Prescribe central density through the continuous enthalpy: \(h(0) - h_{EOS}(\rho_c) = 0\). Generally this is not needed; however, in the particular case of an n=3 polytrope with no rotation the central density becomes ill-defined and must be prescribed to avoid a singularity in the solution. Note that this equation is not responsible for sorting out what point is the center of the star; rather, this is provided to the evaluate method. More...

#include <central_density.hpp>

Inheritance diagram for serif::equations::CentralDensityConstraint< EOST >:

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Collaboration diagram for serif::equations::CentralDensityConstraint< EOST >:

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Public Types
using	Operands = utils::types::TypeList<TestOperand>
	The operand types of the equation, that is the types of the fields which are used to evaluate the equation.

using	Border = discretization::blocks::central_density::border
	The border type of the equation, that is what row of the global system this equation contributes to.

using	ResidualQuantity = dimensions::SpecificEnthalpy
	The physical quantity which is being constrained by this equation, that is the quantity which is being set to a target value.

Public Types inherited from serif::equations::Contribution< discretization::forms::Operand< discretization::blocks::enthalpy::specific > >
using	Test
	The test type of the contribution.

using	TestOperand
	The operand type of the contribution (associating a test function and a term)

using	Support
	The domain support of the contribution (which then boils down to the dofs which are supported by the term on that test function)

Public Member Functions
	CentralDensityConstraint (EOST equation_of_state, dimensions::DensityValue target_density)
	Construct a central density constraint.

PointLinearization< Operands >	evaluate (const EquationPoint< Operands > &point) const
	Evaluate the central density constraint at a given point.

dimensions::DensityValue	target_density () const noexcept
	Return the prescribed central density.

dimensions::SpecificEnthalpyValue	target_enthalpy () const noexcept
	Return the target enthalpy corresponding to the prescribed central density.

dimensions::DensityValue	density_from_enthalpy (dimensions::SpecificEnthalpyValue enthalpy) const
	Convert some enthalpy to a density for physical diagnostics, when the inverse relation exists.

Static Public Attributes
static constexpr std::string_view	name = "central density constraint"
	Compile time name for the equation, used for debugging and logging.

static constexpr bool	position_independent = true
	Whether the equation is independent of the position of the point being evaluated, that is whether the equation is invariant under translations and rotations of the point. This is only used for compile-time checks.

static constexpr bool	affine = true
	Whether the equation is affine, that is whether the equation is linear in the fields being evaluated. This is only used for compile-time checks.

static constexpr std::array< double, 3 >	reference_position {}
	The reference position of the equation, this is only used for compile-time checks and is not used in the evaluation of the equation.

Private Attributes
EOST	m_eos
	The EOS model to use for evaluating the enthalpy from the prescribed density.

dimensions::DensityValue	m_target_density
	The prescribed central density, which must be finite and strictly positive.

double	m_target_enthalpy
	The target enthalpy corresponding to the prescribed central density, which is computed from the EOS and must be finite.

Detailed Description

template<eos::models::EOSModel EOST>
requires eos::models::EOSSupportingRelation<EOST, eos::relations::SpecificEnthalpyFromDensity>
class serif::equations::CentralDensityConstraint< EOST >

Prescribe central density through the continuous enthalpy: \(h(0) - h_{EOS}(\rho_c) = 0\). Generally this is not needed; however, in the particular case of an n=3 polytrope with no rotation the central density becomes ill-defined and must be prescribed to avoid a singularity in the solution. Note that this equation is not responsible for sorting out what point is the center of the star; rather, this is provided to the evaluate method.

Template Parameters

EOST	The EOS model type to use for evaluating the enthalpy from the prescribed density.

Requirements
The EOS model must support the relation SpecificEnthalpyFromDensity

Equation Contributions
Residuals to the specific enthalpy row of the system

Exceptions

std::invalid_argument	If the prescribed density is not finite and strictly positive.
std::domain_error	If the EOS returns a non-finite enthalpy for the prescribed density.

Member Typedef Documentation

◆ Border

template<eos::models::EOSModel EOST>

using serif::equations::CentralDensityConstraint< EOST >::Border = discretization::blocks::central_density::border

The border type of the equation, that is what row of the global system this equation contributes to.

◆ Operands

template<eos::models::EOSModel EOST>

using serif::equations::CentralDensityConstraint< EOST >::Operands = utils::types::TypeList<TestOperand>

The operand types of the equation, that is the types of the fields which are used to evaluate the equation.

◆ ResidualQuantity

template<eos::models::EOSModel EOST>

using serif::equations::CentralDensityConstraint< EOST >::ResidualQuantity = dimensions::SpecificEnthalpy

The physical quantity which is being constrained by this equation, that is the quantity which is being set to a target value.

Constructor & Destructor Documentation

◆ CentralDensityConstraint()

template<eos::models::EOSModel EOST>

serif::equations::CentralDensityConstraint< EOST >::CentralDensityConstraint	(	EOST	equation_of_state,
		dimensions::DensityValue	target_density )

inline

Construct a central density constraint.

Parameters

equation_of_state	The EOS model to use for evaluating the enthalpy from the prescribed density.
target_density	The prescribed central density, which must be finite and strictly positive.

Exceptions

std::invalid_argument	If the prescribed density is not finite and strictly positive.
std::domain_error	If the EOS returns a non-finite enthalpy for the prescribed density.

Todo: We should consider whether we actually need to own the EOS, this choice made lifetime management easier but introduces copy overhead. Moreover, it means that the EOS must be copyable and, more importantly in my view, that the caller must know that the EOS is being copied.

Member Function Documentation

◆ density_from_enthalpy()

template<eos::models::EOSModel EOST>

dimensions::DensityValue serif::equations::CentralDensityConstraint< EOST >::density_from_enthalpy ( dimensions::SpecificEnthalpyValue enthalpy ) const

inlinenodiscard

Convert some enthalpy to a density for physical diagnostics, when the inverse relation exists.

Parameters

enthalpy The specific enthalpy to convert.

Returns: The corresponding density.

Requirements
The EOS model must support the relation DensityFromSpecificEnthalpy, otherwise this method is not available.

Note: Generally this method is only for debugging, if you want to use the density you should really call the EOS directly.

◆ evaluate()

template<eos::models::EOSModel EOST>

PointLinearization< Operands > serif::equations::CentralDensityConstraint< EOST >::evaluate ( const EquationPoint< Operands > & point ) const

inlinenodiscard

Evaluate the central density constraint at a given point.

Parameters

point The point at which to evaluate the equation, which must be the center of the star.

Note: It is the responsibility of the caller (and generally of the border equation backend) to ensure that this residual is applied to the correct row of the global system, the row defined by the Border type alias.

Returns: The linearization of the equation at the given point, which contains the residual and the derivatives of the residual with respect to the fields being evaluated.

◆ target_density()

template<eos::models::EOSModel EOST>

dimensions::DensityValue serif::equations::CentralDensityConstraint< EOST >::target_density ( ) const

inlinenodiscardnoexcept

Return the prescribed central density.

Returns: The prescribed central density.

◆ target_enthalpy()

template<eos::models::EOSModel EOST>

dimensions::SpecificEnthalpyValue serif::equations::CentralDensityConstraint< EOST >::target_enthalpy ( ) const

inlinenodiscardnoexcept

Return the target enthalpy corresponding to the prescribed central density.

Returns: The target enthalpy corresponding to the prescribed central density.

Member Data Documentation

◆ affine

template<eos::models::EOSModel EOST>

bool serif::equations::CentralDensityConstraint< EOST >::affine = true

staticconstexpr

Whether the equation is affine, that is whether the equation is linear in the fields being evaluated. This is only used for compile-time checks.

◆ m_eos

template<eos::models::EOSModel EOST>

EOST serif::equations::CentralDensityConstraint< EOST >::m_eos

private

The EOS model to use for evaluating the enthalpy from the prescribed density.

◆ m_target_density

template<eos::models::EOSModel EOST>

dimensions::DensityValue serif::equations::CentralDensityConstraint< EOST >::m_target_density

private

The prescribed central density, which must be finite and strictly positive.

◆ m_target_enthalpy

template<eos::models::EOSModel EOST>

double serif::equations::CentralDensityConstraint< EOST >::m_target_enthalpy

private

The target enthalpy corresponding to the prescribed central density, which is computed from the EOS and must be finite.

◆ name

template<eos::models::EOSModel EOST>

std::string_view serif::equations::CentralDensityConstraint< EOST >::name = "central density constraint"

staticconstexpr

Compile time name for the equation, used for debugging and logging.

◆ position_independent

template<eos::models::EOSModel EOST>

bool serif::equations::CentralDensityConstraint< EOST >::position_independent = true

staticconstexpr

Whether the equation is independent of the position of the point being evaluated, that is whether the equation is invariant under translations and rotations of the point. This is only used for compile-time checks.

◆ reference_position

template<eos::models::EOSModel EOST>

std::array<double, 3> serif::equations::CentralDensityConstraint< EOST >::reference_position {}

staticconstexpr

The reference position of the equation, this is only used for compile-time checks and is not used in the evaluation of the equation.

The documentation for this class was generated from the following file:

src/include/serif/equations/central_density.hpp

Public Types

Public Member Functions

Static Public Attributes

Private Attributes

Detailed Description

Member Typedef Documentation

◆ Border

◆ Operands

◆ ResidualQuantity

Constructor & Destructor Documentation

◆ CentralDensityConstraint()

Member Function Documentation

◆ density_from_enthalpy()

◆ evaluate()

◆ target_density()

◆ target_enthalpy()

Member Data Documentation

◆ affine

◆ m_eos

◆ m_target_density

◆ m_target_enthalpy

◆ name

◆ position_independent

◆ reference_position