dolfinx::fem::petsc Namespace Reference

Helper functions for assembly into PETSc data structures. More...

Functions
template<std::floating_point T>
Mat	create_matrix (const Form< PetscScalar, T > &a, std::string type=std::string())
	Create a matrix.
template<std::floating_point T>
Mat	create_matrix_block (const std::vector< std::vector< const Form< PetscScalar, T > * > > &a, std::string type=std::string())
	Initialise a monolithic matrix for an array of bilinear forms.
template<std::floating_point T>
Mat	create_matrix_nest (const std::vector< std::vector< const Form< PetscScalar, T > * > > &a, const std::vector< std::vector< std::string > > &types)
	Create nested (MatNest) matrix.
Vec	create_vector_block (const std::vector< std::pair< std::reference_wrapper< const common::IndexMap >, int > > &maps)
Vec	create_vector_nest (const std::vector< std::pair< std::reference_wrapper< const common::IndexMap >, int > > &maps)
	Create nested (VecNest) vector. Vector is not zeroed.
template<std::floating_point T>
void	assemble_vector (Vec b, const Form< PetscScalar, T > &L, std::span< const PetscScalar > constants, const std::map< std::pair< IntegralType, int >, std::pair< std::span< const PetscScalar >, int > > &coeffs)
	Assemble linear form into an already allocated PETSc vector.
template<std::floating_point T>
void	assemble_vector (Vec b, const Form< PetscScalar, T > &L)
template<std::floating_point T>
void	apply_lifting (Vec b, const std::vector< std::shared_ptr< const Form< PetscScalar, T > > > &a, const std::vector< std::span< const PetscScalar > > &constants, const std::vector< std::map< std::pair< IntegralType, int >, std::pair< std::span< const PetscScalar >, int > > > &coeffs, const std::vector< std::vector< std::shared_ptr< const DirichletBC< PetscScalar, T > > > > &bcs1, const std::vector< Vec > &x0, PetscScalar alpha)
	Modify RHS vector to account for Dirichlet boundary conditions.
template<std::floating_point T>
void	apply_lifting (Vec b, const std::vector< std::shared_ptr< const Form< PetscScalar, double > > > &a, const std::vector< std::vector< std::shared_ptr< const DirichletBC< PetscScalar, double > > > > &bcs1, const std::vector< Vec > &x0, PetscScalar alpha)
template<std::floating_point T>
void	set_bc (Vec b, const std::vector< std::shared_ptr< const DirichletBC< PetscScalar, T > > > &bcs, const Vec x0, PetscScalar alpha=1)

Detailed Description

Helper functions for assembly into PETSc data structures.

Function Documentation

apply_lifting() [1/2]

template<std::floating_point T>

void apply_lifting	(	Vec	b,
		const std::vector< std::shared_ptr< const Form< PetscScalar, double > > > &	a,
		const std::vector< std::vector< std::shared_ptr< const DirichletBC< PetscScalar, double > > > > &	bcs1,
		const std::vector< Vec > &	x0,
		PetscScalar	alpha )

Modify b such that:

b <- b - alpha * A_j (g_j - x0_j)

where j is a block (nest) index. For a non-blocked problem j = 0. The boundary conditions bcs1 are on the trial spaces V_j. The forms in [a] must have the same test space as L (from which b was built), but the trial space may differ. If x0 is not supplied, then it is treated as zero.

Ghost contributions are not accumulated (not sent to owner). Caller is responsible for calling VecGhostUpdateBegin/End.

apply_lifting() [2/2]

template<std::floating_point T>

void apply_lifting	(	Vec	b,
		const std::vector< std::shared_ptr< const Form< PetscScalar, T > > > &	a,
		const std::vector< std::span< const PetscScalar > > &	constants,
		const std::vector< std::map< std::pair< IntegralType, int >, std::pair< std::span< const PetscScalar >, int > > > &	coeffs,
		const std::vector< std::vector< std::shared_ptr< const DirichletBC< PetscScalar, T > > > > &	bcs1,
		const std::vector< Vec > &	x0,
		PetscScalar	alpha )

Modify RHS vector to account for Dirichlet boundary conditions.

Modify b such that:

b <- b - alpha * A_j (g_j - x0_j)

where j is a block (nest) index. For a non-blocked problem j = 0. The boundary conditions bcs1 are on the trial spaces V_j. The forms in [a] must have the same test space as L (from which b was built), but the trial space may differ. If x0 is not supplied, then it is treated as zero.

Ghost contributions are not accumulated (not sent to owner). Caller is responsible for calling VecGhostUpdateBegin/End.

assemble_vector() [1/2]

template<std::floating_point T>

void assemble_vector	(	Vec	b,
		const Form< PetscScalar, T > &	L )

Assemble linear form into an already allocated PETSc vector. Ghost contributions are not accumulated (not sent to owner). Caller is responsible for calling VecGhostUpdateBegin/End.

Parameters

[in,out]	b	The PETsc vector to assemble the form into. The vector must already be initialised with the correct size. The process-local contribution of the form is assembled into this vector. It is not zeroed before assembly.
[in]	L	The linear form to assemble

assemble_vector() [2/2]

template<std::floating_point T>

void assemble_vector	(	Vec	b,
		const Form< PetscScalar, T > &	L,
		std::span< const PetscScalar >	constants,
		const std::map< std::pair< IntegralType, int >, std::pair< std::span< const PetscScalar >, int > > &	coeffs )

Assemble linear form into an already allocated PETSc vector.

Ghost contributions are not accumulated (not sent to owner). Caller is responsible for calling VecGhostUpdateBegin/End.

Parameters

[in,out]	b	The PETsc vector to assemble the form into. The vector must already be initialised with the correct size. The process-local contribution of the form is assembled into this vector. It is not zeroed before assembly.
[in]	L	The linear form to assemble
[in]	constants	The constants that appear in L
[in]	coeffs	The coefficients that appear in L

create_matrix()

template<std::floating_point T>

Mat create_matrix	(	const Form< PetscScalar, T > &	a,
		std::string	type = std::string() )

Create a matrix.

Parameters

[in]	a	A bilinear form
[in]	type	The PETSc matrix type to create

Returns

A sparse matrix with a layout and sparsity that matches the bilinear form. The caller is responsible for destroying the Mat object.

create_matrix_block()

template<std::floating_point T>

Mat create_matrix_block	(	const std::vector< std::vector< const Form< PetscScalar, T > * > > &	a,
		std::string	type = std::string() )

Initialise a monolithic matrix for an array of bilinear forms.

Parameters

[in]	a	Rectangular array of bilinear forms. The a(i, j) form will correspond to the (i, j) block in the returned matrix
[in]	type	The type of PETSc Mat. If empty the PETSc default is used.

Returns

A sparse matrix with a layout and sparsity that matches the bilinear forms. The caller is responsible for destroying the Mat object.

create_matrix_nest()

template<std::floating_point T>

Mat create_matrix_nest	(	const std::vector< std::vector< const Form< PetscScalar, T > * > > &	a,
		const std::vector< std::vector< std::string > > &	types )

Create nested (MatNest) matrix.

Note

The caller is responsible for destroying the Mat object.

create_vector_block()

Vec create_vector_block

(

const std::vector< std::pair< std::reference_wrapper< const common::IndexMap >, int > > &

maps

)

Initialise monolithic vector. Vector is not zeroed.

The caller is responsible for destroying the Mat object

set_bc()

template<std::floating_point T>

void set_bc	(	Vec	b,
		const std::vector< std::shared_ptr< const DirichletBC< PetscScalar, T > > > &	bcs,
		const Vec	x0,
		PetscScalar	alpha = 1 )

Set bc values in owned (local) part of the PETSc vector, multiplied by 'alpha'. The vectors b and x0 must have the same local size. The bcs should be on (sub-)spaces of the form L that b represents.