dolfinx::la::petsc Namespace Reference

PETSc linear algebra functions. More...

Classes
class	Vector
class	Matrix
class	KrylovSolver

Functions
std::vector< Vec >	create_vectors (MPI_Comm comm, const std::vector< std::span< const PetscScalar > > &x)
	Create PETSc vectors from the local data. The data is copied into the PETSc vectors and is not shared. Each vector's global size is determined by summing the corresponding local size across all ranks in comm.
Vec	create_vector (const common::IndexMap &map, int bs)
	Create a ghosted PETSc Vec.
Vec	create_vector (MPI_Comm comm, std::array< std::int64_t, 2 > range, std::span< const std::int64_t > ghosts, int bs)
	Create a ghosted PETSc Vec from a local range and ghost indices.
Vec	create_vector_wrap (const common::IndexMap &map, int bs, std::span< const PetscScalar > x)
	Create a PETSc Vec that wraps the data in an array.
template<class V>
Vec	create_vector_wrap (const la::Vector< V > &x)
	Create a PETSc Vec that wraps the data in an array.
std::vector< IS >	create_index_sets (const std::vector< std::pair< std::reference_wrapper< const common::IndexMap >, int > > &maps)
	Compute PETSc IndexSets (IS) for a stack of index maps.
std::vector< std::vector< PetscScalar > >	get_local_vectors (const Vec x, const std::vector< std::pair< std::reference_wrapper< const common::IndexMap >, int > > &maps)
	Copy blocks from Vec into local arrays.
void	scatter_local_vectors (Vec x, const std::vector< std::span< const PetscScalar > > &x_b, const std::vector< std::pair< std::reference_wrapper< const common::IndexMap >, int > > &maps)
	Scatter local vectors to Vec.
Mat	create_matrix (MPI_Comm comm, const SparsityPattern &sp, std::optional< std::string_view > type=std::nullopt)
	Create a PETSc Mat. Caller is responsible for destroying the returned object.
MatNullSpace	create_nullspace (MPI_Comm comm, std::span< const Vec > basis)
	Create PETSc MatNullSpace. Caller is responsible for destruction returned object.

Detailed Description

PETSc linear algebra functions.

Function Documentation

create_index_sets()

std::vector< IS > create_index_sets

(

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

maps

)

Compute PETSc IndexSets (IS) for a stack of index maps.

If map[0] = {0, 1, 2, 3, 4, 5, 6} and map[1] = {0, 1, 2, 4} (in local indices) then IS[0] = {0, 1, 2, 3, 4, 5, 6} and IS[1] = {7, 8, 9, 10}.

Todo

This function could take just the local sizes.

Note

The caller is responsible for destruction of each IS.

Parameters

[in]

maps

Vector of IndexMaps and corresponding block sizes

Returns

Vector of PETSc Index Sets, created on PETSC_COMM_SELF

create_matrix()

Mat create_matrix	(	MPI_Comm	comm,
		const SparsityPattern &	sp,
		std::optional< std::string_view >	type = std::nullopt )

Create a PETSc Mat. Caller is responsible for destroying the returned object.

Parameters

[in]	comm	The MPI communicator
[in]	sp	The sparsity pattern that determines the layout and non-zero structure of the matrix
[in]	type	The PETSc Mat type to create. If std::nullopt or an empty string, the PETSc default is used.

create_nullspace()

MatNullSpace create_nullspace	(	MPI_Comm	comm,
		std::span< const Vec >	basis )

Create PETSc MatNullSpace. Caller is responsible for destruction returned object.

Parameters

[in]	comm	The MPI communicator
[in]	basis	The nullspace basis vectors

Returns

A PETSc nullspace object

create_vector() [1/2]

Vec create_vector	(	const common::IndexMap &	map,
		int	bs )

Create a ghosted PETSc Vec.

Note

Caller is responsible for destroying the returned object

Parameters

[in]	map	The index map describing the parallel layout (by block)
[in]	bs	The block size

Returns

A PETSc Vec

create_vector() [2/2]

Vec create_vector	(	MPI_Comm	comm,
		std::array< std::int64_t, 2 >	range,
		std::span< const std::int64_t >	ghosts,
		int	bs )

Create a ghosted PETSc Vec from a local range and ghost indices.

Note

Caller is responsible for freeing the returned object

Parameters

[in]	comm	The MPI communicator
[in]	range	The local ownership range (by blocks)
[in]	ghosts	Ghost blocks
[in]	bs	The block size. The total number of local entries is bs * (range[1] - range[0]).

Returns

A PETSc Vec

create_vector_wrap() [1/2]

Vec create_vector_wrap	(	const common::IndexMap &	map,
		int	bs,
		std::span< const PetscScalar >	x )

Create a PETSc Vec that wraps the data in an array.

Parameters

[in]	map	The index map that describes the parallel layout of the distributed vector (by block)
[in]	bs	Block size
[in]	x	The local part of the vector, including ghost entries. Must have size at least bs * (map.size_local() + map.num_ghosts()).

Returns

A PETSc Vec object that shares the data in x

Note

The array x must be kept alive to use the PETSc Vec object

The caller should call VecDestroy to free the return PETSc vector

create_vector_wrap() [2/2]

template<class V>

Vec create_vector_wrap

(

const la::Vector< V > &

x

)

Create a PETSc Vec that wraps the data in an array.

Parameters

[in]

x

The vector to be wrapped

Returns

A PETSc Vec object that shares the data in x

create_vectors()

std::vector< Vec > create_vectors	(	MPI_Comm	comm,
		const std::vector< std::span< const PetscScalar > > &	x )

Create PETSc vectors from the local data. The data is copied into the PETSc vectors and is not shared. Each vector's global size is determined by summing the corresponding local size across all ranks in comm.

Note

Caller is responsible for destroying the returned object

Parameters

[in]	comm	The MPI communicator
[in]	x	The vector data owned by the calling rank

Returns

Array of PETSc vectors