+        runtimeFailure(
+            const EvaluationErrorCode code,
+            std::string message
+        ) {
+            return std::unexpected<EvaluationError>{EvaluationError{code, std::move(message)}};
+        }
+
+        const void *m_object;
+        std::span<const RuntimeRelationDescriptor> m_relations;
+        RuntimeEvaluateFunction m_evaluate;
+        RuntimePartialDerivativeFunction m_partialDerivative;
+    };
+} // namespace mean_field::eos

libmeanfield/interface/field/field_mfem.cppm

@@ -1,6 +1,7 @@
 module;
 
 #include <array>
+#include <cmath>
 #include <concepts>
 #include <cstddef>
 #include <memory>
@@ -888,6 +889,282 @@ export namespace mean_field::field {
         mfem::Array<int> m_trueToReduced;
     };
 
+    /*
+     * Boundary rows expressed in a field's reduced solver ordering.
+     *
+     * This object is deliberately independent of any particular physical
+     * surface condition.  Its template constructor below combines a field,
+     * a semantic boundary, and a domain schema.  Consequently the same
+     * topology machinery can be used by any compiled surface formulation;
+     * it is not tied to enthalpy or pressure.
+     */
+    class FieldBoundaryDofMap final {
+    public:
+        FieldBoundaryDofMap() = default;
+
+        FieldBoundaryDofMap(
+            const int fieldReducedSize,
+            const mfem::Array<int> &boundaryReducedDofs
+        )
+            : m_fieldReducedSize(fieldReducedSize),
+              m_boundaryReducedDofs(boundaryReducedDofs) {
+            if (m_fieldReducedSize < 0) {
+                throw std::invalid_argument("FieldBoundaryDofMap requires a non-negative field size.");
+            }
+
+            m_boundaryReducedDofMarker.SetSize(m_fieldReducedSize);
+            m_boundaryReducedDofMarker = 0;
+
+            int previousReducedDof     = -1;
+            for (const int reducedDof : m_boundaryReducedDofs) {
+                if (reducedDof < 0 || reducedDof >= m_fieldReducedSize) {
+                    throw std::invalid_argument("FieldBoundaryDofMap contains a DOF outside the reduced field vector.");
+                }
+                if (reducedDof <= previousReducedDof) {
+                    throw std::invalid_argument("FieldBoundaryDofMap indices must be strictly increasing and unique.");
+                }
+
+                m_boundaryReducedDofMarker[reducedDof] = 1;
+                previousReducedDof                     = reducedDof;
+            }
+        }
+
+        [[nodiscard]] int field_size() const noexcept {
+            return m_fieldReducedSize;
+        }
+
+        [[nodiscard]] int size() const noexcept {
+            return m_boundaryReducedDofs.Size();
+        }
+
+        [[nodiscard]] bool empty() const noexcept {
+            return size() == 0;
+        }
+
+        [[nodiscard]] const mfem::Array<int> &reduced_dofs() const noexcept {
+            return m_boundaryReducedDofs;
+        }
+
+        [[nodiscard]] const mfem::Array<int> &reduced_dof_marker() const noexcept {
+            return m_boundaryReducedDofMarker;
+        }
+
+        [[nodiscard]] bool contains(const int reducedDof) const {
+            if (reducedDof < 0 || reducedDof >= m_fieldReducedSize) {
+                throw std::out_of_range("Reduced DOF index is outside FieldBoundaryDofMap.");
+            }
+            return m_boundaryReducedDofMarker[reducedDof] != 0;
+        }
+
+    private:
+        int m_fieldReducedSize{0};
+        mfem::Array<int> m_boundaryReducedDofs;
+        mfem::Array<int> m_boundaryReducedDofMarker;
+    };
+
+    /* Point-supported rows in a field's reduced solver ordering. */
+    class FieldPointDofMap final {
+    public:
+        FieldPointDofMap() = default;
+
+        FieldPointDofMap(
+            const int fieldReducedSize,
+            const mfem::Array<int> &pointReducedDofs
+        )
+            : m_selectedDofs(
+                  fieldReducedSize,
+                  pointReducedDofs
+              ) {
+        }
+
+        [[nodiscard]] int field_size() const noexcept {
+            return m_selectedDofs.field_size();
+        }
+
+        [[nodiscard]] int size() const noexcept {
+            return m_selectedDofs.size();
+        }
+
+        [[nodiscard]] bool empty() const noexcept {
+            return m_selectedDofs.empty();
+        }
+
+        [[nodiscard]] const mfem::Array<int> &reduced_dofs() const noexcept {
+            return m_selectedDofs.reduced_dofs();
+        }
+
+        [[nodiscard]] const mfem::Array<int> &reduced_dof_marker() const noexcept {
+            return m_selectedDofs.reduced_dof_marker();
+        }
+
+        [[nodiscard]] bool contains(const int reducedDof) const {
+            return m_selectedDofs.contains(reducedDof);
+        }
+
+    private:
+        FieldBoundaryDofMap m_selectedDofs;
+    };
+
+    template <
+        MfemDomainField FieldT,
+        utils::domain::IsBoundary BoundaryT,
+        utils::domain::IsSchema SchemaT>
+    [[nodiscard]] FieldBoundaryDofMap make_field_boundary_dof_map(
+        const mfem::ParFiniteElementSpace &finiteElementSpace,
+        const FieldDofMap &fieldDofMap
+    ) {
+        static_assert(
+            SchemaT::template contains_boundary<BoundaryT>(),
+            "The requested boundary is not registered in the supplied DomainSchema."
+        );
+
+        MFEM_VERIFY(
+            !finiteElementSpace.Nonconforming(),
+            "Field boundary true-DOF resolution currently requires a conforming mfem::ParFiniteElementSpace."
+        );
+        MFEM_VERIFY(
+            fieldDofMap.full_size() == finiteElementSpace.GetTrueVSize(),
+            "The field map and finite-element space have incompatible true-DOF sizes."
+        );
+
+        const mfem::Mesh *mesh = finiteElementSpace.GetMesh();
+        MFEM_VERIFY(mesh != nullptr, "Field boundary DOF resolution requires an MFEM mesh.");
+
+        mfem::Array<int> boundaryVDofMarker(finiteElementSpace.GetVSize());
+        boundaryVDofMarker = 0;
+
+        mfem::Array<int> boundaryElementVDofs;
+        for (int boundaryElement = 0; boundaryElement < mesh->GetNBE(); ++boundaryElement) {
+            if (!SchemaT::template boundary_attribute_matches<BoundaryT>(mesh->GetBdrAttribute(boundaryElement))) {
+                continue;
+            }
+
+            finiteElementSpace.GetBdrElementVDofs(boundaryElement, boundaryElementVDofs);
+            for (const int encodedVDof : boundaryElementVDofs) {
+                const int vdof = mfem::FiniteElementSpace::DecodeDof(encodedVDof);
+                MFEM_VERIFY(
+                    vdof >= 0 && vdof < finiteElementSpace.GetVSize(), "MFEM returned an invalid boundary vector DOF."
+                );
+                boundaryVDofMarker[vdof] = 1;
+            }
+        }
+
+        finiteElementSpace.Synchronize(boundaryVDofMarker);
+
+        mfem::Array<int> boundaryReducedDofMarker(fieldDofMap.reduced_size());
+        boundaryReducedDofMarker = 0;
+
+        for (int vdof = 0; vdof < boundaryVDofMarker.Size(); ++vdof) {
+            if (boundaryVDofMarker[vdof] == 0) {
+                continue;
+            }
+
+            const int trueDof = finiteElementSpace.GetLocalTDofNumber(vdof);
+            if (trueDof < 0) {
+                continue;
+            }
+
+            const std::optional<int> reducedDof = fieldDofMap.reduced_dof(trueDof);
+            MFEM_VERIFY(
+                reducedDof.has_value(),
+                "A boundary DOF selected for the field is absent from that field's reduced solver map."
+            );
+            boundaryReducedDofMarker[*reducedDof] = 1;
+        }
+
+        mfem::Array<int> boundaryReducedDofs;
+        mfem::FiniteElementSpace::MarkerToList(boundaryReducedDofMarker, boundaryReducedDofs);
+        return FieldBoundaryDofMap(fieldDofMap.reduced_size(), boundaryReducedDofs);
+    }
+
+    template <MfemDomainField FieldT>
+    [[nodiscard]] FieldPointDofMap make_field_point_dof_map(
+        const mfem::ParFiniteElementSpace &finiteElementSpace,
+        const FieldDofMap &fieldDofMap,
+        const mfem::Vector &point,
+        const double tolerance
+    ) {
+        MFEM_VERIFY(
+            !finiteElementSpace.Nonconforming(),
+            "Field point true-DOF resolution currently requires a conforming mfem::ParFiniteElementSpace."
+        );
+        MFEM_VERIFY(
+            fieldDofMap.full_size() == finiteElementSpace.GetTrueVSize(),
+            "The field map and finite-element space have incompatible true-DOF sizes."
+        );
+        MFEM_VERIFY(
+            std::isfinite(tolerance) && tolerance >= 0.0, "The field point tolerance must be finite and non-negative."
+        );
+
+        const mfem::Mesh *mesh = finiteElementSpace.GetMesh();
+        MFEM_VERIFY(mesh != nullptr, "Field point DOF resolution requires an MFEM mesh.");
+        MFEM_VERIFY(
+            point.Size() == mesh->SpaceDimension(), "The requested field point has the wrong coordinate dimension."
+        );
+
+        mfem::Array<int> pointVDofMarker(finiteElementSpace.GetVSize());
+        pointVDofMarker = 0;
+
+        mfem::Array<int> vertexVDofs;
+        for (int vertex = 0; vertex < mesh->GetNV(); ++vertex) {
+            const mfem::real_t *coordinates = mesh->GetVertex(vertex);
+            double distanceSquared          = 0.0;
+            for (int component = 0; component < point.Size(); ++component) {
+                const double difference = coordinates[component] - point(component);
+                distanceSquared += difference * difference;
+            }
+            if (std::sqrt(distanceSquared) > tolerance) {
+                continue;
+            }
+
+            finiteElementSpace.GetVertexVDofs(vertex, vertexVDofs);
+            for (const int encodedVDof : vertexVDofs) {
+                const int vdof = mfem::FiniteElementSpace::DecodeDof(encodedVDof);
+                MFEM_VERIFY(
+                    vdof >= 0 && vdof < finiteElementSpace.GetVSize(), "MFEM returned an invalid point vector DOF."
+                );
+                pointVDofMarker[vdof] = 1;
+            }
+        }
+
+        finiteElementSpace.Synchronize(pointVDofMarker);
+
+        mfem::Array<int> pointReducedDofMarker(fieldDofMap.reduced_size());
+        pointReducedDofMarker = 0;
+        for (int vdof = 0; vdof < pointVDofMarker.Size(); ++vdof) {
+            if (pointVDofMarker[vdof] == 0) {
+                continue;
+            }
+
+            const int trueDof = finiteElementSpace.GetLocalTDofNumber(vdof);
+            if (trueDof < 0) {
+                continue;
+            }
+
+            const std::optional<int> reducedDof = fieldDofMap.reduced_dof(trueDof);
+            MFEM_VERIFY(
+                reducedDof.has_value(),
+                "A point DOF selected for the field is absent from that field's reduced solver map."
+            );
+            pointReducedDofMarker[*reducedDof] = 1;
+        }
+
+        mfem::Array<int> pointReducedDofs;
+        mfem::FiniteElementSpace::MarkerToList(pointReducedDofMarker, pointReducedDofs);
+
+        const long long localPointDofCount = pointReducedDofs.Size();
+        long long globalPointDofCount      = 0;
+        MPI_Allreduce(
+            &localPointDofCount, &globalPointDofCount, 1, MPI_LONG_LONG, MPI_SUM, finiteElementSpace.GetComm()
+        );
+        MFEM_VERIFY(
+            globalPointDofCount == finiteElementSpace.GetVDim(),
+            "The requested geometric point must identify exactly one field vertex globally."
+        );
+
+        return FieldPointDofMap(fieldDofMap.reduced_size(), pointReducedDofs);
+    }
+
     /*
      * Canonical adapter between an MFEM GridFunction and a reduced field
      * vector.
@@ -1015,9 +1292,6 @@ export namespace mean_field::field {
     [[nodiscard]]
     FieldDofGridFunctionAdapter
     make_field_dof_grid_function_adapter(const mfem::ParFiniteElementSpace &finiteElementSpace) {
-        return FieldDofGridFunctionAdapter(
+        return FieldDofGridFunctionAdapter(make_field_dof_map<FieldT, SchemaT>(finiteElementSpace), finiteElementSpace);
-            make_field_dof_map<FieldT, SchemaT>(finiteElementSpace),
-            finiteElementSpace
-        );
     }
 } // namespace mean_field::field

libmeanfield/interface/integrators/pressure_gradient.cppm

@@ -41,7 +41,11 @@ export namespace mean_field::integrators {
         const mfem::GridFunction &compactification_coordinate,
         utils::EOS_P<EOS_T> eos
     )
-        : m_mapping(mapper, displacement, compactification_coordinate),
+        : m_mapping(
+              mapper,
+              displacement,
+              compactification_coordinate
+          ),
           m_eos(std::move(eos)) {
     }
 

libmeanfield/interface/mapping/domain_mapper.cppm

@@ -8,13 +8,15 @@ import :mapping.compactification;
 import :utils.user;
 
 export namespace mean_field::mapping {
-enum class FaceElementSide : uint8_t { element_1, element_2 };
+    enum class FaceElementSide : uint8_t { element_1, element_2 };
 
-class ElementDisplacementData {
+    class ElementDisplacementData {
-public:
+    public:
         ElementDisplacementData(
-      const mfem::FiniteElement &element, const mfem::Vector &displacement_dofs,
+            const mfem::FiniteElement &element,
-      mfem::Ordering::Type ordering = mfem::Ordering::byNODES);
+            const mfem::Vector &displacement_dofs,
+            mfem::Ordering::Type ordering = mfem::Ordering::byNODES
+        );
 
         [[nodiscard]] const mfem::FiniteElement &GetElement() const noexcept;
         [[nodiscard]] const mfem::DenseMatrix &GetDofMatrix() const noexcept;
@@ -22,43 +24,46 @@ public:
         [[nodiscard]] int GetDofCount() const noexcept;
         [[nodiscard]] mfem::Ordering::Type GetOrdering() const noexcept;
 
-private:
+    private:
         const mfem::FiniteElement *m_element;
         mfem::DenseMatrix m_dof_matrix;
         int m_dimension;
         mfem::Ordering::Type m_ordering;
-};
+    };
 
-struct CompactificationPointData {
+    struct CompactificationPointData {
         double coordinate{0.0};
         mfem::Vector coordinate_gradient;
-};
+    };
 
-[[nodiscard]] ElementDisplacementData
+    [[nodiscard]] ElementDisplacementData ElementDisplacementDataFromElementVDofs(
-ElementDisplacementDataFromElementVDofs(const mfem::FiniteElement &element,
+        const mfem::FiniteElement &element,
-                                        const mfem::Vector &displacement_dofs);
+        const mfem::Vector &displacement_dofs
+    );
 
-class ElementCompactificationData {
+    class ElementCompactificationData {
-public:
+    public:
-  ElementCompactificationData(const mfem::FiniteElement &element,
+        ElementCompactificationData(
-                              const mfem::Vector &dofs);
+            const mfem::FiniteElement &element,
+            const mfem::Vector &dofs
+        );
 
         [[nodiscard]] const mfem::FiniteElement &GetElement() const noexcept;
         [[nodiscard]] const mfem::Vector &GetDofs() const noexcept;
         [[nodiscard]] int GetDofCount() const noexcept;
 
-private:
+    private:
         const mfem::FiniteElement *m_element;
         mfem::Vector m_dofs;
-};
+    };
 
-struct ElementMappingData {
+    struct ElementMappingData {
         const ElementDisplacementData &displacement;
         const ElementCompactificationData &compactification;
-};
+    };
 
-class DomainMapper {
+    class DomainMapper {
-public:
+    public:
         class Workspace {
         public:
             explicit Workspace(int dimension = 3);
@@ -93,96 +98,113 @@ public:
             compactification::ExteriorMapVariation m_exterior_variation;
         };
 
-public:
+    public:
         DomainMapper(
             utils::DomainMapperOptions options,
-      std::unique_ptr<const compactification::ExteriorDomainMap> exterior_map);
+            std::unique_ptr<const compactification::ExteriorDomainMap> exterior_map
+        );
 
         DomainMapper(const DomainMapper &)            = delete;
         DomainMapper &operator=(const DomainMapper &) = delete;
         DomainMapper(DomainMapper &&)                 = default;
         DomainMapper &operator=(DomainMapper &&)      = default;
 
-  [[nodiscard]] MappingStatus
+        [[nodiscard]] MappingStatus EvaluatePoint(
-  EvaluatePoint(const ElementMappingData &element_data,
+            const ElementMappingData &element_data,
             mfem::ElementTransformation &transformation,
             const mfem::IntegrationPoint &integration_point,
-                Workspace &workspace, MappingPointContext &context) const;
+            Workspace &workspace,
+            MappingPointContext &context
+        ) const;
 
-  [[nodiscard]] MappingStatus
+        [[nodiscard]] MappingStatus EvaluateVolume(
-  EvaluateVolume(const ElementMappingData &element_data,
+            const ElementMappingData &element_data,
             mfem::ElementTransformation &transformation,
             const mfem::IntegrationPoint &integration_point,
-                 Workspace &workspace, VolumeMappingContext &context) const;
+            Workspace &workspace,
+            VolumeMappingContext &context
+        ) const;
 
-  [[nodiscard]] MappingStatus
+        [[nodiscard]] MappingStatus EvaluateFace(
-  EvaluateFace(const ElementMappingData &element_data,
+            const ElementMappingData &element_data,
             mfem::FaceElementTransformations &transformation,
             FaceElementSide side,
             const mfem::IntegrationPoint &integration_point,
-               Workspace &workspace, FaceMappingContext &context) const;
+            Workspace &workspace,
+            FaceMappingContext &context
+        ) const;
 
-  [[nodiscard]] MappingStatus
+        [[nodiscard]] MappingStatus EvaluatePointVariation(
-  EvaluatePointVariation(const ElementMappingData &element_data,
+            const ElementMappingData &element_data,
             const ElementDisplacementData &direction,
             mfem::ElementTransformation &transformation,
             const mfem::IntegrationPoint &integration_point,
             const MappingPointContext &base_context,
             Workspace &workspace,
-                         MappingPointVariation &variation) const;
+            MappingPointVariation &variation
+        ) const;
 
-  [[nodiscard]] MappingStatus
+        [[nodiscard]] MappingStatus EvaluateVolumeVariation(
-  EvaluateVolumeVariation(const ElementMappingData &element_data,
+            const ElementMappingData &element_data,
             const ElementDisplacementData &direction,
             mfem::ElementTransformation &transformation,
             const mfem::IntegrationPoint &integration_point,
             const VolumeMappingContext &base_context,
             Workspace &workspace,
-                          VolumeMappingVariation &variation) const;
+            VolumeMappingVariation &variation
+        ) const;
 
         [[nodiscard]] MappingStatus EvaluateFaceVariation(
             const ElementMappingData &element_data,
             const ElementDisplacementData &direction,
-      mfem::FaceElementTransformations &transformation, FaceElementSide side,
+            mfem::FaceElementTransformations &transformation,
+            FaceElementSide side,
             const mfem::IntegrationPoint &integration_point,
-      const FaceMappingContext &base_context, Workspace &workspace,
+            const FaceMappingContext &base_context,
-      FaceMappingVariation &variation) const;
+            Workspace &workspace,
+            FaceMappingVariation &variation
+        ) const;
 
-  [[nodiscard]] bool IsCompactifiedElement(
+        [[nodiscard]] bool IsCompactifiedElement(const mfem::ElementTransformation &transformation) const noexcept;
-      const mfem::ElementTransformation &transformation) const noexcept;
         [[nodiscard]] int GetDimension() const noexcept;
-  [[nodiscard]] const compactification::ExteriorDomainMap &
+        [[nodiscard]] const compactification::ExteriorDomainMap &GetExteriorMap() const noexcept;
-  GetExteriorMap() const noexcept;
 
-private:
+    private:
         void ValidateElementData(const ElementMappingData &element_data) const;
 
-  void EvaluateField(const ElementDisplacementData &field,
+        void EvaluateField(
+            const ElementDisplacementData &field,
             mfem::ElementTransformation &transformation,
             const mfem::IntegrationPoint &integration_point,
-                     Workspace &workspace, mfem::Vector &value,
+            Workspace &workspace,
-                     mfem::DenseMatrix &jacobian) const;
+            mfem::Vector &value,
+            mfem::DenseMatrix &jacobian
+        ) const;
 
         [[nodiscard]] MappingStatus EvaluateCompactificationCoordinate(
             const ElementCompactificationData &compactification,
             mfem::ElementTransformation &transformation,
-      const mfem::IntegrationPoint &integration_point, Workspace &workspace,
+            const mfem::IntegrationPoint &integration_point,
-      CompactificationPointData &point_data) const;
+            Workspace &workspace,
+            CompactificationPointData &point_data
+        ) const;
 
-  [[nodiscard]] static mfem::ElementTransformation &
+        [[nodiscard]] static mfem::ElementTransformation &SelectFaceElementTransformation(
-  SelectFaceElementTransformation(
+            mfem::FaceElementTransformations &transformation,
-      mfem::FaceElementTransformations &transformation, FaceElementSide side);
+            FaceElementSide side
+        );
 
-  [[nodiscard]] static const mfem::IntegrationPoint &
+        [[nodiscard]] static const mfem::IntegrationPoint &SelectFaceElementIntegrationPoint(
-  SelectFaceElementIntegrationPoint(
+            mfem::FaceElementTransformations &transformation,
-      mfem::FaceElementTransformations &transformation, FaceElementSide side);
+            FaceElementSide side
+        );
 
         utils::DomainMapperOptions m_options;
         std::unique_ptr<const compactification::ExteriorDomainMap> m_exterior_map;
-};
+    };
 
-class GridFunctionMappingEvaluator {
+    class GridFunctionMappingEvaluator {
-public:
+    public:
         /*
          * The evaluator references the supplied grid functions and caches copies of
          * their element-local DOFs. Call InvalidateCache() or Refresh() after either
@@ -194,7 +216,8 @@ public:
         GridFunctionMappingEvaluator(
             const DomainMapper &mapper,
             const mfem::GridFunction &displacement,
-      const mfem::GridFunction &compactification_coordinate);
+            const mfem::GridFunction &compactification_coordinate
+        );
 
         /*
          * Discard all element-local field data. The next evaluation reloads its
@@ -210,37 +233,43 @@ public:
          */
         void Refresh();
 
-  [[nodiscard]] MappingStatus
+        [[nodiscard]] MappingStatus EvaluatePoint(
-  EvaluatePoint(mfem::ElementTransformation &transformation,
+            mfem::ElementTransformation &transformation,
             const mfem::IntegrationPoint &integration_point,
-                MappingPointContext &context);
+            MappingPointContext &context
+        );
 
-  [[nodiscard]] MappingStatus
+        [[nodiscard]] MappingStatus EvaluateVolume(
-  EvaluateVolume(mfem::ElementTransformation &transformation,
+            mfem::ElementTransformation &transformation,
             const mfem::IntegrationPoint &integration_point,
-                 VolumeMappingContext &context);
+            VolumeMappingContext &context
+        );
 
-  [[nodiscard]] MappingStatus
+        [[nodiscard]] MappingStatus EvaluateFace(
-  EvaluateFace(mfem::FaceElementTransformations &transformation,
+            mfem::FaceElementTransformations &transformation,
             FaceElementSide side,
             const mfem::IntegrationPoint &integration_point,
-               FaceMappingContext &context);
+            FaceMappingContext &context
+        );
 
-  [[nodiscard]] VolumeQuadratureContext
+        [[nodiscard]] VolumeQuadratureContext GetQuadratureContext(
-  GetQuadratureContext(mfem::ElementTransformation &transformation,
+            mfem::ElementTransformation &transformation,
-                       const mfem::IntegrationPoint &integration_point);
+            const mfem::IntegrationPoint &integration_point
+        );
 
-  [[nodiscard]] FaceQuadratureContext
+        [[nodiscard]] FaceQuadratureContext GetFaceQuadratureContext(
-  GetFaceQuadratureContext(
             mfem::FaceElementTransformations &transformation,
             const mfem::IntegrationPoint &integration_point,
-      FaceElementSide side = FaceElementSide::element_1);
+            FaceElementSide side = FaceElementSide::element_1
+        );
 
-  void GetPhysicalPoint(mfem::ElementTransformation &transformation,
+        void GetPhysicalPoint(
+            mfem::ElementTransformation &transformation,
             const mfem::IntegrationPoint &integration_point,
-                        mfem::Vector &physical_position);
+            mfem::Vector &physical_position
+        );
 
-private:
+    private:
         void ValidateFieldBindings() const;
         [[nodiscard]] bool InvalidateForChangedSpaces();
         void LoadElement(int element_id);
@@ -261,6 +290,6 @@ private:
         std::unique_ptr<ElementDisplacementData> m_displacement_data;
         std::unique_ptr<ElementCompactificationData> m_compactification_data;
         int m_cached_element_id{-1};
-};
+    };
 
 } // namespace mean_field::mapping

libmeanfield/interface/mean_field.cppm

@@ -54,10 +54,19 @@ export import :operators.prepared_displacement_residual;
 export import :model.structure_profile;
 export import :model.structure.base;
 export import :model.structure.polytropic;
-export import :eos.base;
+export import :eos.quantities;
+export import :eos.relations;
+export import :eos.concepts;
+export import :eos.evaluation;
+export import :eos.pressure_surface;
+export import :eos.runtime;
 export import :eos.polytrope;
-export import :surface.base;
+export import :surface.constant;
-export import :surface.isobaric;
+export import :surface.dependencies;
+export import :surface.compiled;
+export import :surface.compiler;
 export import :model.stellar;
 export import :operators.prepared_mass_normalization;
+export import :operators.prepared_centering_constraint;
+export import :operators.prepared_surface_constraint;
 export import :operators.prepared_stellar_equilibrium;

libmeanfield/interface/models/stellar_model.cppm

@@ -7,62 +7,84 @@ module;
 
 export module mean_field:model.stellar;
 
-export import :eos.base;
+export import :eos.runtime;
 export import :model.structure.base;
-export import :surface.base;
+export import :surface.compiler;
 
 export namespace mean_field::models {
+    namespace detail {
         template <typename Candidate>
-    concept StructurePrescription =
+        concept ConstEquationOfStateReference =
-        std::derived_from<std::remove_cvref_t<Candidate>, mean_field::models::structure::StructureBase>;
+            std::is_lvalue_reference_v<Candidate> && std::is_const_v<std::remove_reference_t<Candidate>> &&
+            eos::EquationOfStateModel<std::remove_cvref_t<Candidate>>;
+    } // namespace detail
 
     template <typename Candidate>
-    concept SurfacePrescription = std::derived_from<std::remove_cvref_t<Candidate>, mean_field::surface::SurfaceBase>;
+    concept StructurePrescription = requires(
+        const std::remove_cvref_t<Candidate> &structurePrescription,
+        const structure::StructureSeedRequest &seedRequest
+    ) {
+        { structurePrescription.equationOfState() } noexcept -> detail::ConstEquationOfStateReference;
+        { structurePrescription.targetMass() } noexcept -> std::same_as<double>;
+        { structurePrescription.makeInitialSeed(seedRequest) } -> std::same_as<structure::StructureSeed>;
+        { structurePrescription.validate() } -> std::same_as<void>;
+    };
 
-    /*
+    template <StructurePrescription Candidate>
-     * Public ownership facade for a physical structure prescription and its
+    using StructureEquationOfStateT =
-     * stellar-surface prescription.
+        std::remove_cvref_t<decltype(std::declval<const std::remove_cvref_t<Candidate> &>().equationOfState())>;
-     *
+
-     * The concrete prescriptions are allocated once at construction. Their
+    template <typename Candidate, typename EquationOfState>
-     * stable addresses allow future prepared operators and contexts to borrow
+    concept SurfacePrescription =
-     * references without making ownership part of the user-facing API.
+        surface::ConstantPressureSurfaceType<Candidate> &&
-     */
+        surface::PressureSurfaceCompilable<surface::BarotropicSurfaceFormulation, std::remove_cvref_t<EquationOfState>>;
+
+    template <StructurePrescription Structure>
+        requires SurfacePrescription<surface::ConstantPressureSurface, StructureEquationOfStateT<Structure>>
     class StellarModel final {
     public:
-        template <
+        using StructurePrescriptionType = Structure;
-            StructurePrescription StructureType,
+        using SurfacePrescriptionType   = surface::ConstantPressureSurface;
-            SurfacePrescription SurfaceType>
+        using EquationOfStateType       = StructureEquationOfStateT<Structure>;
+        using SurfaceConstraintType =
+            surface::CompiledPressureSurfaceConstraintT<surface::BarotropicSurfaceFormulation, EquationOfStateType>;
+
+        template <typename StructureArgument>
+            requires std::same_as<
+                         std::remove_cvref_t<StructureArgument>,
+                         Structure>
         explicit StellarModel(
-            StructureType &&structurePrescription,
+            StructureArgument &&structurePrescription,
-            SurfaceType &&surfacePrescription
+            const surface::ConstantPressureSurface surfacePrescription
         )
-            : StellarModel(
+            : m_structurePrescription(
-                  std::make_unique<std::remove_cvref_t<StructureType>>(
+                  std::make_unique<Structure>(std::forward<StructureArgument>(structurePrescription))
-                      std::forward<StructureType>(structurePrescription)
               ),
-                  std::make_unique<std::remove_cvref_t<SurfaceType>>(std::forward<SurfaceType>(surfacePrescription))
+              m_surfacePrescription(std::make_unique<surface::ConstantPressureSurface>(surfacePrescription)),
+              m_compiledSurfaceConstraint(
+                  std::make_unique<SurfaceConstraintType>(validateAndCompileSurface(
+                      *m_structurePrescription,
+                      *m_surfacePrescription
+                  ))
               ) {
         }
 
         ~StellarModel()                                   = default;
 
         StellarModel(const StellarModel &)                = delete;
-
         StellarModel &operator=(const StellarModel &)     = delete;
-
         StellarModel(StellarModel &&) noexcept            = default;
-
         StellarModel &operator=(StellarModel &&) noexcept = default;
 
-        [[nodiscard]] const mean_field::models::structure::StructureBase &structurePrescription() const noexcept {
+        [[nodiscard]] const Structure &structurePrescription() const noexcept {
             return *m_structurePrescription;
         }
 
-        [[nodiscard]] const mean_field::surface::SurfaceBase &surfacePrescription() const noexcept {
+        [[nodiscard]] const surface::ConstantPressureSurface &surfacePrescription() const noexcept {
             return *m_surfacePrescription;
         }
 
-        [[nodiscard]] const mean_field::eos::EquationOfState &equationOfState() const noexcept {
+        [[nodiscard]] const EquationOfStateType &equationOfState() const noexcept {
             return m_structurePrescription->equationOfState();
         }
 
@@ -70,45 +92,99 @@ export namespace mean_field::models {
             return m_structurePrescription->targetMass();
         }
 
-        [[nodiscard]] mean_field::models::structure::StructureSeed
+        [[nodiscard]] structure::StructureSeed makeInitialSeed(const structure::StructureSeedRequest &request) const {
-        makeInitialSeed(const mean_field::models::structure::StructureSeedRequest &request) const {
             return m_structurePrescription->makeInitialSeed(request);
         }
 
-        [[nodiscard]] const mean_field::surface::ResolvedSurfaceCondition &resolvedSurfaceCondition() const noexcept {
+        [[nodiscard]] const SurfaceConstraintType &compiledSurfaceConstraint() const noexcept {
-            return m_resolvedSurfaceCondition;
+            return *m_compiledSurfaceConstraint;
         }
 
     private:
-        explicit StellarModel(
+        [[nodiscard]] static SurfaceConstraintType validateAndCompileSurface(
-            std::unique_ptr<mean_field::models::structure::StructureBase> structurePrescription,
+            const Structure &structurePrescription,
-            std::unique_ptr<mean_field::surface::SurfaceBase> surfacePrescription
+            const surface::ConstantPressureSurface &surfacePrescription
-        )
-            : m_structurePrescription(std::move(structurePrescription)),
-              m_surfacePrescription(std::move(surfacePrescription)),
-              m_resolvedSurfaceCondition(validateAndResolve(
-                  *m_structurePrescription,
-                  *m_surfacePrescription
-              )) {
-        }
-
-        [[nodiscard]] static mean_field::surface::ResolvedSurfaceCondition validateAndResolve(
-            const mean_field::models::structure::StructureBase &structurePrescription,
-            const mean_field::surface::SurfaceBase &surfacePrescription
         ) {
             structurePrescription.validate();
 
-            const mean_field::eos::EquationOfState &equationOfState = structurePrescription.equationOfState();
+            return surface::compilePressureSurfaceConstraint<surface::BarotropicSurfaceFormulation>(
-
+                surfacePrescription, structurePrescription.equationOfState()
-            surfacePrescription.validate(equationOfState);
+            );
-
-            return surfacePrescription.resolve(equationOfState);
         }
 
-        std::unique_ptr<mean_field::models::structure::StructureBase> m_structurePrescription;
+        std::unique_ptr<Structure> m_structurePrescription;
+        std::unique_ptr<surface::ConstantPressureSurface> m_surfacePrescription;
+        std::unique_ptr<SurfaceConstraintType> m_compiledSurfaceConstraint;
+    };
 
-        std::unique_ptr<mean_field::surface::SurfaceBase> m_surfacePrescription;
+    template <typename Structure>
+    StellarModel(
+        Structure &&,
+        surface::ConstantPressureSurface
+    ) -> StellarModel<std::remove_cvref_t<Structure>>;
 
-        mean_field::surface::ResolvedSurfaceCondition m_resolvedSurfaceCondition;
+    namespace detail {
+        template <typename Candidate> struct IsStellarModel : std::false_type { };
+
+        template <typename Structure> struct IsStellarModel<StellarModel<Structure>> : std::true_type { };
+    } // namespace detail
+
+    template <typename Candidate>
+    concept StellarModelType = detail::IsStellarModel<std::remove_cvref_t<Candidate>>::value;
+
+    class StellarModelView final {
+    public:
+        template <typename Model>
+            requires StellarModelType<Model> &&
+                         eos::RuntimeEquationOfStateModel<typename std::remove_cvref_t<Model>::EquationOfStateType>
+        explicit StellarModelView(Model &model) noexcept
+            : m_equationOfState(model.equationOfState()),
+              m_structurePrescription(std::addressof(model.structurePrescription())),
+              m_makeInitialSeed(&makeInitialSeedFor<typename std::remove_cvref_t<Model>::StructurePrescriptionType>),
+              m_targetMass(model.targetMass()),
+              m_surfaceCondition(model.compiledSurfaceConstraint().descriptor()),
+              m_surfaceDependencies(model.compiledSurfaceConstraint().runtimeDependencies()) {
+        }
+
+        [[nodiscard]] eos::EquationOfStateView equationOfState() const noexcept {
+            return m_equationOfState;
+        }
+
+        [[nodiscard]] double targetMass() const noexcept {
+            return m_targetMass;
+        }
+
+        [[nodiscard]] structure::StructureSeed makeInitialSeed(const structure::StructureSeedRequest &request) const {
+            return m_makeInitialSeed(m_structurePrescription, request);
+        }
+
+        [[nodiscard]] surface::PressureSurfaceDescriptor surfaceCondition() const noexcept {
+            return m_surfaceCondition;
+        }
+
+        [[nodiscard]] surface::RuntimeSurfaceConstraintDependencies surfaceDependencies() const noexcept {
+            return m_surfaceDependencies;
+        }
+
+    private:
+        using MakeInitialSeedFunction = structure::StructureSeed (*)(
+            const void *,
+            const structure::StructureSeedRequest &
+        );
+
+        template <StructurePrescription Structure>
+        [[nodiscard]] static structure::StructureSeed makeInitialSeedFor(
+            const void *structurePrescription,
+            const structure::StructureSeedRequest &request
+        ) {
+            return static_cast<const Structure *>(structurePrescription)->makeInitialSeed(request);
+        }
+
+        eos::EquationOfStateView m_equationOfState;
+        const void *m_structurePrescription;
+        MakeInitialSeedFunction m_makeInitialSeed;
+        double m_targetMass;
+        surface::PressureSurfaceDescriptor m_surfaceCondition;
+        surface::RuntimeSurfaceConstraintDependencies m_surfaceDependencies;
     };
 } // namespace mean_field::models

libmeanfield/interface/models/structure/polytropic.cppm

@@ -12,20 +12,20 @@ export import :model.structure.base;
 import :utils.misc;
 
 export namespace mean_field::models::structure {
-    class PolytropicStructure final : public StructureBase {
+    class PolytropicStructure final {
     public:
         explicit PolytropicStructure(
             eos::Polytrope equationOfState,
             double targetMass
         );
 
-        [[nodiscard]] const eos::EquationOfState &equationOfState() const noexcept override;
+        [[nodiscard]] const eos::Polytrope &equationOfState() const noexcept;
 
-        [[nodiscard]] double targetMass() const noexcept override;
+        [[nodiscard]] double targetMass() const noexcept;
 
-        [[nodiscard]] StructureSeed makeInitialSeed(const StructureSeedRequest &request) const override;
+        [[nodiscard]] StructureSeed makeInitialSeed(const StructureSeedRequest &request) const;
 
-        void validate() const override;
+        void validate() const;
 
     private:
         struct LaneEmdenPoint {

libmeanfield/interface/models/structure/structure_base.cppm

@@ -1,7 +1,7 @@
 module;
 #include <mfem.hpp>
 export module mean_field:model.structure.base;
-export import :eos.base;
+export import :eos.runtime;
 
 export namespace mean_field::models::structure {
     struct StructureSeed {
@@ -23,7 +23,7 @@ export namespace mean_field::models::structure {
     public:
         virtual ~StructureBase()                                                                       = default;
 
-        [[nodiscard]] virtual const eos::EquationOfState &equationOfState() const noexcept             = 0;
+        [[nodiscard]] virtual eos::EquationOfStateView equationOfState() const noexcept                = 0;
 
         [[nodiscard]] virtual double targetMass() const noexcept                                       = 0;
 

libmeanfield/interface/operators/prepared_centering_constraint.cppm

@@ -0,0 +1,103 @@
+module;
+
+#include <cmath>
+#include <utility>
+
+#include <mfem.hpp>
+
+export module mean_field:operators.prepared_centering_constraint;
+
+export import :field.mfem;
+
+export namespace mean_field::operators {
+    struct PreparedCenteringConstraintReport final {
+        bool cachedCenterDisplacement{false};
+
+        [[nodiscard]] bool DidAnyWork() const noexcept {
+            return cachedCenterDisplacement;
+        }
+    };
+
+    /*
+     * Strong translational gauge: the material point at the computational
+     * origin has zero displacement. The three corresponding displacement
+     * residual rows replace redundant force-balance rows.
+     */
+    class PreparedCenteringConstraint final {
+    public:
+        explicit PreparedCenteringConstraint(field::FieldPointDofMap centerRows)
+            : m_centerRows(std::move(centerRows)),
+              m_centerDisplacement(m_centerRows.size()) {
+        }
+
+        [[nodiscard]] PreparedCenteringConstraintReport Prepare(
+            const mfem::Vector &displacement,
+            const bool displacementChanged
+        ) {
+            MFEM_VERIFY(
+                displacement.Size() == m_centerRows.field_size(),
+                "The centering constraint received a displacement vector with the wrong size."
+            );
+
+            PreparedCenteringConstraintReport report;
+            if (!m_isPrepared || displacementChanged) {
+                for (int centerIndex = 0; centerIndex < m_centerRows.size(); ++centerIndex) {
+                    const double value = displacement(m_centerRows.reduced_dofs()[centerIndex]);
+                    MFEM_VERIFY(
+                        std::isfinite(value), "The centering constraint received a non-finite center displacement."
+                    );
+                    m_centerDisplacement(centerIndex) = value;
+                }
+                report.cachedCenterDisplacement = true;
+            }
+
+            m_isPrepared = true;
+            return report;
+        }
+
+        void ApplyResidualRows(mfem::Vector &displacementResidual) const {
+            VerifyPrepared();
+            MFEM_VERIFY(
+                displacementResidual.Size() == m_centerRows.field_size(),
+                "The centering constraint received a displacement residual with the wrong size."
+            );
+
+            for (int centerIndex = 0; centerIndex < m_centerRows.size(); ++centerIndex) {
+                displacementResidual(m_centerRows.reduced_dofs()[centerIndex]) = m_centerDisplacement(centerIndex);
+            }
+        }
+
+        void ApplyJacobianRows(
+            const mfem::Vector &displacementVariation,
+            mfem::Vector &displacementAction
+        ) const {
+            VerifyPrepared();
+            MFEM_VERIFY(
+                displacementVariation.Size() == m_centerRows.field_size() &&
+                    displacementAction.Size() == m_centerRows.field_size(),
+                "The centering constraint received a Jacobian vector with the wrong size."
+            );
+
+            for (const int centerRow : m_centerRows.reduced_dofs()) {
+                displacementAction(centerRow) = displacementVariation(centerRow);
+            }
+        }
+
+        [[nodiscard]] bool IsPrepared() const noexcept {
+            return m_isPrepared;
+        }
+
+        [[nodiscard]] const field::FieldPointDofMap &GetCenterRows() const noexcept {
+            return m_centerRows;
+        }
+
+    private:
+        void VerifyPrepared() const {
+            MFEM_VERIFY(m_isPrepared, "The centering constraint must be prepared before row application.");
+        }
+
+        field::FieldPointDofMap m_centerRows;
+        mfem::Vector m_centerDisplacement;
+        bool m_isPrepared{false};
+    };
+} // namespace mean_field::operators

libmeanfield/interface/operators/prepared_stellar_equilibrium.cppm

@@ -1,7 +1,9 @@
 module;
 
 #include <compare>
+#include <concepts>
 #include <cstdint>
+#include <type_traits>
 
 #include <mfem.hpp>
 
@@ -16,9 +18,11 @@ export import :operators.context.gravity_field;
 export import :operators.gravity_field;
 export import :operators.gravity_field_jacobian;
 export import :operators.prepared_barotropic_closure;
+export import :operators.prepared_centering_constraint;
 export import :operators.prepared_displacement_residual;
 export import :operators.prepared_hydrostatic_equilibrium;
 export import :operators.prepared_mass_normalization;
+export import :operators.prepared_surface_constraint;
 export import :physics.rigid_rotation;
 export import :utils.blocks;
 
@@ -50,11 +54,14 @@ export namespace mean_field::operators {
         PreparedHydrostaticEquilibriumReport hydrostatic;
         PreparedDisplacementResidualReport displacement;
         PreparedMassNormalizationReport massNormalization;
+        PreparedSurfaceConstraintReport surfaceConstraint;
+        PreparedCenteringConstraintReport centeringConstraint;
         bool assembledResidual{false};
 
         [[nodiscard]] bool DidAnyChildWork() const noexcept {
             return gravity.DidAnyWork() || barotropicClosure.DidAnyWork() || hydrostatic.DidAnyWork() ||
-                   displacement.DidAnyWork() || massNormalization.DidAnyWork();
+                   displacement.DidAnyWork() || massNormalization.DidAnyWork() || surfaceConstraint.DidAnyWork() ||
+                   centeringConstraint.DidAnyWork();
         }
 
         [[nodiscard]] bool DidAnyWork() const noexcept {
@@ -74,19 +81,27 @@ export namespace mean_field::operators {
 
     class PreparedStellarEquilibriumOperator final : public mfem::Operator {
     public:
+        template <models::StellarModelType Model>
+            requires std::same_as<
+                         typename std::remove_cvref_t<Model>::EquationOfStateType,
+                         eos::Polytrope> &&
+                     SingleFieldPressureSurfaceConstraintFor<
+                         typename std::remove_cvref_t<Model>::SurfaceConstraintType,
+                         field::Enthalpy> &&
+                     std::is_lvalue_reference_v<Model &&>
         PreparedStellarEquilibriumOperator(
             fem::FEM &f,
             const mapping::DomainMapper &domainMapper,
-            const eos::Polytrope &equationOfState,
+            Model &&stellarModel
-            double targetMass
+        )
-        );
+            : PreparedStellarEquilibriumOperator(
-
+                  f,
-        PreparedStellarEquilibriumOperator(
+                  domainMapper,
-            fem::FEM &f,
+                  stellarModel.equationOfState(),
-            const mapping::DomainMapper &domainMapper,
+                  stellarModel.targetMass(),
-            const eos::Polytrope &equationOfState,
+                  PressureSurfaceConstraintView{stellarModel.compiledSurfaceConstraint()}
-            const models::StellarModel &stellarModel
+              ) {
-        );
+        }
 
         PreparedStellarEquilibriumOperator(const PreparedStellarEquilibriumOperator &)            = delete;
         PreparedStellarEquilibriumOperator &operator=(const PreparedStellarEquilibriumOperator &) = delete;
@@ -122,6 +137,8 @@ export namespace mean_field::operators {
         [[nodiscard]] const PreparedHydrostaticEquilibriumOperator &GetHydrostaticOperator() const noexcept;
         [[nodiscard]] const PreparedDisplacementResidualOperator &GetDisplacementOperator() const noexcept;
         [[nodiscard]] const PreparedMassNormalizationOperator &GetMassNormalizationOperator() const noexcept;
+        [[nodiscard]] const PreparedPressureSurfaceConstraint &GetSurfaceConstraintOperator() const noexcept;
+        [[nodiscard]] const PreparedCenteringConstraint &GetCenteringConstraintOperator() const noexcept;
 
     private:
         struct ConstructionData;
@@ -133,6 +150,15 @@ export namespace mean_field::operators {
             const mapping::DomainMapper &domainMapper,
             const eos::Polytrope &equationOfState,
             double targetMass,
+            PressureSurfaceConstraintView surfaceConstraint
+        );
+
+        PreparedStellarEquilibriumOperator(
+            fem::FEM &f,
+            const mapping::DomainMapper &domainMapper,
+            const eos::Polytrope &equationOfState,
+            double targetMass,
+            PressureSurfaceConstraintView surfaceConstraint,
             ConstructionData constructionData
         );
 
@@ -150,6 +176,8 @@ export namespace mean_field::operators {
         PreparedHydrostaticEquilibriumOperator m_hydrostaticOperator;
         PreparedDisplacementResidualOperator m_displacementOperator;
         PreparedMassNormalizationOperator m_massNormalizationOperator;
+        PreparedPressureSurfaceConstraint m_surfaceConstraintOperator;
+        PreparedCenteringConstraint m_centeringConstraintOperator;
 
         StellarEquilibriumDependencies m_preparedDependencies;
         mfem::Vector m_cachedResidual;

libmeanfield/interface/operators/prepared_surface_constraint.cppm

@@ -0,0 +1,235 @@
+module;
+
+#include <cmath>
+#include <concepts>
+#include <memory>
+#include <type_traits>
+#include <utility>
+
+#include <mfem.hpp>
+
+export module mean_field:operators.prepared_surface_constraint;
+
+export import :field.mfem;
+export import :surface.compiled;
+
+namespace mean_field::operators::detail {
+    template <eos::ThermodynamicQuantityType Quantity> struct SingleQuantitySurfaceState final {
+        eos::QuantityValue<Quantity> quantityValue;
+
+        [[nodiscard]] eos::QuantityValue<Quantity> value(Quantity) const noexcept {
+            return quantityValue;
+        }
+    };
+} // namespace mean_field::operators::detail
+
+export namespace mean_field::operators {
+    /*
+     * Runtime enforcement currently supports a pointwise pressure constraint
+     * whose row field is also its sole state field. The concept is expressed
+     * entirely in compiled-constraint metadata: no thermodynamic carrier or
+     * concrete field is selected by this prepared layer.
+     */
+    template <typename Candidate>
+    concept SingleFieldPressureSurfaceConstraint =
+        requires {
+            typename std::remove_cvref_t<Candidate>::PhysicalQuantity;
+            typename std::remove_cvref_t<Candidate>::CarrierQuantity;
+            typename std::remove_cvref_t<Candidate>::CarrierField;
+            typename std::remove_cvref_t<Candidate>::SurfaceDependencies;
+        } && std::same_as<typename std::remove_cvref_t<Candidate>::PhysicalQuantity, eos::quantity::Pressure> &&
+        std::same_as<
+            typename std::remove_cvref_t<Candidate>::SurfaceDependencies::RowField,
+            typename std::remove_cvref_t<Candidate>::CarrierField> &&
+        std::same_as<
+            typename std::remove_cvref_t<Candidate>::SurfaceDependencies::StateFieldTypes,
+            field::TypeList<typename std::remove_cvref_t<Candidate>::CarrierField>>;
+
+    template <typename Candidate, typename Field>
+    concept SingleFieldPressureSurfaceConstraintFor =
+        SingleFieldPressureSurfaceConstraint<Candidate> &&
+        std::same_as<typename std::remove_cvref_t<Candidate>::SurfaceDependencies::RowField, Field>;
+
+    /*
+     * Non-owning runtime bridge for a statically compiled pressure constraint.
+     * There is one function-pointer dispatch per complete row application;
+     * the concrete loop remains templated so EOS operations can be inlined.
+     */
+    class PressureSurfaceConstraintView final {
+    public:
+        template <SingleFieldPressureSurfaceConstraint Constraint>
+        explicit PressureSurfaceConstraintView(const Constraint &constraint) noexcept
+            : m_constraint(std::addressof(constraint)),
+              m_applyResidualRows(&applyResidualRows<Constraint>),
+              m_applyJacobianRows(&applyJacobianRows<Constraint>),
+              m_descriptor(constraint.descriptor()) {
+        }
+
+        void ApplyResidualRows(
+            const mfem::Vector &surfaceState,
+            const field::FieldBoundaryDofMap &surfaceRows,
+            mfem::Vector &rowResidual
+        ) const {
+            m_applyResidualRows(m_constraint, surfaceState, surfaceRows, rowResidual);
+        }
+
+        void ApplyJacobianRows(
+            const mfem::Vector &surfaceState,
+            const field::FieldBoundaryDofMap &surfaceRows,
+            const mfem::Vector &stateVariation,
+            mfem::Vector &rowAction
+        ) const {
+            m_applyJacobianRows(m_constraint, surfaceState, surfaceRows, stateVariation, rowAction);
+        }
+
+        [[nodiscard]] surface::PressureSurfaceDescriptor descriptor() const noexcept {
+            return m_descriptor;
+        }
+
+    private:
+        using ApplyResidualRowsFunction = void (*)(
+            const void *,
+            const mfem::Vector &,
+            const field::FieldBoundaryDofMap &,
+            mfem::Vector &
+        );
+        using ApplyJacobianRowsFunction = void (*)(
+            const void *,
+            const mfem::Vector &,
+            const field::FieldBoundaryDofMap &,
+            const mfem::Vector &,
+            mfem::Vector &
+        );
+
+        template <SingleFieldPressureSurfaceConstraint Constraint>
+        static void applyResidualRows(
+            const void *constraint,
+            const mfem::Vector &surfaceState,
+            const field::FieldBoundaryDofMap &surfaceRows,
+            mfem::Vector &rowResidual
+        ) {
+            using CarrierQuantity = typename Constraint::CarrierQuantity;
+
+            for (int surfaceIndex = 0; surfaceIndex < surfaceRows.size(); ++surfaceIndex) {
+                const detail::SingleQuantitySurfaceState<CarrierQuantity> state{
+                    eos::QuantityValue<CarrierQuantity>{surfaceState(surfaceIndex)}
+                };
+                rowResidual(surfaceRows.reduced_dofs()[surfaceIndex]) =
+                    static_cast<const Constraint *>(constraint)->residual(state);
+            }
+        }
+
+        template <SingleFieldPressureSurfaceConstraint Constraint>
+        static void applyJacobianRows(
+            const void *constraint,
+            const mfem::Vector &surfaceState,
+            const field::FieldBoundaryDofMap &surfaceRows,
+            const mfem::Vector &stateVariation,
+            mfem::Vector &rowAction
+        ) {
+            using CarrierQuantity = typename Constraint::CarrierQuantity;
+
+            for (int surfaceIndex = 0; surfaceIndex < surfaceRows.size(); ++surfaceIndex) {
+                const int reducedDof = surfaceRows.reduced_dofs()[surfaceIndex];
+                const detail::SingleQuantitySurfaceState<CarrierQuantity> state{
+                    eos::QuantityValue<CarrierQuantity>{surfaceState(surfaceIndex)}
+                };
+                const detail::SingleQuantitySurfaceState<CarrierQuantity> variation{
+                    eos::QuantityValue<CarrierQuantity>{stateVariation(reducedDof)}
+                };
+                rowAction(reducedDof) = static_cast<const Constraint *>(constraint)->jacobianAction(state, variation);
+            }
+        }
+
+        const void *m_constraint;
+        ApplyResidualRowsFunction m_applyResidualRows;
+        ApplyJacobianRowsFunction m_applyJacobianRows;
+        surface::PressureSurfaceDescriptor m_descriptor;
+    };
+
+    struct PreparedSurfaceConstraintReport final {
+        bool cachedSurfaceState{false};
+
+        [[nodiscard]] bool DidAnyWork() const noexcept {
+            return cachedSurfaceState;
+        }
+    };
+
+    class PreparedPressureSurfaceConstraint final {
+    public:
+        PreparedPressureSurfaceConstraint(
+            field::FieldBoundaryDofMap surfaceRows,
+            const PressureSurfaceConstraintView constraint
+        )
+            : m_surfaceRows(std::move(surfaceRows)),
+              m_constraint(constraint),
+              m_surfaceState(m_surfaceRows.size()) {
+        }
+
+        [[nodiscard]] PreparedSurfaceConstraintReport Prepare(
+            const mfem::Vector &reducedState,
+            const bool stateChanged
+        ) {
+            MFEM_VERIFY(
+                reducedState.Size() == m_surfaceRows.field_size(),
+                "The pressure surface constraint received a state vector with the wrong size."
+            );
+
+            PreparedSurfaceConstraintReport report;
+            if (!m_isPrepared || stateChanged) {
+                for (int surfaceIndex = 0; surfaceIndex < m_surfaceRows.size(); ++surfaceIndex) {
+                    const double value = reducedState(m_surfaceRows.reduced_dofs()[surfaceIndex]);
+                    MFEM_VERIFY(std::isfinite(value), "The pressure surface constraint received non-finite state.");
+                    m_surfaceState(surfaceIndex) = value;
+                }
+                report.cachedSurfaceState = true;
+            }
+
+            m_isPrepared = true;
+            return report;
+        }
+
+        void ApplyResidualRows(mfem::Vector &rowResidual) const {
+            VerifyPrepared();
+            MFEM_VERIFY(
+                rowResidual.Size() == m_surfaceRows.field_size(),
+                "The pressure surface constraint received a residual vector with the wrong size."
+            );
+            m_constraint.ApplyResidualRows(m_surfaceState, m_surfaceRows, rowResidual);
+        }
+
+        void ApplyJacobianRows(
+            const mfem::Vector &stateVariation,
+            mfem::Vector &rowAction
+        ) const {
+            VerifyPrepared();
+            MFEM_VERIFY(
+                stateVariation.Size() == m_surfaceRows.field_size() && rowAction.Size() == m_surfaceRows.field_size(),
+                "The pressure surface constraint received a Jacobian vector with the wrong size."
+            );
+            m_constraint.ApplyJacobianRows(m_surfaceState, m_surfaceRows, stateVariation, rowAction);
+        }
+
+        [[nodiscard]] bool IsPrepared() const noexcept {
+            return m_isPrepared;
+        }
+
+        [[nodiscard]] const field::FieldBoundaryDofMap &GetSurfaceRows() const noexcept {
+            return m_surfaceRows;
+        }
+
+        [[nodiscard]] surface::PressureSurfaceDescriptor GetPhysicalCondition() const noexcept {
+            return m_constraint.descriptor();
+        }
+
+    private:
+        void VerifyPrepared() const {
+            MFEM_VERIFY(m_isPrepared, "The pressure surface constraint must be prepared before row application.");
+        }
+
+        field::FieldBoundaryDofMap m_surfaceRows;
+        PressureSurfaceConstraintView m_constraint;
+        mfem::Vector m_surfaceState;
+        bool m_isPrepared{false};
+    };
+} // namespace mean_field::operators

libmeanfield/interface/surface/compiled.cppm

@@ -0,0 +1,66 @@
+module;
+
+export module mean_field:surface.compiled;
+
+export import :eos.pressure_surface;
+export import :surface.constant;
+export import :surface.dependencies;
+
+export namespace mean_field::surface {
+    template <
+        eos::EquationOfStateModel EquationOfState,
+        SurfaceConstraintFormulationType Formulation,
+        eos::ThermodynamicRelationType SelectedRelation,
+        typename Dependencies>
+    class CompiledPressureSurfaceConstraint final {
+    public:
+        using PhysicalCondition   = ConstantPressureSurface;
+        using PhysicalQuantity    = eos::quantity::Pressure;
+        using CarrierQuantity     = typename Formulation::CarrierQuantity;
+        using CarrierField        = typename Formulation::CarrierField;
+        using Relation            = SelectedRelation;
+        using SurfaceDependencies = Dependencies;
+
+        CompiledPressureSurfaceConstraint(
+            const ConstantPressureSurface condition,
+            const EquationOfState &equationOfState
+        ) noexcept
+            : m_condition(condition),
+              m_resolvedRelation(
+                  equationOfState,
+                  condition.targetPressure()
+              ) {
+        }
+
+        [[nodiscard]] eos::PressureValue targetPressure() const noexcept {
+            return m_condition.targetPressure();
+        }
+
+        [[nodiscard]] PressureSurfaceDescriptor descriptor() const noexcept {
+            return m_condition.descriptor();
+        }
+
+        [[nodiscard]] static constexpr RuntimeSurfaceConstraintDependencies runtimeDependencies() noexcept {
+            return SurfaceDependencies::runtimeDescription();
+        }
+
+        template <typename SurfaceState> [[nodiscard]] double residual(const SurfaceState &state) const {
+            return state.value(CarrierQuantity{}).value() - m_resolvedRelation.requiredCarrierValue(state).value();
+        }
+
+        template <
+            typename SurfaceState,
+            typename SurfaceVariation>
+        [[nodiscard]] double jacobianAction(
+            const SurfaceState &state,
+            const SurfaceVariation &variation
+        ) const {
+            return variation.value(CarrierQuantity{}).value() -
+                   m_resolvedRelation.carrierCorrectionJacobianAction(state, variation);
+        }
+
+    private:
+        ConstantPressureSurface m_condition;
+        eos::ResolvedPressureSurfaceRelation<EquationOfState, Relation> m_resolvedRelation;
+    };
+} // namespace mean_field::surface

libmeanfield/interface/surface/compiler.cppm

@@ -0,0 +1,143 @@
+module;
+
+#include <cstddef>
+#include <tuple>
+#include <type_traits>
+
+export module mean_field:surface.compiler;
+
+export import :surface.compiled;
+
+export namespace mean_field::surface {
+    namespace detail {
+        template <typename RelationType, typename Formulation, typename EquationOfState>
+        struct PressureSurfaceRelationMatches : std::false_type { };
+
+        template <typename OutputQuantity, typename... InputQuantities, typename Formulation, typename EquationOfState>
+        struct PressureSurfaceRelationMatches<
+            eos::Relation<OutputQuantity, InputQuantities...>,
+            Formulation,
+            EquationOfState>
+            : std::bool_constant<
+                  std::same_as<OutputQuantity, typename Formulation::CarrierQuantity> &&
+                  (std::same_as<eos::quantity::Pressure, InputQuantities> || ...) &&
+                  ((std::same_as<eos::quantity::Pressure, InputQuantities> ||
+                    (surfaceBindingCount<typename Formulation::StateBindings, InputQuantities> == 1 &&
+                     eos::SupportsPartialDerivative<
+                         EquationOfState,
+                         eos::Relation<OutputQuantity, InputQuantities...>,
+                         InputQuantities>)) &&
+                   ...)> { };
+
+        template <typename Catalog, typename Formulation, typename EquationOfState>
+        struct MatchingPressureSurfaceRelations;
+
+        template <typename... Relations, typename Formulation, typename EquationOfState>
+        struct MatchingPressureSurfaceRelations<eos::RelationCatalog<Relations...>, Formulation, EquationOfState> {
+            using Tuple                        = decltype(std::tuple_cat(
+                std::conditional_t<
+                    PressureSurfaceRelationMatches<Relations, Formulation, EquationOfState>::value,
+                    std::tuple<Relations>,
+                    std::tuple<>>{}...
+            ));
+
+            static constexpr std::size_t count = std::tuple_size_v<Tuple>;
+        };
+
+        template <std::size_t Count, typename Tuple> struct UniquePressureSurfaceRelation {
+            using Type = void;
+        };
+
+        template <typename Tuple> struct UniquePressureSurfaceRelation<1, Tuple> {
+            using Type = std::tuple_element_t<0, Tuple>;
+        };
+
+        template <typename Dependencies, typename Field> struct AppendSurfaceDependency;
+
+        template <typename RowField, typename... StateFields, typename Field>
+        struct AppendSurfaceDependency<SurfaceConstraintDependencies<RowField, StateFields...>, Field> {
+            using Type = SurfaceConstraintDependencies<RowField, StateFields..., Field>;
+        };
+
+        template <typename Dependencies, typename InputQuantity, typename Bindings>
+        struct AppendPressureSurfaceInputDependency {
+            using Type =
+                typename AppendSurfaceDependency<Dependencies, SurfaceFieldForQuantityT<Bindings, InputQuantity>>::Type;
+        };
+
+        template <typename Dependencies, typename Bindings>
+        struct AppendPressureSurfaceInputDependency<Dependencies, eos::quantity::Pressure, Bindings> {
+            using Type = Dependencies;
+        };
+
+        template <typename Dependencies, typename Bindings, typename... InputQuantities>
+        struct AppendPressureSurfaceInputDependencies;
+
+        template <typename Dependencies, typename Bindings>
+        struct AppendPressureSurfaceInputDependencies<Dependencies, Bindings> {
+            using Type = Dependencies;
+        };
+
+        template <typename Dependencies, typename Bindings, typename FirstInput, typename... RemainingInputs>
+        struct AppendPressureSurfaceInputDependencies<Dependencies, Bindings, FirstInput, RemainingInputs...> {
+            using WithFirst = typename AppendPressureSurfaceInputDependency<Dependencies, FirstInput, Bindings>::Type;
+            using Type = typename AppendPressureSurfaceInputDependencies<WithFirst, Bindings, RemainingInputs...>::Type;
+        };
+
+        template <typename RelationType, typename Formulation> struct PressureSurfaceDependenciesForRelation;
+
+        template <typename OutputQuantity, typename... InputQuantities, typename Formulation>
+        struct PressureSurfaceDependenciesForRelation<eos::Relation<OutputQuantity, InputQuantities...>, Formulation> {
+            using InitialDependencies =
+                SurfaceConstraintDependencies<typename Formulation::CarrierField, typename Formulation::CarrierField>;
+            using Type = typename AppendPressureSurfaceInputDependencies<
+                InitialDependencies,
+                typename Formulation::StateBindings,
+                InputQuantities...>::Type;
+        };
+
+        template <SurfaceConstraintFormulationType Formulation, eos::EquationOfStateModel EquationOfState>
+        struct PressureSurfaceCompilation {
+            using Matches =
+                MatchingPressureSurfaceRelations<typename EquationOfState::Relations, Formulation, EquationOfState>;
+            using Relation = typename UniquePressureSurfaceRelation<Matches::count, typename Matches::Tuple>::Type;
+        };
+
+        template <SurfaceConstraintFormulationType Formulation, eos::EquationOfStateModel EquationOfState>
+            requires(PressureSurfaceCompilation<Formulation, EquationOfState>::Matches::count == 1)
+        struct CompiledPressureSurfaceConstraintType {
+            using Compilation  = PressureSurfaceCompilation<Formulation, EquationOfState>;
+            using Relation     = typename Compilation::Relation;
+            using Dependencies = typename PressureSurfaceDependenciesForRelation<Relation, Formulation>::Type;
+            using Type = CompiledPressureSurfaceConstraint<EquationOfState, Formulation, Relation, Dependencies>;
+        };
+    } // namespace detail
+
+    template <typename Formulation, typename EquationOfState>
+    concept PressureSurfaceCompilable =
+        SurfaceConstraintFormulationType<Formulation> && eos::EquationOfStateModel<EquationOfState> &&
+        (detail::PressureSurfaceCompilation<std::remove_cvref_t<Formulation>, std::remove_cvref_t<EquationOfState>>::
+             Matches::count == 1);
+
+    template <SurfaceConstraintFormulationType Formulation, eos::EquationOfStateModel EquationOfState>
+        requires PressureSurfaceCompilable<Formulation, EquationOfState>
+    using CompiledPressureSurfaceConstraintT = typename detail::CompiledPressureSurfaceConstraintType<
+        std::remove_cvref_t<Formulation>,
+        std::remove_cvref_t<EquationOfState>>::Type;
+
+    template <
+        SurfaceConstraintFormulationType Formulation,
+        eos::EquationOfStateModel EquationOfState>
+        requires PressureSurfaceCompilable<
+            Formulation,
+            EquationOfState>
+    [[nodiscard]] CompiledPressureSurfaceConstraintT<
+        Formulation,
+        EquationOfState>
+    compilePressureSurfaceConstraint(
+        const ConstantPressureSurface condition,
+        const EquationOfState &equationOfState
+    ) noexcept {
+        return CompiledPressureSurfaceConstraintT<Formulation, EquationOfState>{condition, equationOfState};
+    }
+} // namespace mean_field::surface

libmeanfield/interface/surface/constant.cppm

@@ -0,0 +1,65 @@
+module;
+
+#include <cmath>
+#include <format>
+#include <stdexcept>
+#include <type_traits>
+
+export module mean_field:surface.constant;
+
+export import :eos.quantities;
+
+export namespace mean_field::surface {
+    struct PressureSurfaceDescriptor final {
+        double targetPressure;
+    };
+
+    /*
+     * The only physical surface prescription currently supported by
+     * MeanField. It says nothing about which thermodynamic variable appears
+     * in a nonlinear state vector; resolving pressure into that representation
+     * is an EOS responsibility.
+     */
+    class ConstantPressureSurface final {
+    public:
+        using PhysicalQuantity = eos::quantity::Pressure;
+        using TargetValue      = eos::PressureValue;
+
+        explicit ConstantPressureSurface(const TargetValue targetPressure) : m_targetPressure(targetPressure) {
+            if (!std::isfinite(targetPressure.value())) {
+                throw std::invalid_argument(
+                    std::format(
+                        "The target surface pressure must be finite. Instead P = {} was provided.",
+                        targetPressure.value()
+                    )
+                );
+            }
+            if (targetPressure.value() < 0.0) {
+                throw std::invalid_argument(
+                    std::format(
+                        "The target surface pressure must be non-negative. Instead P = {} was provided.",
+                        targetPressure.value()
+                    )
+                );
+            }
+        }
+
+        [[nodiscard]] TargetValue targetPressure() const noexcept {
+            return m_targetPressure;
+        }
+
+        [[nodiscard]] PressureSurfaceDescriptor descriptor() const noexcept {
+            return PressureSurfaceDescriptor{.targetPressure = m_targetPressure.value()};
+        }
+
+    private:
+        TargetValue m_targetPressure;
+    };
+
+    template <typename Candidate>
+    concept ConstantPressureSurfaceType = std::same_as<std::remove_cvref_t<Candidate>, ConstantPressureSurface>;
+
+    // Familiar physical terminology retained as a synonym, not as a second
+    // surface-condition type.
+    using Isobaric                      = ConstantPressureSurface;
+} // namespace mean_field::surface

libmeanfield/interface/surface/dependencies.cppm

@@ -0,0 +1,186 @@
+module;
+
+#include <array>
+#include <concepts>
+#include <cstddef>
+#include <span>
+#include <string_view>
+#include <type_traits>
+
+export module mean_field:surface.dependencies;
+
+export import :eos.relations;
+export import :field.registry;
+
+export namespace mean_field::surface {
+    template <typename Candidate>
+    concept SurfaceFieldType = requires {
+        { Candidate::name } -> std::convertible_to<std::string_view>;
+    } && (std::string_view{Candidate::name}.size() > 0);
+
+    class SurfaceFieldId final {
+    public:
+        explicit constexpr SurfaceFieldId(const std::string_view name) noexcept : m_name(name) {
+        }
+
+        [[nodiscard]] constexpr std::string_view name() const noexcept {
+            return m_name;
+        }
+
+        [[nodiscard]] friend constexpr bool operator==(
+            const SurfaceFieldId &,
+            const SurfaceFieldId &
+        ) noexcept = default;
+
+    private:
+        std::string_view m_name;
+    };
+
+    template <SurfaceFieldType Field> inline constexpr SurfaceFieldId surfaceFieldId{std::string_view{Field::name}};
+
+    template <eos::ThermodynamicQuantityType ThermodynamicQuantity, SurfaceFieldType Field>
+    struct SurfaceStateBinding final {
+        using Quantity  = ThermodynamicQuantity;
+        using FieldType = Field;
+    };
+
+    template <typename... Bindings> struct SurfaceStateBindings final { };
+
+    namespace detail {
+        template <typename... Types> struct SurfaceTypesAreUnique : std::true_type { };
+
+        template <typename First, typename... Remaining>
+        struct SurfaceTypesAreUnique<First, Remaining...>
+            : std::bool_constant<
+                  (!std::same_as<First, Remaining> && ...) && SurfaceTypesAreUnique<Remaining...>::value> { };
+
+        template <typename Bindings> struct SurfaceBindingsAreValid : std::false_type { };
+
+        template <typename... Bindings>
+        struct SurfaceBindingsAreValid<SurfaceStateBindings<Bindings...>>
+            : std::bool_constant<
+                  (sizeof...(Bindings) > 0) &&
+                  (requires {
+            typename Bindings::Quantity;
+            typename Bindings::FieldType;
+                  } && ...) &&
+                  (eos::ThermodynamicQuantityType<
+                       typename Bindings::Quantity> && ...) &&
+                  (SurfaceFieldType<typename Bindings::FieldType> && ...) &&
+                  SurfaceTypesAreUnique<
+                      typename Bindings::Quantity...>::value> { };
+
+                  template <typename Bindings, typename Quantity> struct SurfaceBindingCount;
+
+                  template <typename Quantity, typename... Bindings>
+                  struct SurfaceBindingCount<SurfaceStateBindings<Bindings...>, Quantity>
+                      : std::integral_constant<
+                            std::size_t,
+                            (std::size_t{0} + ... +
+                             (std::same_as<Quantity, typename Bindings::Quantity> ? std::size_t{1} : std::size_t{0}))> {
+                  };
+
+                  template <typename Bindings, typename Quantity> struct SurfaceFieldForQuantity;
+
+                  template <typename Quantity, typename First, typename... Remaining>
+                  struct SurfaceFieldForQuantity<SurfaceStateBindings<First, Remaining...>, Quantity>
+                      : std::conditional_t<
+                            std::same_as<Quantity, typename First::Quantity>,
+                            std::type_identity<typename First::FieldType>,
+                            SurfaceFieldForQuantity<SurfaceStateBindings<Remaining...>, Quantity>> { };
+
+                  template <typename Candidate, std::size_t CarrierBindingCount>
+                  struct CarrierFieldMatchesSurfaceBinding : std::false_type { };
+
+                  template <typename Candidate>
+                  struct CarrierFieldMatchesSurfaceBinding<Candidate, 1>
+                      : std::bool_constant<std::same_as<
+                            typename SurfaceFieldForQuantity<
+                                typename Candidate::StateBindings,
+                                typename Candidate::CarrierQuantity>::type,
+                            typename Candidate::CarrierField>> { };
+
+                  template <
+                      typename Candidate,
+                      bool BindingsAreValid = SurfaceBindingsAreValid<typename Candidate::StateBindings>::value>
+                  struct FormulationBindingsMatchCarrier : std::false_type { };
+
+                  template <typename Candidate>
+                  struct FormulationBindingsMatchCarrier<Candidate, true>
+                      : CarrierFieldMatchesSurfaceBinding<
+                            Candidate,
+                            SurfaceBindingCount<
+                                typename Candidate::StateBindings,
+                                typename Candidate::CarrierQuantity>::value> { };
+
+                  template <typename Candidate, typename = void>
+                  struct IsSurfaceConstraintFormulation : std::false_type { };
+
+                  template <typename Candidate>
+                  struct IsSurfaceConstraintFormulation<
+                      Candidate,
+                      std::void_t<
+                          typename Candidate::CarrierQuantity,
+                          typename Candidate::CarrierField,
+                          typename Candidate::StateBindings>>
+                      : std::bool_constant<
+                            eos::ThermodynamicQuantityType<typename Candidate::CarrierQuantity> &&
+                            SurfaceFieldType<typename Candidate::CarrierField> &&
+                            FormulationBindingsMatchCarrier<Candidate>::value> { };
+    } // namespace detail
+
+    template <typename Candidate>
+    concept ValidSurfaceStateBindings = detail::SurfaceBindingsAreValid<std::remove_cv_t<Candidate>>::value;
+
+    template <ValidSurfaceStateBindings Bindings, typename Quantity>
+    inline constexpr std::size_t surfaceBindingCount = detail::SurfaceBindingCount<Bindings, Quantity>::value;
+
+    template <ValidSurfaceStateBindings Bindings, typename Quantity>
+        requires(surfaceBindingCount<Bindings, Quantity> == 1)
+    using SurfaceFieldForQuantityT = typename detail::SurfaceFieldForQuantity<Bindings, Quantity>::type;
+
+    template <
+        eos::ThermodynamicQuantityType CarrierThermodynamicQuantity,
+        SurfaceFieldType CarrierFieldType,
+        ValidSurfaceStateBindings Bindings>
+        requires(
+            surfaceBindingCount<Bindings, CarrierThermodynamicQuantity> == 1 &&
+            std::same_as<SurfaceFieldForQuantityT<Bindings, CarrierThermodynamicQuantity>, CarrierFieldType>
+        )
+    struct SurfaceConstraintFormulation final {
+        using CarrierQuantity = CarrierThermodynamicQuantity;
+        using CarrierField    = CarrierFieldType;
+        using StateBindings   = Bindings;
+    };
+
+    using BarotropicSurfaceFormulation = SurfaceConstraintFormulation<
+        eos::quantity::SpecificEnthalpy,
+        field::Enthalpy,
+        SurfaceStateBindings<SurfaceStateBinding<eos::quantity::SpecificEnthalpy, field::Enthalpy>>>;
+
+    template <typename Candidate>
+    concept SurfaceConstraintFormulationType =
+        detail::IsSurfaceConstraintFormulation<std::remove_cv_t<Candidate>>::value;
+
+    struct RuntimeSurfaceConstraintDependencies final {
+        SurfaceFieldId residualRowField;
+        std::span<const SurfaceFieldId> stateFields;
+    };
+
+    template <SurfaceFieldType ResidualField, SurfaceFieldType... StateFields>
+    struct SurfaceConstraintDependencies final {
+        using RowField        = ResidualField;
+        using StateFieldTypes = field::TypeList<StateFields...>;
+
+        inline static constexpr std::array<SurfaceFieldId, sizeof...(StateFields)> runtimeStateFields{
+            surfaceFieldId<StateFields>...
+        };
+
+        [[nodiscard]] static constexpr RuntimeSurfaceConstraintDependencies runtimeDescription() noexcept {
+            return RuntimeSurfaceConstraintDependencies{
+                .residualRowField = surfaceFieldId<ResidualField>,
+                .stateFields      = std::span<const SurfaceFieldId>{runtimeStateFields}
+            };
+        }
+    };
+} // namespace mean_field::surface

libmeanfield/interface/surface/isobaric.cppm

@@ -1,64 +0,0 @@
-module;
-
-#include <cmath>
-#include <format>
-#include <stdexcept>
-
-export module mean_field:surface.isobaric;
-
-export import :surface.base;
-
-export namespace mean_field::surface {
-    class Isobaric final : public SurfaceBase {
-    public:
-        explicit Isobaric(const double targetPressure = 0.0) : m_targetPressure(targetPressure) {
-            validateTargetPressure();
-        }
-
-        [[nodiscard]] double targetPressure() const noexcept {
-            return m_targetPressure;
-        }
-
-        [[nodiscard]] ResolvedSurfaceCondition
-        resolve(const mean_field::eos::EquationOfState &equationOfState) const override {
-            return ResolvedSurfaceCondition{resolveTargetEnthalpy(equationOfState)};
-        }
-
-        void validate(const mean_field::eos::EquationOfState &equationOfState) const override {
-            static_cast<void>(resolveTargetEnthalpy(equationOfState));
-        }
-
-    private:
-        [[nodiscard]] double resolveTargetEnthalpy(const mean_field::eos::EquationOfState &equationOfState) const {
-            validateTargetPressure();
-
-            const double targetEnthalpy = equationOfState.enthalpy_from_pressure(m_targetPressure);
-
-            if (!std::isfinite(targetEnthalpy) || targetEnthalpy < 0.0) {
-                throw std::domain_error(
-                    std::format(
-                        "The equation of state resolved the isobaric "
-                        "target P = {} to the invalid enthalpy h = {}.",
-                        m_targetPressure, targetEnthalpy
-                    )
-                );
-            }
-
-            return targetEnthalpy;
-        }
-
-        void validateTargetPressure() const {
-            if (!std::isfinite(m_targetPressure) || m_targetPressure < 0.0) {
-                throw std::invalid_argument(
-                    std::format(
-                        "The target surface pressure must be finite and "
-                        "non-negative. Instead P = {} was provided.",
-                        m_targetPressure
-                    )
-                );
-            }
-        }
-
-        double m_targetPressure;
-    };
-} // namespace mean_field::surface

libmeanfield/interface/surface/surface_base.cppm

@@ -1,53 +0,0 @@
-module;
-
-#include <cmath>
-#include <stdexcept>
-
-export module mean_field:surface.base;
-
-export import :eos.base;
-
-export namespace mean_field::surface {
-    struct ResolvedSurfaceCondition final {
-        double targetEnthalpy{0.0};
-
-        explicit ResolvedSurfaceCondition(const double requestedTargetEnthalpy)
-            : targetEnthalpy(requestedTargetEnthalpy) {
-            if (!std::isfinite(targetEnthalpy) || targetEnthalpy < 0.0) {
-                throw std::invalid_argument(
-                    "A resolved surface enthalpy must be finite and "
-                    "non-negative."
-                );
-            }
-        }
-
-        [[nodiscard]] double residual(const double enthalpy) const {
-            if (!std::isfinite(enthalpy)) {
-                throw std::invalid_argument("A surface enthalpy value must be finite.");
-            }
-
-            return enthalpy - targetEnthalpy;
-        }
-
-        [[nodiscard]] static double jacobianAction(const double enthalpyVariation) {
-            if (!std::isfinite(enthalpyVariation)) {
-                throw std::invalid_argument("A surface enthalpy variation must be finite.");
-            }
-
-            return enthalpyVariation;
-        }
-    };
-
-    class SurfaceBase {
-    public:
-        virtual ~SurfaceBase() = default;
-
-        [[nodiscard]] virtual ResolvedSurfaceCondition
-        resolve(const mean_field::eos::EquationOfState &equationOfState) const               = 0;
-
-        virtual void validate(const mean_field::eos::EquationOfState &equationOfState) const = 0;
-
-    protected:
-        SurfaceBase() = default;
-    };
-} // namespace mean_field::surface

libmeanfield/interface/utils/misc.cppm

@@ -11,10 +11,12 @@ export module mean_field:utils.misc;
 import :utils.domain;
 
 export namespace mean_field::utils {
-constexpr double APPROX_MAX_ACCEPTABLE_POTENTIAL_ERROR_SI_BURNING = 1e-4;
+    constexpr double APPROX_MAX_ACCEPTABLE_POTENTIAL_ERROR_SI_BURNING = 1e-4;
 
-bool is_vacuum(const mfem::ElementTransformation &Tr,
+    bool is_vacuum(
-               mfem::Array<mfem::Vector *> elvec) {
+        const mfem::ElementTransformation &Tr,
+        mfem::Array<mfem::Vector *> elvec
+    ) {
         using Schema = domain::CoreEnvelopeVacuumDomainSchema;
 
         if (Schema::template attribute_belongs_to<domain::Vacuum>(Tr.Attribute)) {
@@ -27,10 +29,12 @@ bool is_vacuum(const mfem::ElementTransformation &Tr,
             return true;
         }
         return false;
-}
+    }
 
-bool is_vacuum(const mfem::ElementTransformation &Tr,
+    bool is_vacuum(
-               const mfem::Array2D<mfem::DenseMatrix *> &elmats) {
+        const mfem::ElementTransformation &Tr,
+        const mfem::Array2D<mfem::DenseMatrix *> &elmats
+    ) {
         using Schema = domain::CoreEnvelopeVacuumDomainSchema;
 
         if (Schema::template attribute_belongs_to<domain::Vacuum>(Tr.Attribute)) {
@@ -46,47 +50,51 @@ bool is_vacuum(const mfem::ElementTransformation &Tr,
             return true;
         }
         return false;
-}
+    }
 
-constexpr std::string_view ANSI_GREEN = "\033[32m";
+    constexpr std::string_view ANSI_GREEN    = "\033[32m";
-constexpr std::string_view ANSI_RED = "\033[31m";
+    constexpr std::string_view ANSI_RED      = "\033[31m";
-constexpr std::string_view ANSI_YELLOW = "\033[33m";
+    constexpr std::string_view ANSI_YELLOW   = "\033[33m";
-constexpr std::string_view ANSI_BLUE = "\033[34m";
+    constexpr std::string_view ANSI_BLUE     = "\033[34m";
-constexpr std::string_view ANSI_MAGENTA = "\033[35m";
+    constexpr std::string_view ANSI_MAGENTA  = "\033[35m";
-constexpr std::string_view ANSI_CYAN = "\033[36m";
+    constexpr std::string_view ANSI_CYAN     = "\033[36m";
-constexpr std::string_view ANSI_RESET = "\033[0m";
+    constexpr std::string_view ANSI_RESET    = "\033[0m";
-constexpr std::string_view ANSI_BCYAN = "\033[1;36m";
+    constexpr std::string_view ANSI_BCYAN    = "\033[1;36m";
 
-constexpr double G = 1.0;
+    constexpr double G                       = 1.0;
-constexpr double MASS = 1.0;
+    constexpr double MASS                    = 1.0;
-constexpr double RADIUS = 1.0;
+    constexpr double RADIUS                  = 1.0;
 
-[[maybe_unused]] constexpr char HOST[10] = "localhost";
+    [[maybe_unused]] constexpr char HOST[10] = "localhost";
-[[maybe_unused]] constexpr int PORT = 19916;
+    [[maybe_unused]] constexpr int PORT      = 19916;
 
-template <typename T>
+    template <typename T>
-concept is_xad = std::is_same_v<T, xad::AReal<long double>> ||
+    concept is_xad = std::is_same_v<T, xad::AReal<long double>> || std::is_same_v<T, xad::AReal<double>> ||
-                 std::is_same_v<T, xad::AReal<double>> ||
                      std::is_same_v<T, xad::AReal<float>>;
 
-template <typename T>
+    template <typename T>
-concept is_real = std::is_floating_point_v<T> || is_xad<T>;
+    concept is_real                  = std::is_floating_point_v<T> || is_xad<T>;
 
-template <is_real T>
+    template <is_real T> using EOS_P = std::function<T(const T &rho, const T &temp)>;
-using EOS_P = std::function<T(const T &rho, const T &temp)>;
 
-enum class DOMAINS : uint8_t {
+    enum class DOMAINS : uint8_t {
         CORE     = 1 << 0,
         ENVELOPE = 1 << 1,
         VACUUM   = 1 << 2,
         STELLAR  = CORE | ENVELOPE,
         ALL      = CORE | ENVELOPE | VACUUM
-};
+    };
 
-DOMAINS operator|(DOMAINS lhs, DOMAINS rhs);
+    DOMAINS operator|(
+        DOMAINS lhs,
+        DOMAINS rhs
+    );
 
-DOMAINS operator&(DOMAINS lhs, DOMAINS rhs);
+    DOMAINS operator&(
+        DOMAINS lhs,
+        DOMAINS rhs
+    );
 
-int get_mesh_order(const mfem::Mesh &mesh);
+    int get_mesh_order(const mfem::Mesh &mesh);
 
 } // namespace mean_field::utils

tests/field/field_dof_map.cpp

@@ -94,6 +94,65 @@ namespace field_dof_map_test_utils {
         domain::RelationList<>>;
 } // namespace field_dof_map_test_utils
 
+TEST_CASE(
+    "Field Boundary DOF Map Selects The Stellar Surface In Reduced Field Ordering",
+    tags::surface_boundary_dof_topology
+) {
+    namespace domain             = mean_field::utils::domain;
+    namespace field              = mean_field::field;
+
+    mean_field::utils::Args args = test_utils::setup_args();
+    mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
+    REQUIRE(f.okay());
+
+    const field::FieldDofMap enthalpyMap =
+        field::make_field_dof_map<field::Enthalpy, field_dof_map_test_utils::Schema>(*f.enthalpyFes);
+    const field::FieldBoundaryDofMap stellarSurface =
+        field::make_field_boundary_dof_map<field::Enthalpy, domain::StellarSurface, field_dof_map_test_utils::Schema>(
+            *f.enthalpyFes, enthalpyMap
+        );
+    CHECK(stellarSurface.field_size() == enthalpyMap.reduced_size());
+    CHECK(field_dof_map_test_utils::global_sum(stellarSurface.size()) > 0);
+    CHECK(
+        field_dof_map_test_utils::global_sum(stellarSurface.size()) <
+        field_dof_map_test_utils::global_sum(enthalpyMap.reduced_size())
+    );
+
+    for (const int reducedDof : stellarSurface.reduced_dofs()) {
+        CAPTURE(reducedDof);
+        CHECK(stellarSurface.contains(reducedDof));
+        CHECK(enthalpyMap.contains_true_dof(enthalpyMap.true_dof(reducedDof)));
+    }
+}
+
+TEST_CASE(
+    "Field Point DOF Map Selects One Vector Vertex At The Computational Origin",
+    tags::translational_centering_topology
+) {
+    namespace field              = mean_field::field;
+
+    mean_field::utils::Args args = test_utils::setup_args();
+    mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
+    REQUIRE(f.okay());
+
+    const field::FieldDofMap displacementMap =
+        field::make_field_dof_map<field::Displacement, field_dof_map_test_utils::Schema>(*f.displacementFes);
+    mfem::Vector origin(f.mesh->SpaceDimension());
+    origin = 0.0;
+
+    const field::FieldPointDofMap centerRows =
+        field::make_field_point_dof_map<field::Displacement>(*f.displacementFes, displacementMap, origin, 1.0e-12);
+
+    CHECK(centerRows.field_size() == displacementMap.reduced_size());
+    CHECK(field_dof_map_test_utils::global_sum(centerRows.size()) == f.mesh->SpaceDimension());
+
+    for (const int reducedDof : centerRows.reduced_dofs()) {
+        CAPTURE(reducedDof);
+        CHECK(centerRows.contains(reducedDof));
+        CHECK(displacementMap.contains_true_dof(displacementMap.true_dof(reducedDof)));
+    }
+}
+
 TEST_CASE(
     "Field DOF Map Preserves Canonical Bidirectional Indexing",
     tags::field_dof_unit
@@ -523,9 +582,7 @@ TEST_CASE(
 
     STATIC_REQUIRE(field_dof_map_test_utils::CanMakeFieldDofGridFunctionAdapter<field::Displacement>);
 
-    STATIC_REQUIRE_FALSE(
+    STATIC_REQUIRE_FALSE(field_dof_map_test_utils::CanMakeFieldDofGridFunctionAdapter<field::BarotropicConstant>);
-        field_dof_map_test_utils::CanMakeFieldDofGridFunctionAdapter<field::BarotropicConstant>
-    );
 
     CHECK(true);
 }
@@ -751,8 +808,7 @@ TEST_CASE(
     mfem::ParMesh mesh(MPI_COMM_WORLD, serialMesh);
 
     auto fec                = field::Field<field::Density>::make_fec<field::Density::Scalar>(2);
-    auto finiteElementSpace =
+    auto finiteElementSpace = field::Field<field::Density>::make_fespace<field::Density::Scalar>(mesh, *fec);
-        field::Field<field::Density>::make_fespace<field::Density::Scalar>(mesh, *fec);
 
     REQUIRE(finiteElementSpace != nullptr);
 
@@ -797,8 +853,7 @@ TEST_CASE(
     mfem::ParMesh mesh(MPI_COMM_WORLD, serialMesh);
 
     auto fec                = field::Field<field::Enthalpy>::make_fec<field::Enthalpy::Scalar>(2);
-    auto finiteElementSpace =
+    auto finiteElementSpace = field::Field<field::Enthalpy>::make_fespace<field::Enthalpy::Scalar>(mesh, *fec);
-        field::Field<field::Enthalpy>::make_fespace<field::Enthalpy::Scalar>(mesh, *fec);
 
     REQUIRE(finiteElementSpace != nullptr);
 
@@ -850,8 +905,7 @@ TEST_CASE(
     mfem::ParMesh mesh(MPI_COMM_WORLD, serialMesh);
 
     auto fec                = field::Field<field::Density>::make_fec<field::Density::Scalar>(2);
-    auto finiteElementSpace =
+    auto finiteElementSpace = field::Field<field::Density>::make_fespace<field::Density::Scalar>(mesh, *fec);
-        field::Field<field::Density>::make_fespace<field::Density::Scalar>(mesh, *fec);
 
     REQUIRE(finiteElementSpace != nullptr);
 
@@ -901,8 +955,7 @@ TEST_CASE(
     mfem::ParMesh mesh(MPI_COMM_WORLD, serialMesh);
 
     auto fec                = field::Field<field::Displacement>::make_fec<field::Displacement::Vector>(2);
-    auto finiteElementSpace =
+    auto finiteElementSpace = field::Field<field::Displacement>::make_fespace<field::Displacement::Vector>(mesh, *fec);
-        field::Field<field::Displacement>::make_fespace<field::Displacement::Vector>(mesh, *fec);
 
     REQUIRE(finiteElementSpace != nullptr);
 
@@ -940,12 +993,10 @@ TEST_CASE(
     mfem::ParMesh mesh(MPI_COMM_WORLD, serialMesh);
 
     auto fec                     = field::Field<field::Density>::make_fec<field::Density::Scalar>(2);
-    auto finiteElementSpace =
+    auto finiteElementSpace      = field::Field<field::Density>::make_fespace<field::Density::Scalar>(mesh, *fec);
-        field::Field<field::Density>::make_fespace<field::Density::Scalar>(mesh, *fec);
 
     auto otherFec                = field::Field<field::Density>::make_fec<field::Density::Scalar>(2);
-    auto otherFiniteElementSpace =
+    auto otherFiniteElementSpace = field::Field<field::Density>::make_fespace<field::Density::Scalar>(mesh, *otherFec);
-        field::Field<field::Density>::make_fespace<field::Density::Scalar>(mesh, *otherFec);
 
     REQUIRE(finiteElementSpace != nullptr);
     REQUIRE(otherFiniteElementSpace != nullptr);
@@ -959,8 +1010,7 @@ TEST_CASE(
     const mfem::Array<int> empty;
     CHECK_THROWS_AS(
         (field::FieldDofGridFunctionAdapter(
-            field::FieldDofMap(finiteElementSpace->GetTrueVSize() + 1, empty),
+            field::FieldDofMap(finiteElementSpace->GetTrueVSize() + 1, empty), *finiteElementSpace
-            *finiteElementSpace
         )),
         std::invalid_argument
     );

tests/integrators/centrifugal.cpp

@@ -11,7 +11,10 @@ using namespace mean_field;
 namespace {
     struct SerialMappingData {
         explicit SerialMappingData(mfem::Mesh &mesh)
-            : compactification_fes(&mesh, &compactification_fec),
+            : compactification_fes(
+                  &mesh,
+                  &compactification_fec
+              ),
               compactification_coordinate(&compactification_fes),
               mapper(field_dof_test_utils::make_domain_mapper()) {
             compactification_coordinate = 0.0;

tests/integrators/gravity.cpp

@@ -129,8 +129,7 @@ TEST_CASE(
     element_residual[displacement_block]      = &displacement_residual;
 
     integrators::GravityMomentumIntegrator integrator(
-        domain_mapper, displacement, compactification_coordinate,
+        domain_mapper, displacement, compactification_coordinate, integrators::GravityForceJacobianMode::field_coupled
-        integrators::GravityForceJacobianMode::field_coupled
     );
 
     const int maximum_order = std::max(
@@ -300,9 +299,7 @@ TEST_CASE(
     compactification_coordinate         = 0.0;
     mapping::DomainMapper domain_mapper = field_dof_test_utils::make_domain_mapper();
 
-    mapping::GridFunctionMappingEvaluator mapping_evaluator(
+    mapping::GridFunctionMappingEvaluator mapping_evaluator(domain_mapper, displacement, compactification_coordinate);
-        domain_mapper, displacement, compactification_coordinate
-    );
 
     auto reference_density          = [](const mfem::Vector &x) { return 1.0 + x(0); };
 
@@ -381,8 +378,7 @@ TEST_CASE(
     element_residual[displacement_block]      = &displacement_residual;
 
     integrators::GravityMomentumIntegrator integrator(
-        domain_mapper, displacement, compactification_coordinate,
+        domain_mapper, displacement, compactification_coordinate, integrators::GravityForceJacobianMode::field_coupled
-        integrators::GravityForceJacobianMode::field_coupled
     );
 
     const mfem::IntegrationRule &integration_rule = mfem::IntRules.Get(velocity_element->GetGeomType(), 8);
@@ -473,9 +469,7 @@ TEST_CASE(
     mfem::GridFunction compactification_coordinate(&compactification_fes);
     compactification_coordinate         = 0.0;
     mapping::DomainMapper domain_mapper = field_dof_test_utils::make_domain_mapper();
-    mapping::GridFunctionMappingEvaluator mapping_evaluator(
+    mapping::GridFunctionMappingEvaluator mapping_evaluator(domain_mapper, displacement, compactification_coordinate);
-        domain_mapper, displacement, compactification_coordinate
-    );
 
     auto radial_gravity = [](const mfem::Vector &x, mfem::Vector &gravity) {
         gravity.SetSize(3);
@@ -553,8 +547,7 @@ TEST_CASE(
     element_residual[displacement_block]      = &displacement_residual;
 
     integrators::GravityMomentumIntegrator integrator(
-        domain_mapper, displacement, compactification_coordinate,
+        domain_mapper, displacement, compactification_coordinate, integrators::GravityForceJacobianMode::field_coupled
-        integrators::GravityForceJacobianMode::field_coupled
     );
 
     const mfem::IntegrationRule &integration_rule = mfem::IntRules.Get(velocity_element->GetGeomType(), 8);

tests/models/stellar_model.cpp

@@ -1,4 +1,6 @@
+#include <array>
 #include <cmath>
+#include <concepts>
 #include <limits>
 #include <memory>
 #include <type_traits>
@@ -12,17 +14,11 @@ import test_helpers;
 namespace {
     struct StellarModelExtensionTracker final {
         int structureValidationCount{0};
-        int surfaceValidationCount{0};
-        int surfaceResolutionCount{0};
 
-        const mean_field::eos::EquationOfState *structureEquationOfState{nullptr};
+        const mean_field::eos::Polytrope *structureEquationOfState{nullptr};
-
-        const mean_field::eos::EquationOfState *surfaceValidationEquationOfState{nullptr};
-
-        const mean_field::eos::EquationOfState *surfaceResolutionEquationOfState{nullptr};
     };
 
-    class StellarModelTestStructure final : public mean_field::models::structure::StructureBase {
+    class StellarModelTestStructure final {
     public:
         explicit StellarModelTestStructure(std::shared_ptr<StellarModelExtensionTracker> tracker)
             : m_tracker(std::move(tracker)),
@@ -32,17 +28,17 @@ namespace {
               ) {
         }
 
-        [[nodiscard]] const mean_field::eos::EquationOfState &equationOfState() const noexcept override {
+        [[nodiscard]] const mean_field::eos::Polytrope &equationOfState() const noexcept {
             m_tracker->structureEquationOfState = &m_equationOfState;
             return m_equationOfState;
         }
 
-        [[nodiscard]] double targetMass() const noexcept override {
+        [[nodiscard]] double targetMass() const noexcept {
             return 2.5;
         }
 
         [[nodiscard]] mean_field::models::structure::StructureSeed
-        makeInitialSeed(const mean_field::models::structure::StructureSeedRequest &request) const override {
+        makeInitialSeed(const mean_field::models::structure::StructureSeedRequest &request) const {
             mean_field::models::structure::StructureSeed seed;
 
             seed.radius.SetSize(2);
@@ -65,7 +61,7 @@ namespace {
             return seed;
         }
 
-        void validate() const override {
+        void validate() const {
             ++m_tracker->structureValidationCount;
         }
 
@@ -74,59 +70,85 @@ namespace {
         mean_field::eos::Polytrope m_equationOfState;
     };
 
-    class StellarModelTestSurface final : public mean_field::surface::SurfaceBase {
+    class StructureWithoutSeed final {
     public:
-        explicit StellarModelTestSurface(std::shared_ptr<StellarModelExtensionTracker> tracker)
+        [[nodiscard]] const mean_field::eos::Polytrope &equationOfState() const noexcept;
-            : m_tracker(std::move(tracker)) {
-        }
 
-        [[nodiscard]]
+        [[nodiscard]] double targetMass() const noexcept;
-        mean_field::surface::ResolvedSurfaceCondition
-        resolve(const mean_field::eos::EquationOfState &equationOfState) const override {
-            ++m_tracker->surfaceResolutionCount;
 
-            m_tracker->surfaceResolutionEquationOfState = &equationOfState;
+        void validate() const;
-
-            return mean_field::surface::ResolvedSurfaceCondition{0.375};
-        }
-
-        void validate(const mean_field::eos::EquationOfState &equationOfState) const override {
-            ++m_tracker->surfaceValidationCount;
-
-            m_tracker->surfaceValidationEquationOfState = &equationOfState;
-        }
-
-    private:
-        std::shared_ptr<StellarModelExtensionTracker> m_tracker;
     };
+
+    class SurfaceWithoutPhysicalQuantity final { };
+
+    struct ModelSurfaceState final {
+        double specificEnthalpy;
+
+        [[nodiscard]] mean_field::eos::SpecificEnthalpyValue
+        value(mean_field::eos::quantity::SpecificEnthalpy) const noexcept {
+            return mean_field::eos::SpecificEnthalpyValue{specificEnthalpy};
+        }
+    };
+
+    using PolytropicStellarModel = mean_field::models::StellarModel<mean_field::models::structure::PolytropicStructure>;
+
+    using ExtensionStellarModel  = mean_field::models::StellarModel<StellarModelTestStructure>;
 } // namespace
 
 TEST_CASE(
     "Stellar Model Owns Structure And Surface Prescriptions",
-    tags::barotrope &tags::unit &tags::model
+    tags::stellar_model_type_contract
 ) {
-    STATIC_REQUIRE_FALSE(std::is_copy_constructible_v<mean_field::models::StellarModel>);
+    STATIC_CHECK(mean_field::models::StructurePrescription<mean_field::models::structure::PolytropicStructure>);
+    STATIC_CHECK(mean_field::models::StructurePrescription<StellarModelTestStructure>);
+    STATIC_CHECK_FALSE(mean_field::models::StructurePrescription<StructureWithoutSeed>);
 
-    STATIC_REQUIRE_FALSE(std::is_copy_assignable_v<mean_field::models::StellarModel>);
+    STATIC_CHECK(
+        mean_field::models::SurfacePrescription<
+            mean_field::surface::ConstantPressureSurface, mean_field::eos::Polytrope>
+    );
+    STATIC_CHECK_FALSE(
+        mean_field::models::SurfacePrescription<SurfaceWithoutPhysicalQuantity, mean_field::eos::Polytrope>
+    );
 
-    STATIC_REQUIRE(std::is_nothrow_move_constructible_v<mean_field::models::StellarModel>);
+    STATIC_CHECK_FALSE(std::derived_from<StellarModelTestStructure, mean_field::models::structure::StructureBase>);
+    STATIC_CHECK_FALSE(
+        std::derived_from<
+            mean_field::models::structure::PolytropicStructure, mean_field::models::structure::StructureBase>
+    );
+    STATIC_CHECK(
+        std::same_as<
+            decltype(std::declval<const mean_field::models::structure::StructureBase &>().equationOfState()),
+            mean_field::eos::EquationOfStateView>
+    );
 
-    STATIC_REQUIRE(std::is_nothrow_move_assignable_v<mean_field::models::StellarModel>);
+    STATIC_REQUIRE_FALSE(std::is_copy_constructible_v<PolytropicStellarModel>);
+
+    STATIC_REQUIRE_FALSE(std::is_copy_assignable_v<PolytropicStellarModel>);
+
+    STATIC_REQUIRE(std::is_nothrow_move_constructible_v<PolytropicStellarModel>);
+
+    STATIC_REQUIRE(std::is_nothrow_move_assignable_v<PolytropicStellarModel>);
 
     mean_field::models::StellarModel model{
         mean_field::models::structure::PolytropicStructure{mean_field::eos::Polytrope{3.0, 0.25}, 1.0},
-        mean_field::surface::Isobaric{0.0}
+        mean_field::surface::ConstantPressureSurface{mean_field::eos::PressureValue{0.0}}
     };
 
-    CHECK(model.targetMass() == 1.0);
+    STATIC_CHECK(std::same_as<decltype(model), PolytropicStellarModel>);
-    CHECK(model.resolvedSurfaceCondition().targetEnthalpy == 0.0);
+    STATIC_CHECK(
-
+        std::same_as<
-    CHECK(
+            decltype(model.structurePrescription()), const mean_field::models::structure::PolytropicStructure &>
-        dynamic_cast<const mean_field::models::structure::PolytropicStructure *>(&model.structurePrescription()) !=
-        nullptr
     );
+    STATIC_CHECK(
+        std::same_as<decltype(model.surfacePrescription()), const mean_field::surface::ConstantPressureSurface &>
+    );
+    STATIC_CHECK(std::same_as<decltype(model.equationOfState()), const mean_field::eos::Polytrope &>);
 
-    CHECK(dynamic_cast<const mean_field::surface::Isobaric *>(&model.surfacePrescription()) != nullptr);
+    CHECK(model.targetMass() == 1.0);
+    CHECK(model.compiledSurfaceConstraint().targetPressure() == mean_field::eos::PressureValue{0.0});
+    CHECK(&model.equationOfState() == &model.structurePrescription().equationOfState());
+    CHECK(model.surfacePrescription().targetPressure() == mean_field::eos::PressureValue{0.0});
 }
 
 TEST_CASE(
@@ -135,7 +157,7 @@ TEST_CASE(
 ) {
     mean_field::models::StellarModel model{
         mean_field::models::structure::PolytropicStructure{mean_field::eos::Polytrope{3.0, 0.25}, 1.0},
-        mean_field::surface::Isobaric{}
+        mean_field::surface::ConstantPressureSurface{mean_field::eos::PressureValue{0.0}}
     };
 
     const mean_field::models::structure::StructureSeed seed =
@@ -153,45 +175,49 @@ TEST_CASE(
 
 TEST_CASE(
     "Moving A Stellar Model Preserves Stable Prescription Addresses",
-    tags::barotrope &tags::unit &tags::model
+    tags::barotrope &tags::unit &tags::model &tags::surface_constraint_lifetime
 ) {
     mean_field::models::StellarModel originalModel{
         mean_field::models::structure::PolytropicStructure{mean_field::eos::Polytrope{3.0, 0.25}, 1.0},
-        mean_field::surface::Isobaric{}
+        mean_field::surface::ConstantPressureSurface{mean_field::eos::PressureValue{0.0}}
     };
 
-    const mean_field::models::structure::StructureBase *structureAddress = &originalModel.structurePrescription();
+    const mean_field::models::structure::PolytropicStructure *structureAddress = &originalModel.structurePrescription();
 
-    const mean_field::surface::SurfaceBase *surfaceAddress               = &originalModel.surfacePrescription();
+    const mean_field::surface::ConstantPressureSurface *surfaceAddress         = &originalModel.surfacePrescription();
 
-    const mean_field::eos::EquationOfState *equationOfStateAddress       = &originalModel.equationOfState();
+    const mean_field::eos::Polytrope *equationOfStateAddress                   = &originalModel.equationOfState();
+
+    const auto *compiledSurfaceConstraintAddress = &originalModel.compiledSurfaceConstraint();
 
     mean_field::models::StellarModel movedModel{std::move(originalModel)};
 
     CHECK(&movedModel.structurePrescription() == structureAddress);
     CHECK(&movedModel.surfacePrescription() == surfaceAddress);
     CHECK(&movedModel.equationOfState() == equationOfStateAddress);
+    CHECK(&movedModel.compiledSurfaceConstraint() == compiledSurfaceConstraintAddress);
     CHECK(movedModel.targetMass() == 1.0);
 }
 
 TEST_CASE(
-    "Stellar Model Resolves A Positive Isobaric Surface",
+    "Stellar Model Compiles A Positive Constant Pressure Surface",
     tags::barotrope &tags::unit &tags::model
 ) {
     constexpr double targetPressure = 0.03125;
 
     mean_field::models::StellarModel model{
         mean_field::models::structure::PolytropicStructure{mean_field::eos::Polytrope{3.0, 0.25}, 1.0},
-        mean_field::surface::Isobaric{targetPressure}
+        mean_field::surface::ConstantPressureSurface{mean_field::eos::PressureValue{targetPressure}}
     };
 
-    const double targetEnthalpy = model.resolvedSurfaceCondition().targetEnthalpy;
+    const double requiredSpecificEnthalpy = mean_field::eos::evaluate<mean_field::eos::quantity::SpecificEnthalpy>(
+                                                model.equationOfState(), mean_field::eos::PressureValue{targetPressure}
+    )
+                                                .value();
 
-    CHECK(targetEnthalpy > 0.0);
+    CHECK(requiredSpecificEnthalpy > 0.0);
-    CHECK(
+    CHECK(model.compiledSurfaceConstraint().targetPressure() == mean_field::eos::PressureValue{targetPressure});
-        std::abs(model.equationOfState().pressure_from_enthalpy(targetEnthalpy) - targetPressure) <
+    CHECK(model.compiledSurfaceConstraint().residual(ModelSurfaceState{requiredSpecificEnthalpy}) == 0.0);
-        64.0 * std::numeric_limits<double>::epsilon()
-    );
 }
 
 TEST_CASE(
@@ -200,27 +226,22 @@ TEST_CASE(
 ) {
     const auto tracker = std::make_shared<StellarModelExtensionTracker>();
 
-    mean_field::models::StellarModel model{StellarModelTestStructure{tracker}, StellarModelTestSurface{tracker}};
+    mean_field::models::StellarModel model{
+        StellarModelTestStructure{tracker},
+        mean_field::surface::ConstantPressureSurface{mean_field::eos::PressureValue{0.375}}
+    };
+
+    STATIC_CHECK(std::same_as<decltype(model), ExtensionStellarModel>);
 
     REQUIRE(tracker->structureValidationCount == 1);
-    REQUIRE(tracker->surfaceValidationCount == 1);
-    REQUIRE(tracker->surfaceResolutionCount == 1);
 
-    CHECK(dynamic_cast<const StellarModelTestStructure *>(&model.structurePrescription()) != nullptr);
+    const mean_field::eos::Polytrope *ownedEquationOfState = &model.equationOfState();
-
-    CHECK(dynamic_cast<const StellarModelTestSurface *>(&model.surfacePrescription()) != nullptr);
-
-    const mean_field::eos::EquationOfState *ownedEquationOfState = &model.equationOfState();
 
     CHECK(tracker->structureEquationOfState == ownedEquationOfState);
 
-    CHECK(tracker->surfaceValidationEquationOfState == ownedEquationOfState);
-
-    CHECK(tracker->surfaceResolutionEquationOfState == ownedEquationOfState);
-
     CHECK(model.targetMass() == 2.5);
 
-    CHECK(model.resolvedSurfaceCondition().targetEnthalpy == 0.375);
+    CHECK(model.compiledSurfaceConstraint().targetPressure() == mean_field::eos::PressureValue{0.375});
 }
 
 TEST_CASE(
@@ -229,21 +250,23 @@ TEST_CASE(
 ) {
     mean_field::models::StellarModel sourceModel{
         mean_field::models::structure::PolytropicStructure{mean_field::eos::Polytrope{3.0, 0.25}, 1.25},
-        mean_field::surface::Isobaric{0.0}
+        mean_field::surface::ConstantPressureSurface{mean_field::eos::PressureValue{0.0}}
     };
 
     mean_field::models::StellarModel destinationModel{
         mean_field::models::structure::PolytropicStructure{mean_field::eos::Polytrope{2.0, 0.5}, 4.0},
-        mean_field::surface::Isobaric{0.02}
+        mean_field::surface::ConstantPressureSurface{mean_field::eos::PressureValue{0.02}}
     };
 
-    const mean_field::models::structure::StructureBase *sourceStructureAddress = &sourceModel.structurePrescription();
+    const mean_field::models::structure::PolytropicStructure *sourceStructureAddress =
+        &sourceModel.structurePrescription();
 
-    const mean_field::surface::SurfaceBase *sourceSurfaceAddress               = &sourceModel.surfacePrescription();
+    const mean_field::surface::ConstantPressureSurface *sourceSurfaceAddress = &sourceModel.surfacePrescription();
 
-    const mean_field::eos::EquationOfState *sourceEquationOfStateAddress       = &sourceModel.equationOfState();
+    const mean_field::eos::Polytrope *sourceEquationOfStateAddress           = &sourceModel.equationOfState();
 
-    const double sourceTargetEnthalpy = sourceModel.resolvedSurfaceCondition().targetEnthalpy;
+    const mean_field::eos::PressureValue sourceTargetPressure =
+        sourceModel.compiledSurfaceConstraint().targetPressure();
 
     destinationModel = std::move(sourceModel);
 
@@ -255,5 +278,83 @@ TEST_CASE(
 
     CHECK(destinationModel.targetMass() == 1.25);
 
-    CHECK(destinationModel.resolvedSurfaceCondition().targetEnthalpy == sourceTargetEnthalpy);
+    CHECK(destinationModel.compiledSurfaceConstraint().targetPressure() == sourceTargetPressure);
+}
+
+TEST_CASE(
+    "Stellar Model View Supports Heterogeneous Typed Models",
+    tags::stellar_model_runtime_view
+) {
+    const auto tracker = std::make_shared<StellarModelExtensionTracker>();
+
+    const mean_field::models::StellarModel polytropicModel{
+        mean_field::models::structure::PolytropicStructure{mean_field::eos::Polytrope{3.0, 0.25}, 1.0},
+        mean_field::surface::ConstantPressureSurface{mean_field::eos::PressureValue{0.0}}
+    };
+
+    const mean_field::models::StellarModel extensionModel{
+        StellarModelTestStructure{tracker},
+        mean_field::surface::ConstantPressureSurface{mean_field::eos::PressureValue{0.375}}
+    };
+
+    STATIC_CHECK(std::is_trivially_copyable_v<mean_field::models::StellarModelView>);
+    STATIC_CHECK_FALSE(std::constructible_from<mean_field::models::StellarModelView, PolytropicStellarModel &&>);
+
+    const std::array views{
+        mean_field::models::StellarModelView{polytropicModel}, mean_field::models::StellarModelView{extensionModel}
+    };
+
+    CHECK(views[0].targetMass() == 1.0);
+    CHECK(views[1].targetMass() == 2.5);
+    CHECK(views[1].surfaceCondition().targetPressure == 0.375);
+    REQUIRE(views[1].surfaceDependencies().stateFields.size() == 1);
+    CHECK(
+        views[1].surfaceDependencies().residualRowField ==
+        mean_field::surface::surfaceFieldId<mean_field::field::Enthalpy>
+    );
+
+    const auto pressure =
+        views[0].equationOfState().tryEvaluate<mean_field::eos::quantity::Pressure>(mean_field::eos::DensityValue{0.7});
+
+    REQUIRE(pressure.has_value());
+    CHECK(
+        pressure->value() == mean_field::eos::evaluate<mean_field::eos::quantity::Pressure>(
+                                 polytropicModel.equationOfState(), mean_field::eos::DensityValue{0.7}
+                             )
+                                 .value()
+    );
+
+    const mean_field::models::structure::StructureSeed seed =
+        views[1].makeInitialSeed({.centralDensity = 1.75, .radialSampleCount = 2});
+
+    CHECK(seed.centralDensity == 1.75);
+    CHECK(seed.radius.Size() == 2);
+}
+
+TEST_CASE(
+    "Stellar Model View Retains Stable Pointees When Its Owner Moves",
+    tags::stellar_model_runtime_view
+) {
+    mean_field::models::StellarModel originalModel{
+        mean_field::models::structure::PolytropicStructure{mean_field::eos::Polytrope{3.0, 0.25}, 1.0},
+        mean_field::surface::ConstantPressureSurface{mean_field::eos::PressureValue{0.0}}
+    };
+
+    const mean_field::models::StellarModelView view{originalModel};
+    PolytropicStellarModel movedModel{std::move(originalModel)};
+
+    const auto pressure =
+        view.equationOfState().tryEvaluate<mean_field::eos::quantity::Pressure>(mean_field::eos::DensityValue{0.7});
+    const mean_field::models::structure::StructureSeed seed =
+        view.makeInitialSeed({.centralDensity = 1.0, .radialSampleCount = 8});
+
+    REQUIRE(pressure.has_value());
+    CHECK(view.targetMass() == movedModel.targetMass());
+    CHECK(
+        pressure->value() == mean_field::eos::evaluate<mean_field::eos::quantity::Pressure>(
+                                 movedModel.equationOfState(), mean_field::eos::DensityValue{0.7}
+                             )
+                                 .value()
+    );
+    CHECK(seed.radius.Size() == 8);
 }

tests/operators/contexts/hydrostatic_equilibrium_context.cpp

@@ -164,9 +164,7 @@ TEST_CASE(
     CHECK_FALSE(gravityPotentialReport.updatedDisplacement);
     CHECK_FALSE(gravityPotentialReport.updatedBernoulliConstant);
 
-    CHECK(
+    CHECK(context.GetBaseGravityPotentialTrue()(context.GetGravityPotentialMap().true_dof(0)) == gravityPotential(0));
-        context.GetBaseGravityPotentialTrue()(context.GetGravityPotentialMap().true_dof(0)) == gravityPotential(0)
-    );
 
     ++dependencies.bernoulliConstant.revision;
 

tests/operators/gravity_displacement_force.cpp

@@ -11,98 +11,86 @@ import mean_field;
 import test_helpers;
 
 namespace gravity_displacement_force_test_utils {
-using CoupledForm = mean_field::utils::blocks::barotropic_equilibrium_form;
+    using CoupledForm = mean_field::utils::blocks::barotropic_equilibrium_form;
 
-constexpr auto densityValue =
+    constexpr auto densityValue =
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::get_value_block<CoupledForm>(mean_field::utils::blocks::density_field.mass_term);
-        mean_field::utils::blocks::density_field.mass_term);
 
-constexpr auto displacementValue =
+    constexpr auto displacementValue = mean_field::utils::blocks::get_value_block<CoupledForm>(
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::displacement_field.geometry_term
-        mean_field::utils::blocks::displacement_field.geometry_term);
+    );
 
-constexpr auto gravityGradientValue =
+    constexpr auto gravityGradientValue =
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::get_value_block<CoupledForm>(mean_field::utils::blocks::gravity_field.gradient_term);
-        mean_field::utils::blocks::gravity_field.gradient_term);
 
-constexpr auto gravityPotentialValue =
+    constexpr auto gravityPotentialValue =
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::get_value_block<CoupledForm>(mean_field::utils::blocks::gravity_field.poisson_term);
-        mean_field::utils::blocks::gravity_field.poisson_term);
 
-constexpr auto enthalpyValue =
+    constexpr auto enthalpyValue = mean_field::utils::blocks::get_value_block<CoupledForm>(
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::enthalpy_field.specific_term
-        mean_field::utils::blocks::enthalpy_field.specific_term);
+    );
 
-constexpr auto barotropicConstantValue =
+    constexpr auto barotropicConstantValue = mean_field::utils::blocks::get_value_block<CoupledForm>(
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::barotropic_constant_field.mass_normalization_term
-        mean_field::utils::blocks::barotropic_constant_field
+    );
-            .mass_normalization_term);
 
-constexpr auto gravityGradientResidual =
+    constexpr auto gravityGradientResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::gravity_field.gradient_term
-        mean_field::utils::blocks::gravity_field.gradient_term);
+    );
 
-constexpr auto gravityPotentialResidual =
+    constexpr auto gravityPotentialResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::gravity_field.poisson_term
-        mean_field::utils::blocks::gravity_field.poisson_term);
+    );
 
-constexpr auto densityResidual =
+    constexpr auto densityResidual =
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::get_residual_block<CoupledForm>(mean_field::utils::blocks::density_field.mass_term);
-        mean_field::utils::blocks::density_field.mass_term);
 
-constexpr auto displacementResidual =
+    constexpr auto displacementResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::displacement_field.geometry_term
-        mean_field::utils::blocks::displacement_field.geometry_term);
+    );
 
-constexpr auto enthalpyResidual =
+    constexpr auto enthalpyResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::enthalpy_field.specific_term
-        mean_field::utils::blocks::enthalpy_field.specific_term);
+    );
 
-constexpr auto massResidual =
+    constexpr auto massResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::barotropic_constant_field.mass_normalization_term
-        mean_field::utils::blocks::barotropic_constant_field
+    );
-            .mass_normalization_term);
 
-[[nodiscard]] mean_field::operators::GravityDisplacementForceLayout
+    [[nodiscard]] mean_field::operators::GravityDisplacementForceLayout make_layout(const mean_field::fem::FEM &f) {
-make_layout(const mean_field::fem::FEM &f) {
         using DomainSchema         = gravity_prepared_test_utils::DomainSchema;
 
-  const auto densityMap =
+        const auto densityMap      = gravity_prepared_test_utils::make_field_map<mean_field::field::Density>(f);
-      gravity_prepared_test_utils::make_field_map<mean_field::field::Density>(
+        const auto displacementMap = gravity_prepared_test_utils::make_field_map<mean_field::field::Displacement>(f);
-          f);
-  const auto displacementMap = gravity_prepared_test_utils::make_field_map<
-      mean_field::field::Displacement>(f);
         const auto gravityFluxMap =
-      mean_field::field::make_field_dof_map<mean_field::field::Gravity,
+            mean_field::field::make_field_dof_map<mean_field::field::Gravity, DomainSchema>(*f.gravityFluxFes);
-                                            DomainSchema>(*f.gravityFluxFes);
+        const auto gravityPotentialMap =
-  const auto gravityPotentialMap = mean_field::field::make_field_dof_map<
+            mean_field::field::make_field_dof_map<mean_field::field::Gravity, DomainSchema>(*f.gravityPotentialFes);
-      mean_field::field::Gravity, DomainSchema>(*f.gravityPotentialFes);
         const auto enthalpyMap =
-      mean_field::field::make_field_dof_map<mean_field::field::Enthalpy,
+            mean_field::field::make_field_dof_map<mean_field::field::Enthalpy, DomainSchema>(*f.enthalpyFes);
-                                            DomainSchema>(*f.enthalpyFes);
 
         const std::array<int, CoupledForm::value_block_count> valueSizes{
-      densityMap.reduced_size(),     displacementMap.reduced_size(),
+            densityMap.reduced_size(),          displacementMap.reduced_size(), gravityFluxMap.reduced_size(),
-      gravityFluxMap.reduced_size(), gravityPotentialMap.reduced_size(),
+            gravityPotentialMap.reduced_size(), enthalpyMap.reduced_size(),     1
-      enthalpyMap.reduced_size(),    1};
+        };
 
         const std::array<int, CoupledForm::residual_block_count> residualSizes{
-      gravityFluxMap.reduced_size(), gravityPotentialMap.reduced_size(),
+            gravityFluxMap.reduced_size(),  gravityPotentialMap.reduced_size(), densityMap.reduced_size(),
-      densityMap.reduced_size(),     displacementMap.reduced_size(),
+            displacementMap.reduced_size(), enthalpyMap.reduced_size(),         1
-      enthalpyMap.reduced_size(),    1};
+        };
 
         return {valueSizes, residualSizes};
-}
+    }
 
-[[nodiscard]] mfem::Vector make_density(const mean_field::fem::FEM &f,
+    [[nodiscard]] mfem::Vector make_density(
-                                        const double phase) {
+        const mean_field::fem::FEM &f,
+        const double phase
+    ) {
         mfem::ParGridFunction densityField(f.densityFes.get());
 
-  mfem::FunctionCoefficient densityCoefficient(
+        mfem::FunctionCoefficient densityCoefficient([phase](const mfem::Vector &position) {
-      [phase](const mfem::Vector &position) {
             return 0.82 + 0.07 * std::sin(0.8 * position(0) + phase) +
-               0.05 * std::cos(0.6 * position(1) - 0.3 * phase) +
+                   0.05 * std::cos(0.6 * position(1) - 0.3 * phase) + 0.03 * position(2) * position(2);
-               0.03 * position(2) * position(2);
         });
 
         densityField.ProjectCoefficient(densityCoefficient);
@@ -110,16 +98,17 @@ make_layout(const mean_field::fem::FEM &f) {
         mfem::Vector densityTrue;
         densityField.GetTrueDofs(densityTrue);
         return densityTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector make_density_direction(const mean_field::fem::FEM &f,
+    [[nodiscard]] mfem::Vector make_density_direction(
-                                                  const double phase) {
+        const mean_field::fem::FEM &f,
+        const double phase
+    ) {
         mfem::ParGridFunction densityField(f.densityFes.get());
 
-  mfem::FunctionCoefficient densityCoefficient(
+        mfem::FunctionCoefficient densityCoefficient([phase](const mfem::Vector &position) {
-      [phase](const mfem::Vector &position) {
+            return 0.19 * std::sin(0.9 * position(0) + phase) - 0.13 * std::cos(0.7 * position(1) - phase) +
-        return 0.19 * std::sin(0.9 * position(0) + phase) -
+                   0.08 * position(2);
-               0.13 * std::cos(0.7 * position(1) - phase) + 0.08 * position(2);
         });
 
         densityField.ProjectCoefficient(densityCoefficient);
@@ -127,14 +116,15 @@ make_layout(const mean_field::fem::FEM &f) {
         mfem::Vector densityTrue;
         densityField.GetTrueDofs(densityTrue);
         return densityTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector make_gravity_gradient(const mean_field::fem::FEM &f,
+    [[nodiscard]] mfem::Vector make_gravity_gradient(
-                                                 const double phase) {
+        const mean_field::fem::FEM &f,
+        const double phase
+    ) {
         mfem::ParGridFunction gravityField(f.gravityFluxFes.get());
 
-  auto gravityFunction = [phase](const mfem::Vector &position,
+        auto gravityFunction = [phase](const mfem::Vector &position, mfem::Vector &value) {
-                                 mfem::Vector &value) {
             value.SetSize(3);
 
             value(0) = 0.31 + 0.08 * position(0) + 0.03 * phase * position(1);
@@ -151,15 +141,15 @@ make_layout(const mean_field::fem::FEM &f) {
         mfem::Vector gravityTrue;
         gravityField.GetTrueDofs(gravityTrue);
         return gravityTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector
+    [[nodiscard]] mfem::Vector make_gravity_gradient_direction(
-make_gravity_gradient_direction(const mean_field::fem::FEM &f,
+        const mean_field::fem::FEM &f,
-                                const double phase) {
+        const double phase
+    ) {
         mfem::ParGridFunction gravityField(f.gravityFluxFes.get());
 
-  auto gravityFunction = [phase](const mfem::Vector &position,
+        auto gravityFunction = [phase](const mfem::Vector &position, mfem::Vector &value) {
-                                 mfem::Vector &value) {
             value.SetSize(3);
 
             value(0) = 0.14 * std::sin(position(0) + phase) + 0.03 * position(1);
@@ -176,22 +166,18 @@ make_gravity_gradient_direction(const mean_field::fem::FEM &f,
         mfem::Vector gravityTrue;
         gravityField.GetTrueDofs(gravityTrue);
         return gravityTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector
+    [[nodiscard]] mfem::Vector make_displacement_direction(const mean_field::fem::FEM &f) {
-make_displacement_direction(const mean_field::fem::FEM &f) {
+        mfem::Vector direction    = gravity_prepared_test_utils::make_displacement(f, 0.83);
-  mfem::Vector direction =
-      gravity_prepared_test_utils::make_displacement(f, 0.83);
 
-  const mfem::Vector second =
+        const mfem::Vector second = gravity_prepared_test_utils::make_displacement(f, 0.29);
-      gravity_prepared_test_utils::make_displacement(f, 0.29);
 
         direction -= second;
         return direction;
-}
+    }
 
-[[nodiscard]] mfem::Vector
+    [[nodiscard]] mfem::Vector make_vacuum_only_density(const mean_field::fem::FEM &f) {
-make_vacuum_only_density(const mean_field::fem::FEM &f) {
         mfem::ParGridFunction densityField(f.densityFes.get());
         densityField              = 0.0;
 
@@ -201,8 +187,7 @@ make_vacuum_only_density(const mean_field::fem::FEM &f) {
         int localVacuumElements = 0;
 
         for (int elementId = 0; elementId < f.mesh->GetNE(); ++elementId) {
-    mfem::ElementTransformation *transformation =
+            mfem::ElementTransformation *transformation = f.mesh->GetElementTransformation(elementId);
-        f.mesh->GetElementTransformation(elementId);
 
             REQUIRE(transformation != nullptr);
 
@@ -219,69 +204,74 @@ make_vacuum_only_density(const mean_field::fem::FEM &f) {
         }
 
         int globalVacuumElements = 0;
-  MPI_Allreduce(&localVacuumElements, &globalVacuumElements, 1, MPI_INT,
+        MPI_Allreduce(&localVacuumElements, &globalVacuumElements, 1, MPI_INT, MPI_SUM, f.mesh->GetComm());
-                MPI_SUM, f.mesh->GetComm());
 
         REQUIRE(globalVacuumElements > 0);
 
         mfem::Vector densityTrue;
         densityField.GetTrueDofs(densityTrue);
         return densityTrue;
-}
+    }
 
-[[nodiscard]] mean_field::operators::context::gravity_field::
+    [[nodiscard]] mean_field::operators::context::gravity_field::GravityFieldRevisions make_revisions() {
-    GravityFieldRevisions
+        return {
-    make_revisions() {
+            .discretization    = {.value = 3},
-  return {.discretization = {.value = 3},
             .displacement      = {.value = 5},
             .density           = {.value = 7},
             .gravity_gradient  = {.value = 11},
-          .gravity_potential = {.value = 13}};
+            .gravity_potential = {.value = 13}
-}
+        };
+    }
 
-void prepare_gravity_context(
+    void prepare_gravity_context(
-    mean_field::operators::context::gravity_field::
+        mean_field::operators::context::gravity_field::GravityFieldLinearizationContext &context,
-        GravityFieldLinearizationContext &context,
+        const mfem::Vector &density,
-    const mfem::Vector &density, const mfem::Vector &displacement,
+        const mfem::Vector &displacement,
-    const mfem::Vector &gravityGradient, const mfem::Vector &gravityPotential,
+        const mfem::Vector &gravityGradient,
-    const mean_field::operators::context::gravity_field::GravityFieldRevisions
+        const mfem::Vector &gravityPotential,
-        &revisions) {
+        const mean_field::operators::context::gravity_field::GravityFieldRevisions &revisions
+    ) {
         context.Prepare(
             {.density           = context.GetDensityMap().gather(density),
              .displacement      = context.GetDisplacementMap().gather(displacement),
-       .gravity_gradient =
+             .gravity_gradient  = context.GetGravityGradientMap().gather(gravityGradient),
-           context.GetGravityGradientMap().gather(gravityGradient),
+             .gravity_potential = context.GetGravityPotentialMap().gather(gravityPotential)},
-       .gravity_potential =
+            revisions
-           context.GetGravityPotentialMap().gather(gravityPotential)},
+        );
-      revisions);
+    }
-}
 
-[[nodiscard]] double relative_difference(const mfem::Vector &left,
+    [[nodiscard]] double relative_difference(
+        const mfem::Vector &left,
         const mfem::Vector &right,
-                                         const MPI_Comm communicator) {
+        const MPI_Comm communicator
-  MFEM_VERIFY(left.Size() == right.Size(),
+    ) {
-              "Cannot compare gravity-displacement-force vectors with "
+        MFEM_VERIFY(
-              "different sizes.");
+            left.Size() == right.Size(), "Cannot compare gravity-displacement-force vectors with "
+                                         "different sizes."
+        );
 
         mfem::Vector difference(left);
         difference -= right;
 
-  const double scale =
+        const double scale = std::max(
-      std::max({gravity_prepared_test_utils::global_norm(left, communicator),
+            {gravity_prepared_test_utils::global_norm(left, communicator),
              gravity_prepared_test_utils::global_norm(right, communicator),
-                100.0 * std::numeric_limits<double>::epsilon()});
+             100.0 * std::numeric_limits<double>::epsilon()}
+        );
 
-  return gravity_prepared_test_utils::global_norm(difference, communicator) /
+        return gravity_prepared_test_utils::global_norm(difference, communicator) / scale;
-         scale;
+    }
-}
 
-[[nodiscard]] mfem::Vector centered_difference(
+    [[nodiscard]] mfem::Vector centered_difference(
-    const mean_field::fem::FEM &f, const mfem::Vector &baseDensity,
+        const mean_field::fem::FEM &f,
+        const mfem::Vector &baseDensity,
         const mfem::Vector &densityDirection,
         const mfem::Vector &baseGravityGradient,
         const mfem::Vector &gravityGradientDirection,
         const mfem::Vector &baseDisplacement,
-    const mfem::Vector &displacementDirection, const double step) {
+        const mfem::Vector &displacementDirection,
+        const double step
+    ) {
         mfem::Vector plusDensity(baseDensity);
         plusDensity.Add(step, densityDirection);
 
@@ -304,23 +294,24 @@ void prepare_gravity_context(
         mfem::Vector minusResidual;
 
         mean_field::operators::kernels::apply_gravity_displacement_force_residual(
-      f, *f.domainMapperStateless, plusDensity, plusGravity, plusDisplacement,
+            f, *f.domainMapperStateless, plusDensity, plusGravity, plusDisplacement, plusResidual
-      plusResidual);
+        );
 
         mean_field::operators::kernels::apply_gravity_displacement_force_residual(
-      f, *f.domainMapperStateless, minusDensity, minusGravity,
+            f, *f.domainMapperStateless, minusDensity, minusGravity, minusDisplacement, minusResidual
-      minusDisplacement, minusResidual);
+        );
 
         plusResidual -= minusResidual;
         plusResidual /= 2.0 * step;
         return plusResidual;
-}
+    }
 
-template <int index>
+    template <int index>
-[[nodiscard]] mfem::Vector copy_residual_block(
+    [[nodiscard]] mfem::Vector copy_residual_block(
         const mfem::Vector &action,
         const mean_field::operators::GravityDisplacementForceLayout &layout,
-    const mean_field::utils::blocks::residual_block<index> block) {
+        const mean_field::utils::blocks::residual_block<index> block
+    ) {
         mfem::Vector result(layout.size(block));
         const int offset = layout.offset(block);
 
@@ -329,21 +320,22 @@ template <int index>
         }
 
         return result;
-}
+    }
 } // namespace gravity_displacement_force_test_utils
 
-TEST_CASE("Gravity Displacement Force Query Includes Every Registered Operand",
+TEST_CASE(
-          tags::gravity_unit) {
+    "Gravity Displacement Force Query Includes Every Registered Operand",
-  using DisplacementField =
+    tags::gravity_unit
-      mean_field::field::Field<mean_field::field::Displacement>;
+) {
+    using DisplacementField           = mean_field::field::Field<mean_field::field::Displacement>;
 
     constexpr int geometryWeightOrder = 4;
 
-  constexpr mean_field::quadrature::Query query = DisplacementField::make_query<
+    constexpr mean_field::quadrature::Query query =
-      mean_field::field::Displacement::Form::GravityForce>(
+        DisplacementField::make_query<mean_field::field::Displacement::Form::GravityForce>(
-      mean_field::quadrature::QuadratureRole::discretization,
+            mean_field::quadrature::QuadratureRole::discretization, geometryWeightOrder, {},
-      geometryWeightOrder, {}, mean_field::utils::DOMAINS::STELLAR,
+            mean_field::utils::DOMAINS::STELLAR, mean_field::quadrature::MappingKind::general
-      mean_field::quadrature::MappingKind::general);
+        );
 
     /*
      * rho: 2
@@ -356,8 +348,7 @@ TEST_CASE("Gravity Displacement Force Query Includes Every Registered Operand",
 
     STATIC_REQUIRE(query.term == mean_field::quadrature::Term::gravity_force);
 
-  STATIC_REQUIRE(query.role ==
+    STATIC_REQUIRE(query.role == mean_field::quadrature::QuadratureRole::discretization);
-                 mean_field::quadrature::QuadratureRole::discretization);
 
     STATIC_REQUIRE(query.domain == mean_field::utils::DOMAINS::STELLAR);
 
@@ -367,9 +358,11 @@ TEST_CASE("Gravity Displacement Force Query Includes Every Registered Operand",
     STATIC_REQUIRE(*query.base_order == expectedBaseOrder);
 }
 
-TEST_CASE("Gravity Displacement Force Uses Positive Grad-Phi Sign And Excludes "
+TEST_CASE(
+    "Gravity Displacement Force Uses Positive Grad-Phi Sign And Excludes "
     "Vacuum",
-          tags::gravity_kernel_accuracy) {
+    tags::gravity_kernel_accuracy
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
@@ -391,8 +384,7 @@ TEST_CASE("Gravity Displacement Force Uses Positive Grad-Phi Sign And Excludes "
         value(0) = 1.0;
     };
 
-  mfem::VectorFunctionCoefficient gravityCoefficient(3,
+    mfem::VectorFunctionCoefficient gravityCoefficient(3, constantGravityFunction);
-                                                     constantGravityFunction);
 
     gravityField.ProjectCoefficient(gravityCoefficient);
 
@@ -405,8 +397,8 @@ TEST_CASE("Gravity Displacement Force Uses Positive Grad-Phi Sign And Excludes "
     mfem::Vector residual;
 
     mean_field::operators::kernels::apply_gravity_displacement_force_residual(
-      f, *f.domainMapperStateless, density, gravityGradient, displacement,
+        f, *f.domainMapperStateless, density, gravityGradient, displacement, residual
-      residual);
+    );
 
     mfem::ParGridFunction testField(f.displacementFes.get());
     testField.ProjectCoefficient(gravityCoefficient);
@@ -414,57 +406,54 @@ TEST_CASE("Gravity Displacement Force Uses Positive Grad-Phi Sign And Excludes "
     mfem::Vector testDirection;
     testField.GetTrueDofs(testDirection);
 
-  const double signedWork = gravity_prepared_test_utils::global_dot(
+    const double signedWork = gravity_prepared_test_utils::global_dot(residual, testDirection, f.mesh->GetComm());
-      residual, testDirection, f.mesh->GetComm());
 
     INFO("Constant +x gravity-force work = " << signedWork);
     CHECK(signedWork > 0.0);
 
-  const mfem::Vector vacuumDensity =
+    const mfem::Vector vacuumDensity = gravity_displacement_force_test_utils::make_vacuum_only_density(f);
-      gravity_displacement_force_test_utils::make_vacuum_only_density(f);
 
     mfem::Vector vacuumResidual;
 
     mean_field::operators::kernels::apply_gravity_displacement_force_residual(
-      f, *f.domainMapperStateless, vacuumDensity, gravityGradient, displacement,
+        f, *f.domainMapperStateless, vacuumDensity, gravityGradient, displacement, vacuumResidual
-      vacuumResidual);
+    );
 
-  CHECK(gravity_prepared_test_utils::global_norm(vacuumResidual,
+    CHECK(gravity_prepared_test_utils::global_norm(vacuumResidual, f.mesh->GetComm()) == 0.0);
-                                                 f.mesh->GetComm()) == 0.0);
 }
 
-TEST_CASE("Prepared Gravity Displacement Force Reuses Shared Gravity Revisions",
+TEST_CASE(
-          tags::gravity_prepared) {
+    "Prepared Gravity Displacement Force Reuses Shared Gravity Revisions",
+    tags::gravity_prepared
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
 
     REQUIRE(f.okay());
 
-  mfem::Vector density =
+    mfem::Vector density               = gravity_displacement_force_test_utils::make_density(f, 0.31);
-      gravity_displacement_force_test_utils::make_density(f, 0.31);
 
-  const mfem::Vector gravityGradient =
+    const mfem::Vector gravityGradient = gravity_displacement_force_test_utils::make_gravity_gradient(f, 0.47);
-      gravity_displacement_force_test_utils::make_gravity_gradient(f, 0.47);
 
-  const mfem::Vector displacement =
+    const mfem::Vector displacement    = gravity_prepared_test_utils::make_displacement(f, 0.61);
-      gravity_prepared_test_utils::make_displacement(f, 0.61);
 
     mfem::Vector gravityPotential(f.gravityPotentialFes->GetTrueVSize());
     gravityPotential = 0.0;
 
     auto revisions   = gravity_displacement_force_test_utils::make_revisions();
 
-  mean_field::operators::context::gravity_field::
+    mean_field::operators::context::gravity_field::GravityFieldLinearizationContext gravityContext(
-      GravityFieldLinearizationContext gravityContext(f,
+        f, *f.domainMapperStateless
-                                                      *f.domainMapperStateless);
+    );
 
     gravity_displacement_force_test_utils::prepare_gravity_context(
-      gravityContext, density, displacement, gravityGradient, gravityPotential,
+        gravityContext, density, displacement, gravityGradient, gravityPotential, revisions
-      revisions);
+    );
 
-  mean_field::operators::PreparedGravityDisplacementForceOperator
+    mean_field::operators::PreparedGravityDisplacementForceOperator preparedOperator(
-      preparedOperator(f, *f.domainMapperStateless, gravityContext);
+        f, *f.domainMapperStateless, gravityContext
+    );
 
     const auto initialReport = preparedOperator.Prepare();
     REQUIRE(initialReport.DidAnyWork());
@@ -476,23 +465,24 @@ TEST_CASE("Prepared Gravity Displacement Force Reuses Shared Gravity Revisions",
     preparedOperator.BuildResidual(preparedResidual);
 
     mean_field::operators::kernels::apply_gravity_displacement_force_residual(
-      f, *f.domainMapperStateless, density, gravityGradient, displacement,
+        f, *f.domainMapperStateless, density, gravityGradient, displacement, kernelResidual
-      kernelResidual);
+    );
 
-  const mfem::Vector kernelResidualReduced =
+    const mfem::Vector kernelResidualReduced = gravityContext.GetDisplacementMap().gather(kernelResidual);
-      gravityContext.GetDisplacementMap().gather(kernelResidual);
 
-  CHECK(gravity_displacement_force_test_utils::relative_difference(
+    CHECK(
-            preparedResidual, kernelResidualReduced, f.mesh->GetComm()) <
+        gravity_displacement_force_test_utils::relative_difference(
-        2.0e-12);
+            preparedResidual, kernelResidualReduced, f.mesh->GetComm()
+        ) < 2.0e-12
+    );
 
     CHECK_FALSE(preparedOperator.Prepare().DidAnyWork());
 
     ++revisions.gravity_potential.value;
 
     gravity_displacement_force_test_utils::prepare_gravity_context(
-      gravityContext, density, displacement, gravityGradient, gravityPotential,
+        gravityContext, density, displacement, gravityGradient, gravityPotential, revisions
-      revisions);
+    );
 
     CHECK(preparedOperator.IsPrepared());
     CHECK_FALSE(preparedOperator.Prepare().DidAnyWork());
@@ -501,8 +491,8 @@ TEST_CASE("Prepared Gravity Displacement Force Reuses Shared Gravity Revisions",
     ++revisions.density.value;
 
     gravity_displacement_force_test_utils::prepare_gravity_context(
-      gravityContext, density, displacement, gravityGradient, gravityPotential,
+        gravityContext, density, displacement, gravityGradient, gravityPotential, revisions
-      revisions);
+    );
 
     CHECK_FALSE(preparedOperator.IsPrepared());
 
@@ -516,79 +506,73 @@ TEST_CASE("Prepared Gravity Displacement Force Reuses Shared Gravity Revisions",
 TEST_CASE(
     "Gravity Displacement Force Jacobian Matches All Columns And Centered "
     "Differences",
-    tags::gravity_prepared_jacobian_accuracy) {
+    tags::gravity_prepared_jacobian_accuracy
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
 
     REQUIRE(f.okay());
 
-  const mfem::Vector density =
+    const mfem::Vector density          = gravity_displacement_force_test_utils::make_density(f, 0.37);
-      gravity_displacement_force_test_utils::make_density(f, 0.37);
 
-  const mfem::Vector densityDirection =
+    const mfem::Vector densityDirection = gravity_displacement_force_test_utils::make_density_direction(f, 0.53);
-      gravity_displacement_force_test_utils::make_density_direction(f, 0.53);
 
-  const mfem::Vector gravityGradient =
+    const mfem::Vector gravityGradient  = gravity_displacement_force_test_utils::make_gravity_gradient(f, 0.67);
-      gravity_displacement_force_test_utils::make_gravity_gradient(f, 0.67);
 
     const mfem::Vector gravityGradientDirection =
-      gravity_displacement_force_test_utils::make_gravity_gradient_direction(
+        gravity_displacement_force_test_utils::make_gravity_gradient_direction(f, 0.71);
-          f, 0.71);
 
-  const mfem::Vector displacement =
+    const mfem::Vector displacement          = gravity_prepared_test_utils::make_displacement(f, 0.59);
-      gravity_prepared_test_utils::make_displacement(f, 0.59);
 
-  const mfem::Vector displacementDirection =
+    const mfem::Vector displacementDirection = gravity_displacement_force_test_utils::make_displacement_direction(f);
-      gravity_displacement_force_test_utils::make_displacement_direction(f);
 
     mfem::Vector gravityPotential(f.gravityPotentialFes->GetTrueVSize());
     gravityPotential = 0.0;
 
-  mean_field::operators::context::gravity_field::
+    mean_field::operators::context::gravity_field::GravityFieldLinearizationContext gravityContext(
-      GravityFieldLinearizationContext gravityContext(f,
+        f, *f.domainMapperStateless
-                                                      *f.domainMapperStateless);
+    );
 
     gravity_displacement_force_test_utils::prepare_gravity_context(
         gravityContext, density, displacement, gravityGradient, gravityPotential,
-      gravity_displacement_force_test_utils::make_revisions());
+        gravity_displacement_force_test_utils::make_revisions()
+    );
 
-  mean_field::operators::PreparedGravityDisplacementForceOperator
+    mean_field::operators::PreparedGravityDisplacementForceOperator preparedOperator(
-      preparedOperator(f, *f.domainMapperStateless, gravityContext);
+        f, *f.domainMapperStateless, gravityContext
+    );
 
     preparedOperator.Prepare();
 
-  const mfem::Vector densityDirectionReduced =
+    const mfem::Vector densityDirectionReduced = gravityContext.GetDensityMap().gather(densityDirection);
-      gravityContext.GetDensityMap().gather(densityDirection);
     const mfem::Vector gravityGradientDirectionReduced =
         gravityContext.GetGravityGradientMap().gather(gravityGradientDirection);
-  const mfem::Vector displacementDirectionReduced =
+    const mfem::Vector displacementDirectionReduced = gravityContext.GetDisplacementMap().gather(displacementDirection);
-      gravityContext.GetDisplacementMap().gather(displacementDirection);
 
     mfem::Vector densityAction;
     mfem::Vector gravityAction;
     mfem::Vector displacementAction;
     mfem::Vector completeAction;
 
-  preparedOperator.ApplyDensityJacobianAction(densityDirectionReduced,
+    preparedOperator.ApplyDensityJacobianAction(densityDirectionReduced, densityAction);
-                                              densityAction);
 
-  preparedOperator.ApplyGravityGradientJacobianAction(
+    preparedOperator.ApplyGravityGradientJacobianAction(gravityGradientDirectionReduced, gravityAction);
-      gravityGradientDirectionReduced, gravityAction);
 
-  preparedOperator.ApplyDisplacementJacobianAction(displacementDirectionReduced,
+    preparedOperator.ApplyDisplacementJacobianAction(displacementDirectionReduced, displacementAction);
-                                                   displacementAction);
 
     preparedOperator.ApplyCompleteJacobianAction(
-      densityDirectionReduced, displacementDirectionReduced,
+        densityDirectionReduced, displacementDirectionReduced, gravityGradientDirectionReduced, completeAction
-      gravityGradientDirectionReduced, completeAction);
+    );
 
     mfem::Vector summedColumns(densityAction);
     summedColumns += gravityAction;
     summedColumns += displacementAction;
 
-  CHECK(gravity_displacement_force_test_utils::relative_difference(
+    CHECK(
-            completeAction, summedColumns, f.mesh->GetComm()) < 2.0e-12);
+        gravity_displacement_force_test_utils::relative_difference(completeAction, summedColumns, f.mesh->GetComm()) <
+        2.0e-12
+    );
 
     mfem::Vector zeroDensity(densityDirection.Size());
     mfem::Vector zeroGravity(gravityGradientDirection.Size());
@@ -599,50 +583,41 @@ TEST_CASE(
 
     constexpr double step                    = 1.0e-5;
 
-  const mfem::Vector densityDifferenceTrue =
+    const mfem::Vector densityDifferenceTrue = gravity_displacement_force_test_utils::centered_difference(
-      gravity_displacement_force_test_utils::centered_difference(
+        f, density, densityDirection, gravityGradient, zeroGravity, displacement, zeroDisplacement, step
-          f, density, densityDirection, gravityGradient, zeroGravity,
+    );
-          displacement, zeroDisplacement, step);
 
-  const mfem::Vector gravityDifferenceTrue =
+    const mfem::Vector gravityDifferenceTrue = gravity_displacement_force_test_utils::centered_difference(
-      gravity_displacement_force_test_utils::centered_difference(
+        f, density, zeroDensity, gravityGradient, gravityGradientDirection, displacement, zeroDisplacement, step
-          f, density, zeroDensity, gravityGradient, gravityGradientDirection,
+    );
-          displacement, zeroDisplacement, step);
 
-  const mfem::Vector displacementDifferenceTrue =
+    const mfem::Vector displacementDifferenceTrue = gravity_displacement_force_test_utils::centered_difference(
-      gravity_displacement_force_test_utils::centered_difference(
+        f, density, zeroDensity, gravityGradient, zeroGravity, displacement, displacementDirection, step
-          f, density, zeroDensity, gravityGradient, zeroGravity, displacement,
+    );
-          displacementDirection, step);
 
-  const mfem::Vector completeDifferenceTrue =
+    const mfem::Vector completeDifferenceTrue = gravity_displacement_force_test_utils::centered_difference(
-      gravity_displacement_force_test_utils::centered_difference(
+        f, density, densityDirection, gravityGradient, gravityGradientDirection, displacement, displacementDirection,
-          f, density, densityDirection, gravityGradient,
+        step
-          gravityGradientDirection, displacement, displacementDirection, step);
+    );
 
-  const mfem::Vector densityDifference =
+    const mfem::Vector densityDifference      = gravityContext.GetDisplacementMap().gather(densityDifferenceTrue);
-      gravityContext.GetDisplacementMap().gather(densityDifferenceTrue);
+    const mfem::Vector gravityDifference      = gravityContext.GetDisplacementMap().gather(gravityDifferenceTrue);
-  const mfem::Vector gravityDifference =
+    const mfem::Vector displacementDifference = gravityContext.GetDisplacementMap().gather(displacementDifferenceTrue);
-      gravityContext.GetDisplacementMap().gather(gravityDifferenceTrue);
+    const mfem::Vector completeDifference     = gravityContext.GetDisplacementMap().gather(completeDifferenceTrue);
-  const mfem::Vector displacementDifference =
-      gravityContext.GetDisplacementMap().gather(displacementDifferenceTrue);
-  const mfem::Vector completeDifference =
-      gravityContext.GetDisplacementMap().gather(completeDifferenceTrue);
 
     const double densityError =
-      gravity_displacement_force_test_utils::relative_difference(
+        gravity_displacement_force_test_utils::relative_difference(densityAction, densityDifference, f.mesh->GetComm());
-          densityAction, densityDifference, f.mesh->GetComm());
 
     const double gravityError =
-      gravity_displacement_force_test_utils::relative_difference(
+        gravity_displacement_force_test_utils::relative_difference(gravityAction, gravityDifference, f.mesh->GetComm());
-          gravityAction, gravityDifference, f.mesh->GetComm());
 
-  const double displacementError =
+    const double displacementError = gravity_displacement_force_test_utils::relative_difference(
-      gravity_displacement_force_test_utils::relative_difference(
+        displacementAction, displacementDifference, f.mesh->GetComm()
-          displacementAction, displacementDifference, f.mesh->GetComm());
+    );
 
-  const double completeError =
+    const double completeError = gravity_displacement_force_test_utils::relative_difference(
-      gravity_displacement_force_test_utils::relative_difference(
+        completeAction, completeDifference, f.mesh->GetComm()
-          completeAction, completeDifference, f.mesh->GetComm());
+    );
 
     INFO("Density-column centered-difference error = " << densityError);
     INFO("Gravity-column centered-difference error = " << gravityError);
@@ -655,82 +630,70 @@ TEST_CASE(
     CHECK(completeError < 3.0e-8);
 }
 
-TEST_CASE("Prepared Gravity Displacement Force MFEM Adapter Routes Only R-d",
+TEST_CASE(
-          tags::gravity_prepared_unit) {
+    "Prepared Gravity Displacement Force MFEM Adapter Routes Only R-d",
+    tags::gravity_prepared_unit
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
 
     REQUIRE(f.okay());
 
-  const mfem::Vector density =
+    const mfem::Vector density          = gravity_displacement_force_test_utils::make_density(f, 0.41);
-      gravity_displacement_force_test_utils::make_density(f, 0.41);
 
-  const mfem::Vector densityDirection =
+    const mfem::Vector densityDirection = gravity_displacement_force_test_utils::make_density_direction(f, 0.57);
-      gravity_displacement_force_test_utils::make_density_direction(f, 0.57);
 
-  const mfem::Vector gravityGradient =
+    const mfem::Vector gravityGradient  = gravity_displacement_force_test_utils::make_gravity_gradient(f, 0.63);
-      gravity_displacement_force_test_utils::make_gravity_gradient(f, 0.63);
 
     const mfem::Vector gravityGradientDirection =
-      gravity_displacement_force_test_utils::make_gravity_gradient_direction(
+        gravity_displacement_force_test_utils::make_gravity_gradient_direction(f, 0.77);
-          f, 0.77);
 
-  const mfem::Vector displacement =
+    const mfem::Vector displacement          = gravity_prepared_test_utils::make_displacement(f, 0.51);
-      gravity_prepared_test_utils::make_displacement(f, 0.51);
 
-  const mfem::Vector displacementDirection =
+    const mfem::Vector displacementDirection = gravity_displacement_force_test_utils::make_displacement_direction(f);
-      gravity_displacement_force_test_utils::make_displacement_direction(f);
 
     mfem::Vector gravityPotential(f.gravityPotentialFes->GetTrueVSize());
     gravityPotential = 0.0;
 
-  mean_field::operators::context::gravity_field::
+    mean_field::operators::context::gravity_field::GravityFieldLinearizationContext gravityContext(
-      GravityFieldLinearizationContext gravityContext(f,
+        f, *f.domainMapperStateless
-                                                      *f.domainMapperStateless);
+    );
 
     gravity_displacement_force_test_utils::prepare_gravity_context(
         gravityContext, density, displacement, gravityGradient, gravityPotential,
-      gravity_displacement_force_test_utils::make_revisions());
+        gravity_displacement_force_test_utils::make_revisions()
+    );
 
-  mean_field::operators::PreparedGravityDisplacementForceOperator
+    mean_field::operators::PreparedGravityDisplacementForceOperator preparedOperator(
-      preparedOperator(f, *f.domainMapperStateless, gravityContext);
+        f, *f.domainMapperStateless, gravityContext
+    );
 
     preparedOperator.Prepare();
 
-  const mfem::Vector densityDirectionReduced =
+    const mfem::Vector densityDirectionReduced = gravityContext.GetDensityMap().gather(densityDirection);
-      gravityContext.GetDensityMap().gather(densityDirection);
     const mfem::Vector gravityGradientDirectionReduced =
         gravityContext.GetGravityGradientMap().gather(gravityGradientDirection);
-  const mfem::Vector displacementDirectionReduced =
+    const mfem::Vector displacementDirectionReduced = gravityContext.GetDisplacementMap().gather(displacementDirection);
-      gravityContext.GetDisplacementMap().gather(displacementDirection);
 
     const auto layout                               = gravity_displacement_force_test_utils::make_layout(f);
 
-  mean_field::operators::PreparedGravityDisplacementForceJacobianOperator
+    mean_field::operators::PreparedGravityDisplacementForceJacobianOperator adapter(layout, preparedOperator);
-      adapter(layout, preparedOperator);
 
     mfem::BlockVector direction(layout.value_offsets());
     direction                                                                        = 0.0;
 
-  direction.GetBlock(gravity_displacement_force_test_utils::densityValue) =
+    direction.GetBlock(gravity_displacement_force_test_utils::densityValue)          = densityDirectionReduced;
-      densityDirectionReduced;
 
-  direction.GetBlock(gravity_displacement_force_test_utils::displacementValue) =
+    direction.GetBlock(gravity_displacement_force_test_utils::displacementValue)     = displacementDirectionReduced;
-      displacementDirectionReduced;
 
-  direction.GetBlock(
+    direction.GetBlock(gravity_displacement_force_test_utils::gravityGradientValue)  = gravityGradientDirectionReduced;
-      gravity_displacement_force_test_utils::gravityGradientValue) =
-      gravityGradientDirectionReduced;
 
-  direction.GetBlock(
+    direction.GetBlock(gravity_displacement_force_test_utils::gravityPotentialValue) = 0.29;
-      gravity_displacement_force_test_utils::gravityPotentialValue) = 0.29;
 
-  direction.GetBlock(gravity_displacement_force_test_utils::enthalpyValue) =
+    direction.GetBlock(gravity_displacement_force_test_utils::enthalpyValue)         = -0.37;
-      -0.37;
 
-  direction.GetBlock(
+    direction.GetBlock(gravity_displacement_force_test_utils::barotropicConstantValue) = 0.43;
-      gravity_displacement_force_test_utils::barotropicConstantValue) = 0.43;
 
     mfem::Vector action;
     adapter.Mult(direction, action);
@@ -738,36 +701,39 @@ TEST_CASE("Prepared Gravity Displacement Force MFEM Adapter Routes Only R-d",
     mfem::Vector expectedDisplacementAction;
 
     preparedOperator.ApplyCompleteJacobianAction(
-      densityDirectionReduced, displacementDirectionReduced,
+        densityDirectionReduced, displacementDirectionReduced, gravityGradientDirectionReduced,
-      gravityGradientDirectionReduced, expectedDisplacementAction);
+        expectedDisplacementAction
+    );
 
-  const mfem::Vector actualDisplacementAction =
+    const mfem::Vector actualDisplacementAction = gravity_displacement_force_test_utils::copy_residual_block(
-      gravity_displacement_force_test_utils::copy_residual_block(
+        action, layout, gravity_displacement_force_test_utils::displacementResidual
-          action, layout,
+    );
-          gravity_displacement_force_test_utils::displacementResidual);
 
-  CHECK(gravity_displacement_force_test_utils::relative_difference(
+    CHECK(
-            actualDisplacementAction, expectedDisplacementAction,
+        gravity_displacement_force_test_utils::relative_difference(
-            f.mesh->GetComm()) < 2.0e-12);
+            actualDisplacementAction, expectedDisplacementAction, f.mesh->GetComm()
+        ) < 2.0e-12
+    );
 
     const std::array<mfem::Vector, 5> zeroRows{
         gravity_displacement_force_test_utils::copy_residual_block(
-          action, layout,
+            action, layout, gravity_displacement_force_test_utils::gravityGradientResidual
-          gravity_displacement_force_test_utils::gravityGradientResidual),
+        ),
         gravity_displacement_force_test_utils::copy_residual_block(
-          action, layout,
+            action, layout, gravity_displacement_force_test_utils::gravityPotentialResidual
-          gravity_displacement_force_test_utils::gravityPotentialResidual),
+        ),
         gravity_displacement_force_test_utils::copy_residual_block(
-          action, layout,
+            action, layout, gravity_displacement_force_test_utils::densityResidual
-          gravity_displacement_force_test_utils::densityResidual),
+        ),
         gravity_displacement_force_test_utils::copy_residual_block(
-          action, layout,
+            action, layout, gravity_displacement_force_test_utils::enthalpyResidual
-          gravity_displacement_force_test_utils::enthalpyResidual),
+        ),
         gravity_displacement_force_test_utils::copy_residual_block(
-          action, layout, gravity_displacement_force_test_utils::massResidual)};
+            action, layout, gravity_displacement_force_test_utils::massResidual
+        )
+    };
 
     for (const mfem::Vector &row : zeroRows) {
-    CHECK(gravity_prepared_test_utils::global_norm(row, f.mesh->GetComm()) ==
+        CHECK(gravity_prepared_test_utils::global_norm(row, f.mesh->GetComm()) == 0.0);
-          0.0);
     }
 }

tests/operators/gravity_displacement_force_analytic_comparisons.cpp

@@ -11,26 +11,34 @@ import mean_field;
 import test_helpers;
 
 namespace gravity_displacement_force_analytic_test_utils {
-struct AffineCase {
+    struct AffineCase {
         const char *name;
         std::array<double, 3> scales;
-};
+    };
 
-[[nodiscard]] double analytic_sphere_volume(const double radius) {
+    [[nodiscard]] double analytic_sphere_volume(const double radius) {
         return (4.0 / 3.0) * std::numbers::pi * radius * radius * radius;
-}
+    }
 
-[[nodiscard]] double determinant(const std::array<double, 3> &scales) {
+    [[nodiscard]] double determinant(
+        const std::array<
+            double,
+            3> &scales
+    ) {
         return scales[0] * scales[1] * scales[2];
-}
+    }
 
-[[nodiscard]] double relative_scalar_error(const double computed,
+    [[nodiscard]] double relative_scalar_error(
-                                           const double expected) {
+        const double computed,
+        const double expected
+    ) {
         return std::abs(computed - expected) / std::max(std::abs(expected), 1.0e-30);
-}
+    }
 
-[[nodiscard]] mfem::Vector make_constant_density(const mean_field::fem::FEM &f,
+    [[nodiscard]] mfem::Vector make_constant_density(
-                                                 const double densityValue) {
+        const mean_field::fem::FEM &f,
+        const double densityValue
+    ) {
         mfem::ParGridFunction densityField(f.densityFes.get());
         mfem::ConstantCoefficient densityCoefficient(densityValue);
         densityField.ProjectCoefficient(densityCoefficient);
@@ -38,133 +46,138 @@ struct AffineCase {
         mfem::Vector densityTrue;
         densityField.GetTrueDofs(densityTrue);
         return densityTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector
+    [[nodiscard]] mfem::Vector make_reference_gravity(
-make_reference_gravity(const mean_field::fem::FEM &f,
+        const mean_field::fem::FEM &f,
-                       const std::array<double, 3> &referenceGravity) {
+        const std::array<
+            double,
+            3> &referenceGravity
+    ) {
         mfem::ParGridFunction gravityField(f.gravityFluxFes.get());
 
         mfem::VectorFunctionCoefficient gravityCoefficient(
-      f.mesh->Dimension(),
+            f.mesh->Dimension(), [referenceGravity](const mfem::Vector &, mfem::Vector &value) {
-      [referenceGravity](const mfem::Vector &, mfem::Vector &value) {
                 value.SetSize(3);
 
                 for (int component = 0; component < 3; ++component) {
-          value(component) =
+                    value(component) = referenceGravity[static_cast<std::size_t>(component)];
-              referenceGravity[static_cast<std::size_t>(component)];
                 }
-      });
+            }
+        );
 
         gravityField.ProjectCoefficient(gravityCoefficient);
 
         mfem::Vector gravityTrue;
         gravityField.GetTrueDofs(gravityTrue);
         return gravityTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector make_radial_gravity(const mean_field::fem::FEM &f,
+    [[nodiscard]] mfem::Vector make_radial_gravity(
-                                               const double radialCoefficient) {
+        const mean_field::fem::FEM &f,
+        const double radialCoefficient
+    ) {
         mfem::ParGridFunction gravityField(f.gravityFluxFes.get());
 
         mfem::VectorFunctionCoefficient gravityCoefficient(
-      f.mesh->Dimension(),
+            f.mesh->Dimension(), [radialCoefficient](const mfem::Vector &position, mfem::Vector &value) {
-      [radialCoefficient](const mfem::Vector &position, mfem::Vector &value) {
                 value.SetSize(position.Size());
 
                 for (int component = 0; component < position.Size(); ++component) {
                     value(component) = radialCoefficient * position(component);
                 }
-      });
+            }
+        );
 
         gravityField.ProjectCoefficient(gravityCoefficient);
 
         mfem::Vector gravityTrue;
         gravityField.GetTrueDofs(gravityTrue);
         return gravityTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector
+    [[nodiscard]] mfem::Vector make_affine_displacement(
-make_affine_displacement(const mean_field::fem::FEM &f,
+        const mean_field::fem::FEM &f,
-                         const std::array<double, 3> &scales) {
+        const std::array<
+            double,
+            3> &scales
+    ) {
         mfem::ParGridFunction displacementField(f.displacementFes.get());
 
         mfem::VectorFunctionCoefficient displacementCoefficient(
-      f.mesh->Dimension(),
+            f.mesh->Dimension(), [scales](const mfem::Vector &position, mfem::Vector &value) {
-      [scales](const mfem::Vector &position, mfem::Vector &value) {
                 value.SetSize(position.Size());
 
                 for (int component = 0; component < position.Size(); ++component) {
-          value(component) =
+                    value(component) = (scales[static_cast<std::size_t>(component)] - 1.0) * position(component);
-              (scales[static_cast<std::size_t>(component)] - 1.0) *
-              position(component);
                 }
-      });
+            }
+        );
 
         displacementField.ProjectCoefficient(displacementCoefficient);
 
         mfem::Vector displacementTrue;
         displacementField.GetTrueDofs(displacementTrue);
         return displacementTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector
+    [[nodiscard]] mfem::Vector make_constant_test_direction(
-make_constant_test_direction(const mean_field::fem::FEM &f,
+        const mean_field::fem::FEM &f,
-                             const int selectedComponent) {
+        const int selectedComponent
+    ) {
         mfem::ParGridFunction testField(f.displacementFes.get());
 
         mfem::VectorFunctionCoefficient testCoefficient(
-      f.mesh->Dimension(),
+            f.mesh->Dimension(), [selectedComponent](const mfem::Vector &position, mfem::Vector &value) {
-      [selectedComponent](const mfem::Vector &position, mfem::Vector &value) {
                 value.SetSize(position.Size());
                 value                    = 0.0;
                 value(selectedComponent) = 1.0;
-      });
+            }
+        );
 
         testField.ProjectCoefficient(testCoefficient);
 
         mfem::Vector testTrue;
         testField.GetTrueDofs(testTrue);
         return testTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector
+    [[nodiscard]] mfem::Vector make_dilation_test_direction(const mean_field::fem::FEM &f) {
-make_dilation_test_direction(const mean_field::fem::FEM &f) {
         mfem::ParGridFunction testField(f.displacementFes.get());
 
         mfem::VectorFunctionCoefficient testCoefficient(
-      f.mesh->Dimension(), [](const mfem::Vector &position,
+            f.mesh->Dimension(), [](const mfem::Vector &position, mfem::Vector &value) { value = position; }
-                              mfem::Vector &value) { value = position; });
+        );
 
         testField.ProjectCoefficient(testCoefficient);
 
         mfem::Vector testTrue;
         testField.GetTrueDofs(testTrue);
         return testTrue;
-}
+    }
 
-void set_mass_normalized_density(mean_field::fem::FEM &f,
+    void set_mass_normalized_density(
+        mean_field::fem::FEM &f,
         const double targetMass,
-                                 mfem::ParGridFunction &densityField) {
+        mfem::ParGridFunction &densityField
-  const mfem::Vector stellarDensityTrue =
+    ) {
-      gravity_prepared_test_utils::make_domain_supported_density(f, true);
+        const mfem::Vector stellarDensityTrue = gravity_prepared_test_utils::make_domain_supported_density(f, true);
 
         densityField.SetFromTrueDofs(stellarDensityTrue);
 
         const double unnormalizedMass =
-      mean_field::analysis::domain_integrate_grid_function(
+            mean_field::analysis::domain_integrate_grid_function(f, densityField, mean_field::utils::DOMAINS::STELLAR);
-          f, densityField, mean_field::utils::DOMAINS::STELLAR);
 
-  MFEM_VERIFY(unnormalizedMass > 0.0,
+        MFEM_VERIFY(unnormalizedMass > 0.0, "The analytic gravity-force test obtained non-positive mass.");
-              "The analytic gravity-force test obtained non-positive mass.");
 
         densityField *= targetMass / unnormalizedMass;
-}
+    }
 } // namespace gravity_displacement_force_analytic_test_utils
 
-TEST_CASE("Gravity Displacement Force Matches Analytic Affine Resultants",
+TEST_CASE(
-          tags::gravity &tags::accuracy &tags::analytic_comparison
+    "Gravity Displacement Force Matches Analytic Affine Resultants",
-              &tags::integration) {
+    tags::gravity &tags::accuracy &tags::analytic_comparison &tags::integration
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
@@ -177,30 +190,23 @@ TEST_CASE("Gravity Displacement Force Matches Analytic Affine Resultants",
 
     constexpr std::array<double, 3> physicalGravity{0.31, -0.47, 0.22};
 
-  constexpr std::array<
+    constexpr std::array<gravity_displacement_force_analytic_test_utils::AffineCase, 3> affineCases{
-      gravity_displacement_force_analytic_test_utils::AffineCase, 3>
+        {{.name = "identity geometry", .scales = {1.0, 1.0, 1.0}},
-      affineCases{{{.name = "identity geometry", .scales = {1.0, 1.0, 1.0}},
+         {.name = "volume-preserving affine geometry", .scales = {1.14, 0.93, 1.0 / (1.14 * 0.93)}},
-                   {.name = "volume-preserving affine geometry",
+         {.name = "volume-changing affine geometry", .scales = {1.11, 0.96, 1.07}}}
-                    .scales = {1.14, 0.93, 1.0 / (1.14 * 0.93)}},
+    };
-                   {.name = "volume-changing affine geometry",
-                    .scales = {1.11, 0.96, 1.07}}}};
 
-  const mfem::Vector density =
+    const mfem::Vector density = gravity_displacement_force_analytic_test_utils::make_constant_density(f, densityValue);
-      gravity_displacement_force_analytic_test_utils::make_constant_density(
-          f, densityValue);
 
     const double referenceVolume =
-      gravity_displacement_force_analytic_test_utils::analytic_sphere_volume(
+        gravity_displacement_force_analytic_test_utils::analytic_sphere_volume(mean_field::utils::RADIUS);
-          mean_field::utils::RADIUS);
 
     constexpr double relativeTolerance = 5.0e-6;
 
-  for (const gravity_displacement_force_analytic_test_utils::AffineCase
+    for (const gravity_displacement_force_analytic_test_utils::AffineCase &affineCase : affineCases) {
-           &affineCase : affineCases) {
         DYNAMIC_SECTION(affineCase.name) {
             const double mapDeterminant =
-          gravity_displacement_force_analytic_test_utils::determinant(
+                gravity_displacement_force_analytic_test_utils::determinant(affineCase.scales);
-              affineCase.scales);
 
             REQUIRE(mapDeterminant > 0.0);
 
@@ -216,42 +222,35 @@ TEST_CASE("Gravity Displacement Force Matches Analytic Affine Resultants",
              */
             for (int component = 0; component < 3; ++component) {
                 referenceGravity[static_cast<std::size_t>(component)] =
-            mapDeterminant *
+                    mapDeterminant * physicalGravity[static_cast<std::size_t>(component)] /
-            physicalGravity[static_cast<std::size_t>(component)] /
                     affineCase.scales[static_cast<std::size_t>(component)];
             }
 
             const mfem::Vector gravityGradient =
-          gravity_displacement_force_analytic_test_utils::
+                gravity_displacement_force_analytic_test_utils::make_reference_gravity(f, referenceGravity);
-              make_reference_gravity(f, referenceGravity);
 
             const mfem::Vector displacement =
-          gravity_displacement_force_analytic_test_utils::
+                gravity_displacement_force_analytic_test_utils::make_affine_displacement(f, affineCase.scales);
-              make_affine_displacement(f, affineCase.scales);
 
             mfem::Vector residual;
 
             mean_field::operators::kernels::apply_gravity_displacement_force_residual(
-          f, *f.domainMapperStateless, density, gravityGradient, displacement,
+                f, *f.domainMapperStateless, density, gravityGradient, displacement, residual
-          residual);
+            );
 
             for (int component = 0; component < 3; ++component) {
                 const mfem::Vector testDirection =
-            gravity_displacement_force_analytic_test_utils::
+                    gravity_displacement_force_analytic_test_utils::make_constant_test_direction(f, component);
-                make_constant_test_direction(f, component);
 
                 const double computedResultant =
-            gravity_prepared_test_utils::global_dot(residual, testDirection,
+                    gravity_prepared_test_utils::global_dot(residual, testDirection, f.mesh->GetComm());
-                                                    f.mesh->GetComm());
 
-        const double expectedResultant =
+                const double expectedResultant = densityValue * physicalGravity[static_cast<std::size_t>(component)] *
-            densityValue *
-            physicalGravity[static_cast<std::size_t>(component)] *
                                                  mapDeterminant * referenceVolume;
 
-        const double relativeError =
+                const double relativeError     = gravity_displacement_force_analytic_test_utils::relative_scalar_error(
-            gravity_displacement_force_analytic_test_utils::
+                    computedResultant, expectedResultant
-                relative_scalar_error(computedResultant, expectedResultant);
+                );
 
                 CAPTURE(component);
                 INFO("Map determinant = " << mapDeterminant);
@@ -267,8 +266,8 @@ TEST_CASE("Gravity Displacement Force Matches Analytic Affine Resultants",
 
 TEST_CASE(
     "Gravity Displacement Force Reproduces Analytic Homogeneous Sphere Work",
-    tags::gravity &tags::accuracy &tags::analytic_comparison
+    tags::gravity &tags::accuracy &tags::analytic_comparison &tags::integration
-        &tags::integration) {
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
@@ -278,21 +277,15 @@ TEST_CASE(
 
     const double radius       = mean_field::utils::RADIUS;
     const double mass         = mean_field::utils::MASS;
-  const double volume =
+    const double volume       = gravity_displacement_force_analytic_test_utils::analytic_sphere_volume(radius);
-      gravity_displacement_force_analytic_test_utils::analytic_sphere_volume(
-          radius);
 
     const double densityValue = mass / volume;
-  const double radialGravityCoefficient =
+    const double radialGravityCoefficient = mean_field::utils::G * mass / (radius * radius * radius);
-      mean_field::utils::G * mass / (radius * radius * radius);
 
-  const mfem::Vector density =
+    const mfem::Vector density = gravity_displacement_force_analytic_test_utils::make_constant_density(f, densityValue);
-      gravity_displacement_force_analytic_test_utils::make_constant_density(
-          f, densityValue);
 
     const mfem::Vector gravityGradient =
-      gravity_displacement_force_analytic_test_utils::make_radial_gravity(
+        gravity_displacement_force_analytic_test_utils::make_radial_gravity(f, radialGravityCoefficient);
-          f, radialGravityCoefficient);
 
     mfem::Vector displacement(f.displacementFes->GetTrueVSize());
     displacement = 0.0;
@@ -300,22 +293,18 @@ TEST_CASE(
     mfem::Vector residual;
 
     mean_field::operators::kernels::apply_gravity_displacement_force_residual(
-      f, *f.domainMapperStateless, density, gravityGradient, displacement,
+        f, *f.domainMapperStateless, density, gravityGradient, displacement, residual
-      residual);
+    );
 
     const mfem::Vector dilationDirection =
-      gravity_displacement_force_analytic_test_utils::
+        gravity_displacement_force_analytic_test_utils::make_dilation_test_direction(f);
-          make_dilation_test_direction(f);
 
-  const double computedWork = gravity_prepared_test_utils::global_dot(
+    const double computedWork = gravity_prepared_test_utils::global_dot(residual, dilationDirection, f.mesh->GetComm());
-      residual, dilationDirection, f.mesh->GetComm());
 
-  const double analyticWork =
+    const double analyticWork = (3.0 / 5.0) * mean_field::utils::G * mass * mass / radius;
-      (3.0 / 5.0) * mean_field::utils::G * mass * mass / radius;
 
     const double relativeError =
-      gravity_displacement_force_analytic_test_utils::relative_scalar_error(
+        gravity_displacement_force_analytic_test_utils::relative_scalar_error(computedWork, analyticWork);
-          computedWork, analyticWork);
 
     INFO("Computed positive gravity work = " << computedWork);
     INFO("Analytic positive gravity work = " << analyticWork);
@@ -327,9 +316,10 @@ TEST_CASE(
     CHECK(relativeError < 1.0e-5);
 }
 
-TEST_CASE("Solved Homogeneous Sphere Gravity Force Matches Analytic Virial",
+TEST_CASE(
-          tags::gravity &tags::accuracy &tags::analytic_comparison
+    "Solved Homogeneous Sphere Gravity Force Matches Analytic Virial",
-              &tags::integration &tags::initialization) {
+    tags::gravity &tags::accuracy &tags::analytic_comparison &tags::integration &tags::initialization
+) {
     mean_field::utils::Args args = test_utils::setup_args();
     args.p.rtol                  = 1.0e-13;
     args.p.max_iters             = std::max(args.p.max_iters, 1000);
@@ -350,12 +340,10 @@ TEST_CASE("Solved Homogeneous Sphere Gravity Force Matches Analytic Virial",
 
     mfem::ParGridFunction densityField(f.densityFes.get());
 
-  gravity_displacement_force_analytic_test_utils::set_mass_normalized_density(
+    gravity_displacement_force_analytic_test_utils::set_mass_normalized_density(f, mass, densityField);
-      f, mass, densityField);
 
     const mean_field::physics::GravitySolution gravitySolution =
-      mean_field::physics::solve_gravity_field(f, args, densityField,
+        mean_field::physics::solve_gravity_field(f, args, densityField, displacementField);
-                                               displacementField);
 
     mfem::Vector densityTrue;
     mfem::Vector gravityGradientTrue;
@@ -368,22 +356,18 @@ TEST_CASE("Solved Homogeneous Sphere Gravity Force Matches Analytic Virial",
     mfem::Vector residual;
 
     mean_field::operators::kernels::apply_gravity_displacement_force_residual(
-      f, *f.domainMapperStateless, densityTrue, gravityGradientTrue,
+        f, *f.domainMapperStateless, densityTrue, gravityGradientTrue, displacementTrue, residual
-      displacementTrue, residual);
+    );
 
     const mfem::Vector dilationDirection =
-      gravity_displacement_force_analytic_test_utils::
+        gravity_displacement_force_analytic_test_utils::make_dilation_test_direction(f);
-          make_dilation_test_direction(f);
 
-  const double computedWork = gravity_prepared_test_utils::global_dot(
+    const double computedWork = gravity_prepared_test_utils::global_dot(residual, dilationDirection, f.mesh->GetComm());
-      residual, dilationDirection, f.mesh->GetComm());
 
-  const double analyticWork =
+    const double analyticWork = (3.0 / 5.0) * mean_field::utils::G * mass * mass / radius;
-      (3.0 / 5.0) * mean_field::utils::G * mass * mass / radius;
 
     const double relativeError =
-      gravity_displacement_force_analytic_test_utils::relative_scalar_error(
+        gravity_displacement_force_analytic_test_utils::relative_scalar_error(computedWork, analyticWork);
-          computedWork, analyticWork);
 
     INFO("Solved-field positive gravity work = " << computedWork);
     INFO("Analytic positive gravity work = " << analyticWork);

tests/operators/kernels/barotropic_closure_kernels.cpp

@@ -72,7 +72,10 @@ TEST_CASE(
 
     constexpr double enthalpyValue  = 0.8;
 
-    const double densityValue       = barotrope.density_from_enthalpy(enthalpyValue);
+    const double densityValue       = mean_field::eos::evaluate<mean_field::eos::quantity::Density>(
+                                          barotrope, mean_field::eos::SpecificEnthalpyValue{enthalpyValue}
+    )
+                                          .value();
 
     const mfem::Vector enthalpy     = project_constant(*f.enthalpyFes, enthalpyValue);
 

tests/operators/kernels/pressure_force_kernels.cpp

@@ -10,48 +10,43 @@ import mean_field;
 import test_helpers;
 
 namespace pressure_force_kernel_test_utils {
-[[nodiscard]] mfem::Vector make_deterministic_vector(const int size,
+    [[nodiscard]] mfem::Vector make_deterministic_vector(
-                                                     const double phase) {
+        const int size,
+        const double phase
+    ) {
         mfem::Vector vector(size);
 
         for (int index = 0; index < size; ++index) {
             const double position = static_cast<double>(index + 1);
 
-    vector(index) = 0.71 + 0.19 * std::sin(0.31 * position + phase) +
+            vector(index) =
-                    0.08 * std::cos(0.17 * position - 0.5 * phase);
+                0.71 + 0.19 * std::sin(0.31 * position + phase) + 0.08 * std::cos(0.17 * position - 0.5 * phase);
         }
 
         return vector;
-}
+    }
 
-[[nodiscard]] mfem::Vector
+    [[nodiscard]] mfem::Vector make_zero_displacement(const mean_field::fem::FEM &f) {
-make_zero_displacement(const mean_field::fem::FEM &f) {
         mfem::Vector displacementTrue(f.displacementFes->GetTrueVSize());
         displacementTrue = 0.0;
         return displacementTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector
+    [[nodiscard]] mfem::Vector make_vacuum_only_enthalpy(const mean_field::fem::FEM &f) {
-make_vacuum_only_enthalpy(const mean_field::fem::FEM &f) {
+        mfem::Vector enthalpyTrue = make_deterministic_vector(f.enthalpyFes->GetTrueVSize(), 0.43);
-  mfem::Vector enthalpyTrue =
-      make_deterministic_vector(f.enthalpyFes->GetTrueVSize(), 0.43);
 
-  using DomainSchema =
+        using DomainSchema        = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
-      mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
         const mean_field::field::FieldDofMap enthalpyMap =
-      mean_field::field::make_field_dof_map<mean_field::field::Enthalpy,
+            mean_field::field::make_field_dof_map<mean_field::field::Enthalpy, DomainSchema>(*f.enthalpyFes);
-                                            DomainSchema>(*f.enthalpyFes);
 
-  for (int reducedDof = 0; reducedDof < enthalpyMap.reduced_size();
+        for (int reducedDof = 0; reducedDof < enthalpyMap.reduced_size(); ++reducedDof) {
-       ++reducedDof) {
             enthalpyTrue(enthalpyMap.true_dof(reducedDof)) = 0.0;
         }
 
         return enthalpyTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector
+    [[nodiscard]] mfem::Vector make_positive_asymmetric_enthalpy(const mean_field::fem::FEM &f) {
-make_positive_asymmetric_enthalpy(const mean_field::fem::FEM &f) {
         mfem::FunctionCoefficient coefficient([](const mfem::Vector &position) {
             return 1.10 + 0.07 * position(0) - 0.04 * position(1) + 0.03 * position(2);
         });
@@ -64,18 +59,18 @@ make_positive_asymmetric_enthalpy(const mean_field::fem::FEM &f) {
         enthalpyField.GetTrueDofs(enthalpyTrue);
 
         return enthalpyTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector
+    [[nodiscard]] mfem::Vector make_component_test_field(
-make_component_test_field(const mean_field::fem::FEM &f, const int component,
+        const mean_field::fem::FEM &f,
-                          const int coordinate) {
+        const int component,
+        const int coordinate
+    ) {
         const int dimension = f.mesh->Dimension();
 
-  MFEM_VERIFY(component >= 0 && component < dimension,
+        MFEM_VERIFY(component >= 0 && component < dimension, "The requested vector component is invalid.");
-              "The requested vector component is invalid.");
 
-  MFEM_VERIFY(coordinate >= -1 && coordinate < dimension,
+        MFEM_VERIFY(coordinate >= -1 && coordinate < dimension, "The requested coordinate is invalid.");
-              "The requested coordinate is invalid.");
 
         /*
          * coordinate == -1 gives the rigid translation e_component.
@@ -85,13 +80,13 @@ make_component_test_field(const mean_field::fem::FEM &f, const int component,
          *     w = x_coordinate e_component.
          */
         mfem::VectorFunctionCoefficient coefficient(
-      dimension, [component, coordinate, dimension](
+            dimension, [component, coordinate, dimension](const mfem::Vector &position, mfem::Vector &value) {
-                     const mfem::Vector &position, mfem::Vector &value) {
                 value.SetSize(dimension);
                 value            = 0.0;
 
                 value(component) = coordinate < 0 ? 1.0 : position(coordinate);
-      });
+            }
+        );
 
         mfem::ParGridFunction field(f.displacementFes.get());
 
@@ -101,13 +96,14 @@ make_component_test_field(const mean_field::fem::FEM &f, const int component,
         field.GetTrueDofs(fieldTrue);
 
         return fieldTrue;
-}
+    }
 
-[[nodiscard]] double global_dot(const mfem::Vector &left,
+    [[nodiscard]] double global_dot(
+        const mfem::Vector &left,
         const mfem::Vector &right,
-                                MPI_Comm communicator) {
+        MPI_Comm communicator
-  MFEM_VERIFY(left.Size() == right.Size(),
+    ) {
-              "The global dot-product vectors have different sizes.");
+        MFEM_VERIFY(left.Size() == right.Size(), "The global dot-product vectors have different sizes.");
 
         const double localDot = left * right;
         double globalDot      = 0.0;
@@ -115,23 +111,28 @@ make_component_test_field(const mean_field::fem::FEM &f, const int component,
         MPI_Allreduce(&localDot, &globalDot, 1, MPI_DOUBLE, MPI_SUM, communicator);
 
         return globalDot;
-}
+    }
 
-[[nodiscard]] double integrate_pressure(
+    [[nodiscard]] double integrate_pressure(
         const mean_field::fem::FEM &f,
         const mean_field::mapping::DomainMapper &domainMapper,
         const mean_field::eos::Polytrope &barotrope,
-    const mfem::Vector &enthalpyTrue, const mfem::Vector &displacementTrue) {
+        const mfem::Vector &enthalpyTrue,
-  MFEM_VERIFY(enthalpyTrue.Size() == f.enthalpyFes->GetTrueVSize(),
+        const mfem::Vector &displacementTrue
-              "The pressure-integral enthalpy vector has the wrong size.");
+    ) {
+        MFEM_VERIFY(
+            enthalpyTrue.Size() == f.enthalpyFes->GetTrueVSize(),
+            "The pressure-integral enthalpy vector has the wrong size."
+        );
 
-  MFEM_VERIFY(displacementTrue.Size() == f.displacementFes->GetTrueVSize(),
+        MFEM_VERIFY(
-              "The pressure-integral displacement vector has the wrong size.");
+            displacementTrue.Size() == f.displacementFes->GetTrueVSize(),
+            "The pressure-integral displacement vector has the wrong size."
+        );
 
         mfem::Vector enthalpyLocal(f.enthalpyFes->GetVSize());
 
-  const mfem::Operator *enthalpyProlongation =
+        const mfem::Operator *enthalpyProlongation = f.enthalpyFes->GetProlongationMatrix();
-      f.enthalpyFes->GetProlongationMatrix();
 
         if (enthalpyProlongation != nullptr) {
             enthalpyProlongation->Mult(enthalpyTrue, enthalpyLocal);
@@ -141,8 +142,7 @@ make_component_test_field(const mean_field::fem::FEM &f, const int component,
 
         mfem::Vector displacementLocal(f.displacementFes->GetVSize());
 
-  const mfem::Operator *displacementProlongation =
+        const mfem::Operator *displacementProlongation = f.displacementFes->GetProlongationMatrix();
-      f.displacementFes->GetProlongationMatrix();
 
         if (displacementProlongation != nullptr) {
             displacementProlongation->Mult(displacementTrue, displacementLocal);
@@ -151,22 +151,19 @@ make_component_test_field(const mean_field::fem::FEM &f, const int component,
         }
 
         const double pressureExtraOrderValue =
-      barotrope.polytropic_index() *
+            barotrope.polytropic_index() * static_cast<double>(mean_field::field::Enthalpy::Scalar::familyOrder);
-      static_cast<double>(mean_field::field::Enthalpy::Scalar::familyOrder);
 
-  MFEM_VERIFY(std::isfinite(pressureExtraOrderValue) &&
+        MFEM_VERIFY(
-                  pressureExtraOrderValue >= 0.0 &&
+            std::isfinite(pressureExtraOrderValue) && pressureExtraOrderValue >= 0.0 &&
-                  pressureExtraOrderValue <=
+                pressureExtraOrderValue <= static_cast<double>(std::numeric_limits<int>::max()),
-                      static_cast<double>(std::numeric_limits<int>::max()),
+            "The pressure-integral EOS order is invalid."
-              "The pressure-integral EOS order is invalid.");
+        );
 
-  const int pressureExtraOrder =
+        const int pressureExtraOrder = static_cast<int>(std::ceil(pressureExtraOrderValue));
-      static_cast<int>(std::ceil(pressureExtraOrderValue));
 
         using EnthalpyField          = mean_field::field::Field<mean_field::field::Enthalpy>;
 
-  mean_field::mapping::DomainMapper::Workspace workspace(
+        mean_field::mapping::DomainMapper::Workspace workspace(f.mesh->Dimension());
-      f.mesh->Dimension());
 
         mean_field::mapping::VolumeMappingContext mappingContext;
 
@@ -184,28 +181,24 @@ make_component_test_field(const mean_field::fem::FEM &f, const int component,
         const int vacuumAttribute    = field_dof_test_utils::vacuum_material_attribute;
 
         for (int elementId = 0; elementId < f.mesh->GetNE(); ++elementId) {
-    mfem::ElementTransformation *transformation =
+            mfem::ElementTransformation *transformation = f.mesh->GetElementTransformation(elementId);
-        f.mesh->GetElementTransformation(elementId);
 
-    MFEM_VERIFY(transformation != nullptr,
+            MFEM_VERIFY(
-                "The pressure-integral reference received a null "
+                transformation != nullptr, "The pressure-integral reference received a null "
-                "element transformation.");
+                                           "element transformation."
+            );
 
             if (transformation->Attribute == vacuumAttribute) {
                 continue;
             }
 
-    const mfem::FiniteElement &enthalpyElement =
+            const mfem::FiniteElement &enthalpyElement         = *f.enthalpyFes->GetFE(elementId);
-        *f.enthalpyFes->GetFE(elementId);
 
-    const mfem::FiniteElement &displacementElement =
+            const mfem::FiniteElement &displacementElement     = *f.displacementFes->GetFE(elementId);
-        *f.displacementFes->GetFE(elementId);
 
-    const mfem::FiniteElement &compactificationElement =
+            const mfem::FiniteElement &compactificationElement = *f.compactificationFes->GetFE(elementId);
-        *f.compactificationFes->GetFE(elementId);
 
-    mfem::DofTransformation *enthalpyDofTransformation =
+            mfem::DofTransformation *enthalpyDofTransformation = f.enthalpyFes->GetElementDofs(elementId, enthalpyDofs);
-        f.enthalpyFes->GetElementDofs(elementId, enthalpyDofs);
 
             mfem::DofTransformation *displacementDofTransformation =
                 f.displacementFes->GetElementVDofs(elementId, displacementDofs);
@@ -217,8 +210,7 @@ make_component_test_field(const mean_field::fem::FEM &f, const int component,
 
             displacementLocal.GetSubVector(displacementDofs, elementDisplacement);
 
-    f.compactificationCoordinate->GetSubVector(compactificationDofs,
+            f.compactificationCoordinate->GetSubVector(compactificationDofs, elementCompactification);
-                                               elementCompactification);
 
             if (enthalpyDofTransformation != nullptr) {
                 enthalpyDofTransformation->InvTransformPrimal(elementEnthalpy);
@@ -229,70 +221,66 @@ make_component_test_field(const mean_field::fem::FEM &f, const int component,
             }
 
             if (compactificationDofTransformation != nullptr) {
-      compactificationDofTransformation->InvTransformPrimal(
+                compactificationDofTransformation->InvTransformPrimal(elementCompactification);
-          elementCompactification);
             }
 
             const mean_field::mapping::ElementDisplacementData displacementData =
-        mean_field::mapping::ElementDisplacementDataFromElementVDofs(
+                mean_field::mapping::ElementDisplacementDataFromElementVDofs(displacementElement, elementDisplacement);
-            displacementElement, elementDisplacement);
 
             const mean_field::mapping::ElementCompactificationData compactificationData(
-        compactificationElement, elementCompactification);
+                compactificationElement, elementCompactification
+            );
 
             const mean_field::mapping::ElementMappingData mappingData{
-        .displacement = displacementData,
+                .displacement = displacementData, .compactification = compactificationData
-        .compactification = compactificationData};
+            };
 
-    const mean_field::quadrature::Query query = EnthalpyField::make_query<
+            const mean_field::quadrature::Query query =
-        mean_field::field::Enthalpy::Form::PressureIntegral>(
+                EnthalpyField::make_query<mean_field::field::Enthalpy::Form::PressureIntegral>(
-        mean_field::quadrature::QuadratureRole::diagnostic,
+                    mean_field::quadrature::QuadratureRole::diagnostic, transformation->OrderW(),
-        transformation->OrderW(), std::array<int, 1>{pressureExtraOrder},
+                    std::array<int, 1>{pressureExtraOrder}, mean_field::utils::DOMAINS::STELLAR,
-        mean_field::utils::DOMAINS::STELLAR,
+                    mean_field::quadrature::MappingKind::general
-        mean_field::quadrature::MappingKind::general);
+                );
 
             const mean_field::quadrature::MfemRule rule =
                 f.quadratureFactory->get(query, transformation->GetGeometryType());
 
-    MFEM_VERIFY(rule.integration_rule != nullptr,
+            MFEM_VERIFY(rule.integration_rule != nullptr, "The pressure-integral quadrature rule is null.");
-                "The pressure-integral quadrature rule is null.");
 
             enthalpyShape.SetSize(enthalpyElement.GetDof());
 
-    for (int quadratureIndex = 0;
+            for (int quadratureIndex = 0; quadratureIndex < rule.integration_rule->GetNPoints(); ++quadratureIndex) {
-         quadratureIndex < rule.integration_rule->GetNPoints();
+                const mfem::IntegrationPoint &integrationPoint = rule.integration_rule->IntPoint(quadratureIndex);
-         ++quadratureIndex) {
-      const mfem::IntegrationPoint &integrationPoint =
-          rule.integration_rule->IntPoint(quadratureIndex);
 
                 transformation->SetIntPoint(&integrationPoint);
 
-      const mean_field::mapping::MappingStatus mappingStatus =
+                const mean_field::mapping::MappingStatus mappingStatus = domainMapper.EvaluateVolume(
-          domainMapper.EvaluateVolume(mappingData, *transformation,
+                    mappingData, *transformation, integrationPoint, workspace, mappingContext
-                                      integrationPoint, workspace,
+                );
-                                      mappingContext);
 
-      MFEM_VERIFY(mappingStatus == mean_field::mapping::MappingStatus::valid,
+                MFEM_VERIFY(
+                    mappingStatus == mean_field::mapping::MappingStatus::valid,
                     "Stateless mapping failed in the "
                     "independent pressure integral. Element: "
-                      << elementId
+                        << elementId << ", attribute: " << transformation->Attribute
-                      << ", attribute: " << transformation->Attribute
+                        << ", quadrature point: " << quadratureIndex << ", status: " << static_cast<int>(mappingStatus)
-                      << ", quadrature point: " << quadratureIndex
+                );
-                      << ", status: " << static_cast<int>(mappingStatus));
 
                 enthalpyElement.CalcShape(integrationPoint, enthalpyShape);
 
                 const double enthalpyValue = elementEnthalpy * enthalpyShape;
 
-      const double pressureValue =
+                const double pressureValue = mean_field::eos::evaluate<mean_field::eos::quantity::Pressure>(
-          barotrope.pressure_from_enthalpy(enthalpyValue);
+                                                 barotrope, mean_field::eos::SpecificEnthalpyValue{enthalpyValue}
+                )
+                                                 .value();
 
-      const double contribution =
+                const double contribution  = pressureValue * mappingContext.quadrature.weight;
-          pressureValue * mappingContext.quadrature.weight;
 
-      MFEM_VERIFY(std::isfinite(pressureValue) && std::isfinite(contribution),
+                MFEM_VERIFY(
-                  "The independent pressure integral "
+                    std::isfinite(pressureValue) && std::isfinite(contribution), "The independent pressure integral "
-                  "encountered a non-finite value.");
+                                                                                 "encountered a non-finite value."
+                );
 
                 localPressureIntegral += contribution;
             }
@@ -300,15 +288,16 @@ make_component_test_field(const mean_field::fem::FEM &f, const int component,
 
         double globalPressureIntegral = 0.0;
 
-  MPI_Allreduce(&localPressureIntegral, &globalPressureIntegral, 1, MPI_DOUBLE,
+        MPI_Allreduce(&localPressureIntegral, &globalPressureIntegral, 1, MPI_DOUBLE, MPI_SUM, f.mesh->GetComm());
-                MPI_SUM, f.mesh->GetComm());
 
         return globalPressureIntegral;
-}
+    }
 } // namespace pressure_force_kernel_test_utils
 
-TEST_CASE("Pressure Force Residual Vanishes For Zero Enthalpy",
+TEST_CASE(
-          tags::barotrope &tags::pressure &tags::kernels &tags::integration) {
+    "Pressure Force Residual Vanishes For Zero Enthalpy",
+    tags::barotrope &tags::pressure &tags::kernels &tags::integration
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
@@ -320,25 +309,25 @@ TEST_CASE("Pressure Force Residual Vanishes For Zero Enthalpy",
     mfem::Vector enthalpyTrue(f.enthalpyFes->GetTrueVSize());
     enthalpyTrue                        = 0.0;
 
-  const mfem::Vector displacementTrue =
+    const mfem::Vector displacementTrue = pressure_force_kernel_test_utils::make_zero_displacement(f);
-      pressure_force_kernel_test_utils::make_zero_displacement(f);
 
     mfem::Vector residualTrue;
 
     mean_field::operators::kernels::apply_pressure_force_residual(
-      f, *f.domainMapperStateless, barotrope, enthalpyTrue, displacementTrue,
+        f, *f.domainMapperStateless, barotrope, enthalpyTrue, displacementTrue, residualTrue
-      residualTrue);
+    );
 
     REQUIRE(residualTrue.Size() == f.displacementFes->GetTrueVSize());
 
-  const double residualNorm =
+    const double residualNorm = gravity_prepared_test_utils::global_norm(residualTrue, f.mesh->GetComm());
-      gravity_prepared_test_utils::global_norm(residualTrue, f.mesh->GetComm());
 
     CHECK(residualNorm == 0.0);
 }
 
-TEST_CASE("Pressure Force Residual Excludes Vacuum Enthalpy Exactly",
+TEST_CASE(
-          tags::barotrope &tags::pressure &tags::kernels &tags::integration) {
+    "Pressure Force Residual Excludes Vacuum Enthalpy Exactly",
+    tags::barotrope &tags::pressure &tags::kernels &tags::integration
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
@@ -347,11 +336,9 @@ TEST_CASE("Pressure Force Residual Excludes Vacuum Enthalpy Exactly",
 
     const mean_field::eos::Polytrope barotrope(3.0, 0.25);
 
-  const mfem::Vector enthalpyTrue =
+    const mfem::Vector enthalpyTrue = pressure_force_kernel_test_utils::make_vacuum_only_enthalpy(f);
-      pressure_force_kernel_test_utils::make_vacuum_only_enthalpy(f);
 
-  const double enthalpyNorm =
+    const double enthalpyNorm       = gravity_prepared_test_utils::global_norm(enthalpyTrue, f.mesh->GetComm());
-      gravity_prepared_test_utils::global_norm(enthalpyTrue, f.mesh->GetComm());
 
     /*
      * Ensure this is a real exclusion test rather than another
@@ -359,25 +346,25 @@ TEST_CASE("Pressure Force Residual Excludes Vacuum Enthalpy Exactly",
      */
     REQUIRE(enthalpyNorm > 0.0);
 
-  const mfem::Vector displacementTrue =
+    const mfem::Vector displacementTrue = pressure_force_kernel_test_utils::make_zero_displacement(f);
-      pressure_force_kernel_test_utils::make_zero_displacement(f);
 
     mfem::Vector residualTrue;
 
     mean_field::operators::kernels::apply_pressure_force_residual(
-      f, *f.domainMapperStateless, barotrope, enthalpyTrue, displacementTrue,
+        f, *f.domainMapperStateless, barotrope, enthalpyTrue, displacementTrue, residualTrue
-      residualTrue);
+    );
 
     REQUIRE(residualTrue.Size() == f.displacementFes->GetTrueVSize());
 
-  const double residualNorm =
+    const double residualNorm = gravity_prepared_test_utils::global_norm(residualTrue, f.mesh->GetComm());
-      gravity_prepared_test_utils::global_norm(residualTrue, f.mesh->GetComm());
 
     CHECK(residualNorm == 0.0);
 }
 
-TEST_CASE("Pressure Force Residual Is Nonzero For Positive Stellar Pressure",
+TEST_CASE(
-          tags::barotrope &tags::pressure &tags::kernels &tags::integration) {
+    "Pressure Force Residual Is Nonzero For Positive Stellar Pressure",
+    tags::barotrope &tags::pressure &tags::kernels &tags::integration
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
@@ -394,17 +381,15 @@ TEST_CASE("Pressure Force Residual Is Nonzero For Positive Stellar Pressure",
     mfem::Vector enthalpyTrue(f.enthalpyFes->GetTrueVSize());
     enthalpyTrue                        = 1.0;
 
-  const mfem::Vector displacementTrue =
+    const mfem::Vector displacementTrue = pressure_force_kernel_test_utils::make_zero_displacement(f);
-      pressure_force_kernel_test_utils::make_zero_displacement(f);
 
     mfem::Vector residualTrue;
 
     mean_field::operators::kernels::apply_pressure_force_residual(
-      f, *f.domainMapperStateless, barotrope, enthalpyTrue, displacementTrue,
+        f, *f.domainMapperStateless, barotrope, enthalpyTrue, displacementTrue, residualTrue
-      residualTrue);
+    );
 
-  const double residualNorm =
+    const double residualNorm = gravity_prepared_test_utils::global_norm(residualTrue, f.mesh->GetComm());
-      gravity_prepared_test_utils::global_norm(residualTrue, f.mesh->GetComm());
 
     INFO("Positive-pressure residual norm = " << residualNorm);
 
@@ -413,9 +398,10 @@ TEST_CASE("Pressure Force Residual Is Nonzero For Positive Stellar Pressure",
     CHECK(residualNorm > 100.0 * std::numeric_limits<double>::epsilon());
 }
 
-TEST_CASE("Pressure Force Residual Does No Work Against Rigid Translations",
+TEST_CASE(
-          tags::barotrope &tags::pressure &tags::kernels &tags::integration
+    "Pressure Force Residual Does No Work Against Rigid Translations",
-              &tags::accuracy) {
+    tags::barotrope &tags::pressure &tags::kernels &tags::integration &tags::accuracy
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
@@ -426,20 +412,17 @@ TEST_CASE("Pressure Force Residual Does No Work Against Rigid Translations",
 
     const mean_field::eos::Polytrope barotrope(3.0, 0.25);
 
-  const mfem::Vector enthalpyTrue =
+    const mfem::Vector enthalpyTrue     = pressure_force_kernel_test_utils::make_positive_asymmetric_enthalpy(f);
-      pressure_force_kernel_test_utils::make_positive_asymmetric_enthalpy(f);
 
-  const mfem::Vector displacementTrue =
+    const mfem::Vector displacementTrue = pressure_force_kernel_test_utils::make_zero_displacement(f);
-      pressure_force_kernel_test_utils::make_zero_displacement(f);
 
     mfem::Vector residualTrue;
 
     mean_field::operators::kernels::apply_pressure_force_residual(
-      f, *f.domainMapperStateless, barotrope, enthalpyTrue, displacementTrue,
+        f, *f.domainMapperStateless, barotrope, enthalpyTrue, displacementTrue, residualTrue
-      residualTrue);
+    );
 
-  const double residualNorm =
+    const double residualNorm = gravity_prepared_test_utils::global_norm(residualTrue, f.mesh->GetComm());
-      gravity_prepared_test_utils::global_norm(residualTrue, f.mesh->GetComm());
 
     REQUIRE(residualNorm > 0.0);
 
@@ -447,17 +430,14 @@ TEST_CASE("Pressure Force Residual Does No Work Against Rigid Translations",
 
     for (int component = 0; component < dimension; ++component) {
         const mfem::Vector translationTrue =
-        pressure_force_kernel_test_utils::make_component_test_field(
+            pressure_force_kernel_test_utils::make_component_test_field(f, component, -1);
-            f, component, -1);
 
-    const double translationNorm = gravity_prepared_test_utils::global_norm(
+        const double translationNorm = gravity_prepared_test_utils::global_norm(translationTrue, f.mesh->GetComm());
-        translationTrue, f.mesh->GetComm());
 
-    const double translationWork = pressure_force_kernel_test_utils::global_dot(
+        const double translationWork =
-        translationTrue, residualTrue, f.mesh->GetComm());
+            pressure_force_kernel_test_utils::global_dot(translationTrue, residualTrue, f.mesh->GetComm());
 
-    const double dotProductScale =
+        const double dotProductScale = std::fmax(residualNorm * translationNorm, 1.0);
-        std::fmax(residualNorm * translationNorm, 1.0);
 
         CAPTURE(component, translationWork, dotProductScale);
 
@@ -465,9 +445,10 @@ TEST_CASE("Pressure Force Residual Does No Work Against Rigid Translations",
     }
 }
 
-TEST_CASE("Pressure Force Residual Matches Independent Pressure Integral",
+TEST_CASE(
-          tags::barotrope &tags::pressure &tags::kernels &tags::integration
+    "Pressure Force Residual Matches Independent Pressure Integral",
-              &tags::accuracy) {
+    tags::barotrope &tags::pressure &tags::kernels &tags::integration &tags::accuracy
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
@@ -478,17 +459,15 @@ TEST_CASE("Pressure Force Residual Matches Independent Pressure Integral",
 
     const mean_field::eos::Polytrope barotrope(3.0, 0.25);
 
-  const mfem::Vector enthalpyTrue =
+    const mfem::Vector enthalpyTrue     = pressure_force_kernel_test_utils::make_positive_asymmetric_enthalpy(f);
-      pressure_force_kernel_test_utils::make_positive_asymmetric_enthalpy(f);
 
-  const mfem::Vector displacementTrue =
+    const mfem::Vector displacementTrue = pressure_force_kernel_test_utils::make_zero_displacement(f);
-      pressure_force_kernel_test_utils::make_zero_displacement(f);
 
     mfem::Vector residualTrue;
 
     mean_field::operators::kernels::apply_pressure_force_residual(
-      f, *f.domainMapperStateless, barotrope, enthalpyTrue, displacementTrue,
+        f, *f.domainMapperStateless, barotrope, enthalpyTrue, displacementTrue, residualTrue
-      residualTrue);
+    );
 
     const int dimension = f.mesh->Dimension();
 
@@ -499,19 +478,16 @@ TEST_CASE("Pressure Force Residual Matches Independent Pressure Integral",
     for (int component = 0; component < dimension; ++component) {
         for (int coordinate = 0; coordinate < dimension; ++coordinate) {
             const mfem::Vector affineTestTrue =
-          pressure_force_kernel_test_utils::make_component_test_field(
+                pressure_force_kernel_test_utils::make_component_test_field(f, component, coordinate);
-              f, component, coordinate);
 
             virtualWork(component, coordinate) =
-          pressure_force_kernel_test_utils::global_dot(
+                pressure_force_kernel_test_utils::global_dot(affineTestTrue, residualTrue, f.mesh->GetComm());
-              affineTestTrue, residualTrue, f.mesh->GetComm());
         }
     }
 
-  const double pressureIntegral =
+    const double pressureIntegral = pressure_force_kernel_test_utils::integrate_pressure(
-      pressure_force_kernel_test_utils::integrate_pressure(
+        f, *f.domainMapperStateless, barotrope, enthalpyTrue, displacementTrue
-          f, *f.domainMapperStateless, barotrope, enthalpyTrue,
+    );
-          displacementTrue);
 
     REQUIRE(std::isfinite(pressureIntegral));
 
@@ -545,28 +521,25 @@ TEST_CASE("Pressure Force Residual Matches Independent Pressure Integral",
         for (int coordinate = 0; coordinate < dimension; ++coordinate) {
             const double computedWork = virtualWork(component, coordinate);
 
-      const double expectedWork =
+            const double expectedWork = component == coordinate ? -pressureIntegral : 0.0;
-          component == coordinate ? -pressureIntegral : 0.0;
 
-      CAPTURE(component, coordinate, computedWork, expectedWork,
+            CAPTURE(component, coordinate, computedWork, expectedWork, pressureIntegral, comparisonTolerance);
-              pressureIntegral, comparisonTolerance);
 
             CHECK(std::abs(computedWork - expectedWork) <= comparisonTolerance);
         }
     }
 
-  const double relativeMeanError =
+    const double relativeMeanError = std::abs(meanDiagonalWork + pressureIntegral) / std::abs(pressureIntegral);
-      std::abs(meanDiagonalWork + pressureIntegral) /
-      std::abs(pressureIntegral);
 
     INFO("Relative mean diagonal error = " << relativeMeanError);
 
     CHECK(relativeMeanError <= 1.0e-6);
 }
 
-TEST_CASE("Pressure Force Residual Matches Deformed Pressure Volume Variation",
+TEST_CASE(
-          tags::barotrope &tags::pressure &tags::kernels &tags::integration
+    "Pressure Force Residual Matches Deformed Pressure Volume Variation",
-              &tags::accuracy) {
+    tags::barotrope &tags::pressure &tags::kernels &tags::integration &tags::accuracy
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
@@ -580,16 +553,14 @@ TEST_CASE("Pressure Force Residual Matches Deformed Pressure Volume Variation",
      * exercises a genuinely nonuniform pressure distribution.
      */
     const mfem::Vector enthalpyTrue =
-      pressure_force_kernel_test_utils::make_deterministic_vector(
+        pressure_force_kernel_test_utils::make_deterministic_vector(f.enthalpyFes->GetTrueVSize(), 0.37);
-          f.enthalpyFes->GetTrueVSize(), 0.37);
 
     /*
      * make_displacement() contains anisotropic diagonal terms and
      * quadratic cross terms. A scale of 0.67 therefore provides a
      * nonzero, nonspherical, valid base geometry.
      */
-  const mfem::Vector baseDisplacementTrue =
+    const mfem::Vector baseDisplacementTrue      = gravity_prepared_test_utils::make_displacement(f, 0.67);
-      gravity_prepared_test_utils::make_displacement(f, 0.67);
 
     /*
      * Differentiate along the same smooth deformation family. Thus
@@ -599,43 +570,38 @@ TEST_CASE("Pressure Force Residual Matches Deformed Pressure Volume Variation",
      * This gives a controlled geometry path while still evaluating
      * the derivative at a genuinely deformed base state.
      */
-  const mfem::Vector displacementVariationTrue =
+    const mfem::Vector displacementVariationTrue = gravity_prepared_test_utils::make_displacement(f, 1.0);
-      gravity_prepared_test_utils::make_displacement(f, 1.0);
 
-  const double baseDisplacementNorm = gravity_prepared_test_utils::global_norm(
+    const double baseDisplacementNorm =
-      baseDisplacementTrue, f.mesh->GetComm());
+        gravity_prepared_test_utils::global_norm(baseDisplacementTrue, f.mesh->GetComm());
 
-  const double variationNorm = gravity_prepared_test_utils::global_norm(
+    const double variationNorm = gravity_prepared_test_utils::global_norm(displacementVariationTrue, f.mesh->GetComm());
-      displacementVariationTrue, f.mesh->GetComm());
 
-  REQUIRE(baseDisplacementNorm >
+    REQUIRE(baseDisplacementNorm > 100.0 * std::numeric_limits<double>::epsilon());
-          100.0 * std::numeric_limits<double>::epsilon());
 
     REQUIRE(variationNorm > 100.0 * std::numeric_limits<double>::epsilon());
 
     mfem::Vector residualTrue;
 
     mean_field::operators::kernels::apply_pressure_force_residual(
-      f, *f.domainMapperStateless, barotrope, enthalpyTrue,
+        f, *f.domainMapperStateless, barotrope, enthalpyTrue, baseDisplacementTrue, residualTrue
-      baseDisplacementTrue, residualTrue);
+    );
 
     REQUIRE(residualTrue.Size() == f.displacementFes->GetTrueVSize());
 
-  const double residualWork = pressure_force_kernel_test_utils::global_dot(
+    const double residualWork =
-      displacementVariationTrue, residualTrue, f.mesh->GetComm());
+        pressure_force_kernel_test_utils::global_dot(displacementVariationTrue, residualTrue, f.mesh->GetComm());
 
     REQUIRE(std::isfinite(residualWork));
 
-  REQUIRE(std::abs(residualWork) >
+    REQUIRE(std::abs(residualWork) > 100.0 * std::numeric_limits<double>::epsilon());
-          100.0 * std::numeric_limits<double>::epsilon());
 
     /*
      * The relatively broad initial sweep lets us see the expected
      * centered-difference convergence before reaching the quadrature
      * and representation plateau.
      */
-  constexpr std::array<double, 4> differenceSteps{1.0e-2, 5.0e-3, 2.5e-3,
+    constexpr std::array<double, 4> differenceSteps{1.0e-2, 5.0e-3, 2.5e-3, 1.25e-3};
-                                                  1.25e-3};
 
     double bestRelativeDiscrepancy = std::numeric_limits<double>::infinity();
 
@@ -648,21 +614,18 @@ TEST_CASE("Pressure Force Residual Matches Deformed Pressure Volume Variation",
 
         displacementMinus.Add(-differenceStep, displacementVariationTrue);
 
-    const double pressureIntegralPlus =
+        const double pressureIntegralPlus = pressure_force_kernel_test_utils::integrate_pressure(
-        pressure_force_kernel_test_utils::integrate_pressure(
+            f, *f.domainMapperStateless, barotrope, enthalpyTrue, displacementPlus
-            f, *f.domainMapperStateless, barotrope, enthalpyTrue,
+        );
-            displacementPlus);
 
-    const double pressureIntegralMinus =
+        const double pressureIntegralMinus = pressure_force_kernel_test_utils::integrate_pressure(
-        pressure_force_kernel_test_utils::integrate_pressure(
+            f, *f.domainMapperStateless, barotrope, enthalpyTrue, displacementMinus
-            f, *f.domainMapperStateless, barotrope, enthalpyTrue,
+        );
-            displacementMinus);
 
         REQUIRE(std::isfinite(pressureIntegralPlus));
         REQUIRE(std::isfinite(pressureIntegralMinus));
 
-    const double pressureVolumeDerivative =
+        const double pressureVolumeDerivative = (pressureIntegralPlus - pressureIntegralMinus) / (2.0 * differenceStep);
-        (pressureIntegralPlus - pressureIntegralMinus) / (2.0 * differenceStep);
 
         REQUIRE(std::isfinite(pressureVolumeDerivative));
 
@@ -674,8 +637,7 @@ TEST_CASE("Pressure Force Residual Matches Deformed Pressure Volume Variation",
 
         REQUIRE(comparisonScale > 100.0 * std::numeric_limits<double>::epsilon());
 
-    const double absoluteDiscrepancy =
+        const double absoluteDiscrepancy = std::abs(residualWork + pressureVolumeDerivative);
-        std::abs(residualWork + pressureVolumeDerivative);
 
         const double relativeDiscrepancy = absoluteDiscrepancy / comparisonScale;
 
@@ -689,8 +651,7 @@ TEST_CASE("Pressure Force Residual Matches Deformed Pressure Volume Variation",
 
         INFO("Pressure-volume derivative = " << pressureVolumeDerivative);
 
-    INFO("Residual work plus derivative = " << residualWork +
+        INFO("Residual work plus derivative = " << residualWork + pressureVolumeDerivative);
-                                                   pressureVolumeDerivative);
 
         INFO("Relative discrepancy = " << relativeDiscrepancy);
 
@@ -702,8 +663,7 @@ TEST_CASE("Pressure Force Residual Matches Deformed Pressure Volume Variation",
         CHECK(residualWork * pressureVolumeDerivative < 0.0);
     }
 
-  INFO("Best pressure-volume relative discrepancy = "
+    INFO("Best pressure-volume relative discrepancy = " << bestRelativeDiscrepancy);
-       << bestRelativeDiscrepancy);
 
     /*
      * This is intentionally a provisional but meaningful threshold.

tests/operators/prepared_barotropic_closure.cpp

@@ -243,7 +243,11 @@ namespace prepared_barotropic_closure_test_utils {
     ) {
         mfem::FunctionCoefficient coefficient([&equationOfState, condition](const mfem::Vector &position) {
             const double enthalpy               = evaluate_enthalpy(position, condition);
-            return condition.densityFactor * equationOfState.density_from_enthalpy(enthalpy) + condition.densityOffset +
+            const double equationOfStateDensity = mean_field::eos::evaluate<mean_field::eos::quantity::Density>(
+                                                      equationOfState, mean_field::eos::SpecificEnthalpyValue{enthalpy}
+            )
+                                                      .value();
+            return condition.densityFactor * equationOfStateDensity + condition.densityOffset +
                    condition.densityGradient * (0.40 * position(0) + 0.25 * position(1) - 0.15 * position(2));
         });
         return project_scalar(*f.densityFes, coefficient);
@@ -785,7 +789,11 @@ namespace prepared_barotropic_closure_test_utils {
         const mean_field::eos::Polytrope equationOfState(3.0, 1.5);
 
         constexpr double enthalpyValue = 1.20;
-        const double equilibriumDensityValue = equationOfState.density_from_enthalpy(enthalpyValue);
+        const double equilibriumDensityValue =
+            mean_field::eos::evaluate<mean_field::eos::quantity::Density>(
+                equationOfState, mean_field::eos::SpecificEnthalpyValue{enthalpyValue}
+            )
+                .value();
 
         const mfem::Vector enthalpy = reduce(maps.enthalpy, make_constant_field(*f.enthalpyFes, enthalpyValue));
         const mfem::Vector equilibriumDensity =

tests/operators/prepared_hdiv_mass.cpp

@@ -10,33 +10,28 @@ using namespace mean_field;
 using Catch::Matchers::WithinAbs;
 namespace prepared_test = gravity_prepared_test_utils;
 
-TEST_CASE("Prepared Mapped Hdiv Mass Matches Stateless Kernel",
+TEST_CASE(
-          tags::gravity_prepared) {
+    "Prepared Mapped Hdiv Mass Matches Stateless Kernel",
+    tags::gravity_prepared
+) {
     auto args  = test_utils::setup_args();
     fem::FEM f = fem::setup_fem(args.mesh_file, args, 0);
 
-  operators::PreparedMappedHDivMassOperator prepared_operator(
+    operators::PreparedMappedHDivMassOperator prepared_operator(f, *f.domainMapperStateless);
-      f, *f.domainMapperStateless);
+    REQUIRE(prepared_operator.Width() == prepared_operator.GetFluxMap().reduced_size());
-  REQUIRE(prepared_operator.Width() ==
+    REQUIRE(prepared_operator.Height() == prepared_operator.GetFluxMap().reduced_size());
-          prepared_operator.GetFluxMap().reduced_size());
-  REQUIRE(prepared_operator.Height() ==
-          prepared_operator.GetFluxMap().reduced_size());
 
     const mfem::Vector gravity_gradient_true =
-      prepared_test::make_deterministic_vector(f.gravityFluxFes->GetTrueVSize(),
+        prepared_test::make_deterministic_vector(f.gravityFluxFes->GetTrueVSize(), 0.21);
-                                               0.21);
+    const mfem::Vector gravity_gradient = prepared_operator.GetFluxMap().gather(gravity_gradient_true);
-  const mfem::Vector gravity_gradient =
-      prepared_operator.GetFluxMap().gather(gravity_gradient_true);
     const MPI_Comm communicator         = f.gravityFluxFes->GetComm();
 
     mfem::Vector identity_action;
     mfem::Vector deformed_action;
 
     for (const double deformation_scale : {0.0, 1.0}) {
-    const mfem::Vector displacement_true =
+        const mfem::Vector displacement_true = prepared_test::make_displacement(f, deformation_scale);
-        prepared_test::make_displacement(f, deformation_scale);
+        const mfem::Vector displacement      = prepared_operator.GetDisplacementMap().gather(displacement_true);
-    const mfem::Vector displacement =
-        prepared_operator.GetDisplacementMap().gather(displacement_true);
 
         prepared_operator.Prepare(displacement);
 
@@ -45,19 +40,15 @@ TEST_CASE("Prepared Mapped Hdiv Mass Matches Stateless Kernel",
         prepared_operator.Mult(gravity_gradient, prepared_action);
         mfem::Vector reference_action_true;
         operators::kernels::apply_mapped_hdiv_mass(
-        f, *f.domainMapperStateless, gravity_gradient_true, displacement_true,
+            f, *f.domainMapperStateless, gravity_gradient_true, displacement_true, reference_action_true
-        reference_action_true);
+        );
-    const mfem::Vector reference_action =
+        const mfem::Vector reference_action = prepared_operator.GetFluxMap().gather(reference_action_true);
-        prepared_operator.GetFluxMap().gather(reference_action_true);
 
-    const double relative_error = prepared_test::relative_error(
+        const double relative_error = prepared_test::relative_error(prepared_action, reference_action, communicator);
-        prepared_action, reference_action, communicator);
 
         INFO("Deformation scale = " << deformation_scale);
-    INFO("Prepared action norm = "
+        INFO("Prepared action norm = " << prepared_test::global_norm(prepared_action, communicator));
-         << prepared_test::global_norm(prepared_action, communicator));
+        INFO("Reference action norm = " << prepared_test::global_norm(reference_action, communicator));
-    INFO("Reference action norm = "
-         << prepared_test::global_norm(reference_action, communicator));
         INFO("Relative prepared-operator error = " << relative_error);
 
         REQUIRE(prepared_operator.IsPrepared());
@@ -70,8 +61,7 @@ TEST_CASE("Prepared Mapped Hdiv Mass Matches Stateless Kernel",
         }
     }
 
-  const double geometry_change = prepared_test::relative_error(
+    const double geometry_change = prepared_test::relative_error(deformed_action, identity_action, communicator);
-      deformed_action, identity_action, communicator);
 
     INFO("Relative action change under deformation = " << geometry_change);
 
@@ -79,30 +69,27 @@ TEST_CASE("Prepared Mapped Hdiv Mass Matches Stateless Kernel",
     CHECK(geometry_change > 1.0e-5);
 }
 
-TEST_CASE("Prepared Mapped Hdiv Mass Preserves Operator Identities",
+TEST_CASE(
-          tags::gravity_prepared) {
+    "Prepared Mapped Hdiv Mass Preserves Operator Identities",
+    tags::gravity_prepared
+) {
     auto args  = test_utils::setup_args();
     fem::FEM f = fem::setup_fem(args.mesh_file, args, 0);
 
-  operators::PreparedMappedHDivMassOperator prepared_operator(
+    operators::PreparedMappedHDivMassOperator prepared_operator(f, *f.domainMapperStateless);
-      f, *f.domainMapperStateless);
+    REQUIRE(prepared_operator.Width() == prepared_operator.GetFluxMap().reduced_size());
-  REQUIRE(prepared_operator.Width() ==
+    REQUIRE(prepared_operator.Height() == prepared_operator.GetFluxMap().reduced_size());
-          prepared_operator.GetFluxMap().reduced_size());
-  REQUIRE(prepared_operator.Height() ==
-          prepared_operator.GetFluxMap().reduced_size());
     const mfem::Vector displacement =
-      prepared_operator.GetDisplacementMap().gather(
+        prepared_operator.GetDisplacementMap().gather(prepared_test::make_displacement(f, 1.0));
-          prepared_test::make_displacement(f, 1.0));
     prepared_operator.Prepare(displacement);
 
     const mfem::Vector first = prepared_operator.GetFluxMap().gather(
-      prepared_test::make_deterministic_vector(f.gravityFluxFes->GetTrueVSize(),
+        prepared_test::make_deterministic_vector(f.gravityFluxFes->GetTrueVSize(), 0.17)
-                                               0.17));
+    );
     const mfem::Vector second = prepared_operator.GetFluxMap().gather(
-      prepared_test::make_deterministic_vector(f.gravityFluxFes->GetTrueVSize(),
+        prepared_test::make_deterministic_vector(f.gravityFluxFes->GetTrueVSize(), 0.83)
-                                               0.83));
+    );
-  const mfem::Vector combination =
+    const mfem::Vector combination = prepared_test::linear_combination(first, 1.7, second, -0.4);
-      prepared_test::linear_combination(first, 1.7, second, -0.4);
 
     mfem::Vector first_action;
     mfem::Vector second_action;
@@ -113,8 +100,7 @@ TEST_CASE("Prepared Mapped Hdiv Mass Preserves Operator Identities",
     prepared_operator.Mult(second, second_action);
     prepared_operator.Mult(combination, combination_action);
 
-  mfem::Vector expected_combination =
+    mfem::Vector expected_combination = prepared_test::linear_combination(first_action, 1.7, second_action, -0.4);
-      prepared_test::linear_combination(first_action, 1.7, second_action, -0.4);
 
     mfem::Vector zero(first.Size());
     zero = 0.0;
@@ -122,20 +108,14 @@ TEST_CASE("Prepared Mapped Hdiv Mass Preserves Operator Identities",
 
     const MPI_Comm communicator       = f.gravityFluxFes->GetComm();
 
-  const double first_second_product =
+    const double first_second_product = prepared_test::global_dot(first, second_action, communicator);
-      prepared_test::global_dot(first, second_action, communicator);
+    const double second_first_product = prepared_test::global_dot(second, first_action, communicator);
-  const double second_first_product =
+    const double symmetry_error = prepared_test::relative_scalar_error(first_second_product, second_first_product);
-      prepared_test::global_dot(second, first_action, communicator);
+    const double linearity_error =
-  const double symmetry_error = prepared_test::relative_scalar_error(
+        prepared_test::relative_error(combination_action, expected_combination, communicator);
-      first_second_product, second_first_product);
+    const double first_energy             = prepared_test::global_dot(first, first_action, communicator);
-  const double linearity_error = prepared_test::relative_error(
+    const double second_energy            = prepared_test::global_dot(second, second_action, communicator);
-      combination_action, expected_combination, communicator);
+    const std::uint64_t preparation_count = prepared_operator.GetPreparationCount();
-  const double first_energy =
-      prepared_test::global_dot(first, first_action, communicator);
-  const double second_energy =
-      prepared_test::global_dot(second, second_action, communicator);
-  const std::uint64_t preparation_count =
-      prepared_operator.GetPreparationCount();
 
     mfem::Vector repeated_action;
     prepared_operator.Mult(first, repeated_action);
@@ -149,25 +129,23 @@ TEST_CASE("Prepared Mapped Hdiv Mass Preserves Operator Identities",
 
     CHECK_THAT(symmetry_error, WithinAbs(0.0, 2.0e-12));
     CHECK_THAT(linearity_error, WithinAbs(0.0, 2.0e-12));
-  CHECK_THAT(prepared_test::global_norm(zero_action, communicator),
+    CHECK_THAT(prepared_test::global_norm(zero_action, communicator), WithinAbs(0.0, 1.0e-14));
-             WithinAbs(0.0, 1.0e-14));
     CHECK(first_energy > 0.0);
     CHECK(second_energy > 0.0);
-  CHECK(prepared_test::relative_error(repeated_action, first_action,
+    CHECK(prepared_test::relative_error(repeated_action, first_action, communicator) < 2.0e-14);
-                                      communicator) < 2.0e-14);
     CHECK(prepared_operator.GetPreparationCount() == preparation_count);
 }
 
-TEST_CASE("Prepared Mapped Hdiv Mass Diagonal Is Positive Across Both Domains",
+TEST_CASE(
-          tags::gravity_prepared) {
+    "Prepared Mapped Hdiv Mass Diagonal Is Positive Across Both Domains",
+    tags::gravity_prepared
+) {
     auto args  = test_utils::setup_args();
     fem::FEM f = fem::setup_fem(args.mesh_file, args, 0);
 
-  operators::PreparedMappedHDivMassOperator prepared_operator(
+    operators::PreparedMappedHDivMassOperator prepared_operator(f, *f.domainMapperStateless);
-      f, *f.domainMapperStateless);
     const mfem::Vector displacement =
-      prepared_operator.GetDisplacementMap().gather(
+        prepared_operator.GetDisplacementMap().gather(prepared_test::make_displacement(f, 1.0));
-          prepared_test::make_displacement(f, 1.0));
     prepared_operator.Prepare(displacement);
 
     mfem::Vector diagonal;
@@ -178,13 +156,11 @@ TEST_CASE("Prepared Mapped Hdiv Mass Diagonal Is Positive Across Both Domains",
     REQUIRE(diagonal.Size() == prepared_operator.Height());
     REQUIRE(true_diagonal.Size() == prepared_operator.GetFluxMap().full_size());
 
-  const mfem::Vector gathered_true_diagonal =
+    const mfem::Vector gathered_true_diagonal = prepared_operator.GetFluxMap().gather(true_diagonal);
-      prepared_operator.GetFluxMap().gather(true_diagonal);
 
     for (int i = 0; i < diagonal.Size(); ++i) {
         REQUIRE(std::isfinite(diagonal(i)));
         CHECK(diagonal(i) > 0.0);
-    CHECK_THAT(diagonal(i), WithinAbs(gathered_true_diagonal(i),
+        CHECK_THAT(diagonal(i), WithinAbs(gathered_true_diagonal(i), 1.0e-14 * std::abs(diagonal(i))));
-                                      1.0e-14 * std::abs(diagonal(i))));
     }
 }

tests/operators/prepared_hydrostatic_equilibrium_analytic_accuracy.cpp

@@ -9,55 +9,67 @@ import mean_field;
 import test_helpers;
 
 namespace prepared_hydrostatic_analytic_solve_test_utils {
-constexpr double bernoulliConstant = 0.83;
+    constexpr double bernoulliConstant = 0.83;
-constexpr double enthalpyAmplitude = 0.61;
+    constexpr double enthalpyAmplitude = 0.61;
 
-struct AnalyticCase {
+    struct AnalyticCase {
         const char *name;
 
         std::array<double, 3> deformationScale;
         std::array<double, 3> angularVelocity;
         std::array<double, 3> rotationCenter;
-};
+    };
 
-class EnthalpyJacobianOperator final : public mfem::Operator {
+    class EnthalpyJacobianOperator final : public mfem::Operator {
-public:
+    public:
         EnthalpyJacobianOperator(
             const int enthalpySize,
-      const mean_field::operators::PreparedHydrostaticEquilibriumOperator
+            const mean_field::operators::PreparedHydrostaticEquilibriumOperator &preparedOperator
-          &preparedOperator)
+        )
-      : mfem::Operator(enthalpySize), m_preparedOperator(preparedOperator) {}
+            : mfem::Operator(enthalpySize),
+              m_preparedOperator(preparedOperator) {
+        }
 
-  void Mult(const mfem::Vector &direction,
+        void Mult(
-            mfem::Vector &action) const override {
+            const mfem::Vector &direction,
+            mfem::Vector &action
+        ) const override {
             m_preparedOperator.ApplyEnthalpyJacobianAction(direction, action);
         }
 
-private:
+    private:
-  const mean_field::operators::PreparedHydrostaticEquilibriumOperator
+        const mean_field::operators::PreparedHydrostaticEquilibriumOperator &m_preparedOperator;
-      &m_preparedOperator;
+    };
-};
 
-mean_field::operators::context::hydrostatic::HydrostaticEquilibriumDependencies
+    mean_field::operators::context::hydrostatic::HydrostaticEquilibriumDependencies make_dependencies() {
-make_dependencies() {
+        return {
-  return {.discretization = {.identity = 701, .revision = 2},
+            .discretization    = {.identity = 701, .revision = 2},
             .enthalpy          = {.identity = 709, .revision = 3},
             .gravityPotential  = {.identity = 719, .revision = 5},
             .displacement      = {.identity = 727, .revision = 7},
             .rotation          = {.identity = 733, .revision = 11},
-          .bernoulliConstant = {.identity = 739, .revision = 13}};
+            .bernoulliConstant = {.identity = 739, .revision = 13}
-}
+        };
+    }
 
-mean_field::operators::context::hydrostatic::HydrostaticEquilibriumStateView
+    mean_field::operators::context::hydrostatic::HydrostaticEquilibriumStateView make_state(
-make_state(const mfem::Vector &enthalpy, const mfem::Vector &gravityPotential,
+        const mfem::Vector &enthalpy,
-           const mfem::Vector &displacement) {
+        const mfem::Vector &gravityPotential,
-  return {.enthalpy = enthalpy,
+        const mfem::Vector &displacement
+    ) {
+        return {
+            .enthalpy          = enthalpy,
             .gravityPotential  = gravityPotential,
             .displacement      = displacement,
-          .bernoulliConstant = bernoulliConstant};
+            .bernoulliConstant = bernoulliConstant
-}
+        };
+    }
 
-mfem::Vector make_vector(const std::array<double, 3> &values) {
+    mfem::Vector make_vector(
+        const std::array<
+            double,
+            3> &values
+    ) {
         mfem::Vector vector(3);
 
         for (int component = 0; component < 3; ++component) {
@@ -65,44 +77,44 @@ mfem::Vector make_vector(const std::array<double, 3> &values) {
         }
 
         return vector;
-}
+    }
 
-mean_field::physics::RigidRotation
+    mean_field::physics::RigidRotation make_rotation(const AnalyticCase &analyticCase) {
-make_rotation(const AnalyticCase &analyticCase) {
         return mean_field::physics::RigidRotation(
-      make_vector(analyticCase.angularVelocity),
+            make_vector(analyticCase.angularVelocity), make_vector(analyticCase.rotationCenter)
-      make_vector(analyticCase.rotationCenter));
+        );
-}
+    }
 
-void map_to_physical(const mfem::Vector &referencePosition,
+    void map_to_physical(
+        const mfem::Vector &referencePosition,
         const AnalyticCase &analyticCase,
-                     mfem::Vector &physicalPosition) {
+        mfem::Vector &physicalPosition
+    ) {
         physicalPosition.SetSize(3);
 
         for (int component = 0; component < 3; ++component) {
             physicalPosition(component) =
-        analyticCase.deformationScale[static_cast<std::size_t>(component)] *
+                analyticCase.deformationScale[static_cast<std::size_t>(component)] * referencePosition(component);
-        referencePosition(component);
+        }
     }
-}
 
-double exact_enthalpy_value(const mfem::Vector &referencePosition) {
+    double exact_enthalpy_value(const mfem::Vector &referencePosition) {
         double normalizedRadiusSquared = 0.0;
 
         for (int component = 0; component < 3; ++component) {
-    const double normalizedCoordinate =
+            const double normalizedCoordinate = referencePosition(component) / mean_field::utils::RADIUS;
-        referencePosition(component) / mean_field::utils::RADIUS;
 
             normalizedRadiusSquared += normalizedCoordinate * normalizedCoordinate;
         }
 
         return enthalpyAmplitude * std::max(0.0, 1.0 - normalizedRadiusSquared);
-}
+    }
 
-double
+    double exact_potential_value(
-exact_potential_value(const mfem::Vector &referencePosition,
+        const mfem::Vector &referencePosition,
         const AnalyticCase &analyticCase,
-                      const mean_field::physics::RigidRotation &rotation) {
+        const mean_field::physics::RigidRotation &rotation
+    ) {
         mfem::Vector physicalPosition;
 
         map_to_physical(referencePosition, analyticCase, physicalPosition);
@@ -114,27 +126,26 @@ exact_potential_value(const mfem::Vector &referencePosition,
          *
          * analytically.
          */
-  return bernoulliConstant + rotation.potential(physicalPosition) -
+        return bernoulliConstant + rotation.potential(physicalPosition) - exact_enthalpy_value(referencePosition);
-         exact_enthalpy_value(referencePosition);
+    }
-}
 
-mfem::Array<int> make_stellar_element_marker(const mean_field::fem::FEM &f) {
+    mfem::Array<int> make_stellar_element_marker(const mean_field::fem::FEM &f) {
         mfem::Array<int> stellarElementMarker(f.mesh->GetNE());
 
         const int vacuumAttribute = field_dof_test_utils::vacuum_material_attribute;
 
         for (int elementId = 0; elementId < f.mesh->GetNE(); ++elementId) {
-    stellarElementMarker[elementId] =
+            stellarElementMarker[elementId] = f.mesh->GetAttribute(elementId) != vacuumAttribute;
-        f.mesh->GetAttribute(elementId) != vacuumAttribute;
         }
 
         return stellarElementMarker;
-}
+    }
 } // namespace prepared_hydrostatic_analytic_solve_test_utils
 
-TEST_CASE("Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
+TEST_CASE(
-          tags::barotrope_hydrostatic_prepared_analytic &tags::convergence
+    "Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
-              &tags::accuracy) {
+    tags::barotrope_hydrostatic_prepared_analytic &tags::convergence &tags::accuracy
+) {
     using prepared_hydrostatic_analytic_solve_test_utils::AnalyticCase;
 
     constexpr double deformationX = 1.08;
@@ -160,7 +171,8 @@ TEST_CASE("Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
          {.name             = "volume-preserving deformed rotating equilibrium",
           .deformationScale = {deformationX, deformationY, deformationZ},
           .angularVelocity  = {0.17, -0.12, 0.43},
-        .rotationCenter = {0.031, -0.024, 0.018}}}};
+          .rotationCenter   = {0.031, -0.024, 0.018}}}
+    };
 
     auto args                   = test_utils::setup_args();
 
@@ -169,59 +181,51 @@ TEST_CASE("Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
     const MPI_Comm communicator = f.mesh->GetComm();
 
     const mean_field::field::FieldDofMap enthalpyMap =
-      field_dof_test_utils::make_map<mean_field::field::Enthalpy>(
+        field_dof_test_utils::make_map<mean_field::field::Enthalpy>(*f.enthalpyFes);
-          *f.enthalpyFes);
 
     const mean_field::field::FieldDofMap gravityPotentialMap =
-      field_dof_test_utils::make_map<mean_field::field::Gravity>(
+        field_dof_test_utils::make_map<mean_field::field::Gravity>(*f.gravityPotentialFes);
-          *f.gravityPotentialFes);
 
     const mean_field::field::FieldDofMap displacementMap =
-      field_dof_test_utils::make_map<mean_field::field::Displacement>(
+        field_dof_test_utils::make_map<mean_field::field::Displacement>(*f.displacementFes);
-          *f.displacementFes);
 
     const mfem::Array<int> stellarElementMarker =
-      prepared_hydrostatic_analytic_solve_test_utils::
+        prepared_hydrostatic_analytic_solve_test_utils::make_stellar_element_marker(f);
-          make_stellar_element_marker(f);
 
     for (const AnalyticCase &analyticCase : analyticCases) {
         DYNAMIC_SECTION(analyticCase.name) {
-      const double deformationDeterminant = analyticCase.deformationScale[0] *
+            const double deformationDeterminant =
-                                            analyticCase.deformationScale[1] *
+                analyticCase.deformationScale[0] * analyticCase.deformationScale[1] * analyticCase.deformationScale[2];
-                                            analyticCase.deformationScale[2];
 
             REQUIRE(std::abs(deformationDeterminant - 1.0) < 2.0e-14);
 
             const mean_field::physics::RigidRotation rotation =
-          prepared_hydrostatic_analytic_solve_test_utils::make_rotation(
+                prepared_hydrostatic_analytic_solve_test_utils::make_rotation(analyticCase);
-              analyticCase);
 
             auto displacementFunction =
-          [&analyticCase](const mfem::Vector &referencePosition,
+                [&analyticCase](const mfem::Vector &referencePosition, mfem::Vector &displacementValue) {
-                          mfem::Vector &displacementValue) {
                     mfem::Vector physicalPosition;
 
                     prepared_hydrostatic_analytic_solve_test_utils::map_to_physical(
-                referencePosition, analyticCase, physicalPosition);
+                        referencePosition, analyticCase, physicalPosition
+                    );
 
                     displacementValue.SetSize(3);
                     displacementValue = physicalPosition;
                     displacementValue -= referencePosition;
                 };
 
-      auto potentialFunction = [&analyticCase, &rotation](
+            auto potentialFunction = [&analyticCase, &rotation](const mfem::Vector &referencePosition) {
-                                   const mfem::Vector &referencePosition) {
+                return prepared_hydrostatic_analytic_solve_test_utils::exact_potential_value(
-        return prepared_hydrostatic_analytic_solve_test_utils::
+                    referencePosition, analyticCase, rotation
-            exact_potential_value(referencePosition, analyticCase, rotation);
+                );
             };
 
             auto enthalpyFunction = [](const mfem::Vector &referencePosition) {
-        return prepared_hydrostatic_analytic_solve_test_utils::
+                return prepared_hydrostatic_analytic_solve_test_utils::exact_enthalpy_value(referencePosition);
-            exact_enthalpy_value(referencePosition);
             };
 
-      mfem::VectorFunctionCoefficient displacementCoefficient(
+            mfem::VectorFunctionCoefficient displacementCoefficient(f.mesh->Dimension(), displacementFunction);
-          f.mesh->Dimension(), displacementFunction);
 
             mfem::FunctionCoefficient potentialCoefficient(potentialFunction);
 
@@ -244,10 +248,8 @@ TEST_CASE("Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
             displacementField.GetTrueDofs(displacementTrue);
             potentialField.GetTrueDofs(gravityPotentialTrue);
 
-      const mfem::Vector displacement =
+            const mfem::Vector displacement     = displacementMap.gather(displacementTrue);
-          displacementMap.gather(displacementTrue);
+            const mfem::Vector gravityPotential = gravityPotentialMap.gather(gravityPotentialTrue);
-      const mfem::Vector gravityPotential =
-          gravityPotentialMap.gather(gravityPotentialTrue);
 
             /*
              * This projection is not used as the solution. It gives
@@ -262,16 +264,15 @@ TEST_CASE("Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
 
             zeroEnthalpyField = 0.0;
 
-      const double exactEnthalpyNorm = zeroEnthalpyField.ComputeL2Error(
+            const double exactEnthalpyNorm =
-          exactEnthalpyCoefficient, nullptr, &stellarElementMarker);
+                zeroEnthalpyField.ComputeL2Error(exactEnthalpyCoefficient, nullptr, &stellarElementMarker);
 
-      const double projectionError = projectedEnthalpyField.ComputeL2Error(
+            const double projectionError =
-          exactEnthalpyCoefficient, nullptr, &stellarElementMarker);
+                projectedEnthalpyField.ComputeL2Error(exactEnthalpyCoefficient, nullptr, &stellarElementMarker);
 
             REQUIRE(exactEnthalpyNorm > 0.0);
 
-      const double relativeProjectionError =
+            const double relativeProjectionError = projectionError / exactEnthalpyNorm;
-          projectionError / exactEnthalpyNorm;
 
             /*
              * Begin deliberately far from equilibrium.
@@ -280,16 +281,14 @@ TEST_CASE("Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
 
             enthalpy          = 0.0;
 
-      auto dependencies =
+            auto dependencies = prepared_hydrostatic_analytic_solve_test_utils::make_dependencies();
-          prepared_hydrostatic_analytic_solve_test_utils::make_dependencies();
 
-      mean_field::operators::PreparedHydrostaticEquilibriumOperator
+            mean_field::operators::PreparedHydrostaticEquilibriumOperator preparedOperator(f, *f.domainMapperStateless);
-          preparedOperator(f, *f.domainMapperStateless);
 
             const auto initialReport = preparedOperator.Prepare(
-          prepared_hydrostatic_analytic_solve_test_utils::make_state(
+                prepared_hydrostatic_analytic_solve_test_utils::make_state(enthalpy, gravityPotential, displacement),
-              enthalpy, gravityPotential, displacement),
+                dependencies, rotation
-          dependencies, rotation);
+            );
 
             REQUIRE(initialReport.preparedResidual);
             REQUIRE(initialReport.preparedAlgebraicJacobianBlocks);
@@ -298,9 +297,7 @@ TEST_CASE("Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
 
             preparedOperator.BuildResidual(initialResidual);
 
-      const double initialResidualNorm =
+            const double initialResidualNorm = gravity_prepared_test_utils::global_norm(initialResidual, communicator);
-          gravity_prepared_test_utils::global_norm(initialResidual,
-                                                   communicator);
 
             REQUIRE(initialResidualNorm > 1.0e-12);
 
@@ -314,8 +311,9 @@ TEST_CASE("Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
              * rotation, and displacement makes this a well-defined
              * enthalpy solve.
              */
-      prepared_hydrostatic_analytic_solve_test_utils::EnthalpyJacobianOperator
+            prepared_hydrostatic_analytic_solve_test_utils::EnthalpyJacobianOperator enthalpyJacobian(
-          enthalpyJacobian(enthalpyMap.reduced_size(), preparedOperator);
+                enthalpyMap.reduced_size(), preparedOperator
+            );
 
             mfem::Vector rightHandSide(initialResidual);
             rightHandSide *= -1.0;
@@ -357,9 +355,9 @@ TEST_CASE("Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
             ++dependencies.enthalpy.revision;
 
             const auto solvedReport = preparedOperator.Prepare(
-          prepared_hydrostatic_analytic_solve_test_utils::make_state(
+                prepared_hydrostatic_analytic_solve_test_utils::make_state(enthalpy, gravityPotential, displacement),
-              enthalpy, gravityPotential, displacement),
+                dependencies, rotation
-          dependencies, rotation);
+            );
 
             CHECK(solvedReport.contextReport.updatedEnthalpy);
 
@@ -373,9 +371,7 @@ TEST_CASE("Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
 
             preparedOperator.BuildResidual(solvedResidual);
 
-      const double solvedResidualNorm =
+            const double solvedResidualNorm = gravity_prepared_test_utils::global_norm(solvedResidual, communicator);
-          gravity_prepared_test_utils::global_norm(solvedResidual,
-                                                   communicator);
 
             const double residualReduction  = solvedResidualNorm / initialResidualNorm;
 
@@ -393,11 +389,10 @@ TEST_CASE("Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
             enthalpyMap.scatter(enthalpy, enthalpyTrue);
             solvedEnthalpyField.SetFromTrueDofs(enthalpyTrue);
 
-      const double solvedAnalyticError = solvedEnthalpyField.ComputeL2Error(
+            const double solvedAnalyticError =
-          exactEnthalpyCoefficient, nullptr, &stellarElementMarker);
+                solvedEnthalpyField.ComputeL2Error(exactEnthalpyCoefficient, nullptr, &stellarElementMarker);
 
-      const double relativeSolvedAnalyticError =
+            const double relativeSolvedAnalyticError = solvedAnalyticError / exactEnthalpyNorm;
-          solvedAnalyticError / exactEnthalpyNorm;
 
             INFO("Deformation determinant = " << deformationDeterminant);
 
@@ -409,8 +404,7 @@ TEST_CASE("Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
 
             INFO("Relative analytic projection floor = " << relativeProjectionError);
 
-      INFO("Relative solved analytic L2 error = "
+            INFO("Relative solved analytic L2 error = " << relativeSolvedAnalyticError);
-           << relativeSolvedAnalyticError);
 
             /*
              * The discrete Bernoulli equation must be solved essentially
@@ -425,8 +419,7 @@ TEST_CASE("Prepared Hydrostatic Operator Solves Analytic Bernoulli Equilibria",
              * also contains potential-projection and mapped-space
              * compatibility errors.
              */
-      CHECK(relativeSolvedAnalyticError <
+            CHECK(relativeSolvedAnalyticError < std::max(5.0 * relativeProjectionError, 1.25e-4));
-            std::max(5.0 * relativeProjectionError, 1.25e-4));
 
             /*
              * Record that the analytic error remains within one order of

tests/operators/prepared_hydrostatic_equilibrium_complete_jacobian.cpp

@@ -138,9 +138,7 @@ TEST_CASE(
     mean_field::operators::PreparedHydrostaticEquilibriumOperator preparedOperator(f, *f.domainMapperStateless);
 
     const mfem::Vector enthalpy =
-        field_dof_test_utils::make_deterministic_supported_vector<mean_field::field::Enthalpy>(
+        field_dof_test_utils::make_deterministic_supported_vector<mean_field::field::Enthalpy>(*f.enthalpyFes, 0.34);
-            *f.enthalpyFes, 0.34
-        );
 
     const mfem::Vector gravityPotential =
         field_dof_test_utils::make_deterministic_supported_vector<mean_field::field::Gravity>(
@@ -161,9 +159,7 @@ TEST_CASE(
     );
 
     const mfem::Vector enthalpyVariation =
-        field_dof_test_utils::make_deterministic_supported_vector<mean_field::field::Enthalpy>(
+        field_dof_test_utils::make_deterministic_supported_vector<mean_field::field::Enthalpy>(*f.enthalpyFes, 1.07);
-            *f.enthalpyFes, 1.07
-        );
 
     const mfem::Vector gravityPotentialVariation =
         field_dof_test_utils::make_deterministic_supported_vector<mean_field::field::Gravity>(
@@ -236,9 +232,7 @@ TEST_CASE(
     mean_field::operators::PreparedHydrostaticEquilibriumOperator preparedOperator(f, *f.domainMapperStateless);
 
     const mfem::Vector enthalpy =
-        field_dof_test_utils::make_deterministic_supported_vector<mean_field::field::Enthalpy>(
+        field_dof_test_utils::make_deterministic_supported_vector<mean_field::field::Enthalpy>(*f.enthalpyFes, 0.41);
-            *f.enthalpyFes, 0.41
-        );
 
     const mfem::Vector gravityPotential =
         field_dof_test_utils::make_deterministic_supported_vector<mean_field::field::Gravity>(
@@ -277,9 +271,7 @@ TEST_CASE(
     CHECK(preparedOperator.GetEnthalpyMap().inactive_size() > 0);
 
     const mfem::Vector enthalpyVariation =
-        field_dof_test_utils::make_deterministic_supported_vector<mean_field::field::Enthalpy>(
+        field_dof_test_utils::make_deterministic_supported_vector<mean_field::field::Enthalpy>(*f.enthalpyFes, 1.12);
-            *f.enthalpyFes, 1.12
-        );
 
     const mfem::Vector gravityPotentialVariation =
         field_dof_test_utils::make_deterministic_supported_vector<mean_field::field::Gravity>(

tests/operators/prepared_mass_normalization.cpp

@@ -26,16 +26,13 @@ namespace mass_normalization_test_utils {
     );
 
     [[nodiscard]] mean_field::operators::MassNormalizationLayout make_layout(const mean_field::fem::FEM &f) {
-        const auto densityMap =
+        const auto densityMap = field_dof_test_utils::make_map<mean_field::field::Density>(*f.densityFes);
-            field_dof_test_utils::make_map<mean_field::field::Density>(*f.densityFes);
         const auto displacementMap =
             field_dof_test_utils::make_map<mean_field::field::Displacement>(*f.displacementFes);
-        const auto gravityFluxMap =
+        const auto gravityFluxMap = field_dof_test_utils::make_map<mean_field::field::Gravity>(*f.gravityFluxFes);
-            field_dof_test_utils::make_map<mean_field::field::Gravity>(*f.gravityFluxFes);
         const auto gravityPotentialMap =
             field_dof_test_utils::make_map<mean_field::field::Gravity>(*f.gravityPotentialFes);
-        const auto enthalpyMap =
+        const auto enthalpyMap = field_dof_test_utils::make_map<mean_field::field::Enthalpy>(*f.enthalpyFes);
-            field_dof_test_utils::make_map<mean_field::field::Enthalpy>(*f.enthalpyFes);
 
         const std::array<int, CoupledForm::value_block_count> valueSizes{
             densityMap.reduced_size(),          displacementMap.reduced_size(), gravityFluxMap.reduced_size(),
@@ -345,8 +342,7 @@ TEST_CASE(
     mean_field::operators::PreparedMassNormalizationOperator massOperator(f, *f.domainMapperStateless, gravityContext);
     massOperator.Prepare({.targetMass = 1.11}, dependencies);
 
-    const mfem::Vector reducedDisplacementDirection =
+    const mfem::Vector reducedDisplacementDirection = gravityContext.GetDisplacementMap().gather(displacementDirection);
-        gravityContext.GetDisplacementMap().gather(displacementDirection);
 
     mfem::Vector analyticAction;
     massOperator.ApplyDisplacementJacobianAction(reducedDisplacementDirection, analyticAction);
@@ -477,8 +473,7 @@ TEST_CASE(
     massOperator.Prepare({.targetMass = 1.19}, dependencies);
 
     const mfem::Vector reducedDensityDirection      = gravityContext.GetDensityMap().gather(densityDirection);
-    const mfem::Vector reducedDisplacementDirection =
+    const mfem::Vector reducedDisplacementDirection = gravityContext.GetDisplacementMap().gather(displacementDirection);
-        gravityContext.GetDisplacementMap().gather(displacementDirection);
 
     mfem::Vector densityAction;
     mfem::Vector displacementAction;
@@ -486,9 +481,7 @@ TEST_CASE(
 
     massOperator.ApplyDensityJacobianAction(reducedDensityDirection, densityAction);
     massOperator.ApplyDisplacementJacobianAction(reducedDisplacementDirection, displacementAction);
-    massOperator.ApplyCompleteJacobianAction(
+    massOperator.ApplyCompleteJacobianAction(reducedDensityDirection, reducedDisplacementDirection, completeAction);
-        reducedDensityDirection, reducedDisplacementDirection, completeAction
-    );
 
     CHECK(
         mass_normalization_test_utils::relative_error(completeAction(0), densityAction(0) + displacementAction(0)) <
@@ -498,10 +491,7 @@ TEST_CASE(
     const auto layout = mass_normalization_test_utils::make_layout(f);
     mean_field::operators::PreparedMassNormalizationJacobianOperator adapter(layout, massOperator);
 
-    CHECK(
+    CHECK(layout.size(mass_normalization_test_utils::densityValue) == gravityContext.GetDensityMap().reduced_size());
-        layout.size(mass_normalization_test_utils::densityValue) ==
-        gravityContext.GetDensityMap().reduced_size()
-    );
     CHECK(
         layout.size(mass_normalization_test_utils::displacementValue) ==
         gravityContext.GetDisplacementMap().reduced_size()

tests/operators/prepared_pressure_force.cpp

@@ -11,11 +11,11 @@ import mean_field;
 import test_helpers;
 
 namespace prepared_pressure_force_test_utils {
-using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
+    using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
 
-using CoupledForm = mean_field::utils::blocks::barotropic_equilibrium_form;
+    using CoupledForm  = mean_field::utils::blocks::barotropic_equilibrium_form;
 
-struct Maps final {
+    struct Maps final {
         mean_field::field::FieldDofMap density;
         mean_field::field::FieldDofMap displacement;
         mean_field::field::FieldDofMap gravityFlux;
@@ -24,59 +24,76 @@ struct Maps final {
 
         explicit Maps(const mean_field::fem::FEM &f)
             : density(
-            mean_field::field::make_field_dof_map<mean_field::field::Density,
+                  mean_field::field::make_field_dof_map<
-                                                  DomainSchema>(*f.densityFes)),
+                      mean_field::field::Density,
-        displacement(mean_field::field::make_field_dof_map<
+                      DomainSchema>(*f.densityFes)
-                     mean_field::field::Displacement, DomainSchema>(
+              ),
-            *f.displacementFes)),
+              displacement(
+                  mean_field::field::make_field_dof_map<
+                      mean_field::field::Displacement,
+                      DomainSchema>(*f.displacementFes)
+              ),
               gravityFlux(
-            mean_field::field::make_field_dof_map<mean_field::field::Gravity,
+                  mean_field::field::make_field_dof_map<
-                                                  DomainSchema>(
+                      mean_field::field::Gravity,
-                *f.gravityFluxFes)),
+                      DomainSchema>(*f.gravityFluxFes)
+              ),
               gravityPotential(
-            mean_field::field::make_field_dof_map<mean_field::field::Gravity,
+                  mean_field::field::make_field_dof_map<
-                                                  DomainSchema>(
+                      mean_field::field::Gravity,
-                *f.gravityPotentialFes)),
+                      DomainSchema>(*f.gravityPotentialFes)
-        enthalpy(mean_field::field::make_field_dof_map<
+              ),
-                 mean_field::field::Enthalpy, DomainSchema>(*f.enthalpyFes)) {}
+              enthalpy(
-};
+                  mean_field::field::make_field_dof_map<
+                      mean_field::field::Enthalpy,
+                      DomainSchema>(*f.enthalpyFes)
+              ) {
+        }
+    };
 
-[[nodiscard]]
+    [[nodiscard]]
-mfem::Vector make_positive_enthalpy_true(const mean_field::fem::FEM &f,
+    mfem::Vector make_positive_enthalpy_true(
-                                         const double phase) {
+        const mean_field::fem::FEM &f,
+        const double phase
+    ) {
         mfem::Vector enthalpy(f.enthalpyFes->GetTrueVSize());
 
         for (int index = 0; index < enthalpy.Size(); ++index) {
             const double position = static_cast<double>(index + 1);
 
-    enthalpy(index) = 0.93 + 0.09 * std::sin(0.23 * position + phase) +
+            enthalpy(index) =
-                      0.04 * std::cos(0.17 * position - 0.5 * phase);
+                0.93 + 0.09 * std::sin(0.23 * position + phase) + 0.04 * std::cos(0.17 * position - 0.5 * phase);
         }
 
         return enthalpy;
-}
+    }
 
-[[nodiscard]]
+    [[nodiscard]]
-mfem::Vector make_enthalpy_direction_true(const mean_field::fem::FEM &f,
+    mfem::Vector make_enthalpy_direction_true(
-                                          const double phase) {
+        const mean_field::fem::FEM &f,
+        const double phase
+    ) {
         mfem::Vector direction(f.enthalpyFes->GetTrueVSize());
 
         for (int index = 0; index < direction.Size(); ++index) {
             const double position = static_cast<double>(index + 1);
 
-    direction(index) = 0.27 * std::sin(0.19 * position + phase) +
+            direction(index) =
-                       0.14 * std::cos(0.13 * position - 0.5 * phase);
+                0.27 * std::sin(0.19 * position + phase) + 0.14 * std::cos(0.13 * position - 0.5 * phase);
         }
 
         return direction;
-}
+    }
 
-[[nodiscard]]
+    [[nodiscard]]
-mfem::Vector make_displacement_direction_true(const mean_field::fem::FEM &f,
+    mfem::Vector make_displacement_direction_true(
-                                              const double phase) {
+        const mean_field::fem::FEM &f,
-  MFEM_VERIFY(f.mesh->Dimension() == 3,
+        const double phase
-              "The prepared pressure-force test requires a "
+    ) {
-              "three-dimensional mesh.");
+        MFEM_VERIFY(
+            f.mesh->Dimension() == 3, "The prepared pressure-force test requires a "
+                                      "three-dimensional mesh."
+        );
 
         mfem::ParGridFunction directionField(f.displacementFes.get());
 
@@ -90,15 +107,13 @@ mfem::Vector make_displacement_direction_true(const mean_field::fem::FEM &f,
 
                 value.SetSize(3);
 
-        value(0) =
+                value(0) = 0.019 * x + 0.011 * y * z - 0.006 * z * z + 0.004 * phase * y;
-            0.019 * x + 0.011 * y * z - 0.006 * z * z + 0.004 * phase * y;
 
-        value(1) =
+                value(1) = -0.016 * y + 0.008 * x * z + 0.005 * x * x - 0.003 * phase * z;
-            -0.016 * y + 0.008 * x * z + 0.005 * x * x - 0.003 * phase * z;
 
-        value(2) =
+                value(2) = 0.013 * z - 0.010 * x * y + 0.006 * y * y + 0.004 * phase * x;
-            0.013 * z - 0.010 * x * y + 0.006 * y * y + 0.004 * phase * x;
+            }
-      });
+        );
 
         directionField.ProjectCoefficient(directionCoefficient);
 
@@ -107,108 +122,107 @@ mfem::Vector make_displacement_direction_true(const mean_field::fem::FEM &f,
         directionField.GetTrueDofs(directionTrue);
 
         return directionTrue;
-}
+    }
 
-[[nodiscard]]
+    [[nodiscard]]
-double relative_difference(const mfem::Vector &left, const mfem::Vector &right,
+    double relative_difference(
-                           const MPI_Comm communicator) {
+        const mfem::Vector &left,
-  MFEM_VERIFY(left.Size() == right.Size(),
+        const mfem::Vector &right,
-              "Cannot compare prepared pressure-force vectors with "
+        const MPI_Comm communicator
-              "different sizes.");
+    ) {
+        MFEM_VERIFY(
+            left.Size() == right.Size(), "Cannot compare prepared pressure-force vectors with "
+                                         "different sizes."
+        );
 
         mfem::Vector difference(left);
 
         difference -= right;
 
-  const double scale =
+        const double scale = std::max(
-      std::max({gravity_prepared_test_utils::global_norm(left, communicator),
+            {gravity_prepared_test_utils::global_norm(left, communicator),
              gravity_prepared_test_utils::global_norm(right, communicator),
-                100.0 * std::numeric_limits<double>::epsilon()});
+             100.0 * std::numeric_limits<double>::epsilon()}
+        );
 
-  return gravity_prepared_test_utils::global_norm(difference, communicator) /
+        return gravity_prepared_test_utils::global_norm(difference, communicator) / scale;
-         scale;
+    }
-}
 
-[[nodiscard]]
+    [[nodiscard]]
-mean_field::operators::context::pressure_force::PressureForceDependencies
+    mean_field::operators::context::pressure_force::PressureForceDependencies make_dependencies() {
-make_dependencies() {
+        return {
-  return {.discretization = {.identity = 1201, .revision = 3},
+            .discretization = {.identity = 1201, .revision = 3},
             .enthalpy       = {.identity = 1213, .revision = 5},
-          .displacement = {.identity = 1217, .revision = 7}};
+            .displacement   = {.identity = 1217, .revision = 7}
-}
+        };
+    }
 
-constexpr auto densityValue =
+    constexpr auto densityValue =
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::get_value_block<CoupledForm>(mean_field::utils::blocks::density_field.mass_term);
-        mean_field::utils::blocks::density_field.mass_term);
 
-constexpr auto displacementValue =
+    constexpr auto displacementValue = mean_field::utils::blocks::get_value_block<CoupledForm>(
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::displacement_field.geometry_term
-        mean_field::utils::blocks::displacement_field.geometry_term);
+    );
 
-constexpr auto gravityGradientValue =
+    constexpr auto gravityGradientValue =
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::get_value_block<CoupledForm>(mean_field::utils::blocks::gravity_field.gradient_term);
-        mean_field::utils::blocks::gravity_field.gradient_term);
 
-constexpr auto gravityPotentialValue =
+    constexpr auto gravityPotentialValue =
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::get_value_block<CoupledForm>(mean_field::utils::blocks::gravity_field.poisson_term);
-        mean_field::utils::blocks::gravity_field.poisson_term);
 
-constexpr auto enthalpyValue =
+    constexpr auto enthalpyValue = mean_field::utils::blocks::get_value_block<CoupledForm>(
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::enthalpy_field.specific_term
-        mean_field::utils::blocks::enthalpy_field.specific_term);
+    );
 
-constexpr auto barotropicConstantValue =
+    constexpr auto barotropicConstantValue = mean_field::utils::blocks::get_value_block<CoupledForm>(
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::barotropic_constant_field.mass_normalization_term
-        mean_field::utils::blocks::barotropic_constant_field
+    );
-            .mass_normalization_term);
 
-constexpr auto gravityGradientResidual =
+    constexpr auto gravityGradientResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::gravity_field.gradient_term
-        mean_field::utils::blocks::gravity_field.gradient_term);
+    );
 
-constexpr auto gravityPotentialResidual =
+    constexpr auto gravityPotentialResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::gravity_field.poisson_term
-        mean_field::utils::blocks::gravity_field.poisson_term);
+    );
 
-constexpr auto densityResidual =
+    constexpr auto densityResidual =
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::get_residual_block<CoupledForm>(mean_field::utils::blocks::density_field.mass_term);
-        mean_field::utils::blocks::density_field.mass_term);
 
-constexpr auto displacementResidual =
+    constexpr auto displacementResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::displacement_field.geometry_term
-        mean_field::utils::blocks::displacement_field.geometry_term);
+    );
 
-constexpr auto enthalpyResidual =
+    constexpr auto enthalpyResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::enthalpy_field.specific_term
-        mean_field::utils::blocks::enthalpy_field.specific_term);
+    );
 
-constexpr auto massResidual =
+    constexpr auto massResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::barotropic_constant_field.mass_normalization_term
-        mean_field::utils::blocks::barotropic_constant_field
+    );
-            .mass_normalization_term);
 
-[[nodiscard]]
+    [[nodiscard]]
-mean_field::operators::BarotropicEquilibriumLayout
+    mean_field::operators::BarotropicEquilibriumLayout make_coupled_layout(const Maps &maps) {
-make_coupled_layout(const Maps &maps) {
         const std::array<int, CoupledForm::value_block_count> valueSizes{
-      maps.density.reduced_size(),     maps.displacement.reduced_size(),
+            maps.density.reduced_size(),          maps.displacement.reduced_size(), maps.gravityFlux.reduced_size(),
-      maps.gravityFlux.reduced_size(), maps.gravityPotential.reduced_size(),
+            maps.gravityPotential.reduced_size(), maps.enthalpy.reduced_size(),     1
-      maps.enthalpy.reduced_size(),    1};
+        };
 
         const std::array<int, CoupledForm::residual_block_count> residualSizes{
-      maps.gravityFlux.reduced_size(), maps.gravityPotential.reduced_size(),
+            maps.gravityFlux.reduced_size(),  maps.gravityPotential.reduced_size(), maps.density.reduced_size(),
-      maps.density.reduced_size(),     maps.displacement.reduced_size(),
+            maps.displacement.reduced_size(), maps.enthalpy.reduced_size(),         1
-      maps.enthalpy.reduced_size(),    1};
+        };
 
         return {valueSizes, residualSizes};
-}
+    }
 
-template <int index>
+    template <int index>
-[[nodiscard]]
+    [[nodiscard]]
-mfem::Vector copy_residual_block(
+    mfem::Vector copy_residual_block(
         const mfem::Vector &action,
         const mean_field::operators::BarotropicEquilibriumLayout &layout,
-    const mean_field::utils::blocks::residual_block<index> block) {
+        const mean_field::utils::blocks::residual_block<index> block
+    ) {
         mfem::Vector result(layout.size(block));
 
         const int offset = layout.offset(block);
@@ -218,13 +232,14 @@ mfem::Vector copy_residual_block(
         }
 
         return result;
-}
+    }
 } // namespace prepared_pressure_force_test_utils
 
 TEST_CASE(
     "Prepared Pressure Force Uses FieldDof Supported Dimensions And Owns Its "
     "Context",
-    tags::barotrope &tags::pressure &tags::prepared &tags::field &tags::unit) {
+    tags::barotrope &tags::pressure &tags::prepared &tags::field &tags::unit
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
@@ -235,8 +250,7 @@ TEST_CASE(
 
     const mean_field::eos::Polytrope equationOfState(3.0, 0.25);
 
-  mean_field::operators::PreparedPressureForceOperator preparedOperator(
+    mean_field::operators::PreparedPressureForceOperator preparedOperator(f, *f.domainMapperStateless, equationOfState);
-      f, *f.domainMapperStateless, equationOfState);
 
     REQUIRE(maps.enthalpy.reduced_size() < maps.enthalpy.full_size());
 
@@ -244,17 +258,18 @@ TEST_CASE(
 
     CHECK(preparedOperator.GetEnthalpySize() == maps.enthalpy.reduced_size());
 
-  CHECK(preparedOperator.GetDisplacementSize() ==
+    CHECK(preparedOperator.GetDisplacementSize() == maps.displacement.reduced_size());
-        maps.displacement.reduced_size());
 
-  CHECK(&preparedOperator.GetContext().GetPreparationStatistics() ==
+    CHECK(
-        &preparedOperator.GetContextPreparationStatistics());
+        &preparedOperator.GetContext().GetPreparationStatistics() == &preparedOperator.GetContextPreparationStatistics()
+    );
 }
 
-TEST_CASE("Prepared Pressure Force Jacobian Matches Full Stateless Columns "
+TEST_CASE(
+    "Prepared Pressure Force Jacobian Matches Full Stateless Columns "
     "Through FieldDof Restriction",
-          tags::barotrope &tags::pressure &tags::prepared &tags::field
+    tags::barotrope &tags::pressure &tags::prepared &tags::field &tags::integration &tags::accuracy
-              &tags::integration &tags::accuracy) {
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
@@ -265,90 +280,87 @@ TEST_CASE("Prepared Pressure Force Jacobian Matches Full Stateless Columns "
 
     const mean_field::eos::Polytrope equationOfState(3.0, 0.25);
 
-  const mfem::Vector enthalpy = maps.enthalpy.gather(
+    const mfem::Vector enthalpy =
-      prepared_pressure_force_test_utils::make_positive_enthalpy_true(f, 0.47));
+        maps.enthalpy.gather(prepared_pressure_force_test_utils::make_positive_enthalpy_true(f, 0.47));
 
-  const mfem::Vector displacement = maps.displacement.gather(
+    const mfem::Vector displacement = maps.displacement.gather(gravity_prepared_test_utils::make_displacement(f, 0.69));
-      gravity_prepared_test_utils::make_displacement(f, 0.69));
 
-  const mfem::Vector enthalpyDirection = maps.enthalpy.gather(
+    const mfem::Vector enthalpyDirection =
-      prepared_pressure_force_test_utils::make_enthalpy_direction_true(f,
+        maps.enthalpy.gather(prepared_pressure_force_test_utils::make_enthalpy_direction_true(f, 0.73));
-                                                                       0.73));
 
-  const mfem::Vector displacementDirection = maps.displacement.gather(
+    const mfem::Vector displacementDirection =
-      prepared_pressure_force_test_utils::make_displacement_direction_true(
+        maps.displacement.gather(prepared_pressure_force_test_utils::make_displacement_direction_true(f, 0.83));
-          f, 0.83));
 
-  mean_field::operators::PreparedPressureForceOperator preparedOperator(
+    mean_field::operators::PreparedPressureForceOperator preparedOperator(f, *f.domainMapperStateless, equationOfState);
-      f, *f.domainMapperStateless, equationOfState);
 
     preparedOperator.Prepare(
-      {.enthalpy = enthalpy, .displacement = displacement},
+        {.enthalpy = enthalpy, .displacement = displacement}, prepared_pressure_force_test_utils::make_dependencies()
-      prepared_pressure_force_test_utils::make_dependencies());
+    );
 
     const mfem::Vector enthalpyTrue              = maps.enthalpy.scatter(enthalpy);
 
     const mfem::Vector displacementTrue          = maps.displacement.scatter(displacement);
 
-  const mfem::Vector enthalpyDirectionTrue =
+    const mfem::Vector enthalpyDirectionTrue     = maps.enthalpy.scatter(enthalpyDirection);
-      maps.enthalpy.scatter(enthalpyDirection);
 
-  const mfem::Vector displacementDirectionTrue =
+    const mfem::Vector displacementDirectionTrue = maps.displacement.scatter(displacementDirection);
-      maps.displacement.scatter(displacementDirection);
 
     mfem::Vector preparedEnthalpyAction;
     mfem::Vector kernelEnthalpyActionTrue;
 
-  preparedOperator.ApplyEnthalpyJacobianAction(enthalpyDirection,
+    preparedOperator.ApplyEnthalpyJacobianAction(enthalpyDirection, preparedEnthalpyAction);
-                                               preparedEnthalpyAction);
 
     mean_field::operators::kernels::apply_pressure_force_enthalpy_action(
-      f, *f.domainMapperStateless, equationOfState, enthalpyTrue,
+        f, *f.domainMapperStateless, equationOfState, enthalpyTrue, enthalpyDirectionTrue, displacementTrue,
-      enthalpyDirectionTrue, displacementTrue, kernelEnthalpyActionTrue);
+        kernelEnthalpyActionTrue
+    );
 
-  const mfem::Vector kernelEnthalpyAction =
+    const mfem::Vector kernelEnthalpyAction = maps.displacement.gather(kernelEnthalpyActionTrue);
-      maps.displacement.gather(kernelEnthalpyActionTrue);
 
-  CHECK(prepared_pressure_force_test_utils::relative_difference(
+    CHECK(
-            preparedEnthalpyAction, kernelEnthalpyAction, f.mesh->GetComm()) <
+        prepared_pressure_force_test_utils::relative_difference(
-        2.0e-12);
+            preparedEnthalpyAction, kernelEnthalpyAction, f.mesh->GetComm()
+        ) < 2.0e-12
+    );
 
     mfem::Vector preparedDisplacementAction;
     mfem::Vector kernelDisplacementActionTrue;
 
-  preparedOperator.ApplyDisplacementJacobianAction(displacementDirection,
+    preparedOperator.ApplyDisplacementJacobianAction(displacementDirection, preparedDisplacementAction);
-                                                   preparedDisplacementAction);
 
     mean_field::operators::kernels::apply_pressure_force_displacement_action(
-      f, *f.domainMapperStateless, equationOfState, enthalpyTrue,
+        f, *f.domainMapperStateless, equationOfState, enthalpyTrue, displacementDirectionTrue, displacementTrue,
-      displacementDirectionTrue, displacementTrue,
+        kernelDisplacementActionTrue
-      kernelDisplacementActionTrue);
+    );
 
-  const mfem::Vector kernelDisplacementAction =
+    const mfem::Vector kernelDisplacementAction = maps.displacement.gather(kernelDisplacementActionTrue);
-      maps.displacement.gather(kernelDisplacementActionTrue);
 
-  CHECK(prepared_pressure_force_test_utils::relative_difference(
+    CHECK(
-            preparedDisplacementAction, kernelDisplacementAction,
+        prepared_pressure_force_test_utils::relative_difference(
-            f.mesh->GetComm()) < 2.0e-12);
+            preparedDisplacementAction, kernelDisplacementAction, f.mesh->GetComm()
+        ) < 2.0e-12
+    );
 
     mfem::Vector fusedAction;
 
-  preparedOperator.ApplyCompleteJacobianAction(
+    preparedOperator.ApplyCompleteJacobianAction(enthalpyDirection, displacementDirection, fusedAction);
-      enthalpyDirection, displacementDirection, fusedAction);
 
     mfem::Vector expectedFusedAction(kernelEnthalpyAction);
 
     expectedFusedAction += kernelDisplacementAction;
 
-  CHECK(prepared_pressure_force_test_utils::relative_difference(
+    CHECK(
-            fusedAction, expectedFusedAction, f.mesh->GetComm()) < 2.0e-12);
+        prepared_pressure_force_test_utils::relative_difference(fusedAction, expectedFusedAction, f.mesh->GetComm()) <
+        2.0e-12
+    );
 }
 
 TEST_CASE(
     "Prepared Pressure Force MFEM Adapter Routes Reduced Coupled FieldDof "
     "Blocks",
-    tags::barotrope &tags::pressure &tags::prepared &tags::field
+    tags::barotrope &tags::pressure &tags::prepared &tags::field &tags::integration &tags::jacobian
-        &tags::integration &tags::jacobian &tags::mfem_operators &tags::unit) {
+        &tags::mfem_operators &tags::unit
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
@@ -359,38 +371,31 @@ TEST_CASE(
 
     const mean_field::eos::Polytrope equationOfState(3.0, 0.25);
 
-  const mfem::Vector enthalpy = maps.enthalpy.gather(
+    const mfem::Vector enthalpy =
-      prepared_pressure_force_test_utils::make_positive_enthalpy_true(f, 0.53));
+        maps.enthalpy.gather(prepared_pressure_force_test_utils::make_positive_enthalpy_true(f, 0.53));
 
-  const mfem::Vector displacement = maps.displacement.gather(
+    const mfem::Vector displacement = maps.displacement.gather(gravity_prepared_test_utils::make_displacement(f, 0.71));
-      gravity_prepared_test_utils::make_displacement(f, 0.71));
 
-  const mfem::Vector enthalpyDirection = maps.enthalpy.gather(
+    const mfem::Vector enthalpyDirection =
-      prepared_pressure_force_test_utils::make_enthalpy_direction_true(f,
+        maps.enthalpy.gather(prepared_pressure_force_test_utils::make_enthalpy_direction_true(f, 0.89));
-                                                                       0.89));
 
-  const mfem::Vector displacementDirection = maps.displacement.gather(
+    const mfem::Vector displacementDirection =
-      prepared_pressure_force_test_utils::make_displacement_direction_true(
+        maps.displacement.gather(prepared_pressure_force_test_utils::make_displacement_direction_true(f, 0.97));
-          f, 0.97));
 
-  mean_field::operators::PreparedPressureForceOperator preparedOperator(
+    mean_field::operators::PreparedPressureForceOperator preparedOperator(f, *f.domainMapperStateless, equationOfState);
-      f, *f.domainMapperStateless, equationOfState);
 
     preparedOperator.Prepare(
-      {.enthalpy = enthalpy, .displacement = displacement},
+        {.enthalpy = enthalpy, .displacement = displacement}, prepared_pressure_force_test_utils::make_dependencies()
-      prepared_pressure_force_test_utils::make_dependencies());
+    );
 
     const mean_field::operators::BarotropicEquilibriumLayout layout =
         prepared_pressure_force_test_utils::make_coupled_layout(maps);
 
-  mean_field::operators::PreparedPressureForceJacobianOperator adapter(
+    mean_field::operators::PreparedPressureForceJacobianOperator adapter(layout, preparedOperator);
-      layout, preparedOperator);
 
-  CHECK(layout.size(prepared_pressure_force_test_utils::enthalpyValue) ==
+    CHECK(layout.size(prepared_pressure_force_test_utils::enthalpyValue) == maps.enthalpy.reduced_size());
-        maps.enthalpy.reduced_size());
 
-  CHECK(layout.size(prepared_pressure_force_test_utils::densityValue) ==
+    CHECK(layout.size(prepared_pressure_force_test_utils::densityValue) == maps.density.reduced_size());
-        maps.density.reduced_size());
 
     mfem::BlockVector direction(layout.value_offsets());
 
@@ -401,66 +406,74 @@ TEST_CASE(
      */
     direction.GetBlock(prepared_pressure_force_test_utils::densityValue)            = 0.37;
 
-  direction.GetBlock(prepared_pressure_force_test_utils::gravityGradientValue) =
+    direction.GetBlock(prepared_pressure_force_test_utils::gravityGradientValue)    = -0.41;
-      -0.41;
 
-  direction.GetBlock(
+    direction.GetBlock(prepared_pressure_force_test_utils::gravityPotentialValue)   = 0.59;
-      prepared_pressure_force_test_utils::gravityPotentialValue) = 0.59;
 
-  direction.GetBlock(
+    direction.GetBlock(prepared_pressure_force_test_utils::barotropicConstantValue) = -0.73;
-      prepared_pressure_force_test_utils::barotropicConstantValue) = -0.73;
 
-  direction.GetBlock(prepared_pressure_force_test_utils::displacementValue) =
+    direction.GetBlock(prepared_pressure_force_test_utils::displacementValue)       = displacementDirection;
-      displacementDirection;
 
-  direction.GetBlock(prepared_pressure_force_test_utils::enthalpyValue) =
+    direction.GetBlock(prepared_pressure_force_test_utils::enthalpyValue)           = enthalpyDirection;
-      enthalpyDirection;
 
     mfem::Vector expectedDisplacementAction;
 
-  preparedOperator.ApplyCompleteJacobianAction(
+    preparedOperator.ApplyCompleteJacobianAction(enthalpyDirection, displacementDirection, expectedDisplacementAction);
-      enthalpyDirection, displacementDirection, expectedDisplacementAction);
 
     mfem::Vector action;
 
     adapter.Mult(direction, action);
 
-  const mfem::Vector displacementResidualAction =
+    const mfem::Vector displacementResidualAction = prepared_pressure_force_test_utils::copy_residual_block(
-      prepared_pressure_force_test_utils::copy_residual_block(
+        action, layout, prepared_pressure_force_test_utils::displacementResidual
-          action, layout,
+    );
-          prepared_pressure_force_test_utils::displacementResidual);
 
-  CHECK(prepared_pressure_force_test_utils::relative_difference(
+    CHECK(
-            displacementResidualAction, expectedDisplacementAction,
+        prepared_pressure_force_test_utils::relative_difference(
-            f.mesh->GetComm()) < 2.0e-14);
+            displacementResidualAction, expectedDisplacementAction, f.mesh->GetComm()
-
+        ) < 2.0e-14
-  CHECK(prepared_pressure_force_test_utils::copy_residual_block(
+    );
-            action, layout,
-            prepared_pressure_force_test_utils::gravityGradientResidual)
-            .Norml2() == 0.0);
-
-  CHECK(prepared_pressure_force_test_utils::copy_residual_block(
-            action, layout,
-            prepared_pressure_force_test_utils::gravityPotentialResidual)
-            .Norml2() == 0.0);
-
-  CHECK(prepared_pressure_force_test_utils::copy_residual_block(
-            action, layout, prepared_pressure_force_test_utils::densityResidual)
-            .Norml2() == 0.0);
 
     CHECK(
         prepared_pressure_force_test_utils::copy_residual_block(
-          action, layout, prepared_pressure_force_test_utils::enthalpyResidual)
+            action, layout, prepared_pressure_force_test_utils::gravityGradientResidual
-          .Norml2() == 0.0);
+        )
+            .Norml2() == 0.0
+    );
 
-  CHECK(prepared_pressure_force_test_utils::copy_residual_block(
+    CHECK(
-            action, layout, prepared_pressure_force_test_utils::massResidual)
+        prepared_pressure_force_test_utils::copy_residual_block(
-            .Norml2() == 0.0);
+            action, layout, prepared_pressure_force_test_utils::gravityPotentialResidual
+        )
+            .Norml2() == 0.0
+    );
+
+    CHECK(
+        prepared_pressure_force_test_utils::copy_residual_block(
+            action, layout, prepared_pressure_force_test_utils::densityResidual
+        )
+            .Norml2() == 0.0
+    );
+
+    CHECK(
+        prepared_pressure_force_test_utils::copy_residual_block(
+            action, layout, prepared_pressure_force_test_utils::enthalpyResidual
+        )
+            .Norml2() == 0.0
+    );
+
+    CHECK(
+        prepared_pressure_force_test_utils::copy_residual_block(
+            action, layout, prepared_pressure_force_test_utils::massResidual
+        )
+            .Norml2() == 0.0
+    );
 }
-TEST_CASE("Pressure Force Residual Converges To A Manufactured Analytic Force",
+TEST_CASE(
-          tags::barotrope &tags::pressure &tags::kernels &tags::integration
+    "Pressure Force Residual Converges To A Manufactured Analytic Force",
-              &tags::convergence &tags::h_refinement &tags::analytic_comparison
+    tags::barotrope &tags::pressure &tags::kernels &tags::integration &tags::convergence &tags::h_refinement
-                  &tags::accuracy) {
+        &tags::analytic_comparison &tags::accuracy
+) {
     constexpr int dimension = 3;
 
     constexpr std::array<int, 2> refinementLevels{0, 1};
@@ -474,12 +487,10 @@ TEST_CASE("Pressure Force Residual Converges To A Manufactured Analytic Force",
 
     std::array<double, refinementLevels.size()> relativeErrors{};
 
-  for (std::size_t levelIndex = 0; levelIndex < refinementLevels.size();
+    for (std::size_t levelIndex = 0; levelIndex < refinementLevels.size(); ++levelIndex) {
-       ++levelIndex) {
         mean_field::utils::Args args = test_utils::setup_args();
 
-    mean_field::fem::FEM f = mean_field::fem::setup_fem(
+        mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, refinementLevels[levelIndex]);
-        args.mesh_file, args, refinementLevels[levelIndex]);
 
         REQUIRE(f.okay());
         REQUIRE(f.mesh->Dimension() == dimension);
@@ -487,15 +498,12 @@ TEST_CASE("Pressure Force Residual Converges To A Manufactured Analytic Force",
 
         const MPI_Comm communicator           = f.mesh->GetComm();
 
-    constexpr double supportRadius =
+        constexpr double supportRadius        = supportRadiusFraction * mean_field::utils::RADIUS;
-        supportRadiusFraction * mean_field::utils::RADIUS;
 
         constexpr double supportRadiusSquared = supportRadius * supportRadius;
 
-    auto analyticEnthalpyFunction = [supportRadiusSquared](
+        auto analyticEnthalpyFunction         = [supportRadiusSquared](const mfem::Vector &position) {
-                                        const mfem::Vector &position) {
+            const double normalizedRadiusSquared = (position * position) / supportRadiusSquared;
-      const double normalizedRadiusSquared =
-          (position * position) / supportRadiusSquared;
 
             if (normalizedRadiusSquared >= 1.0) {
                 return 0.0;
@@ -503,18 +511,14 @@ TEST_CASE("Pressure Force Residual Converges To A Manufactured Analytic Force",
 
             const double distanceToSupportBoundary = 1.0 - normalizedRadiusSquared;
 
-      return amplitude * std::exp(-bumpSharpness * normalizedRadiusSquared /
+            return amplitude * std::exp(-bumpSharpness * normalizedRadiusSquared / distanceToSupportBoundary);
-                                  distanceToSupportBoundary);
         };
 
-    auto analyticPressureForceFunction = [supportRadiusSquared](
+        auto analyticPressureForceFunction = [supportRadiusSquared](const mfem::Vector &position, mfem::Vector &force) {
-                                             const mfem::Vector &position,
-                                             mfem::Vector &force) {
             force.SetSize(dimension);
             force                                = 0.0;
 
-      const double normalizedRadiusSquared =
+            const double normalizedRadiusSquared = (position * position) / supportRadiusSquared;
-          (position * position) / supportRadiusSquared;
 
             if (normalizedRadiusSquared >= 1.0) {
                 return;
@@ -523,24 +527,20 @@ TEST_CASE("Pressure Force Residual Converges To A Manufactured Analytic Force",
             const double distanceToSupportBoundary = 1.0 - normalizedRadiusSquared;
 
             const double enthalpy =
-          amplitude * std::exp(-bumpSharpness * normalizedRadiusSquared /
+                amplitude * std::exp(-bumpSharpness * normalizedRadiusSquared / distanceToSupportBoundary);
-                               distanceToSupportBoundary);
 
             const double pressureGradientScale =
                 -2.0 * bumpSharpness * std::pow(enthalpy, 4.0) /
-          (supportRadiusSquared * distanceToSupportBoundary *
+                (supportRadiusSquared * distanceToSupportBoundary * distanceToSupportBoundary);
-           distanceToSupportBoundary);
 
             for (int component = 0; component < dimension; ++component) {
                 force(component) = pressureGradientScale * position(component);
             }
         };
 
-    mfem::FunctionCoefficient analyticEnthalpyCoefficient(
+        mfem::FunctionCoefficient analyticEnthalpyCoefficient(analyticEnthalpyFunction);
-        analyticEnthalpyFunction);
 
-    mfem::VectorFunctionCoefficient analyticPressureForceCoefficient(
+        mfem::VectorFunctionCoefficient analyticPressureForceCoefficient(dimension, analyticPressureForceFunction);
-        dimension, analyticPressureForceFunction);
 
         mfem::ParGridFunction discreteEnthalpyField(f.enthalpyFes.get());
 
@@ -558,8 +558,8 @@ TEST_CASE("Pressure Force Residual Converges To A Manufactured Analytic Force",
         mfem::Vector discreteResidual;
 
         mean_field::operators::kernels::apply_pressure_force_residual(
-        f, *f.domainMapperStateless, barotrope, discreteEnthalpyTrue,
+            f, *f.domainMapperStateless, barotrope, discreteEnthalpyTrue, zeroDisplacement, discreteResidual
-        zeroDisplacement, discreteResidual);
+        );
 
         REQUIRE(discreteResidual.Size() == f.displacementFes->GetTrueVSize());
 
@@ -569,8 +569,7 @@ TEST_CASE("Pressure Force Residual Converges To A Manufactured Analytic Force",
 
         const int vacuumAttribute = field_dof_test_utils::vacuum_material_attribute;
 
-    for (int attributeIndex = 0; attributeIndex < f.mesh->attributes.Size();
+        for (int attributeIndex = 0; attributeIndex < f.mesh->attributes.Size(); ++attributeIndex) {
-         ++attributeIndex) {
             const int attribute = f.mesh->attributes[attributeIndex];
 
             if (attribute != vacuumAttribute) {
@@ -578,34 +577,28 @@ TEST_CASE("Pressure Force Residual Converges To A Manufactured Analytic Force",
             }
         }
 
-    const mfem::Geometry::Type elementGeometry =
+        const mfem::Geometry::Type elementGeometry = f.displacementFes->GetFE(0)->GetGeomType();
-        f.displacementFes->GetFE(0)->GetGeomType();
 
         for (int element = 1; element < f.mesh->GetNE(); ++element) {
-      REQUIRE(f.displacementFes->GetFE(element)->GetGeomType() ==
+            REQUIRE(f.displacementFes->GetFE(element)->GetGeomType() == elementGeometry);
-              elementGeometry);
         }
 
-    const int referenceQuadratureOrder =
+        const int referenceQuadratureOrder = 2 * f.displacementFes->GetMaxElementOrder() + 16;
-        2 * f.displacementFes->GetMaxElementOrder() + 16;
 
         const mfem::IntegrationRule &referenceQuadrature =
             mfem::IntRules.Get(elementGeometry, referenceQuadratureOrder);
 
-    auto *analyticForceIntegrator =
+        auto *analyticForceIntegrator = new mfem::VectorDomainLFIntegrator(analyticPressureForceCoefficient);
-        new mfem::VectorDomainLFIntegrator(analyticPressureForceCoefficient);
 
         analyticForceIntegrator->SetIntRule(&referenceQuadrature);
 
         mfem::ParLinearForm analyticForceLoad(f.displacementFes.get());
 
-    analyticForceLoad.AddDomainIntegrator(analyticForceIntegrator,
+        analyticForceLoad.AddDomainIntegrator(analyticForceIntegrator, stellarMarker);
-                                          stellarMarker);
 
         analyticForceLoad.Assemble();
 
-    std::unique_ptr<mfem::HypreParVector> analyticForceHypreVector(
+        std::unique_ptr<mfem::HypreParVector> analyticForceHypreVector(analyticForceLoad.ParallelAssemble());
-        analyticForceLoad.ParallelAssemble());
 
         REQUIRE(analyticForceHypreVector != nullptr);
 
@@ -613,8 +606,7 @@ TEST_CASE("Pressure Force Residual Converges To A Manufactured Analytic Force",
 
         REQUIRE(analyticForceTrue.Size() == discreteResidual.Size());
 
-    const double analyticForceNorm = gravity_prepared_test_utils::global_norm(
+        const double analyticForceNorm = gravity_prepared_test_utils::global_norm(analyticForceTrue, communicator);
-        analyticForceTrue, communicator);
 
         REQUIRE(std::isfinite(analyticForceNorm));
         REQUIRE(analyticForceNorm > 0.0);
@@ -631,8 +623,7 @@ TEST_CASE("Pressure Force Residual Converges To A Manufactured Analytic Force",
         rieszForm.Assemble();
         rieszForm.Finalize();
 
-    std::unique_ptr<mfem::HypreParMatrix> rieszMatrix(
+        std::unique_ptr<mfem::HypreParMatrix> rieszMatrix(rieszForm.ParallelAssemble());
-        rieszForm.ParallelAssemble());
 
         REQUIRE(rieszMatrix != nullptr);
         REQUIRE(rieszMatrix->Height() == discreteResidual.Size());
@@ -651,28 +642,28 @@ TEST_CASE("Pressure Force Residual Converges To A Manufactured Analytic Force",
         rieszSolver.SetMaxIter(5000);
         rieszSolver.SetPrintLevel(0);
 
-    auto calculateDualNorm = [&rieszSolver,
+        auto calculateDualNorm = [&rieszSolver, communicator](const mfem::Vector &functional) {
-                              communicator](const mfem::Vector &functional) {
             mfem::Vector rieszRepresentative(functional.Size());
 
             rieszRepresentative = 0.0;
 
             rieszSolver.Mult(functional, rieszRepresentative);
 
-      MFEM_VERIFY(rieszSolver.GetConverged(),
+            MFEM_VERIFY(
-                  "The pressure-force convergence-test Riesz solve "
+                rieszSolver.GetConverged(), "The pressure-force convergence-test Riesz solve "
-                  "did not converge.");
+                                            "did not converge."
+            );
 
-      const double dualNormSquared = gravity_prepared_test_utils::global_dot(
+            const double dualNormSquared =
-          functional, rieszRepresentative, communicator);
+                gravity_prepared_test_utils::global_dot(functional, rieszRepresentative, communicator);
 
-      MFEM_VERIFY(std::isfinite(dualNormSquared),
+            MFEM_VERIFY(std::isfinite(dualNormSquared), "The pressure-force dual norm is not finite.");
-                  "The pressure-force dual norm is not finite.");
 
-      MFEM_VERIFY(dualNormSquared >=
+            MFEM_VERIFY(
-                      -100.0 * std::numeric_limits<double>::epsilon(),
+                dualNormSquared >= -100.0 * std::numeric_limits<double>::epsilon(),
                 "The pressure-force Riesz operator produced a "
-                  "negative dual norm.");
+                "negative dual norm."
+            );
 
             return std::sqrt(std::max(dualNormSquared, 0.0));
         };
@@ -700,12 +691,9 @@ TEST_CASE("Pressure Force Residual Converges To A Manufactured Analytic Force",
         REQUIRE(relativeError > 0.0);
     }
 
-  static_assert(
+    static_assert(refinementLevels.size() == 2, "This reduced convergence test expects exactly two refinement levels.");
-      refinementLevels.size() == 2,
-      "This reduced convergence test expects exactly two refinement levels.");
 
-  const double observedRate =
+    const double observedRate = std::log(relativeErrors[0] / relativeErrors[1]) / std::log(2.0);
-      std::log(relativeErrors[0] / relativeErrors[1]) / std::log(2.0);
 
     INFO("Level 0 pressure-force relative dual error = " << relativeErrors[0]);
 

tests/operators/prepared_rotation_displacement_force.cpp

@@ -11,97 +11,85 @@ import mean_field;
 import test_helpers;
 
 namespace rotational_displacement_force_test_utils {
-using CoupledForm = mean_field::utils::blocks::barotropic_equilibrium_form;
+    using CoupledForm = mean_field::utils::blocks::barotropic_equilibrium_form;
 
-constexpr auto densityValue =
+    constexpr auto densityValue =
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::get_value_block<CoupledForm>(mean_field::utils::blocks::density_field.mass_term);
-        mean_field::utils::blocks::density_field.mass_term);
 
-constexpr auto displacementValue =
+    constexpr auto displacementValue = mean_field::utils::blocks::get_value_block<CoupledForm>(
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::displacement_field.geometry_term
-        mean_field::utils::blocks::displacement_field.geometry_term);
+    );
 
-constexpr auto gravityGradientValue =
+    constexpr auto gravityGradientValue =
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::get_value_block<CoupledForm>(mean_field::utils::blocks::gravity_field.gradient_term);
-        mean_field::utils::blocks::gravity_field.gradient_term);
 
-constexpr auto gravityPotentialValue =
+    constexpr auto gravityPotentialValue =
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::get_value_block<CoupledForm>(mean_field::utils::blocks::gravity_field.poisson_term);
-        mean_field::utils::blocks::gravity_field.poisson_term);
 
-constexpr auto enthalpyValue =
+    constexpr auto enthalpyValue = mean_field::utils::blocks::get_value_block<CoupledForm>(
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::enthalpy_field.specific_term
-        mean_field::utils::blocks::enthalpy_field.specific_term);
+    );
 
-constexpr auto barotropicConstantValue =
+    constexpr auto barotropicConstantValue = mean_field::utils::blocks::get_value_block<CoupledForm>(
-    mean_field::utils::blocks::get_value_block<CoupledForm>(
+        mean_field::utils::blocks::barotropic_constant_field.mass_normalization_term
-        mean_field::utils::blocks::barotropic_constant_field
+    );
-            .mass_normalization_term);
 
-constexpr auto gravityGradientResidual =
+    constexpr auto gravityGradientResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::gravity_field.gradient_term
-        mean_field::utils::blocks::gravity_field.gradient_term);
+    );
 
-constexpr auto gravityPotentialResidual =
+    constexpr auto gravityPotentialResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::gravity_field.poisson_term
-        mean_field::utils::blocks::gravity_field.poisson_term);
+    );
 
-constexpr auto densityResidual =
+    constexpr auto densityResidual =
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::get_residual_block<CoupledForm>(mean_field::utils::blocks::density_field.mass_term);
-        mean_field::utils::blocks::density_field.mass_term);
 
-constexpr auto displacementResidual =
+    constexpr auto displacementResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::displacement_field.geometry_term
-        mean_field::utils::blocks::displacement_field.geometry_term);
+    );
 
-constexpr auto enthalpyResidual =
+    constexpr auto enthalpyResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::enthalpy_field.specific_term
-        mean_field::utils::blocks::enthalpy_field.specific_term);
+    );
 
-constexpr auto massResidual =
+    constexpr auto massResidual = mean_field::utils::blocks::get_residual_block<CoupledForm>(
-    mean_field::utils::blocks::get_residual_block<CoupledForm>(
+        mean_field::utils::blocks::barotropic_constant_field.mass_normalization_term
-        mean_field::utils::blocks::barotropic_constant_field
+    );
-            .mass_normalization_term);
 
-[[nodiscard]] mean_field::operators::RotationalDisplacementForceLayout
+    [[nodiscard]] mean_field::operators::RotationalDisplacementForceLayout make_layout(const mean_field::fem::FEM &f) {
-make_layout(const mean_field::fem::FEM &f) {
         using DomainSchema         = gravity_prepared_test_utils::DomainSchema;
 
-  const auto densityMap =
+        const auto densityMap      = gravity_prepared_test_utils::make_field_map<mean_field::field::Density>(f);
-      gravity_prepared_test_utils::make_field_map<mean_field::field::Density>(
+        const auto displacementMap = gravity_prepared_test_utils::make_field_map<mean_field::field::Displacement>(f);
-          f);
-  const auto displacementMap = gravity_prepared_test_utils::make_field_map<
-      mean_field::field::Displacement>(f);
         const auto gravityFluxMap =
-      mean_field::field::make_field_dof_map<mean_field::field::Gravity,
+            mean_field::field::make_field_dof_map<mean_field::field::Gravity, DomainSchema>(*f.gravityFluxFes);
-                                            DomainSchema>(*f.gravityFluxFes);
+        const auto gravityPotentialMap =
-  const auto gravityPotentialMap = mean_field::field::make_field_dof_map<
+            mean_field::field::make_field_dof_map<mean_field::field::Gravity, DomainSchema>(*f.gravityPotentialFes);
-      mean_field::field::Gravity, DomainSchema>(*f.gravityPotentialFes);
         const auto enthalpyMap =
-      mean_field::field::make_field_dof_map<mean_field::field::Enthalpy,
+            mean_field::field::make_field_dof_map<mean_field::field::Enthalpy, DomainSchema>(*f.enthalpyFes);
-                                            DomainSchema>(*f.enthalpyFes);
 
         const std::array<int, CoupledForm::value_block_count> valueSizes{
-      densityMap.reduced_size(),     displacementMap.reduced_size(),
+            densityMap.reduced_size(),          displacementMap.reduced_size(), gravityFluxMap.reduced_size(),
-      gravityFluxMap.reduced_size(), gravityPotentialMap.reduced_size(),
+            gravityPotentialMap.reduced_size(), enthalpyMap.reduced_size(),     1
-      enthalpyMap.reduced_size(),    1};
+        };
 
         const std::array<int, CoupledForm::residual_block_count> residualSizes{
-      gravityFluxMap.reduced_size(), gravityPotentialMap.reduced_size(),
+            gravityFluxMap.reduced_size(),  gravityPotentialMap.reduced_size(), densityMap.reduced_size(),
-      densityMap.reduced_size(),     displacementMap.reduced_size(),
+            displacementMap.reduced_size(), enthalpyMap.reduced_size(),         1
-      enthalpyMap.reduced_size(),    1};
+        };
 
         return {valueSizes, residualSizes};
-}
+    }
 
-[[nodiscard]] mfem::Vector make_density(const mean_field::fem::FEM &f,
+    [[nodiscard]] mfem::Vector make_density(
-                                        const double phase) {
+        const mean_field::fem::FEM &f,
+        const double phase
+    ) {
         mfem::ParGridFunction densityField(f.densityFes.get());
 
-  mfem::FunctionCoefficient densityCoefficient(
+        mfem::FunctionCoefficient densityCoefficient([phase](const mfem::Vector &position) {
-      [phase](const mfem::Vector &position) {
+            return 0.88 + 0.06 * std::sin(0.7 * position(0) + phase) + 0.04 * std::cos(0.6 * position(1) - phase) +
-        return 0.88 + 0.06 * std::sin(0.7 * position(0) + phase) +
-               0.04 * std::cos(0.6 * position(1) - phase) +
                    0.025 * position(2) * position(2);
         });
 
@@ -110,16 +98,17 @@ make_layout(const mean_field::fem::FEM &f) {
         mfem::Vector densityTrue;
         densityField.GetTrueDofs(densityTrue);
         return densityTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector make_density_direction(const mean_field::fem::FEM &f,
+    [[nodiscard]] mfem::Vector make_density_direction(
-                                                  const double phase) {
+        const mean_field::fem::FEM &f,
+        const double phase
+    ) {
         mfem::ParGridFunction densityField(f.densityFes.get());
 
-  mfem::FunctionCoefficient densityCoefficient(
+        mfem::FunctionCoefficient densityCoefficient([phase](const mfem::Vector &position) {
-      [phase](const mfem::Vector &position) {
+            return 0.17 * std::sin(0.9 * position(0) + phase) - 0.12 * std::cos(0.8 * position(1) - phase) +
-        return 0.17 * std::sin(0.9 * position(0) + phase) -
+                   0.07 * position(2);
-               0.12 * std::cos(0.8 * position(1) - phase) + 0.07 * position(2);
         });
 
         densityField.ProjectCoefficient(densityCoefficient);
@@ -127,22 +116,18 @@ make_layout(const mean_field::fem::FEM &f) {
         mfem::Vector densityTrue;
         densityField.GetTrueDofs(densityTrue);
         return densityTrue;
-}
+    }
 
-[[nodiscard]] mfem::Vector
+    [[nodiscard]] mfem::Vector make_displacement_direction(const mean_field::fem::FEM &f) {
-make_displacement_direction(const mean_field::fem::FEM &f) {
+        mfem::Vector direction    = gravity_prepared_test_utils::make_displacement(f, 0.91);
-  mfem::Vector direction =
-      gravity_prepared_test_utils::make_displacement(f, 0.91);
 
-  const mfem::Vector second =
+        const mfem::Vector second = gravity_prepared_test_utils::make_displacement(f, 0.27);
-      gravity_prepared_test_utils::make_displacement(f, 0.27);
 
         direction -= second;
         return direction;
-}
+    }
 
-[[nodiscard]] mean_field::physics::RigidRotation
+    [[nodiscard]] mean_field::physics::RigidRotation make_rotation(const double scale = 1.0) {
-make_rotation(const double scale = 1.0) {
         mfem::Vector angularVelocity(3);
         angularVelocity(0) = scale * 0.17;
         angularVelocity(1) = scale * -0.09;
@@ -154,19 +139,19 @@ make_rotation(const double scale = 1.0) {
         center(2) = 0.02;
 
         return mean_field::physics::RigidRotation(angularVelocity, center);
-}
+    }
 
-[[nodiscard]] mean_field::operators::context::rotational_displacement_force::
+    [[nodiscard]] mean_field::operators::context::rotational_displacement_force::RotationalDisplacementForceDependencies
-    RotationalDisplacementForceDependencies
     make_dependencies() {
-  return {.discretization = {.identity = 211, .revision = 3},
+        return {
+            .discretization = {.identity = 211, .revision = 3},
             .density        = {.identity = 223, .revision = 5},
             .displacement   = {.identity = 227, .revision = 7},
-          .rotation = {.identity = 229, .revision = 11}};
+            .rotation       = {.identity = 229, .revision = 11}
-}
+        };
+    }
 
-[[nodiscard]] mfem::Vector
+    [[nodiscard]] mfem::Vector make_vacuum_only_density(const mean_field::fem::FEM &f) {
-make_vacuum_only_density(const mean_field::fem::FEM &f) {
         mfem::ParGridFunction densityField(f.densityFes.get());
         densityField              = 0.0;
 
@@ -176,8 +161,7 @@ make_vacuum_only_density(const mean_field::fem::FEM &f) {
         int localVacuumElements = 0;
 
         for (int elementId = 0; elementId < f.mesh->GetNE(); ++elementId) {
-    mfem::ElementTransformation *transformation =
+            mfem::ElementTransformation *transformation = f.mesh->GetElementTransformation(elementId);
-        f.mesh->GetElementTransformation(elementId);
 
             REQUIRE(transformation != nullptr);
 
@@ -195,30 +179,32 @@ make_vacuum_only_density(const mean_field::fem::FEM &f) {
 
         int globalVacuumElements = 0;
 
-  MPI_Allreduce(&localVacuumElements, &globalVacuumElements, 1, MPI_INT,
+        MPI_Allreduce(&localVacuumElements, &globalVacuumElements, 1, MPI_INT, MPI_SUM, f.mesh->GetComm());
-                MPI_SUM, f.mesh->GetComm());
 
         REQUIRE(globalVacuumElements > 0);
 
         mfem::Vector densityTrue;
         densityField.GetTrueDofs(densityTrue);
         return densityTrue;
-}
+    }
 
-[[nodiscard]] double global_norm(const mfem::Vector &vector,
+    [[nodiscard]] double global_norm(
-                                 MPI_Comm communicator) {
+        const mfem::Vector &vector,
+        MPI_Comm communicator
+    ) {
         const double localSquaredNorm = vector * vector;
         double globalSquaredNorm      = 0.0;
 
-  MPI_Allreduce(&localSquaredNorm, &globalSquaredNorm, 1, MPI_DOUBLE, MPI_SUM,
+        MPI_Allreduce(&localSquaredNorm, &globalSquaredNorm, 1, MPI_DOUBLE, MPI_SUM, communicator);
-                communicator);
 
         return std::sqrt(globalSquaredNorm);
-}
+    }
 
-[[nodiscard]] double global_dot(const mfem::Vector &left,
+    [[nodiscard]] double global_dot(
+        const mfem::Vector &left,
         const mfem::Vector &right,
-                                MPI_Comm communicator) {
+        MPI_Comm communicator
+    ) {
         REQUIRE(left.Size() == right.Size());
 
         const double localDot = left * right;
@@ -227,27 +213,31 @@ make_vacuum_only_density(const mean_field::fem::FEM &f) {
         MPI_Allreduce(&localDot, &globalDot, 1, MPI_DOUBLE, MPI_SUM, communicator);
 
         return globalDot;
-}
+    }
 
-[[nodiscard]] double relative_difference(const mfem::Vector &computed,
+    [[nodiscard]] double relative_difference(
+        const mfem::Vector &computed,
         const mfem::Vector &reference,
-                                         MPI_Comm communicator) {
+        MPI_Comm communicator
+    ) {
         REQUIRE(computed.Size() == reference.Size());
 
         mfem::Vector difference(computed);
         difference -= reference;
 
         return global_norm(difference, communicator) /
-         std::max(global_norm(reference, communicator),
+               std::max(global_norm(reference, communicator), std::numeric_limits<double>::epsilon());
-                  std::numeric_limits<double>::epsilon());
+    }
-}
 
-[[nodiscard]] mfem::Vector centered_difference(
+    [[nodiscard]] mfem::Vector centered_difference(
         const mean_field::fem::FEM &f,
         const mean_field::physics::RigidRotation &rotation,
-    const mfem::Vector &baseDensity, const mfem::Vector &densityDirection,
+        const mfem::Vector &baseDensity,
+        const mfem::Vector &densityDirection,
         const mfem::Vector &baseDisplacement,
-    const mfem::Vector &displacementDirection, const double step) {
+        const mfem::Vector &displacementDirection,
+        const double step
+    ) {
         mfem::Vector plusDensity(baseDensity);
         plusDensity.Add(step, densityDirection);
 
@@ -264,23 +254,24 @@ make_vacuum_only_density(const mean_field::fem::FEM &f) {
         mfem::Vector minusResidual;
 
         mean_field::operators::kernels::apply_rotational_displacement_force_residual(
-      f, *f.domainMapperStateless, rotation, plusDensity, plusDisplacement,
+            f, *f.domainMapperStateless, rotation, plusDensity, plusDisplacement, plusResidual
-      plusResidual);
+        );
 
         mean_field::operators::kernels::apply_rotational_displacement_force_residual(
-      f, *f.domainMapperStateless, rotation, minusDensity, minusDisplacement,
+            f, *f.domainMapperStateless, rotation, minusDensity, minusDisplacement, minusResidual
-      minusResidual);
+        );
 
         plusResidual -= minusResidual;
         plusResidual /= 2.0 * step;
         return plusResidual;
-}
+    }
 
-template <int index>
+    template <int index>
-[[nodiscard]] mfem::Vector copy_residual_block(
+    [[nodiscard]] mfem::Vector copy_residual_block(
         const mfem::Vector &action,
         const mean_field::operators::RotationalDisplacementForceLayout &layout,
-    const mean_field::utils::blocks::residual_block<index> block) {
+        const mean_field::utils::blocks::residual_block<index> block
+    ) {
         mfem::Vector result(layout.size(block));
         const int offset = layout.offset(block);
 
@@ -289,24 +280,23 @@ template <int index>
         }
 
         return result;
-}
+    }
 } // namespace rotational_displacement_force_test_utils
 
 TEST_CASE(
     "Rotational Displacement Force Query Includes Density Test And Linear "
     "Position",
-    tags::rotation_prepared_unit) {
+    tags::rotation_prepared_unit
-  using DisplacementField =
+) {
-      mean_field::field::Field<mean_field::field::Displacement>;
+    using DisplacementField           = mean_field::field::Field<mean_field::field::Displacement>;
 
     constexpr int geometryWeightOrder = 4;
 
-  constexpr mean_field::quadrature::Query query = DisplacementField::make_query<
+    constexpr mean_field::quadrature::Query query =
-      mean_field::field::Displacement::Form::CentrifugalForce>(
+        DisplacementField::make_query<mean_field::field::Displacement::Form::CentrifugalForce>(
-      mean_field::quadrature::QuadratureRole::discretization,
+            mean_field::quadrature::QuadratureRole::discretization, geometryWeightOrder, std::array<int, 1>{1},
-      geometryWeightOrder, std::array<int, 1>{1},
+            mean_field::utils::DOMAINS::STELLAR, mean_field::quadrature::MappingKind::general
-      mean_field::utils::DOMAINS::STELLAR,
+        );
-      mean_field::quadrature::MappingKind::general);
 
     /* density: 2, displacement test: 3, position: 1, geometry: 4 */
     constexpr int expectedBaseOrder = 2 + 3 + 1 + 4;
@@ -318,33 +308,33 @@ TEST_CASE(
     STATIC_REQUIRE(*query.base_order == expectedBaseOrder);
 }
 
-TEST_CASE("Rotational Displacement Force Uses Negative Rotation-Potential "
+TEST_CASE(
+    "Rotational Displacement Force Uses Negative Rotation-Potential "
     "Gradient And Excludes Vacuum",
-          tags::rotation_kernel_accuracy) {
+    tags::rotation_kernel_accuracy
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
 
     REQUIRE(f.okay());
 
-  const mfem::Vector density =
+    const mfem::Vector density = rotational_displacement_force_test_utils::make_density(f, 0.31);
-      rotational_displacement_force_test_utils::make_density(f, 0.31);
 
     mfem::Vector displacement(f.displacementFes->GetTrueVSize());
     displacement                                      = 0.0;
 
-  const mean_field::physics::RigidRotation rotation =
+    const mean_field::physics::RigidRotation rotation = rotational_displacement_force_test_utils::make_rotation();
-      rotational_displacement_force_test_utils::make_rotation();
 
     mfem::Vector residual;
 
     mean_field::operators::kernels::apply_rotational_displacement_force_residual(
-      f, *f.domainMapperStateless, rotation, density, displacement, residual);
+        f, *f.domainMapperStateless, rotation, density, displacement, residual
+    );
 
     mfem::ParGridFunction gradientTestField(f.displacementFes.get());
 
-  auto gradientFunction = [&rotation](const mfem::Vector &position,
+    auto gradientFunction = [&rotation](const mfem::Vector &position, mfem::Vector &value) {
-                                      mfem::Vector &value) {
         rotation.potential_gradient(position, value);
     };
 
@@ -356,73 +346,63 @@ TEST_CASE("Rotational Displacement Force Uses Negative Rotation-Potential "
     gradientTestField.GetTrueDofs(gradientTestDirection);
 
     const double signedWork =
-      rotational_displacement_force_test_utils::global_dot(
+        rotational_displacement_force_test_utils::global_dot(residual, gradientTestDirection, f.mesh->GetComm());
-          residual, gradientTestDirection, f.mesh->GetComm());
 
     INFO("Rotation-force work against grad(Psi) = " << signedWork);
     CHECK(signedWork < 0.0);
 
-  const mfem::Vector vacuumDensity =
+    const mfem::Vector vacuumDensity = rotational_displacement_force_test_utils::make_vacuum_only_density(f);
-      rotational_displacement_force_test_utils::make_vacuum_only_density(f);
 
     mfem::Vector vacuumResidual;
 
     mean_field::operators::kernels::apply_rotational_displacement_force_residual(
-      f, *f.domainMapperStateless, rotation, vacuumDensity, displacement,
+        f, *f.domainMapperStateless, rotation, vacuumDensity, displacement, vacuumResidual
-      vacuumResidual);
+    );
 
-  CHECK(rotational_displacement_force_test_utils::global_norm(
+    CHECK(rotational_displacement_force_test_utils::global_norm(vacuumResidual, f.mesh->GetComm()) == 0.0);
-            vacuumResidual, f.mesh->GetComm()) == 0.0);
 
     mfem::Vector zeroAngularVelocity(3);
     mfem::Vector zeroCenter(3);
     zeroAngularVelocity = 0.0;
     zeroCenter          = 0.0;
 
-  const mean_field::physics::RigidRotation zeroRotation(zeroAngularVelocity,
+    const mean_field::physics::RigidRotation zeroRotation(zeroAngularVelocity, zeroCenter);
-                                                        zeroCenter);
 
     mfem::Vector zeroRotationResidual;
 
     mean_field::operators::kernels::apply_rotational_displacement_force_residual(
-      f, *f.domainMapperStateless, zeroRotation, density, displacement,
+        f, *f.domainMapperStateless, zeroRotation, density, displacement, zeroRotationResidual
-      zeroRotationResidual);
+    );
 
-  CHECK(rotational_displacement_force_test_utils::global_norm(
+    CHECK(rotational_displacement_force_test_utils::global_norm(zeroRotationResidual, f.mesh->GetComm()) == 0.0);
-            zeroRotationResidual, f.mesh->GetComm()) == 0.0);
 }
 
-TEST_CASE("Prepared Rotational Displacement Force Reprepares Selectively",
+TEST_CASE(
-          tags::rotation_prepared) {
+    "Prepared Rotational Displacement Force Reprepares Selectively",
+    tags::rotation_prepared
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
 
     REQUIRE(f.okay());
 
-  mfem::Vector densityTrue =
+    mfem::Vector densityTrue                    = rotational_displacement_force_test_utils::make_density(f, 0.37);
-      rotational_displacement_force_test_utils::make_density(f, 0.37);
 
-  const mfem::Vector displacementTrue =
+    const mfem::Vector displacementTrue         = gravity_prepared_test_utils::make_displacement(f, 0.53);
-      gravity_prepared_test_utils::make_displacement(f, 0.53);
 
-  mean_field::physics::RigidRotation rotation =
+    mean_field::physics::RigidRotation rotation = rotational_displacement_force_test_utils::make_rotation(0.81);
-      rotational_displacement_force_test_utils::make_rotation(0.81);
 
-  auto dependencies =
+    auto dependencies                           = rotational_displacement_force_test_utils::make_dependencies();
-      rotational_displacement_force_test_utils::make_dependencies();
 
-  mean_field::operators::PreparedRotationalDisplacementForceOperator
+    mean_field::operators::PreparedRotationalDisplacementForceOperator preparedOperator(f, *f.domainMapperStateless);
-      preparedOperator(f, *f.domainMapperStateless);
 
     const auto &context             = preparedOperator.GetContext();
     mfem::Vector density            = context.GetDensityMap().gather(densityTrue);
-  const mfem::Vector displacement =
+    const mfem::Vector displacement = context.GetDisplacementMap().gather(displacementTrue);
-      context.GetDisplacementMap().gather(displacementTrue);
 
-  const auto initialReport = preparedOperator.Prepare(
+    const auto initialReport =
-      {.density = density, .displacement = displacement}, dependencies,
+        preparedOperator.Prepare({.density = density, .displacement = displacement}, dependencies, rotation);
-      rotation);
 
     REQUIRE(initialReport.DidAnyWork());
     REQUIRE(initialReport.updatedRotation);
@@ -435,19 +415,18 @@ TEST_CASE("Prepared Rotational Displacement Force Reprepares Selectively",
     preparedOperator.BuildResidual(preparedResidual);
 
     mean_field::operators::kernels::apply_rotational_displacement_force_residual(
-      f, *f.domainMapperStateless, rotation, densityTrue, displacementTrue,
+        f, *f.domainMapperStateless, rotation, densityTrue, displacementTrue, kernelResidual
-      kernelResidual);
+    );
 
-  const mfem::Vector kernelResidualReduced =
+    const mfem::Vector kernelResidualReduced = context.GetDisplacementMap().gather(kernelResidual);
-      context.GetDisplacementMap().gather(kernelResidual);
 
-  CHECK(rotational_displacement_force_test_utils::relative_difference(
+    CHECK(
-            preparedResidual, kernelResidualReduced, f.mesh->GetComm()) <
+        rotational_displacement_force_test_utils::relative_difference(
-        2.0e-12);
+            preparedResidual, kernelResidualReduced, f.mesh->GetComm()
+        ) < 2.0e-12
+    );
 
-  CHECK_FALSE(preparedOperator
+    CHECK_FALSE(preparedOperator.Prepare({.density = density, .displacement = displacement}, dependencies, rotation)
-                  .Prepare({.density = density, .displacement = displacement},
-                           dependencies, rotation)
                     .DidAnyWork());
 
     densityTrue = rotational_displacement_force_test_utils::make_density(f, 0.79);
@@ -455,9 +434,8 @@ TEST_CASE("Prepared Rotational Displacement Force Reprepares Selectively",
 
     ++dependencies.density.revision;
 
-  const auto densityReport = preparedOperator.Prepare(
+    const auto densityReport =
-      {.density = density, .displacement = displacement}, dependencies,
+        preparedOperator.Prepare({.density = density, .displacement = displacement}, dependencies, rotation);
-      rotation);
 
     CHECK(densityReport.preparedResidual);
     CHECK_FALSE(densityReport.updatedRotation);
@@ -466,9 +444,8 @@ TEST_CASE("Prepared Rotational Displacement Force Reprepares Selectively",
 
     ++dependencies.rotation.revision;
 
-  const auto rotationReport = preparedOperator.Prepare(
+    const auto rotationReport =
-      {.density = density, .displacement = displacement}, dependencies,
+        preparedOperator.Prepare({.density = density, .displacement = displacement}, dependencies, rotation);
-      rotation);
 
     CHECK(rotationReport.updatedRotation);
     CHECK(rotationReport.preparedResidual);
@@ -476,45 +453,40 @@ TEST_CASE("Prepared Rotational Displacement Force Reprepares Selectively",
     CHECK(preparedOperator.GetResidualApplicationCount() == 1);
 }
 
-TEST_CASE("Rotational Displacement Force Jacobian Matches Both Columns And "
+TEST_CASE(
+    "Rotational Displacement Force Jacobian Matches Both Columns And "
     "Centered Differences",
-          tags::rotation_prepared_jacobian_accuracy) {
+    tags::rotation_prepared_jacobian_accuracy
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
 
     REQUIRE(f.okay());
 
-  const mfem::Vector densityTrue =
+    const mfem::Vector densityTrue          = rotational_displacement_force_test_utils::make_density(f, 0.43);
-      rotational_displacement_force_test_utils::make_density(f, 0.43);
 
-  const mfem::Vector densityDirectionTrue =
+    const mfem::Vector densityDirectionTrue = rotational_displacement_force_test_utils::make_density_direction(f, 0.59);
-      rotational_displacement_force_test_utils::make_density_direction(f, 0.59);
 
-  const mfem::Vector displacementTrue =
+    const mfem::Vector displacementTrue     = gravity_prepared_test_utils::make_displacement(f, 0.61);
-      gravity_prepared_test_utils::make_displacement(f, 0.61);
 
     const mfem::Vector displacementDirectionTrue =
         rotational_displacement_force_test_utils::make_displacement_direction(f);
 
-  const mean_field::physics::RigidRotation rotation =
+    const mean_field::physics::RigidRotation rotation = rotational_displacement_force_test_utils::make_rotation(0.93);
-      rotational_displacement_force_test_utils::make_rotation(0.93);
 
-  mean_field::operators::PreparedRotationalDisplacementForceOperator
+    mean_field::operators::PreparedRotationalDisplacementForceOperator preparedOperator(f, *f.domainMapperStateless);
-      preparedOperator(f, *f.domainMapperStateless);
 
     const auto &context                      = preparedOperator.GetContext();
     const mfem::Vector density               = context.GetDensityMap().gather(densityTrue);
-  const mfem::Vector densityDirection =
+    const mfem::Vector densityDirection      = context.GetDensityMap().gather(densityDirectionTrue);
-      context.GetDensityMap().gather(densityDirectionTrue);
+    const mfem::Vector displacement          = context.GetDisplacementMap().gather(displacementTrue);
-  const mfem::Vector displacement =
+    const mfem::Vector displacementDirection = context.GetDisplacementMap().gather(displacementDirectionTrue);
-      context.GetDisplacementMap().gather(displacementTrue);
-  const mfem::Vector displacementDirection =
-      context.GetDisplacementMap().gather(displacementDirectionTrue);
 
     preparedOperator.Prepare(
         {.density = density, .displacement = displacement},
-      rotational_displacement_force_test_utils::make_dependencies(), rotation);
+        rotational_displacement_force_test_utils::make_dependencies(), rotation
+    );
 
     mfem::Vector densityAction;
     mfem::Vector displacementAction;
@@ -522,17 +494,18 @@ TEST_CASE("Rotational Displacement Force Jacobian Matches Both Columns And "
 
     preparedOperator.ApplyDensityJacobianAction(densityDirection, densityAction);
 
-  preparedOperator.ApplyDisplacementJacobianAction(displacementDirection,
+    preparedOperator.ApplyDisplacementJacobianAction(displacementDirection, displacementAction);
-                                                   displacementAction);
 
-  preparedOperator.ApplyCompleteJacobianAction(
+    preparedOperator.ApplyCompleteJacobianAction(densityDirection, displacementDirection, completeAction);
-      densityDirection, displacementDirection, completeAction);
 
     mfem::Vector summedColumns(densityAction);
     summedColumns += displacementAction;
 
-  CHECK(rotational_displacement_force_test_utils::relative_difference(
+    CHECK(
-            completeAction, summedColumns, f.mesh->GetComm()) < 2.0e-12);
+        rotational_displacement_force_test_utils::relative_difference(
+            completeAction, summedColumns, f.mesh->GetComm()
+        ) < 2.0e-12
+    );
 
     mfem::Vector zeroDensityTrue(densityDirectionTrue.Size());
     mfem::Vector zeroDisplacementTrue(displacementDirectionTrue.Size());
@@ -541,39 +514,33 @@ TEST_CASE("Rotational Displacement Force Jacobian Matches Both Columns And "
 
     constexpr double step                    = 1.0e-5;
 
-  const mfem::Vector densityDifferenceTrue =
+    const mfem::Vector densityDifferenceTrue = rotational_displacement_force_test_utils::centered_difference(
-      rotational_displacement_force_test_utils::centered_difference(
+        f, rotation, densityTrue, densityDirectionTrue, displacementTrue, zeroDisplacementTrue, step
-          f, rotation, densityTrue, densityDirectionTrue, displacementTrue,
+    );
-          zeroDisplacementTrue, step);
 
-  const mfem::Vector displacementDifferenceTrue =
+    const mfem::Vector displacementDifferenceTrue = rotational_displacement_force_test_utils::centered_difference(
-      rotational_displacement_force_test_utils::centered_difference(
+        f, rotation, densityTrue, zeroDensityTrue, displacementTrue, displacementDirectionTrue, step
-          f, rotation, densityTrue, zeroDensityTrue, displacementTrue,
+    );
-          displacementDirectionTrue, step);
 
-  const mfem::Vector completeDifferenceTrue =
+    const mfem::Vector completeDifferenceTrue = rotational_displacement_force_test_utils::centered_difference(
-      rotational_displacement_force_test_utils::centered_difference(
+        f, rotation, densityTrue, densityDirectionTrue, displacementTrue, displacementDirectionTrue, step
-          f, rotation, densityTrue, densityDirectionTrue, displacementTrue,
+    );
-          displacementDirectionTrue, step);
 
-  const mfem::Vector densityDifference =
+    const mfem::Vector densityDifference      = context.GetDisplacementMap().gather(densityDifferenceTrue);
-      context.GetDisplacementMap().gather(densityDifferenceTrue);
+    const mfem::Vector displacementDifference = context.GetDisplacementMap().gather(displacementDifferenceTrue);
-  const mfem::Vector displacementDifference =
+    const mfem::Vector completeDifference     = context.GetDisplacementMap().gather(completeDifferenceTrue);
-      context.GetDisplacementMap().gather(displacementDifferenceTrue);
-  const mfem::Vector completeDifference =
-      context.GetDisplacementMap().gather(completeDifferenceTrue);
 
-  const double densityError =
+    const double densityError                 = rotational_displacement_force_test_utils::relative_difference(
-      rotational_displacement_force_test_utils::relative_difference(
+        densityAction, densityDifference, f.mesh->GetComm()
-          densityAction, densityDifference, f.mesh->GetComm());
+    );
 
-  const double displacementError =
+    const double displacementError = rotational_displacement_force_test_utils::relative_difference(
-      rotational_displacement_force_test_utils::relative_difference(
+        displacementAction, displacementDifference, f.mesh->GetComm()
-          displacementAction, displacementDifference, f.mesh->GetComm());
+    );
 
-  const double completeError =
+    const double completeError = rotational_displacement_force_test_utils::relative_difference(
-      rotational_displacement_force_test_utils::relative_difference(
+        completeAction, completeDifference, f.mesh->GetComm()
-          completeAction, completeDifference, f.mesh->GetComm());
+    );
 
     INFO("Density-column centered-difference error = " << densityError);
     INFO("Displacement-column centered-difference error = " << displacementError);
@@ -584,109 +551,95 @@ TEST_CASE("Rotational Displacement Force Jacobian Matches Both Columns And "
     CHECK(completeError < 4.0e-8);
 }
 
-TEST_CASE("Prepared Rotational Displacement Force MFEM Adapter Routes Only R-d",
+TEST_CASE(
-          tags::rotation_prepared_unit) {
+    "Prepared Rotational Displacement Force MFEM Adapter Routes Only R-d",
+    tags::rotation_prepared_unit
+) {
     mean_field::utils::Args args = test_utils::setup_args();
 
     mean_field::fem::FEM f       = mean_field::fem::setup_fem(args.mesh_file, args, 0);
 
     REQUIRE(f.okay());
 
-  const mfem::Vector densityTrue =
+    const mfem::Vector densityTrue          = rotational_displacement_force_test_utils::make_density(f, 0.47);
-      rotational_displacement_force_test_utils::make_density(f, 0.47);
 
-  const mfem::Vector densityDirectionTrue =
+    const mfem::Vector densityDirectionTrue = rotational_displacement_force_test_utils::make_density_direction(f, 0.63);
-      rotational_displacement_force_test_utils::make_density_direction(f, 0.63);
 
-  const mfem::Vector displacementTrue =
+    const mfem::Vector displacementTrue     = gravity_prepared_test_utils::make_displacement(f, 0.57);
-      gravity_prepared_test_utils::make_displacement(f, 0.57);
 
     const mfem::Vector displacementDirectionTrue =
         rotational_displacement_force_test_utils::make_displacement_direction(f);
 
-  const mean_field::physics::RigidRotation rotation =
+    const mean_field::physics::RigidRotation rotation = rotational_displacement_force_test_utils::make_rotation(0.87);
-      rotational_displacement_force_test_utils::make_rotation(0.87);
 
-  mean_field::operators::PreparedRotationalDisplacementForceOperator
+    mean_field::operators::PreparedRotationalDisplacementForceOperator preparedOperator(f, *f.domainMapperStateless);
-      preparedOperator(f, *f.domainMapperStateless);
 
     const auto &context                      = preparedOperator.GetContext();
     const mfem::Vector density               = context.GetDensityMap().gather(densityTrue);
-  const mfem::Vector densityDirection =
+    const mfem::Vector densityDirection      = context.GetDensityMap().gather(densityDirectionTrue);
-      context.GetDensityMap().gather(densityDirectionTrue);
+    const mfem::Vector displacement          = context.GetDisplacementMap().gather(displacementTrue);
-  const mfem::Vector displacement =
+    const mfem::Vector displacementDirection = context.GetDisplacementMap().gather(displacementDirectionTrue);
-      context.GetDisplacementMap().gather(displacementTrue);
-  const mfem::Vector displacementDirection =
-      context.GetDisplacementMap().gather(displacementDirectionTrue);
 
     preparedOperator.Prepare(
         {.density = density, .displacement = displacement},
-      rotational_displacement_force_test_utils::make_dependencies(), rotation);
+        rotational_displacement_force_test_utils::make_dependencies(), rotation
+    );
 
     const auto layout = rotational_displacement_force_test_utils::make_layout(f);
 
-  mean_field::operators::PreparedRotationalDisplacementForceJacobianOperator
+    mean_field::operators::PreparedRotationalDisplacementForceJacobianOperator adapter(layout, preparedOperator);
-      adapter(layout, preparedOperator);
 
     mfem::BlockVector direction(layout.value_offsets());
     direction                                                                             = 0.0;
 
-  direction.GetBlock(rotational_displacement_force_test_utils::densityValue) =
+    direction.GetBlock(rotational_displacement_force_test_utils::densityValue)            = densityDirection;
-      densityDirection;
 
-  direction.GetBlock(
+    direction.GetBlock(rotational_displacement_force_test_utils::displacementValue)       = displacementDirection;
-      rotational_displacement_force_test_utils::displacementValue) =
-      displacementDirection;
 
-  direction.GetBlock(
+    direction.GetBlock(rotational_displacement_force_test_utils::gravityGradientValue)    = 0.23;
-      rotational_displacement_force_test_utils::gravityGradientValue) = 0.23;
 
-  direction.GetBlock(
+    direction.GetBlock(rotational_displacement_force_test_utils::gravityPotentialValue)   = -0.31;
-      rotational_displacement_force_test_utils::gravityPotentialValue) = -0.31;
 
-  direction.GetBlock(rotational_displacement_force_test_utils::enthalpyValue) =
+    direction.GetBlock(rotational_displacement_force_test_utils::enthalpyValue)           = 0.37;
-      0.37;
 
-  direction.GetBlock(
+    direction.GetBlock(rotational_displacement_force_test_utils::barotropicConstantValue) = -0.41;
-      rotational_displacement_force_test_utils::barotropicConstantValue) =
-      -0.41;
 
     mfem::Vector action;
     adapter.Mult(direction, action);
 
     mfem::Vector expectedDisplacementAction;
 
-  preparedOperator.ApplyCompleteJacobianAction(
+    preparedOperator.ApplyCompleteJacobianAction(densityDirection, displacementDirection, expectedDisplacementAction);
-      densityDirection, displacementDirection, expectedDisplacementAction);
 
-  const mfem::Vector actualDisplacementAction =
+    const mfem::Vector actualDisplacementAction = rotational_displacement_force_test_utils::copy_residual_block(
-      rotational_displacement_force_test_utils::copy_residual_block(
+        action, layout, rotational_displacement_force_test_utils::displacementResidual
-          action, layout,
+    );
-          rotational_displacement_force_test_utils::displacementResidual);
 
-  CHECK(rotational_displacement_force_test_utils::relative_difference(
+    CHECK(
-            actualDisplacementAction, expectedDisplacementAction,
+        rotational_displacement_force_test_utils::relative_difference(
-            f.mesh->GetComm()) < 2.0e-12);
+            actualDisplacementAction, expectedDisplacementAction, f.mesh->GetComm()
+        ) < 2.0e-12
+    );
 
     const std::array<mfem::Vector, 5> zeroRows{
         rotational_displacement_force_test_utils::copy_residual_block(
-          action, layout,
+            action, layout, rotational_displacement_force_test_utils::gravityGradientResidual
-          rotational_displacement_force_test_utils::gravityGradientResidual),
+        ),
         rotational_displacement_force_test_utils::copy_residual_block(
-          action, layout,
+            action, layout, rotational_displacement_force_test_utils::gravityPotentialResidual
-          rotational_displacement_force_test_utils::gravityPotentialResidual),
+        ),
         rotational_displacement_force_test_utils::copy_residual_block(
-          action, layout,
+            action, layout, rotational_displacement_force_test_utils::densityResidual
-          rotational_displacement_force_test_utils::densityResidual),
+        ),
         rotational_displacement_force_test_utils::copy_residual_block(
-          action, layout,
+            action, layout, rotational_displacement_force_test_utils::enthalpyResidual
-          rotational_displacement_force_test_utils::enthalpyResidual),
+        ),
         rotational_displacement_force_test_utils::copy_residual_block(
-          action, layout,
+            action, layout, rotational_displacement_force_test_utils::massResidual
-          rotational_displacement_force_test_utils::massResidual)};
+        )
+    };
 
     for (const mfem::Vector &row : zeroRows) {
-    CHECK(rotational_displacement_force_test_utils::global_norm(
+        CHECK(rotational_displacement_force_test_utils::global_norm(row, f.mesh->GetComm()) == 0.0);
-              row, f.mesh->GetComm()) == 0.0);
     }
 }

tests/physics/barotrope.cpp

@@ -8,115 +8,202 @@
 import mean_field;
 import test_helpers;
 
-TEST_CASE("Polytropic EOS Satisfies Its Analytic Identities",
+TEST_CASE(
-          tags::barotrope_eos_unit) {
+    "Polytropic EOS Satisfies Its Analytic Identities",
+    tags::barotrope_eos_unit
+) {
+    using namespace mean_field::eos;
+
     constexpr double polytropic_index    = 3.0;
     constexpr double polytropic_constant = 1.5;
 
-  const mean_field::eos::Polytrope barotrope(polytropic_index,
+    const Polytrope barotrope(polytropic_index, polytropic_constant);
-                                             polytropic_constant);
 
-  const std::array<double, 5> densities{1.0e-6, 1.0e-3, 0.1, 0.7, 2.0};
+    using densityV  = DensityValue;
+    using pressureV = PressureValue;
+    using enthalpyV = SpecificEnthalpyValue;
 
-  for (const double density : densities) {
+    constexpr std::array<densityV, 5> densities{
-    const double pressure = barotrope.pressure_from_density(density);
+        densityV{1.0e-6}, densityV{1.0e-3}, densityV{0.1}, densityV{0.7}, densityV{2.0}
+    };
 
-    const double enthalpy = barotrope.enthalpy_from_density(density);
+    for (const densityV density : densities) {
+        const pressureV pressure               = evaluate<quantity::Pressure>(barotrope, density);
 
-    const double reconstructed_density =
+        const enthalpyV enthalpy               = evaluate<quantity::SpecificEnthalpy>(barotrope, density);
-        barotrope.density_from_enthalpy(enthalpy);
+        const densityV reconstructed_density   = evaluate<quantity::Density>(barotrope, enthalpy);
 
-    const double reconstructed_pressure =
+        const pressureV reconstructed_pressure = evaluate<quantity::Pressure>(barotrope, enthalpy);
-        barotrope.pressure_from_enthalpy(enthalpy);
 
-    const double reconstructed_enthalpy =
+        const enthalpyV reconstructed_enthalpy = evaluate<quantity::SpecificEnthalpy>(barotrope, pressure);
-        barotrope.enthalpy_from_pressure(pressure);
 
-    CHECK_THAT(reconstructed_density,
+        CHECK_THAT(reconstructed_density.value(), Catch::Matchers::WithinRel(density.value(), 2.0e-14));
-               Catch::Matchers::WithinRel(density, 2.0e-14));
 
-    CHECK_THAT(reconstructed_pressure,
+        CHECK_THAT(reconstructed_pressure.value(), Catch::Matchers::WithinRel(pressure.value(), 2.0e-14));
-               Catch::Matchers::WithinRel(pressure, 2.0e-14));
 
-    CHECK_THAT(reconstructed_enthalpy,
+        CHECK_THAT(reconstructed_enthalpy.value(), Catch::Matchers::WithinRel(enthalpy.value(), 2.0e-14));
-               Catch::Matchers::WithinRel(enthalpy, 2.0e-14));
-
-    CHECK_THAT(pressure,
-               Catch::Matchers::WithinRel(
-                   density * enthalpy / (polytropic_index + 1.0), 2.0e-14));
-
-    CHECK_THAT(barotrope.pressure_derivative_from_enthalpy(enthalpy),
-               Catch::Matchers::WithinRel(density, 2.0e-14));
 
         CHECK_THAT(
-        barotrope.pressure_derivative_from_density(density),
+            pressure.value(),
-        Catch::Matchers::WithinRel(enthalpy / polytropic_index, 2.0e-14));
+            Catch::Matchers::WithinRel(density.value() * enthalpy.value() / (polytropic_index + 1.0), 2.0e-14)
+        );
+
+        CHECK_THAT(
+            (mean_field::eos::partialDerivative<
+                 mean_field::eos::quantity::Pressure, mean_field::eos::quantity::SpecificEnthalpy>(
+                 barotrope, mean_field::eos::SpecificEnthalpyValue{enthalpy}
+            )
+                 .value()),
+            Catch::Matchers::WithinRel(density.value(), 2.0e-14)
+        );
+
+        CHECK_THAT(
+            (mean_field::eos::partialDerivative<
+                 mean_field::eos::quantity::Pressure, mean_field::eos::quantity::Density>(
+                 barotrope, mean_field::eos::DensityValue{density}
+            )
+                 .value()),
+            Catch::Matchers::WithinRel(enthalpy.value() / polytropic_index, 2.0e-14)
+        );
     }
 }
 
-TEST_CASE("Polytropic EOS Derivatives Match Centered Differences",
+TEST_CASE(
-          tags::barotrope_eos_jacobian) {
+    "Polytropic EOS Derivatives Match Centered Differences",
-  const mean_field::eos::Polytrope barotrope(3.0, 1.5);
+    tags::barotrope_eos_jacobian
+) {
+    using namespace mean_field::eos;
 
-  const std::array<double, 4> enthalpies{0.05, 0.2, 0.7, 1.4};
+    const Polytrope barotrope(3.0, 1.5);
 
-  for (const double enthalpy : enthalpies) {
+    using densityV  = DensityValue;
-    const double step = 1.0e-6 * std::max(1.0, enthalpy);
+    using pressureV = PressureValue;
+    using enthalpyV = SpecificEnthalpyValue;
 
-    const double density_difference =
+    constexpr std::array<enthalpyV, 4> enthalpies{enthalpyV{0.05}, enthalpyV{0.2}, enthalpyV{0.7}, enthalpyV{1.4}};
-        (barotrope.density_from_enthalpy(enthalpy + step) -
-         barotrope.density_from_enthalpy(enthalpy - step)) /
-        (2.0 * step);
 
-    const double pressure_difference =
+    for (const enthalpyV enthalpy : enthalpies) {
-        (barotrope.pressure_from_enthalpy(enthalpy + step) -
+        const enthalpyV step                = enthalpyV{1.0e-6} * std::max(1.0, enthalpy.value());
-         barotrope.pressure_from_enthalpy(enthalpy - step)) /
+
-        (2.0 * step);
+        const densityV density_difference   = (evaluate<quantity::Density>(barotrope, enthalpy + step) -
+                                               evaluate<quantity::Density>(barotrope, enthalpy - step)) /
+                                              (2.0 * step.value());
+
+        const pressureV pressure_difference = (evaluate<quantity::Pressure>(barotrope, enthalpy + step) -
+                                               evaluate<quantity::Pressure>(barotrope, enthalpy - step)) /
+                                              (2.0 * step.value());
 
         CHECK_THAT(
-        density_difference,
+            density_difference.value(),
             Catch::Matchers::WithinRel(
-            barotrope.density_derivative_from_enthalpy(enthalpy), 5.0e-10));
+                mean_field::eos::partialDerivative<
+                    mean_field::eos::quantity::Density, mean_field::eos::quantity::SpecificEnthalpy>(
+                    barotrope, enthalpy
+                )
+                    .value(),
+                5.0e-10
+            )
+        );
 
         CHECK_THAT(
-        pressure_difference,
+            pressure_difference.value(),
             Catch::Matchers::WithinRel(
-            barotrope.pressure_derivative_from_enthalpy(enthalpy), 5.0e-10));
+                mean_field::eos::partialDerivative<
+                    mean_field::eos::quantity::Pressure, mean_field::eos::quantity::SpecificEnthalpy>(
+                    barotrope, enthalpy
+                )
+                    .value(),
+                5.0e-10
+            )
+        );
     }
 }
 
-TEST_CASE("Polytropic EOS Has An Exact Zero Density Surface",
+TEST_CASE(
-          tags::barotrope_eos_unit) {
+    "Polytropic EOS Has An Exact Zero Density Surface",
+    tags::barotrope_eos_unit
+) {
     const mean_field::eos::Polytrope barotrope(3.0, 1.5);
 
-  CHECK(barotrope.density_from_enthalpy(-1.0) == 0.0);
+    CHECK(
-  CHECK(barotrope.density_from_enthalpy(0.0) == 0.0);
+        mean_field::eos::evaluate<mean_field::eos::quantity::Density>(
+            barotrope, mean_field::eos::SpecificEnthalpyValue{-1.0}
+        )
+            .value() == 0.0
+    );
+    CHECK(
+        mean_field::eos::evaluate<mean_field::eos::quantity::Density>(
+            barotrope, mean_field::eos::SpecificEnthalpyValue{0.0}
+        )
+            .value() == 0.0
+    );
 
-  CHECK(barotrope.pressure_from_enthalpy(-1.0) == 0.0);
+    CHECK(
-  CHECK(barotrope.pressure_from_enthalpy(0.0) == 0.0);
+        mean_field::eos::evaluate<mean_field::eos::quantity::Pressure>(
+            barotrope, mean_field::eos::SpecificEnthalpyValue{-1.0}
+        )
+            .value() == 0.0
+    );
+    CHECK(
+        mean_field::eos::evaluate<mean_field::eos::quantity::Pressure>(
+            barotrope, mean_field::eos::SpecificEnthalpyValue{0.0}
+        )
+            .value() == 0.0
+    );
 
-  CHECK(barotrope.density_derivative_from_enthalpy(-1.0) == 0.0);
+    CHECK(
+        (mean_field::eos::partialDerivative<
+             mean_field::eos::quantity::Density, mean_field::eos::quantity::SpecificEnthalpy>(
+             barotrope, mean_field::eos::SpecificEnthalpyValue{-1.0}
+         )
+             .value() == 0.0)
+    );
 
-  CHECK(barotrope.density_derivative_from_enthalpy(0.0) == 0.0);
+    CHECK(
+        (mean_field::eos::partialDerivative<
+             mean_field::eos::quantity::Density, mean_field::eos::quantity::SpecificEnthalpy>(
+             barotrope, mean_field::eos::SpecificEnthalpyValue{0.0}
+         )
+             .value() == 0.0)
+    );
 
-  CHECK(barotrope.pressure_derivative_from_enthalpy(0.0) == 0.0);
+    CHECK(
+        (mean_field::eos::partialDerivative<
+             mean_field::eos::quantity::Pressure, mean_field::eos::quantity::SpecificEnthalpy>(
+             barotrope, mean_field::eos::SpecificEnthalpyValue{0.0}
+         )
+             .value() == 0.0)
+    );
 }
 
-TEST_CASE("Polytropic EOS Rejects Invalid Material Parameters",
+TEST_CASE(
-          tags::barotrope_eos_unit) {
+    "Polytropic EOS Rejects Invalid Material Parameters",
+    tags::barotrope_eos_unit
+) {
     CHECK_THROWS_AS(mean_field::eos::Polytrope(0.5, 1.0), std::invalid_argument);
 
     CHECK_THROWS_AS(mean_field::eos::Polytrope(3.0, 0.0), std::invalid_argument);
 
-  CHECK_THROWS_AS(
+    CHECK_THROWS_AS(mean_field::eos::Polytrope(std::numeric_limits<double>::infinity(), 1.0), std::invalid_argument);
-      mean_field::eos::Polytrope(std::numeric_limits<double>::infinity(), 1.0),
-      std::invalid_argument);
 
     const mean_field::eos::Polytrope barotrope(3.0, 1.0);
 
-  CHECK_THROWS_AS(barotrope.pressure_from_density(-1.0), std::domain_error);
+    CHECK_THROWS_AS(
+        mean_field::eos::evaluate<mean_field::eos::quantity::Pressure>(barotrope, mean_field::eos::DensityValue{-1.0}),
+        std::domain_error
+    );
 
-  CHECK_THROWS_AS(barotrope.enthalpy_from_density(-1.0), std::domain_error);
+    CHECK_THROWS_AS(
+        mean_field::eos::evaluate<mean_field::eos::quantity::SpecificEnthalpy>(
+            barotrope, mean_field::eos::DensityValue{-1.0}
+        ),
+        std::domain_error
+    );
 
-  CHECK_THROWS_AS(barotrope.enthalpy_from_pressure(-1.0), std::domain_error);
+    CHECK_THROWS_AS(
+        mean_field::eos::evaluate<mean_field::eos::quantity::SpecificEnthalpy>(
+            barotrope, mean_field::eos::PressureValue{-1.0}
+        ),
+        std::domain_error
+    );
 }

tests/physics/barotrope_pressure.cpp

@@ -13,32 +13,39 @@
 import mean_field;
 import test_helpers;
 
-namespace polytropic_eos_test_utils {
+namespace eos = mean_field::eos;
-template <typename Function>
-double centered_derivative(Function &&function, const double position,
-                           const double step) {
-  return (function(position + step) - function(position - step)) / (2.0 * step);
-}
 
-template <typename Integrand>
+namespace polytropic_eos_test_utils {
-double integrate_cube(const mfem::IntegrationRule &integrationRule,
+    template <typename Function>
-                      Integrand &&integrand) {
+    double centered_derivative(
+        Function &&function,
+        const double position,
+        const double step
+    ) {
+        return (function(position + step) - function(position - step)) / (2.0 * step);
+    }
+
+    template <typename Integrand>
+    double integrate_cube(
+        const mfem::IntegrationRule &integrationRule,
+        Integrand &&integrand
+    ) {
         double integral = 0.0;
 
-  for (int pointIndex = 0; pointIndex < integrationRule.GetNPoints();
+        for (int pointIndex = 0; pointIndex < integrationRule.GetNPoints(); ++pointIndex) {
-       ++pointIndex) {
+            const mfem::IntegrationPoint &integrationPoint = integrationRule.IntPoint(pointIndex);
-    const mfem::IntegrationPoint &integrationPoint =
-        integrationRule.IntPoint(pointIndex);
 
             integral += integrationPoint.weight * integrand(integrationPoint);
         }
 
         return integral;
-}
+    }
 } // namespace polytropic_eos_test_utils
 
-TEST_CASE("Polytropic EOS Satisfies Its Thermodynamic Identities",
+TEST_CASE(
-          tags::barotrope_eos_unit) {
+    "Polytropic EOS Satisfies Its Thermodynamic Identities",
+    tags::barotrope_eos_unit
+) {
     constexpr std::array<double, 3> polytropicIndices{1.0, 1.5, 3.0};
 
     constexpr std::array<double, 4> densities{1.0e-4, 0.02, 0.37, 2.4};
@@ -47,11 +54,9 @@ TEST_CASE("Polytropic EOS Satisfies Its Thermodynamic Identities",
 
     for (const double polytropicIndex : polytropicIndices) {
         DYNAMIC_SECTION("polytropic index n = " << polytropicIndex) {
-      const mean_field::eos::Polytrope barotrope(polytropicIndex,
+            const mean_field::eos::Polytrope barotrope(polytropicIndex, polytropicConstant);
-                                                 polytropicConstant);
 
-      const double expectedEnthalpyScale =
+            const double expectedEnthalpyScale = (polytropicIndex + 1.0) * polytropicConstant;
-          (polytropicIndex + 1.0) * polytropicConstant;
 
             CHECK(barotrope.polytropic_index() == polytropicIndex);
 
@@ -62,45 +67,41 @@ TEST_CASE("Polytropic EOS Satisfies Its Thermodynamic Identities",
             for (const double density : densities) {
                 CAPTURE(polytropicIndex, polytropicConstant, density);
 
-        const double expectedPressure =
+                const double expectedPressure = polytropicConstant * std::pow(density, 1.0 + 1.0 / polytropicIndex);
-            polytropicConstant * std::pow(density, 1.0 + 1.0 / polytropicIndex);
 
-        const double expectedEnthalpy =
+                const double expectedEnthalpy = expectedEnthalpyScale * std::pow(density, 1.0 / polytropicIndex);
-            expectedEnthalpyScale * std::pow(density, 1.0 / polytropicIndex);
 
                 const double pressureFromDensity =
-            barotrope.pressure_from_density(density);
+                    eos::evaluate<eos::quantity::Pressure>(barotrope, eos::DensityValue{density}).value();
 
                 const double enthalpyFromDensity =
-            barotrope.enthalpy_from_density(density);
+                    eos::evaluate<eos::quantity::SpecificEnthalpy>(barotrope, eos::DensityValue{density}).value();
 
                 const double recoveredDensity =
-            barotrope.density_from_enthalpy(enthalpyFromDensity);
+                    eos::evaluate<eos::quantity::Density>(barotrope, eos::SpecificEnthalpyValue{enthalpyFromDensity})
+                        .value();
 
                 const double pressureFromEnthalpy =
-            barotrope.pressure_from_enthalpy(enthalpyFromDensity);
+                    eos::evaluate<eos::quantity::Pressure>(barotrope, eos::SpecificEnthalpyValue{enthalpyFromDensity})
+                        .value();
 
-        CHECK_THAT(pressureFromDensity,
+                CHECK_THAT(pressureFromDensity, Catch::Matchers::WithinRel(expectedPressure, 2.0e-13));
-                   Catch::Matchers::WithinRel(expectedPressure, 2.0e-13));
 
-        CHECK_THAT(enthalpyFromDensity,
+                CHECK_THAT(enthalpyFromDensity, Catch::Matchers::WithinRel(expectedEnthalpy, 2.0e-13));
-                   Catch::Matchers::WithinRel(expectedEnthalpy, 2.0e-13));
 
-        CHECK_THAT(recoveredDensity,
+                CHECK_THAT(recoveredDensity, Catch::Matchers::WithinRel(density, 5.0e-13));
-                   Catch::Matchers::WithinRel(density, 5.0e-13));
 
-        CHECK_THAT(pressureFromEnthalpy,
+                CHECK_THAT(pressureFromEnthalpy, Catch::Matchers::WithinRel(expectedPressure, 5.0e-13));
-                   Catch::Matchers::WithinRel(expectedPressure, 5.0e-13));
 
                 /*
                  * Polytropic identity:
                  *
                  *     P = rho h / (n + 1).
                  */
-        CHECK_THAT(pressureFromEnthalpy,
+                CHECK_THAT(
-                   Catch::Matchers::WithinRel(density * enthalpyFromDensity /
+                    pressureFromEnthalpy,
-                                                  (polytropicIndex + 1.0),
+                    Catch::Matchers::WithinRel(density * enthalpyFromDensity / (polytropicIndex + 1.0), 5.0e-13)
-                                              5.0e-13));
+                );
 
                 /*
                  * Polytropic identity:
@@ -108,11 +109,14 @@ TEST_CASE("Polytropic EOS Satisfies Its Thermodynamic Identities",
                  *     dP / dh = rho.
                  *
                  * The implementation should return the same
-         * value as density_from_enthalpy().
+                 * value as the density from specific enthalpy relation.
                  */
                 CHECK(
-            barotrope.pressure_derivative_from_enthalpy(enthalpyFromDensity) ==
+                    (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>(
-            barotrope.density_from_enthalpy(enthalpyFromDensity));
+                         barotrope, eos::SpecificEnthalpyValue{enthalpyFromDensity}
+                     )
+                         .value() == recoveredDensity)
+                );
 
                 /*
                  * Since
@@ -123,16 +127,22 @@ TEST_CASE("Polytropic EOS Satisfies Its Thermodynamic Identities",
                  *
                  *     dP / d rho = h / n.
                  */
-        CHECK_THAT(barotrope.pressure_derivative_from_density(density),
+                CHECK_THAT(
-                   Catch::Matchers::WithinRel(
+                    (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::Density>(
-                       enthalpyFromDensity / polytropicIndex, 5.0e-13));
+                         barotrope, eos::DensityValue{density}
+                    )
+                         .value()),
+                    Catch::Matchers::WithinRel(enthalpyFromDensity / polytropicIndex, 5.0e-13)
+                );
             }
         }
     }
 }
 
-TEST_CASE("Polytropic EOS Pressure Derivatives Match Centered Differences",
+TEST_CASE(
-          tags::barotrope_eos_jacobian) {
+    "Polytropic EOS Pressure Derivatives Match Centered Differences",
+    tags::barotrope_eos_jacobian
+) {
     constexpr std::array<double, 3> polytropicIndices{1.0, 1.5, 3.0};
 
     constexpr std::array<double, 3> positiveValues{0.2, 0.73, 1.8};
@@ -140,55 +150,62 @@ TEST_CASE("Polytropic EOS Pressure Derivatives Match Centered Differences",
     constexpr double polytropicConstant = 0.61;
 
     for (const double polytropicIndex : polytropicIndices) {
-    const mean_field::eos::Polytrope barotrope(polytropicIndex,
+        const mean_field::eos::Polytrope barotrope(polytropicIndex, polytropicConstant);
-                                               polytropicConstant);
 
         DYNAMIC_SECTION("polytropic index n = " << polytropicIndex) {
             for (const double enthalpy : positiveValues) {
                 const double step                = 2.0e-6 * std::max(1.0, std::abs(enthalpy));
 
-        const double numericalDerivative =
+                const double numericalDerivative = polytropic_eos_test_utils::centered_derivative(
-            polytropic_eos_test_utils::centered_derivative(
                     [&barotrope](const double perturbedEnthalpy) {
-                  return barotrope.pressure_from_enthalpy(perturbedEnthalpy);
+                        return eos::evaluate<eos::quantity::Pressure>(
+                                   barotrope, eos::SpecificEnthalpyValue{perturbedEnthalpy}
+                        )
+                            .value();
                     },
-                enthalpy, step);
+                    enthalpy, step
+                );
 
                 const double analyticDerivative =
-            barotrope.pressure_derivative_from_enthalpy(enthalpy);
+                    eos::partialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>(
+                        barotrope, eos::SpecificEnthalpyValue{enthalpy}
+                    )
+                        .value();
 
-        CAPTURE(polytropicIndex, enthalpy, step, numericalDerivative,
+                CAPTURE(polytropicIndex, enthalpy, step, numericalDerivative, analyticDerivative);
-                analyticDerivative);
 
-        CHECK_THAT(numericalDerivative,
+                CHECK_THAT(numericalDerivative, Catch::Matchers::WithinRel(analyticDerivative, 5.0e-8));
-                   Catch::Matchers::WithinRel(analyticDerivative, 5.0e-8));
             }
 
             for (const double density : positiveValues) {
                 const double step                = 2.0e-6 * std::max(1.0, std::abs(density));
 
-        const double numericalDerivative =
+                const double numericalDerivative = polytropic_eos_test_utils::centered_derivative(
-            polytropic_eos_test_utils::centered_derivative(
                     [&barotrope](const double perturbedDensity) {
-                  return barotrope.pressure_from_density(perturbedDensity);
+                        return eos::evaluate<eos::quantity::Pressure>(barotrope, eos::DensityValue{perturbedDensity})
+                            .value();
                     },
-                density, step);
+                    density, step
+                );
 
                 const double analyticDerivative =
-            barotrope.pressure_derivative_from_density(density);
+                    eos::partialDerivative<eos::quantity::Pressure, eos::quantity::Density>(
+                        barotrope, eos::DensityValue{density}
+                    )
+                        .value();
 
-        CAPTURE(polytropicIndex, density, step, numericalDerivative,
+                CAPTURE(polytropicIndex, density, step, numericalDerivative, analyticDerivative);
-                analyticDerivative);
 
-        CHECK_THAT(numericalDerivative,
+                CHECK_THAT(numericalDerivative, Catch::Matchers::WithinRel(analyticDerivative, 5.0e-8));
-                   Catch::Matchers::WithinRel(analyticDerivative, 5.0e-8));
             }
         }
     }
 }
 
-TEST_CASE("Polytropic EOS Density Derivative Matches Centered Differences",
+TEST_CASE(
-          tags::barotrope_eos_jacobian) {
+    "Polytropic EOS Density Derivative Matches Centered Differences",
+    tags::barotrope_eos_jacobian
+) {
     constexpr std::array<double, 3> polytropicIndices{1.0, 1.5, 3.0};
 
     constexpr std::array<double, 3> enthalpies{0.2, 0.73, 1.8};
@@ -196,72 +213,100 @@ TEST_CASE("Polytropic EOS Density Derivative Matches Centered Differences",
     constexpr double polytropicConstant = 0.61;
 
     for (const double polytropicIndex : polytropicIndices) {
-    const mean_field::eos::Polytrope barotrope(polytropicIndex,
+        const mean_field::eos::Polytrope barotrope(polytropicIndex, polytropicConstant);
-                                               polytropicConstant);
 
         DYNAMIC_SECTION("polytropic index n = " << polytropicIndex) {
             for (const double enthalpy : enthalpies) {
                 const double step                = 2.0e-6 * std::max(1.0, std::abs(enthalpy));
 
-        const double numericalDerivative =
+                const double numericalDerivative = polytropic_eos_test_utils::centered_derivative(
-            polytropic_eos_test_utils::centered_derivative(
                     [&barotrope](const double perturbedEnthalpy) {
-                  return barotrope.density_from_enthalpy(perturbedEnthalpy);
+                        return eos::evaluate<eos::quantity::Density>(
+                                   barotrope, eos::SpecificEnthalpyValue{perturbedEnthalpy}
+                        )
+                            .value();
                     },
-                enthalpy, step);
+                    enthalpy, step
+                );
 
                 const double analyticDerivative =
-            barotrope.density_derivative_from_enthalpy(enthalpy);
+                    eos::partialDerivative<eos::quantity::Density, eos::quantity::SpecificEnthalpy>(
+                        barotrope, eos::SpecificEnthalpyValue{enthalpy}
+                    )
+                        .value();
 
-        CAPTURE(polytropicIndex, enthalpy, step, numericalDerivative,
+                CAPTURE(polytropicIndex, enthalpy, step, numericalDerivative, analyticDerivative);
-                analyticDerivative);
 
-        CHECK_THAT(numericalDerivative,
+                CHECK_THAT(numericalDerivative, Catch::Matchers::WithinRel(analyticDerivative, 5.0e-8));
-                   Catch::Matchers::WithinRel(analyticDerivative, 5.0e-8));
             }
         }
     }
 }
 
-TEST_CASE("Polytropic EOS Defines Consistent Surface And Exterior Behavior",
+TEST_CASE(
-          tags::barotrope_eos_unit) {
+    "Polytropic EOS Defines Consistent Surface And Exterior Behavior",
+    tags::barotrope_eos_unit
+) {
     constexpr std::array<double, 3> polytropicIndices{1.0, 1.5, 3.0};
 
     constexpr double polytropicConstant = 0.47;
     constexpr double exteriorEnthalpy   = -0.3;
 
     for (const double polytropicIndex : polytropicIndices) {
-    const mean_field::eos::Polytrope barotrope(polytropicIndex,
+        const mean_field::eos::Polytrope barotrope(polytropicIndex, polytropicConstant);
-                                               polytropicConstant);
 
         DYNAMIC_SECTION("polytropic index n = " << polytropicIndex) {
             /*
              * Exact surface values.
              */
-      CHECK(barotrope.density_from_enthalpy(0.0) == 0.0);
+            CHECK(eos::evaluate<eos::quantity::Density>(barotrope, eos::SpecificEnthalpyValue{0.0}).value() == 0.0);
 
-      CHECK(barotrope.pressure_from_enthalpy(0.0) == 0.0);
+            CHECK(eos::evaluate<eos::quantity::Pressure>(barotrope, eos::SpecificEnthalpyValue{0.0}).value() == 0.0);
 
-      CHECK(barotrope.pressure_derivative_from_enthalpy(0.0) == 0.0);
+            CHECK(
+                (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>(
+                     barotrope, eos::SpecificEnthalpyValue{0.0}
+                 )
+                     .value() == 0.0)
+            );
 
-      CHECK(barotrope.pressure_from_density(0.0) == 0.0);
+            CHECK(eos::evaluate<eos::quantity::Pressure>(barotrope, eos::DensityValue{0.0}).value() == 0.0);
 
-      CHECK(barotrope.enthalpy_from_density(0.0) == 0.0);
+            CHECK(eos::evaluate<eos::quantity::SpecificEnthalpy>(barotrope, eos::DensityValue{0.0}).value() == 0.0);
 
-      CHECK(barotrope.pressure_derivative_from_density(0.0) == 0.0);
+            CHECK(
+                (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::Density>(
+                     barotrope, eos::DensityValue{0.0}
+                 )
+                     .value() == 0.0)
+            );
 
             /*
              * Positive-part extension into h < 0.
              */
-      CHECK(barotrope.density_from_enthalpy(exteriorEnthalpy) == 0.0);
+            CHECK(
+                eos::evaluate<eos::quantity::Density>(barotrope, eos::SpecificEnthalpyValue{exteriorEnthalpy})
+                    .value() == 0.0
+            );
 
-      CHECK(barotrope.pressure_from_enthalpy(exteriorEnthalpy) == 0.0);
+            CHECK(
+                eos::evaluate<eos::quantity::Pressure>(barotrope, eos::SpecificEnthalpyValue{exteriorEnthalpy})
+                    .value() == 0.0
+            );
 
-      CHECK(barotrope.density_derivative_from_enthalpy(exteriorEnthalpy) ==
+            CHECK(
-            0.0);
+                (eos::partialDerivative<eos::quantity::Density, eos::quantity::SpecificEnthalpy>(
+                     barotrope, eos::SpecificEnthalpyValue{exteriorEnthalpy}
+                 )
+                     .value() == 0.0)
+            );
 
-      CHECK(barotrope.pressure_derivative_from_enthalpy(exteriorEnthalpy) ==
+            CHECK(
-            0.0);
+                (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>(
+                     barotrope, eos::SpecificEnthalpyValue{exteriorEnthalpy}
+                 )
+                     .value() == 0.0)
+            );
 
             /*
              * At h = 0, rho(h) has a nonzero right
@@ -270,20 +315,23 @@ TEST_CASE("Polytropic EOS Defines Consistent Surface And Exterior Behavior",
             const double expectedSurfaceDensityDerivative =
                 polytropicIndex == 1.0 ? 1.0 / barotrope.enthalpy_scale() : 0.0;
 
-      CHECK(barotrope.density_derivative_from_enthalpy(0.0) ==
+            CHECK(
-            expectedSurfaceDensityDerivative);
+                (eos::partialDerivative<eos::quantity::Density, eos::quantity::SpecificEnthalpy>(
+                     barotrope, eos::SpecificEnthalpyValue{0.0}
+                 )
+                     .value() == expectedSurfaceDensityDerivative)
+            );
         }
     }
 }
 
-TEST_CASE("Polytropic EOS Rejects Invalid Physical Inputs",
+TEST_CASE(
-          tags::barotrope_eos_unit) {
+    "Polytropic EOS Rejects Invalid Physical Inputs",
-  CHECK_THROWS_AS(mean_field::eos::Polytrope(0.999, 1.0),
+    tags::barotrope_eos_unit
-                  std::invalid_argument);
+) {
+    CHECK_THROWS_AS(mean_field::eos::Polytrope(0.999, 1.0), std::invalid_argument);
 
-  CHECK_THROWS_AS(
+    CHECK_THROWS_AS(mean_field::eos::Polytrope(std::numeric_limits<double>::infinity(), 1.0), std::invalid_argument);
-      mean_field::eos::Polytrope(std::numeric_limits<double>::infinity(), 1.0),
-      std::invalid_argument);
 
     CHECK_THROWS_AS(mean_field::eos::Polytrope(3.0, 0.0), std::invalid_argument);
 
@@ -291,37 +339,55 @@ TEST_CASE("Polytropic EOS Rejects Invalid Physical Inputs",
 
     const mean_field::eos::Polytrope barotrope(3.0, 0.75);
 
-  CHECK_THROWS_AS(barotrope.pressure_from_density(-0.1), std::domain_error);
+    CHECK_THROWS_AS(eos::evaluate<eos::quantity::Pressure>(barotrope, eos::DensityValue{-0.1}), std::domain_error);
 
-  CHECK_THROWS_AS(barotrope.enthalpy_from_density(-0.1), std::domain_error);
+    CHECK_THROWS_AS(
+        eos::evaluate<eos::quantity::SpecificEnthalpy>(barotrope, eos::DensityValue{-0.1}), std::domain_error
+    );
 
-  CHECK_THROWS_AS(barotrope.pressure_derivative_from_density(-0.1),
+    CHECK_THROWS_AS(
-                  std::domain_error);
+        (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::Density>(barotrope, eos::DensityValue{-0.1})),
+        std::domain_error
+    );
 
     constexpr std::array<double, 3> nonfiniteValues{
-      std::numeric_limits<double>::infinity(),
+        std::numeric_limits<double>::infinity(), -std::numeric_limits<double>::infinity(),
-      -std::numeric_limits<double>::infinity(),
+        std::numeric_limits<double>::quiet_NaN()
-      std::numeric_limits<double>::quiet_NaN()};
+    };
 
     for (const double nonfiniteValue : nonfiniteValues) {
         CAPTURE(nonfiniteValue);
 
-    CHECK_THROWS_AS(barotrope.density_from_enthalpy(nonfiniteValue),
+        CHECK_THROWS_AS(
-                    std::domain_error);
+            eos::evaluate<eos::quantity::Density>(barotrope, eos::SpecificEnthalpyValue{nonfiniteValue}),
+            std::domain_error
+        );
 
-    CHECK_THROWS_AS(barotrope.pressure_from_enthalpy(nonfiniteValue),
+        CHECK_THROWS_AS(
-                    std::domain_error);
+            eos::evaluate<eos::quantity::Pressure>(barotrope, eos::SpecificEnthalpyValue{nonfiniteValue}),
+            std::domain_error
+        );
 
-    CHECK_THROWS_AS(barotrope.density_derivative_from_enthalpy(nonfiniteValue),
+        CHECK_THROWS_AS(
-                    std::domain_error);
+            (eos::partialDerivative<eos::quantity::Density, eos::quantity::SpecificEnthalpy>(
+                barotrope, eos::SpecificEnthalpyValue{nonfiniteValue}
+            )),
+            std::domain_error
+        );
 
-    CHECK_THROWS_AS(barotrope.pressure_derivative_from_enthalpy(nonfiniteValue),
+        CHECK_THROWS_AS(
-                    std::domain_error);
+            (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>(
+                barotrope, eos::SpecificEnthalpyValue{nonfiniteValue}
+            )),
+            std::domain_error
+        );
     }
 }
 
-TEST_CASE("Pressure Force And Pressure Integral Have Distinct Registered Forms",
+TEST_CASE(
-          tags::barotrope_pressure_quadrature_unit) {
+    "Pressure Force And Pressure Integral Have Distinct Registered Forms",
+    tags::barotrope_pressure_quadrature_unit
+) {
     using EnthalpyField               = mean_field::field::Field<mean_field::field::Enthalpy>;
 
     /*
@@ -336,38 +402,34 @@ TEST_CASE("Pressure Force And Pressure Integral Have Distinct Registered Forms",
      *
      * beyond the registered enthalpy operand.
      */
-  constexpr int enthalpyOrder =
+    constexpr int enthalpyOrder       = mean_field::field::Enthalpy::Scalar::familyOrder;
-      mean_field::field::Enthalpy::Scalar::familyOrder;
 
     constexpr int pressureExtraOrder  = 3 * enthalpyOrder;
 
     constexpr int geometryWeightOrder = 2;
 
     constexpr mean_field::quadrature::Query pressureIntegralQuery =
-      EnthalpyField::make_query<
+        EnthalpyField::make_query<mean_field::field::Enthalpy::Form::PressureIntegral>(
-          mean_field::field::Enthalpy::Form::PressureIntegral>(
+            mean_field::quadrature::QuadratureRole::diagnostic, geometryWeightOrder,
-          mean_field::quadrature::QuadratureRole::diagnostic,
+            std::array<int, 1>{pressureExtraOrder}, mean_field::utils::DOMAINS::STELLAR,
-          geometryWeightOrder, std::array<int, 1>{pressureExtraOrder},
+            mean_field::quadrature::MappingKind::general
-          mean_field::utils::DOMAINS::STELLAR,
+        );
-          mean_field::quadrature::MappingKind::general);
 
     constexpr mean_field::quadrature::Query pressureForceQuery =
-      EnthalpyField::make_query<
+        EnthalpyField::make_query<mean_field::field::Enthalpy::Form::PressureForce>(
-          mean_field::field::Enthalpy::Form::PressureForce>(
+            mean_field::quadrature::QuadratureRole::discretization, geometryWeightOrder,
-          mean_field::quadrature::QuadratureRole::discretization,
+            std::array<int, 1>{pressureExtraOrder}, mean_field::utils::DOMAINS::STELLAR,
-          geometryWeightOrder, std::array<int, 1>{pressureExtraOrder},
+            mean_field::quadrature::MappingKind::general
-          mean_field::utils::DOMAINS::STELLAR,
+        );
-          mean_field::quadrature::MappingKind::general);
+
+    STATIC_CHECK(mean_field::field::Enthalpy::Form::PressureIntegral::dynamicOrderCount == 1);
+
+    STATIC_CHECK(mean_field::field::Enthalpy::Form::PressureForce::dynamicOrderCount == 1);
 
     STATIC_CHECK(
-      mean_field::field::Enthalpy::Form::PressureIntegral::dynamicOrderCount ==
+        mean_field::field::Enthalpy::Form::PressureIntegral::policyKey !=
-      1);
+        mean_field::field::Enthalpy::Form::PressureForce::policyKey
-
+    );
-  STATIC_CHECK(
-      mean_field::field::Enthalpy::Form::PressureForce::dynamicOrderCount == 1);
-
-  STATIC_CHECK(mean_field::field::Enthalpy::Form::PressureIntegral::policyKey !=
-               mean_field::field::Enthalpy::Form::PressureForce::policyKey);
 
     REQUIRE(pressureIntegralQuery.base_order.has_value());
 
@@ -394,17 +456,13 @@ TEST_CASE("Pressure Force And Pressure Integral Have Distinct Registered Forms",
      */
     CHECK(*pressureForceQuery.base_order == 16);
 
-  CHECK(pressureIntegralQuery.term ==
+    CHECK(pressureIntegralQuery.term == mean_field::quadrature::Term::pressure_integral);
-        mean_field::quadrature::Term::pressure_integral);
 
-  CHECK(pressureForceQuery.term ==
+    CHECK(pressureForceQuery.term == mean_field::quadrature::Term::pressure_force);
-        mean_field::quadrature::Term::pressure_force);
 
-  CHECK(pressureIntegralQuery.role ==
+    CHECK(pressureIntegralQuery.role == mean_field::quadrature::QuadratureRole::diagnostic);
-        mean_field::quadrature::QuadratureRole::diagnostic);
 
-  CHECK(pressureForceQuery.role ==
+    CHECK(pressureForceQuery.role == mean_field::quadrature::QuadratureRole::discretization);
-        mean_field::quadrature::QuadratureRole::discretization);
 
     CHECK(pressureIntegralQuery.domain == mean_field::utils::DOMAINS::STELLAR);
 
@@ -415,19 +473,16 @@ TEST_CASE("Pressure Force And Pressure Integral Have Distinct Registered Forms",
      * controls.
      */
     mean_field::quadrature::RuleSet ruleSet =
-      mean_field::quadrature::make_rule_set(
+        mean_field::quadrature::make_rule_set(mean_field::quadrature::Mode::production);
-          mean_field::quadrature::Mode::production);
 
     ruleSet.pressure_integral.boost = 3;
     ruleSet.pressure_force.boost    = 5;
 
     const mean_field::quadrature::Policy policy(std::move(ruleSet));
 
-  const mean_field::quadrature::Resolution pressureIntegralResolution =
+    const mean_field::quadrature::Resolution pressureIntegralResolution = policy.resolve(pressureIntegralQuery);
-      policy.resolve(pressureIntegralQuery);
 
-  const mean_field::quadrature::Resolution pressureForceResolution =
+    const mean_field::quadrature::Resolution pressureForceResolution    = policy.resolve(pressureForceQuery);
-      policy.resolve(pressureForceQuery);
 
     CHECK(pressureIntegralResolution.base_order == 14);
 
@@ -442,12 +497,13 @@ TEST_CASE("Pressure Force And Pressure Integral Have Distinct Registered Forms",
     CHECK(pressureForceResolution.order == 21);
 }
 
-TEST_CASE("Pressure Quadrature Exactly Integrates An N Three Polynomial",
+TEST_CASE(
-          tags::barotrope_pressure_quadrature_accuracy) {
+    "Pressure Quadrature Exactly Integrates An N Three Polynomial",
+    tags::barotrope_pressure_quadrature_accuracy
+) {
     using EnthalpyField              = mean_field::field::Field<mean_field::field::Enthalpy>;
 
-  constexpr int enthalpyOrder =
+    constexpr int enthalpyOrder      = mean_field::field::Enthalpy::Scalar::familyOrder;
-      mean_field::field::Enthalpy::Scalar::familyOrder;
 
     constexpr int pressureExtraOrder = 3 * enthalpyOrder;
 
@@ -461,24 +517,20 @@ TEST_CASE("Pressure Quadrature Exactly Integrates An N Three Polynomial",
     const mean_field::eos::Polytrope barotrope(3.0, 0.25);
 
     constexpr mean_field::quadrature::Query pressureIntegralQuery =
-      EnthalpyField::make_query<
+        EnthalpyField::make_query<mean_field::field::Enthalpy::Form::PressureIntegral>(
-          mean_field::field::Enthalpy::Form::PressureIntegral>(
+            mean_field::quadrature::QuadratureRole::diagnostic, 0, std::array<int, 1>{pressureExtraOrder},
-          mean_field::quadrature::QuadratureRole::diagnostic, 0,
+            mean_field::utils::DOMAINS::STELLAR, mean_field::quadrature::MappingKind::affine
-          std::array<int, 1>{pressureExtraOrder},
+        );
-          mean_field::utils::DOMAINS::STELLAR,
-          mean_field::quadrature::MappingKind::affine);
 
     constexpr mean_field::quadrature::Query pressureForceQuery =
-      EnthalpyField::make_query<
+        EnthalpyField::make_query<mean_field::field::Enthalpy::Form::PressureForce>(
-          mean_field::field::Enthalpy::Form::PressureForce>(
+            mean_field::quadrature::QuadratureRole::discretization, 0, std::array<int, 1>{pressureExtraOrder},
-          mean_field::quadrature::QuadratureRole::discretization, 0,
+            mean_field::utils::DOMAINS::STELLAR, mean_field::quadrature::MappingKind::affine
-          std::array<int, 1>{pressureExtraOrder},
+        );
-          mean_field::utils::DOMAINS::STELLAR,
-          mean_field::quadrature::MappingKind::affine);
 
     const mean_field::quadrature::RuleFactory ruleFactory{
-      mean_field::quadrature::Policy(mean_field::quadrature::make_rule_set(
+        mean_field::quadrature::Policy(mean_field::quadrature::make_rule_set(mean_field::quadrature::Mode::production))
-          mean_field::quadrature::Mode::production))};
+    };
 
     const mean_field::quadrature::MfemRule pressureIntegralRule =
         ruleFactory.get(pressureIntegralQuery, mfem::Geometry::CUBE);
@@ -496,17 +548,15 @@ TEST_CASE("Pressure Quadrature Exactly Integrates An N Three Polynomial",
      *
      *     P = x^12 y^12 z^12 / 4.
      */
-  const double numericalPressureIntegral =
+    const double numericalPressureIntegral = polytropic_eos_test_utils::integrate_cube(
-      polytropic_eos_test_utils::integrate_cube(
+        *pressureIntegralRule.integration_rule, [&barotrope](const mfem::IntegrationPoint &integrationPoint) {
-          *pressureIntegralRule.integration_rule,
+            const double coordinateProduct = integrationPoint.x * integrationPoint.y * integrationPoint.z;
-          [&barotrope](const mfem::IntegrationPoint &integrationPoint) {
-            const double coordinateProduct =
-                integrationPoint.x * integrationPoint.y * integrationPoint.z;
 
             const double enthalpy          = std::pow(coordinateProduct, 3.0);
 
-            return barotrope.pressure_from_enthalpy(enthalpy);
+            return eos::evaluate<eos::quantity::Pressure>(barotrope, eos::SpecificEnthalpyValue{enthalpy}).value();
-          });
+        }
+    );
 
     const double analyticPressureIntegral       = 0.25 / std::pow(13.0, 3.0);
 
@@ -521,38 +571,33 @@ TEST_CASE("Pressure Quadrature Exactly Integrates An N Three Polynomial",
      *     -P div(w)
      *       = -x^14 y^14 z^14 / 4.
      */
-  const double numericalPressureForceIntegral =
+    const double numericalPressureForceIntegral = polytropic_eos_test_utils::integrate_cube(
-      polytropic_eos_test_utils::integrate_cube(
+        *pressureForceRule.integration_rule, [&barotrope](const mfem::IntegrationPoint &integrationPoint) {
-          *pressureForceRule.integration_rule,
+            const double coordinateProduct = integrationPoint.x * integrationPoint.y * integrationPoint.z;
-          [&barotrope](const mfem::IntegrationPoint &integrationPoint) {
-            const double coordinateProduct =
-                integrationPoint.x * integrationPoint.y * integrationPoint.z;
 
             const double enthalpy          = std::pow(coordinateProduct, 3.0);
 
-            const double pressure = barotrope.pressure_from_enthalpy(enthalpy);
+            const double pressure =
+                eos::evaluate<eos::quantity::Pressure>(barotrope, eos::SpecificEnthalpyValue{enthalpy}).value();
 
-            const double testDivergence =
+            const double testDivergence = integrationPoint.x * integrationPoint.x * integrationPoint.y *
-                integrationPoint.x * integrationPoint.x * integrationPoint.y *
                                           integrationPoint.y * integrationPoint.z * integrationPoint.z;
 
             return -pressure * testDivergence;
-          });
+        }
+    );
 
     const double analyticPressureForceIntegral = -0.25 / std::pow(15.0, 3.0);
 
-  INFO("Pressure-integral quadrature order = "
+    INFO("Pressure-integral quadrature order = " << pressureIntegralRule.resolution.order);
-       << pressureIntegralRule.resolution.order);
 
-  INFO("Pressure-force quadrature order = "
+    INFO("Pressure-force quadrature order = " << pressureForceRule.resolution.order);
-       << pressureForceRule.resolution.order);
 
     INFO("Numerical pressure integral = " << numericalPressureIntegral);
 
     INFO("Analytic pressure integral = " << analyticPressureIntegral);
 
-  INFO(
+    INFO("Numerical pressure-force integral = " << numericalPressureForceIntegral);
-      "Numerical pressure-force integral = " << numericalPressureForceIntegral);
 
     INFO("Analytic pressure-force integral = " << analyticPressureForceIntegral);
 
@@ -564,10 +609,7 @@ TEST_CASE("Pressure Quadrature Exactly Integrates An N Three Polynomial",
 
     CHECK(pressureForceRule.resolution.order == 14);
 
-  CHECK_THAT(numericalPressureIntegral,
+    CHECK_THAT(numericalPressureIntegral, Catch::Matchers::WithinAbs(analyticPressureIntegral, 5.0e-14));
-             Catch::Matchers::WithinAbs(analyticPressureIntegral, 5.0e-14));
 
-  CHECK_THAT(
+    CHECK_THAT(numericalPressureForceIntegral, Catch::Matchers::WithinAbs(analyticPressureForceIntegral, 5.0e-14));
-      numericalPressureForceIntegral,
-      Catch::Matchers::WithinAbs(analyticPressureForceIntegral, 5.0e-14));
 }

tests/physics/equation_of_state_consumer_contracts.cpp

@@ -0,0 +1,125 @@
+#include <catch2/catch_test_macros.hpp>
+
+import mean_field;
+import test_helpers;
+
+namespace {
+    namespace eos = mean_field::eos;
+
+    class DensityClosureEquationOfState final {
+    public:
+        using Relations = eos::RelationCatalog<eos::DensityFromSpecificEnthalpy>;
+
+        [[nodiscard]] constexpr eos::DensityValue evaluate(
+            eos::DensityFromSpecificEnthalpy,
+            const eos::SpecificEnthalpyValue specificEnthalpy
+        ) const noexcept {
+            return eos::DensityValue{specificEnthalpy.value()};
+        }
+
+        [[nodiscard]] constexpr eos::PartialDerivative<
+            eos::quantity::Density,
+            eos::quantity::SpecificEnthalpy>
+        partialDerivative(
+            eos::DensityFromSpecificEnthalpy,
+            eos::WithRespectTo<eos::quantity::SpecificEnthalpy>,
+            eos::SpecificEnthalpyValue
+        ) const noexcept {
+            return eos::PartialDerivative<eos::quantity::Density, eos::quantity::SpecificEnthalpy>{1.0};
+        }
+    };
+
+    class DensityClosureWithoutDerivative final {
+    public:
+        using Relations = eos::RelationCatalog<eos::DensityFromSpecificEnthalpy>;
+
+        [[nodiscard]] constexpr eos::DensityValue evaluate(
+            eos::DensityFromSpecificEnthalpy,
+            const eos::SpecificEnthalpyValue specificEnthalpy
+        ) const noexcept {
+            return eos::DensityValue{specificEnthalpy.value()};
+        }
+    };
+
+    class EnthalpyPressureEquationOfState final {
+    public:
+        using Relations = eos::RelationCatalog<eos::PressureFromSpecificEnthalpy>;
+
+        [[nodiscard]] constexpr eos::PressureValue evaluate(
+            eos::PressureFromSpecificEnthalpy,
+            const eos::SpecificEnthalpyValue specificEnthalpy
+        ) const noexcept {
+            return eos::PressureValue{2.0 * specificEnthalpy.value()};
+        }
+
+        [[nodiscard]] constexpr eos::PartialDerivative<
+            eos::quantity::Pressure,
+            eos::quantity::SpecificEnthalpy>
+        partialDerivative(
+            eos::PressureFromSpecificEnthalpy,
+            eos::WithRespectTo<eos::quantity::SpecificEnthalpy>,
+            eos::SpecificEnthalpyValue
+        ) const noexcept {
+            return eos::PartialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>{2.0};
+        }
+    };
+
+    class DensitySeedEquationOfState final {
+    public:
+        using Relations = eos::RelationCatalog<eos::SpecificEnthalpyFromDensity>;
+
+        [[nodiscard]] constexpr eos::SpecificEnthalpyValue evaluate(
+            eos::SpecificEnthalpyFromDensity,
+            const eos::DensityValue density
+        ) const noexcept {
+            return eos::SpecificEnthalpyValue{3.0 * density.value()};
+        }
+    };
+
+    class GeneralEquationOfStateWithoutCurrentConsumerRelations final {
+    public:
+        using Relations = eos::RelationCatalog<eos::SpecificEnthalpyFromPressure>;
+
+        [[nodiscard]] constexpr eos::SpecificEnthalpyValue evaluate(
+            eos::SpecificEnthalpyFromPressure,
+            const eos::PressureValue pressure
+        ) const noexcept {
+            return eos::SpecificEnthalpyValue{pressure.value()};
+        }
+    };
+} // namespace
+
+TEST_CASE(
+    "Barotropic Closure EOS Requires Density And Its Enthalpy Derivative",
+    tags::barotropic_closure_equation_of_state_contract
+) {
+    STATIC_CHECK(eos::BarotropicClosureEquationOfState<eos::Polytrope>);
+    STATIC_CHECK(eos::BarotropicClosureEquationOfState<DensityClosureEquationOfState>);
+    STATIC_CHECK(eos::EquationOfStateModel<DensityClosureWithoutDerivative>);
+    STATIC_CHECK_FALSE(eos::BarotropicClosureEquationOfState<DensityClosureWithoutDerivative>);
+    STATIC_CHECK_FALSE(eos::BarotropicClosureEquationOfState<EnthalpyPressureEquationOfState>);
+}
+
+TEST_CASE(
+    "Pressure Force EOS Requires Pressure And Its Enthalpy Derivative",
+    tags::pressure_force_equation_of_state_contract
+) {
+    STATIC_CHECK(eos::PressureForceEquationOfState<eos::Polytrope>);
+    STATIC_CHECK(eos::PressureForceEquationOfState<EnthalpyPressureEquationOfState>);
+    STATIC_CHECK_FALSE(eos::PressureForceEquationOfState<DensityClosureEquationOfState>);
+    STATIC_CHECK_FALSE(eos::PressureForceEquationOfState<DensityClosureWithoutDerivative>);
+}
+
+TEST_CASE(
+    "Structure Seed EOS Requires Enthalpy From Density",
+    tags::structure_seed_equation_of_state_contract
+) {
+    STATIC_CHECK(eos::StructureSeedEquationOfState<eos::Polytrope>);
+    STATIC_CHECK(eos::StructureSeedEquationOfState<DensitySeedEquationOfState>);
+    STATIC_CHECK_FALSE(eos::StructureSeedEquationOfState<DensityClosureEquationOfState>);
+
+    STATIC_CHECK(eos::EquationOfStateModel<GeneralEquationOfStateWithoutCurrentConsumerRelations>);
+    STATIC_CHECK_FALSE(eos::StructureSeedEquationOfState<GeneralEquationOfStateWithoutCurrentConsumerRelations>);
+    STATIC_CHECK_FALSE(eos::BarotropicClosureEquationOfState<GeneralEquationOfStateWithoutCurrentConsumerRelations>);
+    STATIC_CHECK_FALSE(eos::PressureForceEquationOfState<GeneralEquationOfStateWithoutCurrentConsumerRelations>);
+}

tests/physics/equation_of_state_runtime_view.cpp

@@ -0,0 +1,322 @@
+#include <array>
+#include <concepts>
+#include <expected>
+#include <limits>
+#include <memory>
+#include <span>
+#include <string_view>
+#include <type_traits>
+
+#include <catch2/catch_test_macros.hpp>
+
+import mean_field;
+import test_helpers;
+
+namespace {
+    namespace eos = mean_field::eos;
+
+    class LinearPressureEquationOfState final {
+    public:
+        using Relations = eos::RelationCatalog<eos::PressureFromDensity>;
+
+        [[nodiscard]] constexpr eos::PressureValue evaluate(
+            eos::PressureFromDensity,
+            const eos::DensityValue density
+        ) const noexcept {
+            return eos::PressureValue{2.0 * density.value() + 0.5};
+        }
+    };
+
+    struct DensityAlias final : eos::ThermodynamicQuantity {
+        static constexpr std::string_view identifier = "density";
+    };
+
+    class AmbiguouslyIdentifiedEquationOfState final {
+    public:
+        using Relations = eos::RelationCatalog<eos::Relation<DensityAlias, eos::quantity::Density>>;
+
+        [[nodiscard]] constexpr eos::QuantityValue<DensityAlias> evaluate(
+            eos::Relation<
+                DensityAlias,
+                eos::quantity::Density>,
+            const eos::DensityValue density
+        ) const noexcept {
+            return eos::QuantityValue<DensityAlias>{density.value()};
+        }
+    };
+
+    [[nodiscard]] std::expected<
+        eos::PressureValue,
+        eos::EvaluationError>
+    pressureAtDensity(
+        const eos::EquationOfStateView equationOfState,
+        const eos::DensityValue density
+    ) {
+        return equationOfState.tryEvaluate<eos::quantity::Pressure>(density);
+    }
+
+    [[nodiscard]] const eos::RuntimeRelationDescriptor *findRelation(
+        const eos::EquationOfStateView equationOfState,
+        const eos::ThermodynamicQuantityId output,
+        const eos::ThermodynamicQuantityId input
+    ) {
+        for (const eos::RuntimeRelationDescriptor &relation : equationOfState.relations()) {
+            if (relation.outputQuantity == output && relation.inputQuantities.size() == 1 &&
+                relation.inputQuantities[0] == input) {
+                return std::addressof(relation);
+            }
+        }
+
+        return nullptr;
+    }
+} // namespace
+
+TEST_CASE(
+    "Runtime EOS View Generates The Polytropic Relation Catalog",
+    tags::equation_of_state_runtime_contract
+) {
+    STATIC_CHECK(eos::RuntimeEquationOfStateModel<eos::Polytrope>);
+    STATIC_CHECK(eos::RuntimeEquationOfStateModel<LinearPressureEquationOfState>);
+    STATIC_CHECK(eos::EquationOfStateModel<AmbiguouslyIdentifiedEquationOfState>);
+    STATIC_CHECK_FALSE(eos::RuntimeEquationOfStateModel<AmbiguouslyIdentifiedEquationOfState>);
+    STATIC_CHECK(std::is_trivially_copyable_v<eos::EquationOfStateView>);
+    STATIC_CHECK_FALSE(std::constructible_from<eos::EquationOfStateView, eos::Polytrope &&>);
+
+    const eos::Polytrope equationOfState(3.0, 0.25);
+    const eos::Polytrope secondEquationOfState(1.5, 0.73);
+
+    const eos::EquationOfStateView view{equationOfState};
+    const eos::EquationOfStateView secondView{secondEquationOfState};
+
+    REQUIRE(view.relations().size() == eos::Polytrope::Relations::size);
+    CHECK(view.relations().data() == secondView.relations().data());
+
+    CHECK(eos::thermodynamicQuantityId<eos::quantity::Density>.name() == "density");
+    CHECK(eos::thermodynamicQuantityId<eos::quantity::Pressure>.name() == "pressure");
+    CHECK(eos::thermodynamicQuantityId<eos::quantity::SpecificEnthalpy>.name() == "specific_enthalpy");
+
+    const eos::RuntimeRelationDescriptor *pressureFromDensity = findRelation(
+        view, eos::thermodynamicQuantityId<eos::quantity::Pressure>,
+        eos::thermodynamicQuantityId<eos::quantity::Density>
+    );
+
+    REQUIRE(pressureFromDensity != nullptr);
+    CHECK(pressureFromDensity->hasPartialDerivative(0));
+
+    const eos::RuntimeRelationDescriptor *specificEnthalpyFromPressure = findRelation(
+        view, eos::thermodynamicQuantityId<eos::quantity::SpecificEnthalpy>,
+        eos::thermodynamicQuantityId<eos::quantity::Pressure>
+    );
+
+    REQUIRE(specificEnthalpyFromPressure != nullptr);
+    CHECK_FALSE(specificEnthalpyFromPressure->hasPartialDerivative(0));
+
+    const eos::RuntimeRelationDescriptor *pressureFromSpecificEnthalpy = findRelation(
+        view, eos::thermodynamicQuantityId<eos::quantity::Pressure>,
+        eos::thermodynamicQuantityId<eos::quantity::SpecificEnthalpy>
+    );
+
+    REQUIRE(pressureFromSpecificEnthalpy != nullptr);
+    CHECK(pressureFromSpecificEnthalpy->hasPartialDerivative(0));
+
+    const eos::RuntimeRelationDescriptor *specificEnthalpyFromDensity = findRelation(
+        view, eos::thermodynamicQuantityId<eos::quantity::SpecificEnthalpy>,
+        eos::thermodynamicQuantityId<eos::quantity::Density>
+    );
+
+    REQUIRE(specificEnthalpyFromDensity != nullptr);
+    CHECK_FALSE(specificEnthalpyFromDensity->hasPartialDerivative(0));
+
+    const eos::RuntimeRelationDescriptor *densityFromSpecificEnthalpy = findRelation(
+        view, eos::thermodynamicQuantityId<eos::quantity::Density>,
+        eos::thermodynamicQuantityId<eos::quantity::SpecificEnthalpy>
+    );
+
+    REQUIRE(densityFromSpecificEnthalpy != nullptr);
+    CHECK(densityFromSpecificEnthalpy->hasPartialDerivative(0));
+}
+
+TEST_CASE(
+    "Runtime EOS View Matches Typed Polytropic Evaluation",
+    tags::equation_of_state_runtime_compatibility
+) {
+    const eos::Polytrope equationOfState(3.0, 0.25);
+    const eos::EquationOfStateView view{equationOfState};
+
+    const eos::DensityValue density{0.7};
+    const eos::SpecificEnthalpyValue specificEnthalpy{0.9};
+    const eos::PressureValue pressure{0.04};
+
+    const auto runtimePressureFromDensity          = view.tryEvaluate<eos::quantity::Pressure>(density);
+    const auto runtimePressureFromSpecificEnthalpy = view.tryEvaluate<eos::quantity::Pressure>(specificEnthalpy);
+    const auto runtimeSpecificEnthalpyFromDensity  = view.tryEvaluate<eos::quantity::SpecificEnthalpy>(density);
+    const auto runtimeSpecificEnthalpyFromPressure = view.tryEvaluate<eos::quantity::SpecificEnthalpy>(pressure);
+    const auto runtimeDensityFromSpecificEnthalpy  = view.tryEvaluate<eos::quantity::Density>(specificEnthalpy);
+
+    REQUIRE(runtimePressureFromDensity.has_value());
+    REQUIRE(runtimePressureFromSpecificEnthalpy.has_value());
+    REQUIRE(runtimeSpecificEnthalpyFromDensity.has_value());
+    REQUIRE(runtimeSpecificEnthalpyFromPressure.has_value());
+    REQUIRE(runtimeDensityFromSpecificEnthalpy.has_value());
+
+    CHECK(
+        runtimePressureFromDensity->value() == eos::evaluate<eos::quantity::Pressure>(equationOfState, density).value()
+    );
+    CHECK(
+        runtimePressureFromSpecificEnthalpy->value() ==
+        eos::evaluate<eos::quantity::Pressure>(equationOfState, specificEnthalpy).value()
+    );
+    CHECK(
+        runtimeSpecificEnthalpyFromDensity->value() ==
+        eos::evaluate<eos::quantity::SpecificEnthalpy>(equationOfState, density).value()
+    );
+    CHECK(
+        runtimeSpecificEnthalpyFromPressure->value() ==
+        eos::evaluate<eos::quantity::SpecificEnthalpy>(equationOfState, pressure).value()
+    );
+    CHECK(
+        runtimeDensityFromSpecificEnthalpy->value() ==
+        eos::evaluate<eos::quantity::Density>(equationOfState, specificEnthalpy).value()
+    );
+
+    const std::array runtimeDensityInput{
+        eos::RuntimeQuantityValue{eos::thermodynamicQuantityId<eos::quantity::Density>, density.value()}
+    };
+
+    const auto erasedPressureFromDensity = view.tryEvaluate(
+        eos::thermodynamicQuantityId<eos::quantity::Pressure>,
+        std::span<const eos::RuntimeQuantityValue>{runtimeDensityInput}
+    );
+
+    REQUIRE(erasedPressureFromDensity.has_value());
+    CHECK(erasedPressureFromDensity->quantity == eos::thermodynamicQuantityId<eos::quantity::Pressure>);
+    CHECK(erasedPressureFromDensity->value == runtimePressureFromDensity->value());
+
+    const auto runtimePressureDerivative =
+        view.tryPartialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>(specificEnthalpy);
+
+    const auto runtimeDensityDerivative =
+        view.tryPartialDerivative<eos::quantity::Density, eos::quantity::SpecificEnthalpy>(specificEnthalpy);
+
+    const auto runtimePressureDensityDerivative =
+        view.tryPartialDerivative<eos::quantity::Pressure, eos::quantity::Density>(density);
+
+    REQUIRE(runtimePressureDerivative.has_value());
+    REQUIRE(runtimeDensityDerivative.has_value());
+    REQUIRE(runtimePressureDensityDerivative.has_value());
+
+    CHECK(
+        runtimePressureDerivative->value() ==
+        eos::partialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>(
+            equationOfState, specificEnthalpy
+        )
+            .value()
+    );
+    CHECK(
+        runtimeDensityDerivative->value() ==
+        eos::partialDerivative<eos::quantity::Density, eos::quantity::SpecificEnthalpy>(
+            equationOfState, specificEnthalpy
+        )
+            .value()
+    );
+    CHECK(
+        runtimePressureDensityDerivative->value() ==
+        eos::partialDerivative<eos::quantity::Pressure, eos::quantity::Density>(equationOfState, density).value()
+    );
+
+    const auto erasedPressureDensityDerivative = view.tryPartialDerivative(
+        eos::thermodynamicQuantityId<eos::quantity::Pressure>, eos::thermodynamicQuantityId<eos::quantity::Density>,
+        std::span<const eos::RuntimeQuantityValue>{runtimeDensityInput}
+    );
+
+    REQUIRE(erasedPressureDensityDerivative.has_value());
+    CHECK(*erasedPressureDensityDerivative == runtimePressureDensityDerivative->value());
+}
+
+TEST_CASE(
+    "Runtime EOS View Reports Unsupported And Invalid Requests",
+    tags::equation_of_state_runtime_contract
+) {
+    const eos::Polytrope equationOfState(3.0, 0.25);
+    const eos::EquationOfStateView view{equationOfState};
+
+    constexpr eos::ThermodynamicQuantityId temperature{"temperature"};
+
+    const std::array densityInput{eos::RuntimeQuantityValue{eos::thermodynamicQuantityId<eos::quantity::Density>, 0.7}};
+
+    const std::array pressureInput{
+        eos::RuntimeQuantityValue{eos::thermodynamicQuantityId<eos::quantity::Pressure>, 0.04}
+    };
+
+    const std::array<eos::RuntimeQuantityValue, 0> noInputs{};
+
+    const auto unsupportedOutput =
+        view.tryEvaluate(temperature, std::span<const eos::RuntimeQuantityValue>{densityInput});
+    REQUIRE_FALSE(unsupportedOutput.has_value());
+    CHECK(unsupportedOutput.error().code() == eos::EvaluationErrorCode::unsupported_relation);
+
+    const auto wrongInputCount = view.tryEvaluate(
+        eos::thermodynamicQuantityId<eos::quantity::Pressure>, std::span<const eos::RuntimeQuantityValue>{noInputs}
+    );
+    REQUIRE_FALSE(wrongInputCount.has_value());
+    CHECK(wrongInputCount.error().code() == eos::EvaluationErrorCode::wrong_input_count);
+
+    const auto wrongInputQuantity = view.tryEvaluate(
+        eos::thermodynamicQuantityId<eos::quantity::Density>, std::span<const eos::RuntimeQuantityValue>{pressureInput}
+    );
+    REQUIRE_FALSE(wrongInputQuantity.has_value());
+    CHECK(wrongInputQuantity.error().code() == eos::EvaluationErrorCode::wrong_input_quantity);
+
+    const auto unsupportedDerivative = view.tryPartialDerivative(
+        eos::thermodynamicQuantityId<eos::quantity::SpecificEnthalpy>,
+        eos::thermodynamicQuantityId<eos::quantity::Pressure>, std::span<const eos::RuntimeQuantityValue>{pressureInput}
+    );
+    REQUIRE_FALSE(unsupportedDerivative.has_value());
+    CHECK(unsupportedDerivative.error().code() == eos::EvaluationErrorCode::unsupported_derivative);
+
+    const auto invalidDensity = view.tryEvaluate<eos::quantity::Pressure>(eos::DensityValue{-0.1});
+    REQUIRE_FALSE(invalidDensity.has_value());
+    CHECK(invalidDensity.error().code() == eos::EvaluationErrorCode::outside_domain);
+
+    const auto nonfiniteDensity =
+        view.tryEvaluate<eos::quantity::Pressure>(eos::DensityValue{std::numeric_limits<double>::quiet_NaN()});
+    REQUIRE_FALSE(nonfiniteDensity.has_value());
+    CHECK(nonfiniteDensity.error().code() == eos::EvaluationErrorCode::nonfinite_input);
+}
+
+TEST_CASE(
+    "One Runtime EOS Function Accepts Heterogeneous Concrete Models",
+    tags::equation_of_state_runtime_compatibility
+) {
+    const eos::Polytrope polytrope(3.0, 0.25);
+    const LinearPressureEquationOfState linearEquationOfState;
+
+    const std::array views{eos::EquationOfStateView{polytrope}, eos::EquationOfStateView{linearEquationOfState}};
+
+    const eos::DensityValue density{0.7};
+
+    const auto polytropicPressure = pressureAtDensity(views[0], density);
+    const auto linearPressure     = pressureAtDensity(views[1], density);
+
+    REQUIRE(polytropicPressure.has_value());
+    REQUIRE(linearPressure.has_value());
+
+    CHECK(polytropicPressure->value() == eos::evaluate<eos::quantity::Pressure>(polytrope, density).value());
+    CHECK(linearPressure->value() == 1.9);
+}
+
+TEST_CASE(
+    "Runtime EOS View Remains Valid When Stable Ownership Moves",
+    tags::equation_of_state_runtime_contract
+) {
+    auto owner = std::make_unique<const eos::Polytrope>(3.0, 0.25);
+    const eos::EquationOfStateView view{*owner};
+
+    auto movedOwner     = std::move(owner);
+
+    const auto pressure = view.tryEvaluate<eos::quantity::Pressure>(eos::DensityValue{0.7});
+
+    REQUIRE(movedOwner != nullptr);
+    REQUIRE(pressure.has_value());
+    CHECK(pressure->value() == eos::evaluate<eos::quantity::Pressure>(*movedOwner, eos::DensityValue{0.7}).value());
+}

tests/physics/equation_of_state_type_system.cpp

@@ -0,0 +1,228 @@
+#include <concepts>
+#include <string_view>
+#include <type_traits>
+
+#include <catch2/catch_test_macros.hpp>
+
+import mean_field;
+import test_helpers;
+
+namespace {
+    namespace eos = mean_field::eos;
+
+    struct Entropy final : eos::ThermodynamicQuantity { };
+    struct ElectronFraction final : eos::ThermodynamicQuantity { };
+
+    using SpecificEnthalpyFromPressureAndEntropy =
+        eos::Relation<eos::quantity::SpecificEnthalpy, eos::quantity::Pressure, Entropy>;
+
+    class CompleteEquationOfState final {
+    public:
+        using Relations = eos::RelationCatalog<
+            eos::PressureFromDensity,
+            eos::SpecificEnthalpyFromPressure,
+            SpecificEnthalpyFromPressureAndEntropy>;
+
+        [[nodiscard]] constexpr eos::PressureValue evaluate(
+            eos::PressureFromDensity,
+            const eos::DensityValue density
+        ) const noexcept {
+            return eos::PressureValue{2.0 * density.value()};
+        }
+
+        [[nodiscard]] constexpr eos::SpecificEnthalpyValue evaluate(
+            eos::SpecificEnthalpyFromPressure,
+            const eos::PressureValue pressure
+        ) const noexcept {
+            return eos::SpecificEnthalpyValue{3.0 * pressure.value()};
+        }
+
+        [[nodiscard]] constexpr eos::SpecificEnthalpyValue evaluate(
+            SpecificEnthalpyFromPressureAndEntropy,
+            const eos::PressureValue pressure,
+            const eos::QuantityValue<Entropy> entropy
+        ) const noexcept {
+            return eos::SpecificEnthalpyValue{3.0 * pressure.value() + 5.0 * entropy.value()};
+        }
+
+        [[nodiscard]] constexpr eos::PartialDerivative<
+            eos::quantity::SpecificEnthalpy,
+            Entropy>
+        partialDerivative(
+            SpecificEnthalpyFromPressureAndEntropy,
+            eos::WithRespectTo<Entropy>,
+            eos::PressureValue,
+            eos::QuantityValue<Entropy>
+        ) const noexcept {
+            return eos::PartialDerivative<eos::quantity::SpecificEnthalpy, Entropy>{5.0};
+        }
+    };
+
+    class MissingRelationImplementation final {
+    public:
+        using Relations = eos::RelationCatalog<eos::PressureFromDensity, eos::SpecificEnthalpyFromPressure>;
+
+        [[nodiscard]] eos::PressureValue evaluate(
+            eos::PressureFromDensity,
+            eos::DensityValue density
+        ) const {
+            return eos::PressureValue{density.value()};
+        }
+    };
+
+    class IncorrectRelationOutput final {
+    public:
+        using Relations = eos::RelationCatalog<eos::PressureFromDensity>;
+
+        [[nodiscard]] eos::DensityValue evaluate(
+            eos::PressureFromDensity,
+            eos::DensityValue density
+        ) const {
+            return density;
+        }
+    };
+
+    class InvalidRelationCatalog final {
+    public:
+        using Relations = eos::RelationCatalog<eos::Relation<double, eos::quantity::Density>>;
+    };
+
+    template <typename EquationOfState>
+    concept CanEvaluateDensityFromSpecificEnthalpy = requires(const EquationOfState &equationOfState) {
+        eos::evaluate<eos::quantity::Density>(equationOfState, eos::SpecificEnthalpyValue{1.0});
+    };
+} // namespace
+
+TEST_CASE(
+    "Thermodynamic Values Preserve Physical Quantity Types",
+    tags::equation_of_state_quantity_types
+) {
+    STATIC_CHECK(eos::ThermodynamicQuantityType<eos::quantity::Density>);
+    STATIC_CHECK(eos::ThermodynamicQuantityType<eos::quantity::Pressure>);
+    STATIC_CHECK(eos::ThermodynamicQuantityType<eos::quantity::SpecificEnthalpy>);
+    STATIC_CHECK_FALSE(eos::ThermodynamicQuantityType<const eos::quantity::Pressure>);
+
+    STATIC_CHECK_FALSE(std::same_as<eos::DensityValue, eos::PressureValue>);
+    STATIC_CHECK_FALSE(std::same_as<eos::PressureValue, eos::SpecificEnthalpyValue>);
+    STATIC_CHECK_FALSE(std::is_convertible_v<double, eos::PressureValue>);
+    STATIC_CHECK_FALSE(std::is_constructible_v<eos::PressureValue, eos::DensityValue>);
+
+    STATIC_CHECK(std::is_trivially_copyable_v<eos::DensityValue>);
+    STATIC_CHECK(std::is_standard_layout_v<eos::DensityValue>);
+    STATIC_CHECK(sizeof(eos::DensityValue) == sizeof(double));
+    STATIC_CHECK(sizeof(eos::PressureValue) == sizeof(double));
+    STATIC_CHECK(sizeof(eos::SpecificEnthalpyValue) == sizeof(double));
+    STATIC_CHECK(std::is_empty_v<eos::PressureFromDensity>);
+
+    constexpr eos::DensityValue density{-0.25};
+    STATIC_CHECK(density.value() == -0.25);
+}
+
+TEST_CASE(
+    "Thermodynamic Derivatives Preserve Numerator And Denominator Types",
+    tags::equation_of_state_quantity_types
+) {
+    using PressureByDensity          = eos::PartialDerivative<eos::quantity::Pressure, eos::quantity::Density>;
+
+    using PressureBySpecificEnthalpy = eos::PartialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>;
+
+    STATIC_CHECK_FALSE(std::same_as<PressureByDensity, PressureBySpecificEnthalpy>);
+    STATIC_CHECK_FALSE(std::is_convertible_v<PressureByDensity, PressureBySpecificEnthalpy>);
+    STATIC_CHECK(std::is_trivially_copyable_v<PressureByDensity>);
+    STATIC_CHECK(std::is_standard_layout_v<PressureByDensity>);
+    STATIC_CHECK(sizeof(PressureByDensity) == sizeof(double));
+
+    constexpr PressureByDensity derivative{1.75};
+    STATIC_CHECK(derivative.value() == 1.75);
+}
+
+TEST_CASE(
+    "EOS Relation Catalog Rejects Invalid And Duplicate Relations",
+    tags::equation_of_state_relation_contract
+) {
+    using ValidCatalog     = eos::RelationCatalog<eos::PressureFromDensity, eos::SpecificEnthalpyFromPressure>;
+
+    using DuplicateCatalog = eos::RelationCatalog<eos::PressureFromDensity, eos::PressureFromDensity>;
+
+    using InvalidRelation  = eos::Relation<double, eos::quantity::Density>;
+    using InvalidCatalog   = eos::RelationCatalog<InvalidRelation>;
+    using RepeatedInputRelation =
+        eos::Relation<eos::quantity::Pressure, eos::quantity::Density, eos::quantity::Density>;
+    using RepeatedInputCatalog = eos::RelationCatalog<RepeatedInputRelation>;
+
+    STATIC_CHECK(eos::ValidRelationCatalog<ValidCatalog>);
+    STATIC_CHECK_FALSE(eos::ValidRelationCatalog<DuplicateCatalog>);
+    STATIC_CHECK_FALSE(eos::ValidRelationCatalog<InvalidCatalog>);
+    STATIC_CHECK_FALSE(eos::ValidRelationCatalog<RepeatedInputCatalog>);
+    STATIC_CHECK_FALSE(eos::ValidRelationCatalog<eos::RelationCatalog<>>);
+
+    STATIC_CHECK(eos::relationCatalogContains<ValidCatalog, eos::PressureFromDensity>);
+    STATIC_CHECK_FALSE(eos::relationCatalogContains<ValidCatalog, eos::DensityFromSpecificEnthalpy>);
+    STATIC_CHECK(eos::relationContainsInput<eos::PressureFromDensity, eos::quantity::Density>);
+    STATIC_CHECK_FALSE(eos::relationContainsInput<eos::PressureFromDensity, eos::quantity::Pressure>);
+
+    STATIC_CHECK(std::same_as<eos::RelationOutputT<eos::PressureFromDensity>, eos::quantity::Pressure>);
+    STATIC_CHECK(std::same_as<eos::RelationInputT<0, eos::PressureFromDensity>, eos::quantity::Density>);
+}
+
+TEST_CASE(
+    "EOS Model Contract Requires Every Declared Relation",
+    tags::equation_of_state_relation_contract
+) {
+    STATIC_CHECK(eos::EquationOfStateModel<CompleteEquationOfState>);
+    STATIC_CHECK_FALSE(eos::EquationOfStateModel<MissingRelationImplementation>);
+    STATIC_CHECK_FALSE(eos::EquationOfStateModel<IncorrectRelationOutput>);
+    STATIC_CHECK_FALSE(eos::EquationOfStateModel<InvalidRelationCatalog>);
+
+    STATIC_CHECK(eos::SupportsRelation<CompleteEquationOfState, eos::PressureFromDensity>);
+    STATIC_CHECK_FALSE(eos::SupportsRelation<CompleteEquationOfState, eos::DensityFromSpecificEnthalpy>);
+    STATIC_CHECK_FALSE(CanEvaluateDensityFromSpecificEnthalpy<CompleteEquationOfState>);
+    STATIC_CHECK(
+        eos::SupportsPartialDerivative<CompleteEquationOfState, SpecificEnthalpyFromPressureAndEntropy, Entropy>
+    );
+    STATIC_CHECK_FALSE(
+        eos::SupportsPartialDerivative<
+            CompleteEquationOfState, SpecificEnthalpyFromPressureAndEntropy, ElectronFraction>
+    );
+}
+
+TEST_CASE(
+    "EOS Evaluation Selects Relations From Typed Inputs",
+    tags::equation_of_state_relation_contract
+) {
+    constexpr CompleteEquationOfState equationOfState;
+
+    constexpr eos::PressureValue pressure =
+        eos::evaluate<eos::quantity::Pressure>(equationOfState, eos::DensityValue{1.25});
+
+    constexpr eos::SpecificEnthalpyValue specificEnthalpy = eos::evaluate<eos::quantity::SpecificEnthalpy>(
+        equationOfState, eos::PressureValue{0.5}, eos::QuantityValue<Entropy>{0.2}
+    );
+
+    constexpr auto entropyDerivative = eos::partialDerivative<eos::quantity::SpecificEnthalpy, Entropy>(
+        equationOfState, eos::PressureValue{0.5}, eos::QuantityValue<Entropy>{0.2}
+    );
+
+    STATIC_CHECK(noexcept(eos::evaluate<eos::quantity::Pressure>(equationOfState, eos::DensityValue{1.25})));
+    STATIC_CHECK(
+        noexcept(eos::partialDerivative<eos::quantity::SpecificEnthalpy, Entropy>(
+            equationOfState, eos::PressureValue{0.5}, eos::QuantityValue<Entropy>{0.2}
+        ))
+    );
+
+    STATIC_CHECK(pressure.value() == 2.5);
+    STATIC_CHECK(specificEnthalpy.value() == 2.5);
+    STATIC_CHECK(entropyDerivative.value() == 5.0);
+}
+
+TEST_CASE(
+    "EOS Evaluation Errors Retain A Structured Cause",
+    tags::equation_of_state_relation_contract
+) {
+    const eos::EvaluationError error(
+        eos::EvaluationErrorCode::outside_domain, "Density is outside the relation domain."
+    );
+
+    CHECK(error.code() == eos::EvaluationErrorCode::outside_domain);
+    CHECK(std::string_view{error.what()} == "Density is outside the relation domain.");
+}

tests/physics/polytropic_eos_characterization.cpp

@@ -0,0 +1,156 @@
+#include <array>
+#include <cmath>
+#include <limits>
+#include <stdexcept>
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers_floating_point.hpp>
+
+import mean_field;
+import test_helpers;
+
+namespace eos = mean_field::eos;
+
+TEST_CASE(
+    "Polytropic EOS Pressure To Specific Enthalpy Relation Is Characterized",
+    tags::polytropic_eos_characterization
+) {
+    constexpr std::array<double, 3> polytropicIndices{1.0, 1.5, 3.0};
+    constexpr std::array<double, 3> polytropicConstants{0.25, 0.73, 2.0};
+    constexpr std::array<double, 5> pressures{0.0, 1.0e-12, 1.0e-4, 0.3, 5.0};
+
+    for (const double polytropicIndex : polytropicIndices) {
+        for (const double polytropicConstant : polytropicConstants) {
+            const mean_field::eos::Polytrope equationOfState(polytropicIndex, polytropicConstant);
+
+            for (const double pressure : pressures) {
+                CAPTURE(polytropicIndex, polytropicConstant, pressure);
+
+                const double indexPlusOne     = polytropicIndex + 1.0;
+                const double expectedEnthalpy = indexPlusOne *
+                                                std::pow(polytropicConstant, polytropicIndex / indexPlusOne) *
+                                                std::pow(pressure, 1.0 / indexPlusOne);
+
+                const double enthalpy =
+                    eos::evaluate<eos::quantity::SpecificEnthalpy>(equationOfState, eos::PressureValue{pressure})
+                        .value();
+
+                if (pressure == 0.0) {
+                    CHECK(enthalpy == 0.0);
+                } else {
+                    CHECK_THAT(enthalpy, Catch::Matchers::WithinRel(expectedEnthalpy, 5.0e-14));
+
+                    const double recoveredPressure =
+                        eos::evaluate<eos::quantity::Pressure>(equationOfState, eos::SpecificEnthalpyValue{enthalpy})
+                            .value();
+
+                    CHECK_THAT(recoveredPressure, Catch::Matchers::WithinRel(pressure, 5.0e-13));
+                }
+            }
+        }
+    }
+}
+
+TEST_CASE(
+    "Polytropic EOS Domain Contract Covers Every Relation",
+    tags::polytropic_eos_characterization
+) {
+    constexpr double infinity = std::numeric_limits<double>::infinity();
+    constexpr double quietNaN = std::numeric_limits<double>::quiet_NaN();
+
+    for (const double invalidIndex : std::array<double, 4>{0.999, infinity, -infinity, quietNaN}) {
+        CAPTURE(invalidIndex);
+        CHECK_THROWS_AS(mean_field::eos::Polytrope(invalidIndex, 1.0), std::invalid_argument);
+    }
+
+    for (const double invalidConstant : std::array<double, 5>{0.0, -0.1, infinity, -infinity, quietNaN}) {
+        CAPTURE(invalidConstant);
+        CHECK_THROWS_AS(mean_field::eos::Polytrope(3.0, invalidConstant), std::invalid_argument);
+    }
+
+    const mean_field::eos::Polytrope equationOfState(3.0, 0.75);
+
+    constexpr double negativeDensity = -0.1;
+    CHECK_THROWS_AS(
+        eos::evaluate<eos::quantity::Pressure>(equationOfState, eos::DensityValue{negativeDensity}), std::domain_error
+    );
+    CHECK_THROWS_AS(
+        eos::evaluate<eos::quantity::SpecificEnthalpy>(equationOfState, eos::DensityValue{negativeDensity}),
+        std::domain_error
+    );
+    CHECK_THROWS_AS(
+        (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::Density>(
+            equationOfState, eos::DensityValue{negativeDensity}
+        )),
+        std::domain_error
+    );
+
+    CHECK_THROWS_AS(
+        eos::evaluate<eos::quantity::SpecificEnthalpy>(equationOfState, eos::PressureValue{-0.1}), std::domain_error
+    );
+
+    constexpr double exteriorEnthalpy = -0.1;
+    CHECK(
+        eos::evaluate<eos::quantity::Density>(equationOfState, eos::SpecificEnthalpyValue{exteriorEnthalpy}).value() ==
+        0.0
+    );
+    CHECK(
+        eos::evaluate<eos::quantity::Pressure>(equationOfState, eos::SpecificEnthalpyValue{exteriorEnthalpy}).value() ==
+        0.0
+    );
+    CHECK(
+        (eos::partialDerivative<eos::quantity::Density, eos::quantity::SpecificEnthalpy>(
+             equationOfState, eos::SpecificEnthalpyValue{exteriorEnthalpy}
+         )
+             .value() == 0.0)
+    );
+    CHECK(
+        (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>(
+             equationOfState, eos::SpecificEnthalpyValue{exteriorEnthalpy}
+         )
+             .value() == 0.0)
+    );
+
+    for (const double nonfiniteValue : std::array<double, 3>{infinity, -infinity, quietNaN}) {
+        CAPTURE(nonfiniteValue);
+
+        CHECK_THROWS_AS(
+            eos::evaluate<eos::quantity::Pressure>(equationOfState, eos::DensityValue{nonfiniteValue}),
+            std::domain_error
+        );
+        CHECK_THROWS_AS(
+            eos::evaluate<eos::quantity::SpecificEnthalpy>(equationOfState, eos::DensityValue{nonfiniteValue}),
+            std::domain_error
+        );
+        CHECK_THROWS_AS(
+            (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::Density>(
+                equationOfState, eos::DensityValue{nonfiniteValue}
+            )),
+            std::domain_error
+        );
+        CHECK_THROWS_AS(
+            eos::evaluate<eos::quantity::SpecificEnthalpy>(equationOfState, eos::PressureValue{nonfiniteValue}),
+            std::domain_error
+        );
+        CHECK_THROWS_AS(
+            eos::evaluate<eos::quantity::Density>(equationOfState, eos::SpecificEnthalpyValue{nonfiniteValue}),
+            std::domain_error
+        );
+        CHECK_THROWS_AS(
+            eos::evaluate<eos::quantity::Pressure>(equationOfState, eos::SpecificEnthalpyValue{nonfiniteValue}),
+            std::domain_error
+        );
+        CHECK_THROWS_AS(
+            (eos::partialDerivative<eos::quantity::Density, eos::quantity::SpecificEnthalpy>(
+                equationOfState, eos::SpecificEnthalpyValue{nonfiniteValue}
+            )),
+            std::domain_error
+        );
+        CHECK_THROWS_AS(
+            (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>(
+                equationOfState, eos::SpecificEnthalpyValue{nonfiniteValue}
+            )),
+            std::domain_error
+        );
+    }
+}

tests/physics/polytropic_eos_relations.cpp

@@ -0,0 +1,200 @@
+#include <array>
+#include <cmath>
+#include <concepts>
+#include <limits>
+#include <type_traits>
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers_floating_point.hpp>
+
+import mean_field;
+import test_helpers;
+
+namespace {
+    namespace eos = mean_field::eos;
+
+    template <typename Candidate>
+    concept HasAnyUnaryEquationOfStateConversion =
+        requires(const Candidate &candidate, const double value) { candidate.pressure_from_density(value); } ||
+        requires(const Candidate &candidate, const double value) { candidate.pressure_from_enthalpy(value); } ||
+        requires(const Candidate &candidate, const double value) { candidate.enthalpy_from_density(value); } ||
+        requires(const Candidate &candidate, const double value) { candidate.enthalpy_from_pressure(value); } ||
+        requires(const Candidate &candidate, const double value) { candidate.density_from_enthalpy(value); } ||
+        requires(const Candidate &candidate, const double value) {
+            candidate.density_derivative_from_enthalpy(value);
+        } ||
+        requires(const Candidate &candidate, const double value) {
+            candidate.pressure_derivative_from_enthalpy(value);
+        } ||
+        requires(const Candidate &candidate, const double value) { candidate.pressure_derivative_from_density(value); };
+} // namespace
+
+TEST_CASE(
+    "Polytropic EOS Declares Its Thermodynamic Relation Contract",
+    tags::polytropic_eos_relation_contract
+) {
+    using Polytrope = eos::Polytrope;
+
+    STATIC_CHECK(eos::EquationOfStateModel<Polytrope>);
+    STATIC_CHECK_FALSE(std::is_polymorphic_v<Polytrope>);
+    STATIC_CHECK_FALSE(HasAnyUnaryEquationOfStateConversion<Polytrope>);
+    STATIC_CHECK(Polytrope::Relations::size == 5);
+
+    STATIC_CHECK(eos::SupportsRelation<Polytrope, eos::PressureFromDensity>);
+    STATIC_CHECK(eos::SupportsRelation<Polytrope, eos::PressureFromSpecificEnthalpy>);
+    STATIC_CHECK(eos::SupportsRelation<Polytrope, eos::SpecificEnthalpyFromDensity>);
+    STATIC_CHECK(eos::SupportsRelation<Polytrope, eos::SpecificEnthalpyFromPressure>);
+    STATIC_CHECK(eos::SupportsRelation<Polytrope, eos::DensityFromSpecificEnthalpy>);
+
+    STATIC_CHECK(eos::SupportsPartialDerivative<Polytrope, eos::PressureFromDensity, eos::quantity::Density>);
+    STATIC_CHECK(
+        eos::SupportsPartialDerivative<Polytrope, eos::PressureFromSpecificEnthalpy, eos::quantity::SpecificEnthalpy>
+    );
+    STATIC_CHECK(
+        eos::SupportsPartialDerivative<Polytrope, eos::DensityFromSpecificEnthalpy, eos::quantity::SpecificEnthalpy>
+    );
+
+    STATIC_CHECK_FALSE(
+        eos::SupportsPartialDerivative<Polytrope, eos::SpecificEnthalpyFromPressure, eos::quantity::Pressure>
+    );
+    STATIC_CHECK_FALSE(
+        eos::SupportsPartialDerivative<Polytrope, eos::SpecificEnthalpyFromDensity, eos::quantity::Density>
+    );
+}
+
+TEST_CASE(
+    "Polytropic EOS Typed Relations Preserve Analytic Values",
+    tags::polytropic_eos_characterization
+) {
+    constexpr std::array<double, 3> polytropicIndices{1.0, 1.5, 3.0};
+    constexpr std::array<double, 2> polytropicConstants{0.25, 0.73};
+    constexpr std::array<double, 4> densities{0.0, 1.0e-6, 0.2, 2.0};
+    constexpr std::array<double, 4> specificEnthalpies{-0.3, 0.0, 0.2, 1.7};
+    constexpr std::array<double, 4> pressures{0.0, 1.0e-8, 0.3, 4.0};
+
+    for (const double polytropicIndex : polytropicIndices) {
+        for (const double polytropicConstant : polytropicConstants) {
+            const eos::Polytrope equationOfState(polytropicIndex, polytropicConstant);
+
+            for (const double density : densities) {
+                CAPTURE(polytropicIndex, polytropicConstant, density);
+
+                const double expectedPressure = polytropicConstant * std::pow(density, 1.0 + 1.0 / polytropicIndex);
+                const double expectedSpecificEnthalpy =
+                    (polytropicIndex + 1.0) * polytropicConstant * std::pow(density, 1.0 / polytropicIndex);
+
+                CHECK(
+                    eos::evaluate<eos::quantity::Pressure>(equationOfState, eos::DensityValue{density}).value() ==
+                    expectedPressure
+                );
+
+                CHECK(
+                    eos::evaluate<eos::quantity::SpecificEnthalpy>(equationOfState, eos::DensityValue{density})
+                        .value() == expectedSpecificEnthalpy
+                );
+
+                CHECK_THAT(
+                    (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::Density>(
+                         equationOfState, eos::DensityValue{density}
+                    )
+                         .value()),
+                    Catch::Matchers::WithinRel(
+                        density == 0.0 ? 0.0 : expectedSpecificEnthalpy / polytropicIndex, 2.0e-15
+                    )
+                );
+            }
+
+            for (const double specificEnthalpy : specificEnthalpies) {
+                CAPTURE(polytropicIndex, polytropicConstant, specificEnthalpy);
+
+                const double expectedDensity =
+                    specificEnthalpy <= 0.0
+                        ? 0.0
+                        : std::pow(specificEnthalpy / ((polytropicIndex + 1.0) * polytropicConstant), polytropicIndex);
+
+                CHECK(
+                    eos::evaluate<eos::quantity::Density>(equationOfState, eos::SpecificEnthalpyValue{specificEnthalpy})
+                        .value() == expectedDensity
+                );
+
+                CHECK(
+                    eos::evaluate<eos::quantity::Pressure>(
+                        equationOfState, eos::SpecificEnthalpyValue{specificEnthalpy}
+                    )
+                        .value() ==
+                    (specificEnthalpy <= 0.0 ? 0.0 : expectedDensity * specificEnthalpy / (polytropicIndex + 1.0))
+                );
+
+                CHECK(
+                    (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>(
+                         equationOfState, eos::SpecificEnthalpyValue{specificEnthalpy}
+                     )
+                         .value() == expectedDensity)
+                );
+            }
+
+            for (const double pressure : pressures) {
+                CAPTURE(polytropicIndex, polytropicConstant, pressure);
+
+                const double indexPlusOne             = polytropicIndex + 1.0;
+                const double expectedSpecificEnthalpy = indexPlusOne *
+                                                        std::pow(polytropicConstant, polytropicIndex / indexPlusOne) *
+                                                        std::pow(pressure, 1.0 / indexPlusOne);
+
+                CHECK(
+                    eos::evaluate<eos::quantity::SpecificEnthalpy>(equationOfState, eos::PressureValue{pressure})
+                        .value() == expectedSpecificEnthalpy
+                );
+            }
+        }
+    }
+}
+
+TEST_CASE(
+    "Typed Polytropic EOS Preserves Domain And Exterior Semantics",
+    tags::polytropic_eos_relation_contract
+) {
+    const eos::Polytrope equationOfState(3.0, 0.75);
+
+    try {
+        static_cast<void>(eos::evaluate<eos::quantity::Pressure>(equationOfState, eos::DensityValue{-0.1}));
+        FAIL("A negative density must be rejected.");
+    } catch (const eos::EvaluationError &error) {
+        CHECK(error.code() == eos::EvaluationErrorCode::outside_domain);
+    }
+
+    try {
+        static_cast<void>(eos::evaluate<eos::quantity::SpecificEnthalpy>(
+            equationOfState, eos::PressureValue{std::numeric_limits<double>::quiet_NaN()}
+        ));
+        FAIL("A nonfinite pressure must be rejected.");
+    } catch (const eos::EvaluationError &error) {
+        CHECK(error.code() == eos::EvaluationErrorCode::nonfinite_input);
+    }
+
+    constexpr double exteriorSpecificEnthalpy = -0.3;
+
+    CHECK(
+        eos::evaluate<eos::quantity::Density>(equationOfState, eos::SpecificEnthalpyValue{exteriorSpecificEnthalpy})
+            .value() == 0.0
+    );
+
+    CHECK(
+        eos::evaluate<eos::quantity::Pressure>(equationOfState, eos::SpecificEnthalpyValue{exteriorSpecificEnthalpy})
+            .value() == 0.0
+    );
+
+    CHECK(
+        (eos::partialDerivative<eos::quantity::Density, eos::quantity::SpecificEnthalpy>(
+             equationOfState, eos::SpecificEnthalpyValue{exteriorSpecificEnthalpy}
+         )
+             .value() == 0.0)
+    );
+
+    CHECK(
+        (eos::partialDerivative<eos::quantity::Pressure, eos::quantity::SpecificEnthalpy>(
+             equationOfState, eos::SpecificEnthalpyValue{exteriorSpecificEnthalpy}
+         )
+             .value() == 0.0)
+    );
+}

tests/surface/constant_surface_compilation.cpp

@@ -0,0 +1,329 @@
+#include <cmath>
+#include <concepts>
+#include <limits>
+#include <string_view>
+#include <type_traits>
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers_floating_point.hpp>
+
+import mean_field;
+import test_helpers;
+
+namespace {
+    namespace eos     = mean_field::eos;
+    namespace field   = mean_field::field;
+    namespace surface = mean_field::surface;
+
+    struct Entropy final : eos::ThermodynamicQuantity {
+        static constexpr std::string_view identifier = "entropy";
+    };
+
+    struct ElectronFraction final : eos::ThermodynamicQuantity {
+        static constexpr std::string_view identifier = "electron_fraction";
+    };
+
+    struct EntropyField final {
+        static constexpr std::string_view name = "entropy";
+    };
+
+    struct ElectronFractionField final {
+        static constexpr std::string_view name = "electron_fraction";
+    };
+
+    using SpecificEnthalpyFromPressureEntropyAndElectronFraction =
+        eos::Relation<eos::quantity::SpecificEnthalpy, eos::quantity::Pressure, Entropy, ElectronFraction>;
+
+    class GeneralStellarMatterEquationOfState final {
+    public:
+        using Relations = eos::RelationCatalog<SpecificEnthalpyFromPressureEntropyAndElectronFraction>;
+
+        [[nodiscard]] constexpr eos::SpecificEnthalpyValue evaluate(
+            SpecificEnthalpyFromPressureEntropyAndElectronFraction,
+            const eos::PressureValue pressure,
+            const eos::QuantityValue<Entropy> entropy,
+            const eos::QuantityValue<ElectronFraction> electronFraction
+        ) const noexcept {
+            return eos::SpecificEnthalpyValue{
+                2.0 * pressure.value() + 3.0 * entropy.value() + 5.0 * electronFraction.value()
+            };
+        }
+
+        [[nodiscard]] constexpr eos::PartialDerivative<
+            eos::quantity::SpecificEnthalpy,
+            Entropy>
+        partialDerivative(
+            SpecificEnthalpyFromPressureEntropyAndElectronFraction,
+            eos::WithRespectTo<Entropy>,
+            eos::PressureValue,
+            eos::QuantityValue<Entropy>,
+            eos::QuantityValue<ElectronFraction>
+        ) const noexcept {
+            return eos::PartialDerivative<eos::quantity::SpecificEnthalpy, Entropy>{3.0};
+        }
+
+        [[nodiscard]] constexpr eos::PartialDerivative<
+            eos::quantity::SpecificEnthalpy,
+            ElectronFraction>
+        partialDerivative(
+            SpecificEnthalpyFromPressureEntropyAndElectronFraction,
+            eos::WithRespectTo<ElectronFraction>,
+            eos::PressureValue,
+            eos::QuantityValue<Entropy>,
+            eos::QuantityValue<ElectronFraction>
+        ) const noexcept {
+            return eos::PartialDerivative<eos::quantity::SpecificEnthalpy, ElectronFraction>{5.0};
+        }
+    };
+
+    class GeneralEquationOfStateWithoutElectronFractionPartial final {
+    public:
+        using Relations = eos::RelationCatalog<SpecificEnthalpyFromPressureEntropyAndElectronFraction>;
+
+        [[nodiscard]] constexpr eos::SpecificEnthalpyValue evaluate(
+            SpecificEnthalpyFromPressureEntropyAndElectronFraction,
+            const eos::PressureValue pressure,
+            const eos::QuantityValue<Entropy> entropy,
+            const eos::QuantityValue<ElectronFraction> electronFraction
+        ) const noexcept {
+            return eos::SpecificEnthalpyValue{pressure.value() + entropy.value() + electronFraction.value()};
+        }
+
+        [[nodiscard]] constexpr eos::PartialDerivative<
+            eos::quantity::SpecificEnthalpy,
+            Entropy>
+        partialDerivative(
+            SpecificEnthalpyFromPressureEntropyAndElectronFraction,
+            eos::WithRespectTo<Entropy>,
+            eos::PressureValue,
+            eos::QuantityValue<Entropy>,
+            eos::QuantityValue<ElectronFraction>
+        ) const noexcept {
+            return eos::PartialDerivative<eos::quantity::SpecificEnthalpy, Entropy>{1.0};
+        }
+    };
+
+    using SpecificEnthalpyFromPressureAndEntropy =
+        eos::Relation<eos::quantity::SpecificEnthalpy, eos::quantity::Pressure, Entropy>;
+
+    class AmbiguousSurfaceEquationOfState final {
+    public:
+        using Relations =
+            eos::RelationCatalog<eos::SpecificEnthalpyFromPressure, SpecificEnthalpyFromPressureAndEntropy>;
+
+        [[nodiscard]] constexpr eos::SpecificEnthalpyValue evaluate(
+            eos::SpecificEnthalpyFromPressure,
+            const eos::PressureValue pressure
+        ) const noexcept {
+            return eos::SpecificEnthalpyValue{pressure.value()};
+        }
+
+        [[nodiscard]] constexpr eos::SpecificEnthalpyValue evaluate(
+            SpecificEnthalpyFromPressureAndEntropy,
+            const eos::PressureValue pressure,
+            const eos::QuantityValue<Entropy> entropy
+        ) const noexcept {
+            return eos::SpecificEnthalpyValue{pressure.value() + entropy.value()};
+        }
+
+        [[nodiscard]] constexpr eos::PartialDerivative<
+            eos::quantity::SpecificEnthalpy,
+            Entropy>
+        partialDerivative(
+            SpecificEnthalpyFromPressureAndEntropy,
+            eos::WithRespectTo<Entropy>,
+            eos::PressureValue,
+            eos::QuantityValue<Entropy>
+        ) const noexcept {
+            return eos::PartialDerivative<eos::quantity::SpecificEnthalpy, Entropy>{1.0};
+        }
+    };
+
+    class DensityOnlyEquationOfState final {
+    public:
+        using Relations = eos::RelationCatalog<eos::PressureFromDensity>;
+
+        [[nodiscard]] constexpr eos::PressureValue evaluate(
+            eos::PressureFromDensity,
+            const eos::DensityValue density
+        ) const noexcept {
+            return eos::PressureValue{density.value()};
+        }
+    };
+
+    using GeneralSurfaceFormulation = surface::SurfaceConstraintFormulation<
+        eos::quantity::SpecificEnthalpy,
+        field::Enthalpy,
+        surface::SurfaceStateBindings<
+            surface::SurfaceStateBinding<eos::quantity::SpecificEnthalpy, field::Enthalpy>,
+            surface::SurfaceStateBinding<Entropy, EntropyField>,
+            surface::SurfaceStateBinding<ElectronFraction, ElectronFractionField>>>;
+
+    struct PolytropicSurfaceState final {
+        double specificEnthalpy;
+
+        [[nodiscard]] eos::SpecificEnthalpyValue value(eos::quantity::SpecificEnthalpy) const noexcept {
+            return eos::SpecificEnthalpyValue{specificEnthalpy};
+        }
+    };
+
+    struct GeneralSurfaceState final {
+        double specificEnthalpy;
+        double entropy;
+        double electronFraction;
+
+        [[nodiscard]] eos::SpecificEnthalpyValue value(eos::quantity::SpecificEnthalpy) const noexcept {
+            return eos::SpecificEnthalpyValue{specificEnthalpy};
+        }
+
+        [[nodiscard]] eos::QuantityValue<Entropy> value(Entropy) const noexcept {
+            return eos::QuantityValue<Entropy>{entropy};
+        }
+
+        [[nodiscard]] eos::QuantityValue<ElectronFraction> value(ElectronFraction) const noexcept {
+            return eos::QuantityValue<ElectronFraction>{electronFraction};
+        }
+    };
+
+    template <typename Candidate>
+    concept HasTargetEnthalpy = requires(const Candidate &candidate) { candidate.targetEnthalpy; };
+} // namespace
+
+TEST_CASE(
+    "Constant Pressure Surface Prescribes Only A Pressure Quantity",
+    tags::surface_prescription_type_contract
+) {
+    STATIC_CHECK(std::same_as<surface::ConstantPressureSurface::PhysicalQuantity, eos::quantity::Pressure>);
+    STATIC_CHECK(std::constructible_from<surface::ConstantPressureSurface, eos::PressureValue>);
+    STATIC_CHECK_FALSE(std::constructible_from<surface::ConstantPressureSurface, eos::SpecificEnthalpyValue>);
+    STATIC_CHECK_FALSE(std::constructible_from<surface::ConstantPressureSurface, double>);
+    STATIC_CHECK(std::same_as<surface::Isobaric, surface::ConstantPressureSurface>);
+    STATIC_CHECK(std::is_trivially_copyable_v<surface::ConstantPressureSurface>);
+    STATIC_CHECK(std::is_trivially_copyable_v<surface::PressureSurfaceDescriptor>);
+    STATIC_CHECK(std::is_trivially_copyable_v<surface::RuntimeSurfaceConstraintDependencies>);
+
+    const surface::ConstantPressureSurface pressureSurface{eos::PressureValue{0.03125}};
+
+    CHECK(pressureSurface.targetPressure() == eos::PressureValue{0.03125});
+    CHECK(pressureSurface.descriptor().targetPressure == 0.03125);
+
+    CHECK_THROWS_AS(surface::ConstantPressureSurface{eos::PressureValue{-0.1}}, std::invalid_argument);
+    CHECK_THROWS_AS(
+        surface::ConstantPressureSurface{eos::PressureValue{std::numeric_limits<double>::infinity()}},
+        std::invalid_argument
+    );
+}
+
+TEST_CASE(
+    "Polytropic EOS Resolves Constant Surface Pressure Through Its Enthalpy Relation",
+    tags::surface_constraint_compilation
+) {
+    using Formulation = surface::BarotropicSurfaceFormulation;
+
+    STATIC_CHECK(surface::PressureSurfaceCompilable<Formulation, eos::Polytrope>);
+    STATIC_CHECK_FALSE(surface::PressureSurfaceCompilable<Formulation, DensityOnlyEquationOfState>);
+
+    const eos::Polytrope equationOfState(3.0, 0.25);
+    const surface::ConstantPressureSurface pressureSurface{eos::PressureValue{0.03125}};
+    const auto constraint = surface::compilePressureSurfaceConstraint<Formulation>(pressureSurface, equationOfState);
+
+    using Constraint      = std::remove_cvref_t<decltype(constraint)>;
+    using Dependencies    = Constraint::SurfaceDependencies;
+
+    STATIC_CHECK(std::is_trivially_copyable_v<Constraint>);
+    STATIC_CHECK(std::same_as<Constraint::Relation, eos::SpecificEnthalpyFromPressure>);
+    STATIC_CHECK(std::same_as<Dependencies::RowField, field::Enthalpy>);
+    STATIC_CHECK(std::same_as<Dependencies::StateFieldTypes, field::TypeList<field::Enthalpy>>);
+    STATIC_CHECK_FALSE(HasTargetEnthalpy<Constraint>);
+
+    const double requiredSpecificEnthalpy =
+        eos::evaluate<eos::quantity::SpecificEnthalpy>(equationOfState, pressureSurface.targetPressure()).value();
+    const PolytropicSurfaceState state{requiredSpecificEnthalpy};
+    const PolytropicSurfaceState variation{-0.19};
+
+    CHECK(constraint.targetPressure() == eos::PressureValue{0.03125});
+    CHECK(constraint.residual(state) == 0.0);
+    CHECK(constraint.jacobianAction(state, variation) == -0.19);
+
+    const auto runtimeDependencies = constraint.runtimeDependencies();
+    REQUIRE(runtimeDependencies.stateFields.size() == 1);
+    CHECK(runtimeDependencies.residualRowField == surface::surfaceFieldId<field::Enthalpy>);
+    CHECK(runtimeDependencies.stateFields[0] == surface::surfaceFieldId<field::Enthalpy>);
+}
+
+TEST_CASE(
+    "General EOS Resolves Constant Surface Pressure With Local Composition",
+    tags::surface_constraint_compilation
+) {
+    STATIC_CHECK(surface::PressureSurfaceCompilable<GeneralSurfaceFormulation, GeneralStellarMatterEquationOfState>);
+    STATIC_CHECK_FALSE(
+        surface::PressureSurfaceCompilable<surface::BarotropicSurfaceFormulation, GeneralStellarMatterEquationOfState>
+    );
+    STATIC_CHECK_FALSE(
+        surface::PressureSurfaceCompilable<
+            GeneralSurfaceFormulation, GeneralEquationOfStateWithoutElectronFractionPartial>
+    );
+    STATIC_CHECK_FALSE(surface::PressureSurfaceCompilable<GeneralSurfaceFormulation, AmbiguousSurfaceEquationOfState>);
+
+    const GeneralStellarMatterEquationOfState equationOfState;
+    const surface::ConstantPressureSurface pressureSurface{eos::PressureValue{0.4}};
+    const auto constraint =
+        surface::compilePressureSurfaceConstraint<GeneralSurfaceFormulation>(pressureSurface, equationOfState);
+
+    using Constraint   = std::remove_cvref_t<decltype(constraint)>;
+    using Dependencies = Constraint::SurfaceDependencies;
+
+    STATIC_CHECK(std::same_as<Constraint::Relation, SpecificEnthalpyFromPressureEntropyAndElectronFraction>);
+    STATIC_CHECK(
+        std::same_as<
+            Dependencies::StateFieldTypes, field::TypeList<field::Enthalpy, EntropyField, ElectronFractionField>>
+    );
+
+    constexpr GeneralSurfaceState firstSurface{
+        .specificEnthalpy = 2.0 * 0.4 + 3.0 * 0.2 + 5.0 * 0.1, .entropy = 0.2, .electronFraction = 0.1
+    };
+    constexpr GeneralSurfaceState secondSurface{
+        .specificEnthalpy = 2.0 * 0.4 + 3.0 * 0.3 + 5.0 * 0.1, .entropy = 0.3, .electronFraction = 0.1
+    };
+
+    CHECK(firstSurface.specificEnthalpy != secondSurface.specificEnthalpy);
+    CHECK(constraint.residual(firstSurface) == 0.0);
+    CHECK(constraint.residual(secondSurface) == 0.0);
+
+    const auto runtimeDependencies = constraint.runtimeDependencies();
+    REQUIRE(runtimeDependencies.stateFields.size() == 3);
+    CHECK(runtimeDependencies.stateFields[0] == surface::surfaceFieldId<field::Enthalpy>);
+    CHECK(runtimeDependencies.stateFields[1] == surface::surfaceFieldId<EntropyField>);
+    CHECK(runtimeDependencies.stateFields[2] == surface::surfaceFieldId<ElectronFractionField>);
+}
+
+TEST_CASE(
+    "General EOS Pressure Surface Jacobian Includes Every Local State Dependency",
+    tags::surface_constraint_jacobian
+) {
+    const GeneralStellarMatterEquationOfState equationOfState;
+    const surface::ConstantPressureSurface pressureSurface{eos::PressureValue{0.4}};
+    const auto constraint =
+        surface::compilePressureSurfaceConstraint<GeneralSurfaceFormulation>(pressureSurface, equationOfState);
+
+    constexpr GeneralSurfaceState state{.specificEnthalpy = 1.7, .entropy = 0.2, .electronFraction = 0.1};
+    constexpr GeneralSurfaceState variation{.specificEnthalpy = 0.7, .entropy = -0.2, .electronFraction = 0.05};
+    constexpr double step = 1.0e-7;
+
+    const GeneralSurfaceState forward{
+        .specificEnthalpy = state.specificEnthalpy + step * variation.specificEnthalpy,
+        .entropy          = state.entropy + step * variation.entropy,
+        .electronFraction = state.electronFraction + step * variation.electronFraction
+    };
+    const GeneralSurfaceState backward{
+        .specificEnthalpy = state.specificEnthalpy - step * variation.specificEnthalpy,
+        .entropy          = state.entropy - step * variation.entropy,
+        .electronFraction = state.electronFraction - step * variation.electronFraction
+    };
+
+    const double finiteDifference = (constraint.residual(forward) - constraint.residual(backward)) / (2.0 * step);
+    const double jacobianAction   = constraint.jacobianAction(state, variation);
+
+    CHECK(jacobianAction == variation.specificEnthalpy - 3.0 * variation.entropy - 5.0 * variation.electronFraction);
+    CHECK_THAT(finiteDifference, Catch::Matchers::WithinAbs(jacobianAction, 2.0e-9));
+}

tests/surface/isobaric.cpp

@@ -1,76 +0,0 @@
-#include <cmath>
-#include <limits>
-#include <stdexcept>
-
-#include <catch2/catch_test_macros.hpp>
-
-import mean_field;
-import test_helpers;
-
-TEST_CASE(
-    "Isobaric Surface Resolves Zero Pressure To Zero Enthalpy",
-    tags::barotrope &tags::unit &tags::surface
-) {
-    const mean_field::eos::Polytrope equationOfState(3.0, 0.25);
-
-    const mean_field::surface::Isobaric surface;
-
-    const mean_field::surface::ResolvedSurfaceCondition resolved = surface.resolve(equationOfState);
-
-    CHECK(surface.targetPressure() == 0.0);
-    CHECK(resolved.targetEnthalpy == 0.0);
-    CHECK(resolved.residual(0.0) == 0.0);
-    CHECK(resolved.residual(0.37) == 0.37);
-    CHECK(resolved.jacobianAction(-0.19) == -0.19);
-}
-
-TEST_CASE(
-    "Isobaric Surface Resolves Positive Pressure Through The EOS",
-    tags::barotrope &tags::unit &tags::surface
-) {
-    const mean_field::eos::Polytrope equationOfState(3.0, 0.25);
-
-    constexpr double targetPressure = 0.03125;
-
-    const mean_field::surface::Isobaric surface(targetPressure);
-
-    const mean_field::surface::ResolvedSurfaceCondition resolved = surface.resolve(equationOfState);
-
-    const double recoveredPressure = equationOfState.pressure_from_enthalpy(resolved.targetEnthalpy);
-
-    INFO("Resolved surface enthalpy = " << resolved.targetEnthalpy);
-    INFO("Recovered surface pressure = " << recoveredPressure);
-
-    CHECK(resolved.targetEnthalpy > 0.0);
-    CHECK(std::abs(recoveredPressure - targetPressure) < 64.0 * std::numeric_limits<double>::epsilon());
-    CHECK(resolved.residual(resolved.targetEnthalpy) == 0.0);
-}
-
-TEST_CASE(
-    "Isobaric Surface Rejects Invalid Pressure Targets",
-    tags::barotrope &tags::unit &tags::surface
-) {
-    CHECK_THROWS_AS(mean_field::surface::Isobaric(-1.0), std::invalid_argument);
-
-    CHECK_THROWS_AS(mean_field::surface::Isobaric(std::numeric_limits<double>::infinity()), std::invalid_argument);
-
-    CHECK_THROWS_AS(mean_field::surface::Isobaric(std::numeric_limits<double>::quiet_NaN()), std::invalid_argument);
-}
-
-TEST_CASE(
-    "Surface Base Dispatch Preserves The Isobaric Prescription",
-    tags::barotrope &tags::unit &tags::surface
-) {
-    const mean_field::eos::Polytrope equationOfState(3.0, 0.25);
-
-    const mean_field::surface::Isobaric isobaric(0.02);
-
-    const mean_field::surface::SurfaceBase &surface = isobaric;
-
-    surface.validate(equationOfState);
-
-    const mean_field::surface::ResolvedSurfaceCondition resolved = surface.resolve(equationOfState);
-
-    CHECK(resolved.targetEnthalpy > 0.0);
-    CHECK(resolved.residual(resolved.targetEnthalpy) == 0.0);
-}

tests/test_helpers.cppm

@@ -16,18 +16,25 @@ template <std::size_t N> struct Tag {
     std::array<char, N> chars{};
 
     // ReSharper disable once CppNonExplicitConvertingConstructor
-  consteval Tag(std::array<char, N> arr) : chars(arr) {}
+    consteval Tag(
+        std::array<
+            char,
+            N> arr
+    )
+        : chars(arr) {
+    }
 
     // ReSharper disable once CppNonExplicitConversionOperator
-  constexpr operator const char *() const { return chars.data(); }
+    constexpr operator const char *() const {
+        return chars.data();
+    }
 
     // ReSharper disable once CppNonExplicitConversionOperator
     constexpr operator Catch::StringRef() const {
         return Catch::StringRef(chars.data(), N - 1);
     }
 
-  template <std::size_t M>
+    template <std::size_t M> consteval Tag<N + M - 1> operator&(const Tag<M> &other) const {
-  consteval Tag<N + M - 1> operator&(const Tag<M> &other) const {
         std::array<char, N + M - 1> res{};
         std::ranges::copy(chars.begin(), chars.end() - 1, res.begin());
         std::ranges::copy(other.chars, res.begin() + (N - 1));
@@ -44,109 +51,112 @@ template <std::size_t N> consteval auto make_tag(const char (&str)[N]) {
     return Tag<N + 2>{res};
 }
 
-template <std::size_t N, std::size_t M>
+template <
-consteval auto sub_tag(const Tag<N> &parent, const char (&str)[M]) {
+    std::size_t N,
+    std::size_t M>
+consteval auto sub_tag(
+    const Tag<N> &parent,
+    const char (&str)[M]
+) {
     return parent & make_tag(str);
 }
 
 namespace test_utils::detail {
-std::optional<mean_field::utils::Args> configured_args;
+    std::optional<mean_field::utils::Args> configured_args;
 
-mean_field::utils::Args make_default_args() {
+    mean_field::utils::Args make_default_args() {
         mean_field::utils::Args args;
         args.mesh_file = "sandbox.smesh";
         args.p.rtol    = 1.0e-12;
         args.p.atol    = 1.0e-12;
         return args;
-}
+    }
 } // namespace test_utils::detail
 
 export namespace test_utils {
-void set_args(mean_field::utils::Args args) {
+    void set_args(mean_field::utils::Args args) {
         detail::configured_args = std::move(args);
-}
+    }
 
-mean_field::utils::Args setup_args() {
+    mean_field::utils::Args setup_args() {
         if (detail::configured_args.has_value()) {
             return *detail::configured_args;
         }
 
         return detail::make_default_args();
-}
+    }
 } // namespace test_utils
 
 export namespace gravity_prepared_test_utils {
-using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
+    using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
 
-template <typename FieldT>
+    template <typename FieldT> inline mean_field::field::FieldDofMap make_field_map(const mean_field::fem::FEM &f) {
-inline mean_field::field::FieldDofMap
-make_field_map(const mean_field::fem::FEM &f) {
         if constexpr (std::same_as<FieldT, mean_field::field::Density>) {
-    return mean_field::field::make_field_dof_map<FieldT, DomainSchema>(
+            return mean_field::field::make_field_dof_map<FieldT, DomainSchema>(*f.densityFes);
-        *f.densityFes);
         } else if constexpr (std::same_as<FieldT, mean_field::field::Displacement>) {
-    return mean_field::field::make_field_dof_map<FieldT, DomainSchema>(
+            return mean_field::field::make_field_dof_map<FieldT, DomainSchema>(*f.displacementFes);
-        *f.displacementFes);
         } else {
             static_assert(std::same_as<FieldT, mean_field::field::Gravity>);
-    return mean_field::field::make_field_dof_map<FieldT, DomainSchema>(
+            return mean_field::field::make_field_dof_map<FieldT, DomainSchema>(*f.gravityFluxFes);
-        *f.gravityFluxFes);
+        }
     }
-}
 
-template <typename FieldT>
+    template <typename FieldT>
-inline mfem::Vector gather_field(const mean_field::fem::FEM &f,
+    inline mfem::Vector gather_field(
-                                 const mfem::Vector &true_vector) {
+        const mean_field::fem::FEM &f,
+        const mfem::Vector &true_vector
+    ) {
         return make_field_map<FieldT>(f).gather(true_vector);
-}
+    }
 
-inline mfem::Vector make_deterministic_vector(const int size,
+    inline mfem::Vector make_deterministic_vector(
-                                              const double phase = 0.0) {
+        const int size,
+        const double phase = 0.0
+    ) {
         mfem::Vector vector(size);
 
         for (int i = 0; i < size; ++i) {
             const double index = static_cast<double>(i + 1);
-    vector(i) = std::sin(0.37 * index + phase) +
+            vector(i)          = std::sin(0.37 * index + phase) + 0.31 * std::cos(0.19 * index - 0.5 * phase);
-                0.31 * std::cos(0.19 * index - 0.5 * phase);
         }
 
         return vector;
-}
+    }
 
-inline mfem::Vector make_displacement(const mean_field::fem::FEM &f,
+    inline mfem::Vector make_displacement(
-                                      const double scale) {
+        const mean_field::fem::FEM &f,
+        const double scale
+    ) {
         mfem::ParGridFunction displacement(f.displacementFes.get());
 
-  auto displacement_function = [scale](const mfem::Vector &position,
+        auto displacement_function = [scale](const mfem::Vector &position, mfem::Vector &value) {
-                                       mfem::Vector &value) {
             value.SetSize(3);
             value(0) = scale * (0.04 * position(0) + 0.01 * position(1) * position(2));
-    value(1) =
+            value(1) = scale * (-0.03 * position(1) + 0.008 * position(0) * position(2));
-        scale * (-0.03 * position(1) + 0.008 * position(0) * position(2));
             value(2) = scale * (0.02 * position(2) - 0.006 * position(0) * position(1));
         };
 
-  mfem::VectorFunctionCoefficient coefficient(f.mesh->Dimension(),
+        mfem::VectorFunctionCoefficient coefficient(f.mesh->Dimension(), displacement_function);
-                                              displacement_function);
         displacement.ProjectCoefficient(coefficient);
 
         mfem::Vector displacement_true;
         displacement.GetTrueDofs(displacement_true);
         return displacement_true;
-}
+    }
 
-inline mfem::Vector make_domain_supported_density(const mean_field::fem::FEM &f,
+    inline mfem::Vector make_domain_supported_density(
-                                                  const bool stellar) {
+        const mean_field::fem::FEM &f,
+        const bool stellar
+    ) {
         mfem::Vector attribute_values(f.mesh->attributes.Max());
         attribute_values   = 0.0;
 
-  using DomainSchema =
+        using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
-      mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
 
         for (int i = 0; i < f.mesh->attributes.Size(); ++i) {
             const int attribute = f.mesh->attributes[i];
-    const bool is_stellar = DomainSchema::template attribute_belongs_to<
+            const bool is_stellar =
-        mean_field::utils::domain::Stellar>(attribute);
+                DomainSchema::template attribute_belongs_to<mean_field::utils::domain::Stellar>(attribute);
 
             if (is_stellar == stellar) {
                 attribute_values(attribute - 1) = 1.0;
@@ -160,109 +170,114 @@ inline mfem::Vector make_domain_supported_density(const mean_field::fem::FEM &f,
         mfem::Vector density_true;
         density.GetTrueDofs(density_true);
         return density_true;
-}
+    }
 
-inline mfem::Vector linear_combination(const mfem::Vector &first,
+    inline mfem::Vector linear_combination(
+        const mfem::Vector &first,
         const double first_scale,
         const mfem::Vector &second,
-                                       const double second_scale) {
+        const double second_scale
-  MFEM_VERIFY(first.Size() == second.Size(),
+    ) {
-              "Cannot combine vectors with different sizes.");
+        MFEM_VERIFY(first.Size() == second.Size(), "Cannot combine vectors with different sizes.");
 
         mfem::Vector combination(first);
         combination *= first_scale;
         combination.Add(second_scale, second);
         return combination;
-}
+    }
 
-inline double global_norm(const mfem::Vector &vector, MPI_Comm communicator) {
+    inline double global_norm(
+        const mfem::Vector &vector,
+        MPI_Comm communicator
+    ) {
         const double local_norm_squared = vector * vector;
         double global_norm_squared      = 0.0;
-  MPI_Allreduce(&local_norm_squared, &global_norm_squared, 1, MPI_DOUBLE,
+        MPI_Allreduce(&local_norm_squared, &global_norm_squared, 1, MPI_DOUBLE, MPI_SUM, communicator);
-                MPI_SUM, communicator);
         return std::sqrt(global_norm_squared);
-}
+    }
 
-inline double global_dot(const mfem::Vector &first, const mfem::Vector &second,
+    inline double global_dot(
-                         MPI_Comm communicator) {
+        const mfem::Vector &first,
-  MFEM_VERIFY(first.Size() == second.Size(),
+        const mfem::Vector &second,
-              "Cannot take the dot product of vectors with different sizes.");
+        MPI_Comm communicator
+    ) {
+        MFEM_VERIFY(first.Size() == second.Size(), "Cannot take the dot product of vectors with different sizes.");
 
         const double local_dot = first * second;
         double global_dot      = 0.0;
         MPI_Allreduce(&local_dot, &global_dot, 1, MPI_DOUBLE, MPI_SUM, communicator);
         return global_dot;
-}
+    }
 
-inline double relative_error(const mfem::Vector &computed,
+    inline double relative_error(
+        const mfem::Vector &computed,
         const mfem::Vector &reference,
-                             MPI_Comm communicator) {
+        MPI_Comm communicator
-  MFEM_VERIFY(computed.Size() == reference.Size(),
+    ) {
-              "Cannot compare vectors with different sizes.");
+        MFEM_VERIFY(computed.Size() == reference.Size(), "Cannot compare vectors with different sizes.");
 
         mfem::Vector difference(computed);
         difference -= reference;
 
         return global_norm(difference, communicator) /
-         std::max(global_norm(reference, communicator),
+               std::max(global_norm(reference, communicator), std::numeric_limits<double>::epsilon());
-                  std::numeric_limits<double>::epsilon());
+    }
-}
 
-inline double relative_scalar_error(const double computed,
+    inline double relative_scalar_error(
-                                    const double reference) {
+        const double computed,
-  return std::abs(computed - reference) /
+        const double reference
-         std::max(std::abs(reference), std::numeric_limits<double>::epsilon());
+    ) {
-}
+        return std::abs(computed - reference) / std::max(std::abs(reference), std::numeric_limits<double>::epsilon());
+    }
 } // namespace gravity_prepared_test_utils
 
 export namespace field_dof_test_utils {
-using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
+    using DomainSchema = mean_field::utils::domain::CoreEnvelopeVacuumDomainSchema;
 
-inline mean_field::mapping::DomainMapper make_domain_mapper() {
+    inline mean_field::mapping::DomainMapper make_domain_mapper() {
         const mean_field::utils::Args args = test_utils::setup_args();
         return mean_field::mapping::DomainMapper(
             args.domain_mapper_options,
-      std::make_unique<const mean_field::mapping::compactification::
+            std::make_unique<const mean_field::mapping::compactification::KelvinCompactification>(args.kelvin_options)
-                           KelvinCompactification>(args.kelvin_options));
+        );
-}
+    }
 
-inline constexpr int vacuum_material_attribute =
+    inline constexpr int vacuum_material_attribute =
-    DomainSchema::template material_attribute<
+        DomainSchema::template material_attribute<mean_field::utils::domain::Vacuum>();
-        mean_field::utils::domain::Vacuum>();
 
-template <typename FieldT>
+    template <typename FieldT>
-inline mean_field::field::FieldDofMap
+    inline mean_field::field::FieldDofMap make_map(const mfem::ParFiniteElementSpace &finiteElementSpace) {
-make_map(const mfem::ParFiniteElementSpace &finiteElementSpace) {
+        return mean_field::field::make_field_dof_map<FieldT, DomainSchema>(finiteElementSpace);
-  return mean_field::field::make_field_dof_map<FieldT, DomainSchema>(
+    }
-      finiteElementSpace);
-}
 
-template <typename FieldT>
+    template <typename FieldT>
-inline mfem::Vector make_deterministic_supported_vector(
+    inline mfem::Vector make_deterministic_supported_vector(
-    const mfem::ParFiniteElementSpace &finiteElementSpace, const double phase) {
+        const mfem::ParFiniteElementSpace &finiteElementSpace,
-  const mean_field::field::FieldDofMap map =
+        const double phase
-      make_map<FieldT>(finiteElementSpace);
+    ) {
-  const mfem::Vector full =
+        const mean_field::field::FieldDofMap map = make_map<FieldT>(finiteElementSpace);
-      gravity_prepared_test_utils::make_deterministic_vector(map.full_size(),
+        const mfem::Vector full = gravity_prepared_test_utils::make_deterministic_vector(map.full_size(), phase);
-                                                             phase);
         return map.gather(full);
-}
+    }
 
-inline mfem::Vector make_supported_displacement(const mean_field::fem::FEM &f,
+    inline mfem::Vector make_supported_displacement(
-                                                const double phase) {
+        const mean_field::fem::FEM &f,
-  const mean_field::field::FieldDofMap map =
+        const double phase
-      make_map<mean_field::field::Displacement>(*f.displacementFes);
+    ) {
+        const mean_field::field::FieldDofMap map = make_map<mean_field::field::Displacement>(*f.displacementFes);
         return map.gather(gravity_prepared_test_utils::make_displacement(f, phase));
-}
+    }
 
-inline void apply_hydrostatic_reference(
+    inline void apply_hydrostatic_reference(
         const mean_field::fem::FEM &f,
         const mean_field::physics::RigidRotation &rotation,
-    const mfem::Vector &enthalpy, const mfem::Vector &gravityPotential,
+        const mfem::Vector &enthalpy,
-    const mfem::Vector &displacement, const double bernoulliConstant,
+        const mfem::Vector &gravityPotential,
-    mfem::Vector &residual) {
+        const mfem::Vector &displacement,
-  const mean_field::field::FieldDofMap enthalpyMap =
+        const double bernoulliConstant,
-      make_map<mean_field::field::Enthalpy>(*f.enthalpyFes);
+        mfem::Vector &residual
+    ) {
+        const mean_field::field::FieldDofMap enthalpyMap = make_map<mean_field::field::Enthalpy>(*f.enthalpyFes);
         const mean_field::field::FieldDofMap gravityPotentialMap =
             make_map<mean_field::field::Gravity>(*f.gravityPotentialFes);
         const mean_field::field::FieldDofMap displacementMap =
@@ -278,191 +293,189 @@ inline void apply_hydrostatic_reference(
         displacementMap.scatter(displacement, displacementTrue);
 
         mean_field::operators::kernels::apply_hydrostatic_equilibrium(
-      f, *f.domainMapperStateless, rotation, enthalpyTrue, gravityPotentialTrue,
+            f, *f.domainMapperStateless, rotation, enthalpyTrue, gravityPotentialTrue, displacementTrue,
-      displacementTrue, bernoulliConstant, residualTrue);
+            bernoulliConstant, residualTrue
+        );
 
         residual.SetSize(enthalpyMap.reduced_size());
         enthalpyMap.gather(residualTrue, residual);
-}
+    }
 } // namespace field_dof_test_utils
 
 export namespace tags {
-inline constexpr auto geometry = make_tag("geometry");
+    inline constexpr auto geometry                     = make_tag("geometry");
-inline constexpr auto physics = make_tag("physics");
+    inline constexpr auto physics                      = make_tag("physics");
-inline constexpr auto unit = make_tag("unit");
+    inline constexpr auto unit                         = make_tag("unit");
-inline constexpr auto mesh = make_tag("mesh");
+    inline constexpr auto mesh                         = make_tag("mesh");
-inline constexpr auto integration = make_tag("integration");
+    inline constexpr auto integration                  = make_tag("integration");
-inline constexpr auto solver = make_tag("solver");
+    inline constexpr auto solver                       = make_tag("solver");
-inline constexpr auto integrator = make_tag("integrator");
+    inline constexpr auto integrator                   = make_tag("integrator");
-inline constexpr auto mapping = make_tag("mapping");
+    inline constexpr auto mapping                      = make_tag("mapping");
-inline constexpr auto utils = make_tag("utils");
+    inline constexpr auto utils                        = make_tag("utils");
-inline constexpr auto mfem_operators = make_tag("operators");
+    inline constexpr auto mfem_operators               = make_tag("operators");
-inline constexpr auto initialization = make_tag("initialization");
+    inline constexpr auto initialization               = make_tag("initialization");
-inline constexpr auto accuracy = make_tag("accuracy");
+    inline constexpr auto accuracy                     = make_tag("accuracy");
-inline constexpr auto closure = make_tag("closure");
+    inline constexpr auto closure                      = make_tag("closure");
-inline constexpr auto kernels = make_tag("kernels");
+    inline constexpr auto kernels                      = make_tag("kernels");
-inline constexpr auto surface = make_tag("surface");
+    inline constexpr auto surface                      = make_tag("surface");
-inline constexpr auto model = make_tag("model");
+    inline constexpr auto model                        = make_tag("model");
 
-inline constexpr auto field = sub_tag(mesh & physics, "field");
+    inline constexpr auto field                        = sub_tag(mesh & physics, "field");
-inline constexpr auto field_dof = field & make_tag("dof");
+    inline constexpr auto field_dof                    = field & make_tag("dof");
-inline constexpr auto field_dof_unit = field_dof & unit;
+    inline constexpr auto field_dof_unit               = field_dof & unit;
-inline constexpr auto field_dof_integration = field_dof & integration;
+    inline constexpr auto field_dof_integration        = field_dof & integration;
 
-inline constexpr auto pressure = sub_tag(physics, "pressure");
+    inline constexpr auto pressure                     = sub_tag(physics, "pressure");
 
-inline constexpr auto hydro = sub_tag(physics, "hydro");
+    inline constexpr auto hydro                        = sub_tag(physics, "hydro");
-inline constexpr auto jacobian = sub_tag(integration & physics, "jacobian");
+    inline constexpr auto jacobian                     = sub_tag(integration & physics, "jacobian");
-inline constexpr auto residuals = sub_tag(integration & physics, "residuals");
+    inline constexpr auto residuals                    = sub_tag(integration & physics, "residuals");
-inline constexpr auto volume = sub_tag(mesh & geometry, "volume");
+    inline constexpr auto volume                       = sub_tag(mesh & geometry, "volume");
-inline constexpr auto quadrature =
+    inline constexpr auto quadrature                   = sub_tag(mesh & geometry & solver, "quadrature");
-    sub_tag(mesh & geometry & solver, "quadrature");
+    inline constexpr auto convergence                  = sub_tag(solver, "convergence");
-inline constexpr auto convergence = sub_tag(solver, "convergence");
+    inline constexpr auto transformations              = sub_tag(mesh & geometry, "transformations");
-inline constexpr auto transformations =
-    sub_tag(mesh & geometry, "transformations");
 
-inline constexpr auto h_refinement =
+    inline constexpr auto h_refinement                 = sub_tag(mesh & convergence, "h_refinement");
-    sub_tag(mesh & convergence, "h_refinement");
+    inline constexpr auto p_refinement                 = sub_tag(mesh & convergence, "p_refinement");
-inline constexpr auto p_refinement =
-    sub_tag(mesh & convergence, "p_refinement");
 
-inline constexpr auto analytic_comparison =
+    inline constexpr auto analytic_comparison          = sub_tag(solver & physics & residuals, "analytic_comparison");
-    sub_tag(solver & physics & residuals, "analytic_comparison");
+    inline constexpr auto self_consistency             = sub_tag(solver & physics, "self_consistency");
-inline constexpr auto self_consistency =
-    sub_tag(solver & physics, "self_consistency");
 
-inline constexpr auto centrifugal = sub_tag(solver & physics, "centrifugal");
+    inline constexpr auto centrifugal                  = sub_tag(solver & physics, "centrifugal");
-inline constexpr auto advection = sub_tag(solver & physics, "advection");
+    inline constexpr auto advection                    = sub_tag(solver & physics, "advection");
-inline constexpr auto coriolis = sub_tag(solver & physics, "coriolis");
+    inline constexpr auto coriolis                     = sub_tag(solver & physics, "coriolis");
-inline constexpr auto gravity = sub_tag(solver & physics, "gravity");
+    inline constexpr auto gravity                      = sub_tag(solver & physics, "gravity");
-inline constexpr auto enthalpy = sub_tag(solver & physics, "enthalpy");
+    inline constexpr auto enthalpy                     = sub_tag(solver & physics, "enthalpy");
-inline constexpr auto barotrope = sub_tag(physics, "barotrope");
+    inline constexpr auto barotrope                    = sub_tag(physics, "barotrope");
-inline constexpr auto mass_continuity =
+    inline constexpr auto mass_continuity              = sub_tag(solver & physics, "mass_continuity");
-    sub_tag(solver & physics, "mass_continuity");
+    inline constexpr auto pressure_gradient            = sub_tag(solver & physics, "pressure_gradient");
-inline constexpr auto pressure_gradient =
+    inline constexpr auto viscosity                    = sub_tag(solver & physics, "viscosity");
-    sub_tag(solver & physics, "pressure_gradient");
-inline constexpr auto viscosity = sub_tag(solver & physics, "viscosity");
 
-inline constexpr auto compactification =
+    inline constexpr auto compactification             = sub_tag(mesh & mapping, "compactification");
-    sub_tag(mesh & mapping, "compactification");
+    inline constexpr auto kelvin                       = sub_tag(compactification, "kelvin");
-inline constexpr auto kelvin = sub_tag(compactification, "kelvin");
+    inline constexpr auto mapping_evaluator            = mapping & make_tag("grid_function_evaluator");
-inline constexpr auto mapping_evaluator =
+    inline constexpr auto mapping_evaluator_unit       = mapping_evaluator & unit;
-    mapping & make_tag("grid_function_evaluator");
-inline constexpr auto mapping_evaluator_unit = mapping_evaluator & unit;
 
-inline constexpr auto prepared = sub_tag(solver & physics, "prepared");
+    inline constexpr auto prepared                     = sub_tag(solver & physics, "prepared");
-inline constexpr auto contexts = sub_tag(solver, "contexts");
+    inline constexpr auto contexts                     = sub_tag(solver, "contexts");
 
-inline constexpr auto domain = sub_tag(mesh, "domain");
+    inline constexpr auto domain                       = sub_tag(mesh, "domain");
 
-// Canonical gravity-suite tags. These intentionally compose leaf tags
+    // Canonical gravity-suite tags. These intentionally compose leaf tags
-// exactly once so Catch2 output remains useful and free of repeated
+    // exactly once so Catch2 output remains useful and free of repeated
-// [solver]/[physics] entries inherited from older composite tags.
+    // [solver]/[physics] entries inherited from older composite tags.
-inline constexpr auto gravity_unit = gravity & unit;
+    inline constexpr auto gravity_unit                 = gravity & unit;
-inline constexpr auto gravity_integration = gravity & integration;
+    inline constexpr auto gravity_integration          = gravity & integration;
-inline constexpr auto gravity_operator = gravity & mfem_operators;
+    inline constexpr auto gravity_operator             = gravity & mfem_operators;
-inline constexpr auto gravity_prepared = gravity & make_tag("prepared");
+    inline constexpr auto gravity_prepared             = gravity & make_tag("prepared");
-inline constexpr auto gravity_context = gravity & make_tag("context");
+    inline constexpr auto gravity_context              = gravity & make_tag("context");
-inline constexpr auto gravity_kernel = gravity & kernels;
+    inline constexpr auto gravity_kernel               = gravity & kernels;
-inline constexpr auto gravity_accuracy = gravity & accuracy;
+    inline constexpr auto gravity_accuracy             = gravity & accuracy;
-inline constexpr auto gravity_operator_unit = gravity_operator & unit;
+    inline constexpr auto gravity_operator_unit        = gravity_operator & unit;
-inline constexpr auto gravity_operator_integration =
+    inline constexpr auto gravity_operator_integration = gravity_operator & integration;
-    gravity_operator & integration;
+    inline constexpr auto gravity_operator_convergence = gravity_operator & integration & make_tag("convergence");
-inline constexpr auto gravity_operator_convergence =
+    inline constexpr auto gravity_analytic             = gravity & integration & make_tag("analytic_comparison");
-    gravity_operator & integration & make_tag("convergence");
+    inline constexpr auto gravity_consistency          = gravity & integration & make_tag("self_consistency");
-inline constexpr auto gravity_analytic =
+    inline constexpr auto gravity_prepared_jacobian    = gravity_prepared & integration & make_tag("jacobian");
-    gravity & integration & make_tag("analytic_comparison");
+    inline constexpr auto gravity_prepared_unit        = gravity_prepared & unit;
-inline constexpr auto gravity_consistency =
+    inline constexpr auto gravity_prepared_jacobian_accuracy = gravity_prepared_jacobian & accuracy;
-    gravity & integration & make_tag("self_consistency");
+    inline constexpr auto gravity_kernel_accuracy            = gravity_kernel & accuracy;
-inline constexpr auto gravity_prepared_jacobian =
+    inline constexpr auto gravity_kernel_integration         = gravity_kernel & integration;
-    gravity_prepared & integration & make_tag("jacobian");
+    inline constexpr auto gravity_kernel_convergence         = gravity_kernel & integration & make_tag("convergence");
-inline constexpr auto gravity_prepared_unit = gravity_prepared & unit;
+    inline constexpr auto gravity_analytic_accuracy          = gravity_analytic & accuracy;
-inline constexpr auto gravity_prepared_jacobian_accuracy =
+    inline constexpr auto gravity_consistency_accuracy       = gravity_consistency & accuracy;
-    gravity_prepared_jacobian & accuracy;
+    inline constexpr auto gravity_integrator_unit            = gravity & integrator & unit;
-inline constexpr auto gravity_kernel_accuracy = gravity_kernel & accuracy;
-inline constexpr auto gravity_kernel_integration = gravity_kernel & integration;
-inline constexpr auto gravity_kernel_convergence =
-    gravity_kernel & integration & make_tag("convergence");
-inline constexpr auto gravity_analytic_accuracy = gravity_analytic & accuracy;
-inline constexpr auto gravity_consistency_accuracy =
-    gravity_consistency & accuracy;
-inline constexpr auto gravity_integrator_unit = gravity & integrator & unit;
 
-inline constexpr auto barotrope_prepared =
+    inline constexpr auto barotrope_prepared                 = barotrope & solver & make_tag("prepared");
-    barotrope & solver & make_tag("prepared");
+    inline constexpr auto barotrope_eos_unit                 = barotrope & unit & make_tag("eos");
-inline constexpr auto barotrope_eos_unit = barotrope & unit & make_tag("eos");
+    inline constexpr auto barotrope_eos_jacobian             = barotrope_eos_unit & integration & make_tag("jacobian");
-inline constexpr auto barotrope_eos_jacobian =
+    inline constexpr auto polytropic_eos_characterization =
-    barotrope_eos_unit & integration & make_tag("jacobian");
+        barotrope & unit & make_tag("eos") & make_tag("characterization");
-inline constexpr auto barotrope_pressure_quadrature =
+    inline constexpr auto polytropic_eos_relation_contract =
-    barotrope & mesh & geometry & solver & make_tag("pressure") &
+        barotrope & unit & make_tag("eos") & make_tag("relation_contract");
+    inline constexpr auto polytropic_eos_compatibility = barotrope & unit & make_tag("eos") & make_tag("compatibility");
+    inline constexpr auto equation_of_state            = physics & make_tag("eos");
+    inline constexpr auto equation_of_state_type_system    = equation_of_state & unit & make_tag("type_system");
+    inline constexpr auto equation_of_state_quantity_types = equation_of_state_type_system & make_tag("quantity_types");
+    inline constexpr auto equation_of_state_relation_contract =
+        equation_of_state_type_system & make_tag("relation_contract");
+    inline constexpr auto equation_of_state_runtime_view = equation_of_state & unit & make_tag("runtime_view");
+    inline constexpr auto equation_of_state_runtime_contract =
+        equation_of_state_runtime_view & make_tag("relation_contract");
+    inline constexpr auto equation_of_state_runtime_compatibility =
+        equation_of_state_runtime_view & make_tag("compatibility");
+    inline constexpr auto equation_of_state_consumer_contract =
+        equation_of_state & unit & make_tag("consumer_contract");
+    inline constexpr auto barotropic_closure_equation_of_state_contract =
+        equation_of_state_consumer_contract & make_tag("barotropic_closure");
+    inline constexpr auto pressure_force_equation_of_state_contract =
+        equation_of_state_consumer_contract & make_tag("pressure_force");
+    inline constexpr auto structure_seed_equation_of_state_contract =
+        equation_of_state_consumer_contract & make_tag("structure_seed");
+    inline constexpr auto stellar_model_type_contract = barotrope & model & unit & make_tag("type_contract");
+    inline constexpr auto stellar_model_runtime_view  = barotrope & model & unit & make_tag("runtime_view");
+    inline constexpr auto surface_prescription_type_contract =
+        surface & physics & unit & make_tag("prescription") & make_tag("type_contract");
+    inline constexpr auto surface_constraint_compilation =
+        surface & physics & unit & make_tag("constraint_compilation");
+    inline constexpr auto surface_constraint_jacobian = surface_constraint_compilation & jacobian;
+    inline constexpr auto surface_constraint_lifetime = surface & model & unit & make_tag("constraint_lifetime");
+    inline constexpr auto surface_boundary_dof_topology =
+        surface & field_dof & integration & make_tag("boundary_topology");
+    inline constexpr auto surface_row_replacement =
+        surface & barotrope_prepared & integration & make_tag("row_replacement");
+    inline constexpr auto translational_centering = geometry & solver & make_tag("translational_centering");
+    inline constexpr auto translational_centering_topology =
+        translational_centering & field_dof & integration & make_tag("point_topology");
+    inline constexpr auto translational_centering_enforcement =
+        translational_centering & barotrope_prepared & integration & make_tag("row_replacement");
+    inline constexpr auto barotrope_pressure_quadrature = barotrope & mesh & geometry & solver & make_tag("pressure") &
                                                           make_tag("pressure_gradient") & make_tag("quadrature");
-inline constexpr auto barotrope_pressure_quadrature_unit =
+    inline constexpr auto barotrope_pressure_quadrature_unit     = barotrope_pressure_quadrature & unit;
-    barotrope_pressure_quadrature & unit;
+    inline constexpr auto barotrope_pressure_quadrature_accuracy = barotrope_pressure_quadrature & accuracy;
-inline constexpr auto barotrope_pressure_quadrature_accuracy =
+    inline constexpr auto barotrope_prepared_jacobian   = barotrope_prepared & integration & make_tag("jacobian");
-    barotrope_pressure_quadrature & accuracy;
+    inline constexpr auto barotrope_context             = barotrope & solver & make_tag("context");
-inline constexpr auto barotrope_prepared_jacobian =
+    inline constexpr auto barotrope_context_integration = barotrope_context & integration;
-    barotrope_prepared & integration & make_tag("jacobian");
+    inline constexpr auto barotrope_prepared_analytic =
-inline constexpr auto barotrope_context =
-    barotrope & solver & make_tag("context");
-inline constexpr auto barotrope_context_integration =
-    barotrope_context & integration;
-inline constexpr auto barotrope_prepared_analytic =
         barotrope_prepared & integration & make_tag("analytic_comparison");
-inline constexpr auto barotrope_prepared_jacobian_accuracy =
+    inline constexpr auto barotrope_prepared_jacobian_accuracy = barotrope_prepared_jacobian & accuracy;
-    barotrope_prepared_jacobian & accuracy;
+    inline constexpr auto barotrope_prepared_jacobian_geometry = barotrope_prepared_jacobian & geometry;
-inline constexpr auto barotrope_prepared_jacobian_geometry =
+    inline constexpr auto barotrope_prepared_jacobian_unit     = barotrope_prepared_jacobian & unit;
-    barotrope_prepared_jacobian & geometry;
-inline constexpr auto barotrope_prepared_jacobian_unit =
-    barotrope_prepared_jacobian & unit;
 
-// Canonical hydrostatic-suite tags. The leaf tags are composed directly
+    // Canonical hydrostatic-suite tags. The leaf tags are composed directly
-// so inherited [physics]/[solver] tags appear only once.
+    // so inherited [physics]/[solver] tags appear only once.
-inline constexpr auto barotrope_hydrostatic =
+    inline constexpr auto barotrope_hydrostatic                = barotrope & solver & make_tag("hydro");
-    barotrope & solver & make_tag("hydro");
+    inline constexpr auto barotrope_hydrostatic_context        = barotrope_hydrostatic & make_tag("context");
-inline constexpr auto barotrope_hydrostatic_context =
+    inline constexpr auto barotrope_hydrostatic_prepared       = barotrope_hydrostatic & make_tag("prepared");
-    barotrope_hydrostatic & make_tag("context");
+    inline constexpr auto barotrope_hydrostatic_prepared_residual =
-inline constexpr auto barotrope_hydrostatic_prepared =
-    barotrope_hydrostatic & make_tag("prepared");
-inline constexpr auto barotrope_hydrostatic_prepared_residual =
         barotrope_hydrostatic_prepared & integration & make_tag("residual");
-inline constexpr auto barotrope_hydrostatic_prepared_jacobian =
+    inline constexpr auto barotrope_hydrostatic_prepared_jacobian =
         barotrope_hydrostatic_prepared & integration & make_tag("jacobian");
-inline constexpr auto barotrope_hydrostatic_prepared_analytic =
+    inline constexpr auto barotrope_hydrostatic_prepared_analytic =
-    barotrope_hydrostatic_prepared & integration &
+        barotrope_hydrostatic_prepared & integration & make_tag("analytic_comparison");
-    make_tag("analytic_comparison");
 
-inline constexpr auto barotrope_mass_normalization =
+    inline constexpr auto barotrope_mass_normalization          = barotrope & solver & make_tag("mass_normalization");
-    barotrope & solver & make_tag("mass_normalization");
+    inline constexpr auto barotrope_mass_normalization_context  = barotrope_mass_normalization & make_tag("context");
-inline constexpr auto barotrope_mass_normalization_context =
+    inline constexpr auto barotrope_mass_normalization_prepared = barotrope_mass_normalization & make_tag("prepared");
-    barotrope_mass_normalization & make_tag("context");
+    inline constexpr auto barotrope_mass_normalization_jacobian =
-inline constexpr auto barotrope_mass_normalization_prepared =
-    barotrope_mass_normalization & make_tag("prepared");
-inline constexpr auto barotrope_mass_normalization_jacobian =
         barotrope_mass_normalization_prepared & integration & make_tag("jacobian");
-inline constexpr auto barotrope_mass_normalization_analytic =
+    inline constexpr auto barotrope_mass_normalization_analytic =
-    barotrope_mass_normalization_prepared & integration &
+        barotrope_mass_normalization_prepared & integration & make_tag("analytic_comparison");
-    make_tag("analytic_comparison");
 
-inline constexpr auto rotation_prepared = centrifugal & make_tag("prepared");
+    inline constexpr auto rotation_prepared          = centrifugal & make_tag("prepared");
-inline constexpr auto rotation_context = centrifugal & make_tag("context");
+    inline constexpr auto rotation_context           = centrifugal & make_tag("context");
-inline constexpr auto rotation_analytic =
+    inline constexpr auto rotation_analytic          = centrifugal & integration & make_tag("analytic_comparison");
-    centrifugal & integration & make_tag("analytic_comparison");
+    inline constexpr auto rotation_context_unit      = rotation_context & unit;
-inline constexpr auto rotation_context_unit = rotation_context & unit;
+    inline constexpr auto rotation_prepared_unit     = rotation_prepared & unit;
-inline constexpr auto rotation_prepared_unit = rotation_prepared & unit;
+    inline constexpr auto rotation_prepared_jacobian = rotation_prepared & integration & make_tag("jacobian");
-inline constexpr auto rotation_prepared_jacobian =
+    inline constexpr auto rotation_prepared_jacobian_accuracy = rotation_prepared_jacobian & accuracy;
-    rotation_prepared & integration & make_tag("jacobian");
+    inline constexpr auto rotation_kernel_accuracy            = centrifugal & kernels & accuracy;
-inline constexpr auto rotation_prepared_jacobian_accuracy =
+    inline constexpr auto rotation_integrator_unit            = centrifugal & integrator & unit;
-    rotation_prepared_jacobian & accuracy;
+    inline constexpr auto rotation_integrator_integration     = centrifugal & integrator & integration;
-inline constexpr auto rotation_kernel_accuracy =
+    inline constexpr auto rotation_integrator_convergence =
-    centrifugal & kernels & accuracy;
-inline constexpr auto rotation_integrator_unit = centrifugal & integrator & unit;
-inline constexpr auto rotation_integrator_integration =
-    centrifugal & integrator & integration;
-inline constexpr auto rotation_integrator_convergence =
         rotation_integrator_integration & convergence & h_refinement;
-inline constexpr auto rotation_analytic_unit = rotation_analytic & unit;
+    inline constexpr auto rotation_analytic_unit              = rotation_analytic & unit;
-inline constexpr auto rotation_analytic_accuracy = rotation_analytic & accuracy;
+    inline constexpr auto rotation_analytic_accuracy          = rotation_analytic & accuracy;
-inline constexpr auto rotation_analytic_accuracy_geometry =
+    inline constexpr auto rotation_analytic_accuracy_geometry = rotation_analytic_accuracy & geometry;
-    rotation_analytic_accuracy & geometry;
 
 } // namespace tags

tests/test_main.cpp

@@ -3,6 +3,7 @@
 #include <catch2/catch_test_case_info.hpp>
 #include <catch2/reporters/catch_reporter_registrars.hpp>
 #include <catch2/reporters/catch_reporter_streaming_base.hpp>
+#include <chrono>
 #include <fstream>
 #include <iomanip>
 #include <iostream>
@@ -223,6 +224,7 @@ class CheckReporter : public Catch::StreamingReporterBase {
         bool passed;
         std::size_t assertionsPassed;
         std::size_t assertionsFailed;
+        double durationSeconds;
         std::vector<std::string> failureMessages;
         std::vector<std::string> infoMessages;
     };
@@ -231,6 +233,7 @@ class CheckReporter : public Catch::StreamingReporterBase {
     std::vector<std::string> m_currentInfos;
     std::unordered_set<unsigned int> m_currentInfoSequences;
     std::vector<TestCaseData> m_testRunData;
+    std::chrono::time_point<std::chrono::steady_clock> m_testStartTime;
 
     void captureInfoMessages(Catch::AssertionStats const &assertionStats) {
         for (auto const &message : assertionStats.infoMessages) {
@@ -253,9 +256,8 @@ public:
     }
 
     static std::string getDescription() {
-        return "Console reporter with wrapping, tags, and collapsible HTML "
+        return "Console reporter with wrapping, tags, live test progress, and collapsible HTML "
-               "export "
+               "export with ANSI color rendering.";
-               "with ANSI color rendering.";
     }
 
     void testRunStarting(Catch::TestRunInfo const &_testRunInfo) override {
@@ -263,8 +265,20 @@ public:
 
         std::cout << '\n';
         std::cout << std::left << std::setw(85) << "Test Case Name"
-                  << "Status    " << std::right << std::setw(8) << "Passed" << std::setw(8) << "Failed" << '\n';
+                  << "Status    " << std::right << std::setw(8) << "Passed" << std::setw(8) << "Failed" << std::setw(12)
-        std::cout << std::string(121, '-') << '\n';
+                  << "Time (s)" << '\n';
+        std::cout << std::string(133, '-') << '\n';
+    }
+
+    void testCaseStarting(Catch::TestCaseInfo const &testInfo) override {
+        StreamingReporterBase::testCaseStarting(testInfo);
+
+        m_testStartTime  = std::chrono::steady_clock::now();
+        std::string name = testInfo.name;
+        auto wrappedName = wrapText(name, 83);
+
+        // Print progress line, \r to overwrite later, \033[K to clear till end of line
+        std::cout << "\r\033[K" << std::left << std::setw(85) << (wrappedName[0] + " ...") << std::flush;
     }
 
     void assertionEnded(Catch::AssertionStats const &assertionStats) override {
@@ -300,14 +314,20 @@ public:
     void testCaseEnded(Catch::TestCaseStats const &stats) override {
         StreamingReporterBase::testCaseEnded(stats);
 
+        auto endTime                          = std::chrono::steady_clock::now();
+        std::chrono::duration<double> elapsed = endTime - m_testStartTime;
+        double duration_s                     = elapsed.count();
+
         bool passed                           = stats.totals.assertions.allPassed();
         std::string mark                      = passed ? "\033[32m✓\033[0m" : "\033[31m✗\033[0m";
 
         std::string name                      = stats.testInfo->name;
         auto wrappedName                      = wrapText(name, 83);
 
-        std::cout << std::left << std::setw(85) << wrappedName[0] << mark << "         " << std::right << std::setw(8)
+        // Overwrite the loading line with the actual result
-                  << stats.totals.assertions.passed << std::setw(8) << stats.totals.assertions.failed << '\n';
+        std::cout << "\r\033[K" << std::left << std::setw(85) << wrappedName[0] << mark << "         " << std::right
+                  << std::setw(8) << stats.totals.assertions.passed << std::setw(8) << stats.totals.assertions.failed
+                  << std::setw(11) << std::fixed << std::setprecision(3) << duration_s << "s\n";
 
         for (size_t i = 1; i < wrappedName.size(); ++i) {
             std::cout << "  \033[90m↳ \033[0m" // Dim indent arrow
@@ -327,12 +347,12 @@ public:
             for (auto const &failure : m_currentFailures) {
                 std::cout << failure << '\n';
             }
-            std::cout << std::string(121, '-') << '\n';
+            std::cout << std::string(133, '-') << '\n';
         }
 
         m_testRunData.push_back(
-            {name, tagsStr, passed, stats.totals.assertions.passed, stats.totals.assertions.failed, m_currentFailures,
+            {name, tagsStr, passed, stats.totals.assertions.passed, stats.totals.assertions.failed, duration_s,
-             m_currentInfos}
+             m_currentFailures, m_currentInfos}
         );
 
         m_currentFailures.clear();
@@ -343,7 +363,7 @@ public:
     void testRunEnded(Catch::TestRunStats const &_testRunStats) override {
         StreamingReporterBase::testRunEnded(_testRunStats);
 
-        std::cout << std::string(121, '=') << '\n';
+        std::cout << std::string(133, '=') << '\n';
 
         auto const &tc = _testRunStats.totals.testCases;
         auto const &as = _testRunStats.totals.assertions;
@@ -444,7 +464,9 @@ private:
             html << "    </div>\n";
             html << "    <div class='stats'>\n";
             html << "      <span class='text-green'>&#10003; " << test.assertionsPassed << "</span> | ";
-            html << "      <span class='text-red'>&#10007; " << test.assertionsFailed << "</span>\n";
+            html << "      <span class='text-red'>&#10007; " << test.assertionsFailed << "</span> | ";
+            html << "      <span style='color: #34495e;'>&#8987; " << std::fixed << std::setprecision(3)
+                 << test.durationSeconds << "s</span>\n";
             html << "    </div>\n";
             html << "  </div>\n";