Interface for setting (strong) Dirichlet boundary conditions. More...

#include <DirichletBC.h>

Public Member Functions
template<typename U >
	DirichletBC (const std::shared_ptr< const fem::Function< T >> &g, U &&dofs)
	Create a representation of a Dirichlet boundary condition where the space being constrained is the same as the function that defines the constraint values, i.e. share the same `FunctionSpace`. More...

	DirichletBC (const std::shared_ptr< const fem::Function< T >> &g, const std::array< std::vector< std::int32_t >, 2 > &V_g_dofs, std::shared_ptr< const fem::FunctionSpace > V)
	Create a representation of a Dirichlet boundary condition where the space being constrained and the function that defines the constraint values do not share the same `FunctionSpace`. A typical examples is when applying a constraint on a subspace. The (sub)space and the constrain function must have the same finite element. More...

	DirichletBC (const DirichletBC &bc)=default
	Copy constructor. More...

	DirichletBC (DirichletBC &&bc)=default
	Move constructor. More...

	~DirichletBC ()=default
	Destructor.

DirichletBC &	operator= (const DirichletBC &bc)=default
	Assignment operator. More...

DirichletBC &	operator= (DirichletBC &&bc)=default
	Move assignment operator.

std::shared_ptr< const fem::FunctionSpace >	function_space () const
	The function space to which boundary conditions are applied. More...

std::shared_ptr< const fem::Function< T > >	value () const
	Return boundary value function g. More...

std::pair< xtl::span< const std::int32_t >, std::int32_t >	dof_indices () const
	Access dof indices (local indices, unrolled), including ghosts, to which a Dirichlet condition is applied, and the index to the first non-owned (ghost) index. The array of indices is sorted. More...

void	set (xtl::span< T > x, double scale=1.0) const
	Set bc entries in `x` to `scale * x_bc` More...

void	set (xtl::span< T > x, const xtl::span< const T > &x0, double scale=1.0) const
	Set bc entries in `x` to `scale * (x0 - x_bc)` More...

void	dof_values (xtl::span< T > values) const

void	mark_dofs (std::vector< bool > &markers) const
	Set markers[i] = true if dof i has a boundary condition applied. Value of markers[i] is not changed otherwise. More...

Detailed Description

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

Interface for setting (strong) Dirichlet boundary conditions.

\(u = g \ \text{on} \ G\),

where \(u\) is the solution to be computed, \(g\) is a function and \(G\) is a sub domain of the mesh.

A DirichletBC is specified by the function \(g\), the function space (trial space) and degrees of freedom to which the boundary condition applies.

Constructor & Destructor Documentation

◆ DirichletBC() [1/4]

template<typename T >

template<typename U >

dolfinx::fem::DirichletBC< T >::DirichletBC	(	const std::shared_ptr< const fem::Function< T >> &	g,
		U &&	dofs
	)

inline

Create a representation of a Dirichlet boundary condition where the space being constrained is the same as the function that defines the constraint values, i.e. share the same FunctionSpace.

Parameters

[in]	g	The boundary condition value. The boundary condition can be applied to a function on the same space as g.
[in]	dofs	Degree-of-freedom block indices (`std::vector<std::int32_t>`) in the space of the boundary value function applied to V_dofs[i]. The dof block indices must be sorted.

Note: The indices in dofs are for blocks, e.g. a block index maps to 3 degrees-of-freedom if the dofmap associated with g has block size 3

◆ DirichletBC() [2/4]

template<typename T >

dolfinx::fem::DirichletBC< T >::DirichletBC	(	const std::shared_ptr< const fem::Function< T >> &	g,
		const std::array< std::vector< std::int32_t >, 2 > &	V_g_dofs,
		std::shared_ptr< const fem::FunctionSpace >	V
	)

inline

Create a representation of a Dirichlet boundary condition where the space being constrained and the function that defines the constraint values do not share the same FunctionSpace. A typical examples is when applying a constraint on a subspace. The (sub)space and the constrain function must have the same finite element.

Parameters

[in]	g	The boundary condition value
[in]	V_g_dofs	Two arrays of degree-of-freedom indices. First array are indices in the space where boundary condition is applied (V), second array are indices in the space of the boundary condition value function g. The arrays must be sorted by the indices in the first array. The dof indices are unrolled, i.e. are not by dof block.
[in]	V	The function (sub)space on which the boundary condition is applied

Note: The indices in dofs are unrolled and not for blocks

◆ DirichletBC() [3/4]

template<typename T >

dolfinx::fem::DirichletBC< T >::DirichletBC ( const DirichletBC< T > & bc )

default

Copy constructor.

Parameters

[in] bc The object to be copied

◆ DirichletBC() [4/4]

template<typename T >

dolfinx::fem::DirichletBC< T >::DirichletBC ( DirichletBC< T > && bc )

default

Move constructor.

Parameters

[in] bc The object to be moved

Member Function Documentation

◆ dof_indices()

template<typename T >

std::pair<xtl::span<const std::int32_t>, std::int32_t> dolfinx::fem::DirichletBC< T >::dof_indices ( ) const

inline

Access dof indices (local indices, unrolled), including ghosts, to which a Dirichlet condition is applied, and the index to the first non-owned (ghost) index. The array of indices is sorted.

Returns: Sorted array of dof indices (unrolled) and index to the first entry in the dof index array that is not owned. Entries dofs[:pos] are owned and entries dofs[pos:] are ghosts.

◆ dof_values()

template<typename T >

void dolfinx::fem::DirichletBC< T >::dof_values ( xtl::span< T > values ) const

inline

Todo:: Review this function - it is almost identical to the 'DirichletBC::set' function

Set boundary condition value for entries with an applied boundary condition. Other entries are not modified.

Parameters

[in,out] values The array in which to set the dof values. The array must be at least as long as the array associated with V1 (the space of the function that provides the dof values)

◆ function_space()

template<typename T >

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

inline

The function space to which boundary conditions are applied.

Returns: The function space

◆ mark_dofs()

template<typename T >

void dolfinx::fem::DirichletBC< T >::mark_dofs ( std::vector< bool > & markers ) const

inline

Set markers[i] = true if dof i has a boundary condition applied. Value of markers[i] is not changed otherwise.

Parameters

[in,out] markers Entry makers[i] is set to true if dof i in V0 had a boundary condition applied, i.e. dofs which are fixed by a boundary condition. Other entries in markers are left unchanged.

◆ operator=()

template<typename T >

DirichletBC& dolfinx::fem::DirichletBC< T >::operator= ( const DirichletBC< T > & bc )

default

Assignment operator.

Parameters

[in] bc Another DirichletBC object

◆ set() [1/2]

template<typename T >

void dolfinx::fem::DirichletBC< T >::set	(	xtl::span< T >	x,
		const xtl::span< const T > &	x0,
		double	scale = `1.0`
	)		const

inline

Set bc entries in x to scale * (x0 - x_bc)

Parameters

[in]	x	The array in which to set `scale * (x0 - x_bc)`
[in]	x0	The array used in compute the value to set
[in]	scale	The scaling value to apply

◆ set() [2/2]

template<typename T >

void dolfinx::fem::DirichletBC< T >::set	(	xtl::span< T >	x,
		double	scale = `1.0`
	)		const

inline

Set bc entries in x to scale * x_bc

Parameters

[in]	x	The array in which to set `scale * x_bc[i]`, where x_bc[i] is the boundary value of x[i]. Entries in x that do not have a Dirichlet condition applied to them are unchanged. The length of x must be less than or equal to the index of the greatest boundary dof index. To set values only for degrees-of-freedom that are owned by the calling rank, the length of the array `x` should be equal to the number of dofs owned by this rank.
[in]	scale	The scaling value to apply

◆ value()

template<typename T >

std::shared_ptr<const fem::Function<T> > dolfinx::fem::DirichletBC< T >::value ( ) const

inline

Return boundary value function g.

Returns: The boundary values Function

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

/__w/dolfinx/dolfinx/cpp/dolfinx/fem/assembler.h
/__w/dolfinx/dolfinx/cpp/dolfinx/fem/DirichletBC.h

Public Member Functions

Detailed Description

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

Constructor & Destructor Documentation

◆ DirichletBC() [1/4]

◆ DirichletBC() [2/4]

◆ DirichletBC() [3/4]

◆ DirichletBC() [4/4]

Member Function Documentation

◆ dof_indices()

◆ dof_values()

◆ function_space()

◆ mark_dofs()

◆ operator=()

◆ set() [1/2]

◆ set() [2/2]

◆ value()

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