serif::utils::laneemden Namespace Reference

Classes
struct	IntegrationOptions
	Dimensionless integration controls; the surface tolerance does not bound the global integration error. More...
struct	PhysicalSample
	Physical scalar fields; gravity is the outward potential derivative, not the inward force component. More...
struct	PhysicalScales
	A physical conversion of one finite-radius dimensionless polytrope, in the caller's consistent units. More...
struct	Sample
	The regular Lane–Emden solution and its first derivative at one dimensionless radius. More...
struct	Solution
	A regular profile, ending at its first zero or the requested integration radius. More...

Functions
std::expected< PhysicalScales, std::string >	scale_from_mass (const Solution &solution, dimensions::QuantityValue< dimensions::Mass > mass, dimensions::QuantityValue< dimensions::MassDensity > central_density, dimensions::QuantityValue< dimensions::GravitationalConstant > gravitational_constant)
	Fix a reference star by mass and central density; its implied K is an output, never a change to an EOS.
std::expected< PhysicalScales, std::string >	scale_from_enthalpy (const Solution &solution, dimensions::QuantityValue< dimensions::SpecificEnthalpy > central_enthalpy, dimensions::QuantityValue< dimensions::MassDensity > central_density, dimensions::QuantityValue< dimensions::GravitationalConstant > gravitational_constant)
	Fix a physical star by central enthalpy and density, including the incompressible n = 0 limit.
std::expected< PhysicalScales, std::string >	scale_from_polytropic_constant (const Solution &solution, double polytropic_constant, dimensions::QuantityValue< dimensions::MassDensity > central_density, dimensions::QuantityValue< dimensions::GravitationalConstant > gravitational_constant)
	Fix a polytropic EOS through its K and central density; n must be strictly positive.
std::expected< PhysicalSample, std::string >	evaluate_physical (const Solution &solution, const PhysicalScales &scales, dimensions::QuantityValue< dimensions::Length > radius)
	Evaluate physical fields, continuing into vacuum beyond the stellar surface.
std::expected< Solution, std::string >	solve (double n, IntegrationOptions options={})
	Integrate theta'' + 2 theta'/xi + theta^n = 0 from the regular center.
std::expected< Sample, std::string >	evaluate (const Solution &solution, double xi)
	Evaluate a solved dimensionless profile with cubic Hermite interpolation, without extrapolation.

Function Documentation

evaluate()

std::expected< Sample, std::string > serif::utils::laneemden::evaluate ( const Solution & solution, double xi )

nodiscard

Evaluate a solved dimensionless profile with cubic Hermite interpolation, without extrapolation.

evaluate_physical()

std::expected< PhysicalSample, std::string > serif::utils::laneemden::evaluate_physical ( const Solution & solution, const PhysicalScales & scales, dimensions::QuantityValue< dimensions::Length > radius )

nodiscard

Evaluate physical fields, continuing into vacuum beyond the stellar surface.

The potential vanishes at infinity. Density, pressure, and enthalpy are zero at and beyond the surface, including the exterior side of the incompressible density jump.

scale_from_enthalpy()

std::expected< PhysicalScales, std::string > serif::utils::laneemden::scale_from_enthalpy ( const Solution & solution, dimensions::QuantityValue< dimensions::SpecificEnthalpy > central_enthalpy, dimensions::QuantityValue< dimensions::MassDensity > central_density, dimensions::QuantityValue< dimensions::GravitationalConstant > gravitational_constant )

nodiscard

Fix a physical star by central enthalpy and density, including the incompressible n = 0 limit.

scale_from_mass()

std::expected< PhysicalScales, std::string > serif::utils::laneemden::scale_from_mass ( const Solution & solution, dimensions::QuantityValue< dimensions::Mass > mass, dimensions::QuantityValue< dimensions::MassDensity > central_density, dimensions::QuantityValue< dimensions::GravitationalConstant > gravitational_constant )

nodiscard

Fix a reference star by mass and central density; its implied K is an output, never a change to an EOS.

scale_from_polytropic_constant()

std::expected< PhysicalScales, std::string > serif::utils::laneemden::scale_from_polytropic_constant ( const Solution & solution, double polytropic_constant, dimensions::QuantityValue< dimensions::MassDensity > central_density, dimensions::QuantityValue< dimensions::GravitationalConstant > gravitational_constant )

nodiscard

Fix a polytropic EOS through its K and central density; n must be strictly positive.

solve()

std::expected< Solution, std::string > serif::utils::laneemden::solve ( double n, IntegrationOptions options = {} )

nodiscard

Integrate theta'' + 2 theta'/xi + theta^n = 0 from the regular center.

The central series follows Boudreaux's original power-series recurrence. Both dependent variables now advance through the same four Runge–Kutta stages. A missing surface is a valid finite-interval result, including the n >= 5 solutions. Exhausting the step budget or producing an unrepresentable numerical state returns a failure instead.