belfem::material::JcFunctionUserDefined Class Reference

User-defined critical current density (Jc) or power law exponent (n) function. More...

#include <cl_JcFunction_UserDefined.hpp>

Inheritance diagram for belfem::material::JcFunctionUserDefined:

Collaboration diagram for belfem::material::JcFunctionUserDefined:

Public Member Functions
	JcFunctionUserDefined (Material *Mat)
	Constructor.
	JcFunctionUserDefined (const JcFunctionUserDefined &)=delete
JcFunctionUserDefined &	operator= (const JcFunctionUserDefined &)=delete
	~JcFunctionUserDefined () override=default
real	eval (const real normB, const real angle) const override
	Evaluate the function (2-parameter version).
real	eval (const real normB, const real angle, const real T) const override
	Evaluate the function (3-parameter version).
void	set_jc_function (MatFunc2 *Function)
	Set the user-defined function pointer (2-parameter version).
void	set_jc_function (MatFunc3 *Function)
	Set the user-defined function pointer (3-parameter version).
Public Member Functions inherited from belfem::material::JcFunction
	JcFunction ()=default
	Default constructor.
virtual	~JcFunction ()=default
	Virtual destructor.
bool	depends_on (const JcParameter aParameter) const
	Check if function depends on a parameter.
virtual real	min_value () const
	Smallest value this function can return, when known.
bool	is_constant () const
	Check if function is constant (no dependencies).
virtual real	deval_dB (const real normB, const real angle, const real T) const
	Derivative of eval with respect to the field magnitude.
virtual real	deval_dbeta (const real normB, const real angle, const real T) const
	Derivative of eval with respect to the field angle.
virtual real	deval_dT (const real normB, const real angle, const real T) const
	Derivative of eval with respect to temperature.

Additional Inherited Members
Protected Member Functions inherited from belfem::material::JcFunction
void	set_dependency (const JcParameter aParameter)
	Mark function as depending on a parameter.
Protected Attributes inherited from belfem::material::JcFunction
JcDependency	mDependency

Detailed Description

User-defined critical current density (Jc) or power law exponent (n) function.

This class provides a wrapper for user-defined functions that compute Jc or n for superconducting materials. It supports both 2-parameter and 3-parameter function signatures:

• MatFunc2: f(Material*, normB, angle) - Field and angle dependent
• MatFunc3: f(Material*, normB, angle, T) - Field, angle, and temperature dependent

ANGLE CONTRACT (changed 2026-08-16): the angle is the UNFOLDED field-to-tape-normal angle θ ∈ [0, π] — before that change it arrived folded into [0, π/2]. A user function that is even in θ (cos², sin² only) is unaffected; one that used cos(θ) linearly or assumed θ ≤ π/2 must fold internally now. Plugins compiled against the old contract get the new angle silently — recompile and review.

The user provides a function pointer that will be called to evaluate the property. This allows complete customization while maintaining compatibility with the material framework.

IMPORTANT: This class is typically created and managed by UserDefinedMaterial. The material owns the JcFunctionUserDefined instance and will delete it.

Example usage (within a user-defined material library):

// User's custom Jc function
real my_jc_function(const Material* mat, real B, real angle, real T) {
    // Custom implementation
    return 1e9 / (1.0 + B/5.0) * exp(-T/90.0);
}
 
// In the material initialization function
extern "C" void MyMaterial_init(Material* mat) {
    mat->set_user_defined_function(
        MaterialProperty::jc,
        MaterialDependency::normB,
        MaterialDependency::angleNxB,
        MaterialDependency::T,
        &my_jc_function
    );
}

Constructor & Destructor Documentation

JcFunctionUserDefined() [1/2]

belfem::material::JcFunctionUserDefined::JcFunctionUserDefined ( Material * Mat )

inline

Constructor.

Parameters

Mat	Pointer to the parent material (not owned by this class)

JcFunctionUserDefined() [2/2]

belfem::material::JcFunctionUserDefined::JcFunctionUserDefined ( const JcFunctionUserDefined & )

delete

~JcFunctionUserDefined()

belfem::material::JcFunctionUserDefined::~JcFunctionUserDefined ( )

overridedefault

Member Function Documentation

eval() [1/2]

real belfem::material::JcFunctionUserDefined::eval ( const real normB, const real angle ) const

inlineoverridevirtual

Evaluate the function (2-parameter version).

Parameters

normB	Magnetic flux density magnitude [T]
angle	Angle between field and normal direction [rad]

Returns

Critical current density [A/m²] or power law exponent [dimensionless]

Reimplemented from belfem::material::JcFunction.

eval() [2/2]

real belfem::material::JcFunctionUserDefined::eval ( const real normB, const real angle, const real T ) const

inlineoverridevirtual

Evaluate the function (3-parameter version).

Parameters

normB	Magnetic flux density magnitude [T]
angle	Angle between field and normal direction [rad]
T	Temperature [K]

Returns

Critical current density [A/m²] or power law exponent [dimensionless]

Reimplemented from belfem::material::JcFunction.

operator=()

JcFunctionUserDefined & belfem::material::JcFunctionUserDefined::operator= ( const JcFunctionUserDefined & )

delete

set_jc_function() [1/2]

void belfem::material::JcFunctionUserDefined::set_jc_function ( MatFunc2 * Function )

inline

Set the user-defined function pointer (2-parameter version).

Parameters

Function

Pointer to user function with signature: real(Material*, real, real)

set_jc_function() [2/2]

void belfem::material::JcFunctionUserDefined::set_jc_function ( MatFunc3 * Function )

inline

Set the user-defined function pointer (3-parameter version).

Parameters

Function

Pointer to user function with signature: real(Material*, real, real, real)

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

• src/physics/materials/cl_JcFunction_UserDefined.hpp