dolfinx::la::petsc Namespace Reference

PETSc linear algebra functions. More...

Namespaces
namespace	options
	These class provides static functions that permit users to set and retrieve PETSc options via the PETSc option/parameter system. The option must not be prefixed by '-', e.g.

Classes
class	KrylovSolver
	This class implements Krylov methods for linear systems of the form Ax = b. It is a wrapper for the Krylov solvers of PETSc. More...
class	Matrix
	It is a simple wrapper for a PETSc matrix pointer (Mat). Its main purpose is to assist memory management of PETSc Mat objects. More...
class	Operator
	This class is a base class for matrices that can be used in petsc::KrylovSolver. More...
class	Vector
	A simple wrapper for a PETSc vector pointer (Vec). Its main purpose is to assist with memory/lifetime management of PETSc Vec objects. More...

Functions
void	error (int error_code, std::string filename, std::string petsc_function)
	Print error message for PETSc calls that return an error.
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.
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)
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 vectors.
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, const std::string &type=std::string())
	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

)

Todo:

This function could take just the local sizes

Compute PETSc IndexSets (IS) for a stack of index maps. E.g., 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}.

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 onPETSC_COMM_SELF

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

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.

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. All components must have the same length.

Returns

Array of PETSc vectors