Emily Boudreaux
cb20faeb3d
The test suite is extensive. Note that LLMs were used to aid in the development of the test suite. All LLM generated code was manually reviewed.
68 lines
3.1 KiB
C++
68 lines
3.1 KiB
C++
#include <numbers>
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#include <print>
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#include "serif/eos/models/polytropic.hpp"
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#include "serif/equations/angular_momentum.hpp"
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#include "serif/equations/barotropic_density.hpp"
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#include "serif/equations/surface_potential.hpp"
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#include "serif/equations/mass_normalization.hpp"
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#include "serif/equations/primal_gravity.hpp"
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#include "serif/equations/registry.hpp"
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#include "serif/model/description.hpp"
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#include "serif/model/eos_reference.hpp"
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#include "serif/geometry/surface/isobaric.hpp"
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namespace
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{
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namespace model = serif::model;
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namespace equations = serif::equations;
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namespace dimensions = serif::dimensions;
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namespace surface = serif::geometry::surface;
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}
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/** @brief Inspect an explicitly chosen rotating equilibrium formulation without creating a mesh or solving it. */
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int main()
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{
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// This list is the physical formulation. The EOS supplies relations; it does not choose equations.
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const auto equilibrium = [](const auto& physics)
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{
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const auto eos = model::borrow_eos(physics.equation_of_state());
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const auto& rotation = physics.template specification<model::FixedAngularMomentum>();
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return model::EquilibriumEquations
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{
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.interior_equations = equations::EquationRegistry
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{
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equations::BarotropicDensityBalance{eos, dimensions::PressureValue{0.0}, rotation.axis(), rotation.center()},
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equations::PrimalPoissonBalance{4.0 * std::numbers::pi},
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equations::MassNormalization{physics.template specification<model::FixedTotalMass>().target().value()},
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equations::AngularMomentumConstraint{rotation.target().value(), rotation.axis(), rotation.center()}
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},
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.shape_force = equations::SurfacePotentialBalance{rotation.axis(), rotation.center()},
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.surface_condition = surface::Isobaric{dimensions::PressureValue{0.0}}
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};
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};
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// Mass and angular momentum are prescribed. Density, potential, surface level, angular velocity and shape are solved.
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const auto star = model::StellarModel
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{
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serif::eos::models::Polytrope{3.0, 0.25},
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equilibrium,
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model::FixedTotalMass{dimensions::MassValue{1.0}},
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model::FixedAngularMomentum{dimensions::AngularMomentumValue{0.02}}
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};
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// In this example G = 1 in the chosen physical units, and scalar Poisson balance supplies gravity.
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// Rigid rotation uses the same axis and origin in the density equation and on the pressure surface.
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// Resolving reads immutable physics once. Keep star alive while the resolved equations borrow its EOS.
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const auto chosen = model::resolve_equilibrium_equations(star);
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std::println("Interior equations:");
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chosen.interior_equations.for_each([](const auto& equation)
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{
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std::println(" {}", equation.name);
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});
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std::println("Shape equation: {}", chosen.shape_force.name);
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std::println("Surface pressure: {}", chosen.surface_condition.target_pressure().value());
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std::println("Prescribed mass: {}; angular momentum: {}", star.specification<model::FixedTotalMass>().target().value(), star.specification<model::FixedAngularMomentum>().target().value());
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}
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