Files
GridFire/src/include/gridfire/partition/partition_ground.h

109 lines
4.2 KiB
C++

#pragma once
#include "gridfire/partition/partition_abstract.h"
#include "fourdst/logging/logging.h"
#include <unordered_map>
#include <memory>
#include "quill/Logger.h"
namespace gridfire::partition {
/**
* @class GroundStatePartitionFunction
* @brief Partition function implementation for nuclear ground states.
*
* Computes the partition function as (2J + 1) based on the ground state spin J of each isotope.
* The temperature derivative is always zero. Ground state spins are loaded from the
* fourdst::atomic::species registry at construction.
* @see partition_ground.cpp for implementation details.
*/
class GroundStatePartitionFunction final : public PartitionFunction {
public:
/**
* @brief Construct and populate the ground state spin map.
+ *
* Loads spins for all isotopes from the atomic species registry into m_ground_state_spin.
* @pre atomic::species registry is initialized and non-empty.
* @post m_ground_state_spin contains entries for each isotope.
+ */
GroundStatePartitionFunction();
/**
* @brief Evaluate the ground state partition function.
+ *
* @param z Proton number (atomic number) of the isotope; must be >= 1.
* @param a Mass number of the isotope; must be >= z.
* @param T9 Temperature in units of 10^9 K; unused for ground state.
* @pre supports(z,a) returns true.
* @post No side effects.
* @return Dimensionless partition function value = 2*spin + 1.
* @throws std::out_of_range If the isotope key is not found in m_ground_state_spin.
+ */
double evaluate(
const int z,
const int a,
const double T9
) const override;
/**
* @brief Evaluate the temperature derivative of the ground state partition function.
+ *
* Always returns zero as ground state has no temperature dependence.
* @param z Proton number of the isotope; must be supported.
* @param a Mass number of the isotope; must be supported.
* @param T9 Temperature in units of 10^9 K; unused.
* @pre supports(z,a) returns true.
* @post No side effects.
* @return Zero.
* @throws std::out_of_range If the isotope key is not found.
+ */
double evaluateDerivative(
const int z,
const int a,
const double T9
) const override;
/**
* @brief Check if ground state data exists for the given isotope.
+ *
* @param z Proton number of the isotope.
* @param a Mass number of the isotope.
* @return True if m_ground_state_spin contains the key; false otherwise.
* @post No side effects.
+ */
bool supports(
const int z,
const int a
) const override;
/**
* @brief Get the type identifier of this partition function.
* @return The string literal "GroundState".
* @post No side effects.
+ */
std::string type() const override { return "GroundState"; }
/**
* @brief Create a deep copy of this partition function.
* @return Unique_ptr to a new GroundStatePartitionFunction cloned from this object.
* @post Caller owns the returned instance.
+ */
std::unique_ptr<PartitionFunction> clone() const override {
return std::make_unique<GroundStatePartitionFunction>(*this);
}
private:
quill::Logger* m_logger = fourdst::logging::LogManager::getInstance().getLogger("log");
std::unordered_map<int, double> m_ground_state_spin;
/**
* @brief Generate a unique lookup key for an isotope.
+ *
* Combines atomic number z and mass number a into a single integer.
* @param z Proton number of the isotope.
* @param a Mass number of the isotope; should be < 1000 to avoid collisions.
* @pre a < 1000.
* @return Integer key = z * 1000 + a.
+ */
static constexpr int make_key(
const int z,
const int a);
};
}