dolfinx::fem::Function< T > Class Template Reference

This class represents a function \( u_h \) in a finite element function space \( V_h \), given by. More...

#include <Function.h>

Public Member Functions
	Function (std::shared_ptr< const FunctionSpace > V)
	Create function on given function space. More...
	Function (std::shared_ptr< const FunctionSpace > V, std::shared_ptr< la::Vector< T >> x)
	Create function on given function space with a given vector. More...
	Function (const Function &v)=delete
	Function (Function &&v)
	Move constructor.
virtual	~Function ()
	Destructor.
Function &	operator= (Function &&v) noexcept
	Move assignment.
Function &	operator= (const Function &v)=delete
Function	sub (int i) const
	Extract subfunction (view into the Function) More...
Function	collapse () const
	Collapse a subfunction (view into the Function) to a stand-alone Function. More...
std::shared_ptr< const FunctionSpace >	function_space () const
	Return shared pointer to function space. More...
Vec	vector () const
	Return vector of expansion coefficients as a PETSc Vec. Throws an exception if a PETSc Vec cannot be created due to a type mismatch. More...
std::shared_ptr< const la::Vector< T > >	x () const
	Underlying vector.
std::shared_ptr< la::Vector< T > >	x ()
	Underlying vector.
void	interpolate (const Function< T > &v)
	Interpolate a Function (on possibly non-matching meshes) More...
void	interpolate (const std::function< xt::xarray< T >(const xt::xtensor< double, 2 > &)> &f)
	Interpolate an expression. More...
void	eval (const xt::xtensor< double, 2 > &x, const xtl::span< const std::int32_t > &cells, xt::xtensor< T, 2 > &u) const
	Evaluate the Function at points. More...
xt::xtensor< T, 2 >	compute_point_values () const
	Compute values at all mesh 'nodes'. More...
std::size_t	id () const
	ID.

Public Attributes
std::string	name = "u"
	Name.

Detailed Description

template<typename T>
class dolfinx::fem::Function< T >

This class represents a function \( u_h \) in a finite element function space \( V_h \), given by.

\[ u_h = \sum_{i=1}^{n} U_i \phi_i \]

where \( \{\phi_i\}_{i=1}^{n} \) is a basis for \( V_h \), and \( U \) is a vector of expansion coefficients for \( u_h \).

Constructor & Destructor Documentation

Function() [1/2]

template<typename T >

dolfinx::fem::Function< T >::Function ( std::shared_ptr< const FunctionSpace >  V )

inlineexplicit

Create function on given function space.

Parameters

[in]

V

The function space

Function() [2/2]

template<typename T >

dolfinx::fem::Function< T >::Function ( std::shared_ptr< const FunctionSpace >  V, std::shared_ptr< la::Vector< T >>  x  )

inline

Create function on given function space with a given vector.

Warning: This constructor is intended for internal library use only

Parameters

[in]	V	The function space
[in]	x	The vector

Member Function Documentation

collapse()

template<typename T >

Function dolfinx::fem::Function< T >::collapse ( ) const

inline

Collapse a subfunction (view into the Function) to a stand-alone Function.

Returns

New collapsed Function

compute_point_values()

template<typename T >

xt::xtensor<T, 2> dolfinx::fem::Function< T >::compute_point_values ( ) const

inline

Compute values at all mesh 'nodes'.

Returns

The values at all geometric points

eval()

template<typename T >

void dolfinx::fem::Function< T >::eval ( const xt::xtensor< double, 2 > &  x, const xtl::span< const std::int32_t > &  cells, xt::xtensor< T, 2 > &  u  ) const

inline

Evaluate the Function at points.

Parameters

[in]	x	The coordinates of the points. It has shape (num_points, 3).
[in]	cells	An array of cell indices. cells[i] is the index of the cell that contains the point x(i). Negative cell indices can be passed, and the corresponding point will be ignored.
[in,out]	u	The values at the points. Values are not computed for points with a negative cell index. This argument must be passed with the correct size.

function_space()

template<typename T >

std::shared_ptr<const FunctionSpace> dolfinx::fem::Function< T >::function_space ( ) const

inline

Return shared pointer to function space.

Returns

The function space

interpolate() [1/2]

template<typename T >

void dolfinx::fem::Function< T >::interpolate ( const Function< T > &  v )

inline

Interpolate a Function (on possibly non-matching meshes)

Parameters

[in]

v

The function to be interpolated.

interpolate() [2/2]

template<typename T >

void dolfinx::fem::Function< T >::interpolate ( const std::function< xt::xarray< T >(const xt::xtensor< double, 2 > &)> &  f )

inline

Interpolate an expression.

Parameters

[in]

f

The expression to be interpolated

sub()

template<typename T >

Function dolfinx::fem::Function< T >::sub ( int  i ) const

inline

Extract subfunction (view into the Function)

Parameters

[in]

i

Index of subfunction

Returns

The subfunction

vector()

template<typename T >

Vec dolfinx::fem::Function< T >::vector ( ) const

inline

Return vector of expansion coefficients as a PETSc Vec. Throws an exception if a PETSc Vec cannot be created due to a type mismatch.

Returns

The vector of expansion coefficients

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

• /__w/dolfinx/dolfinx/cpp/dolfinx/fem/Form.h
• /__w/dolfinx/dolfinx/cpp/dolfinx/fem/Function.h