dolfinx::la Namespace Reference

Linear algebra interface. More...

Classes
class	PETScKrylovSolver
	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	PETScMatrix
	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	PETScOperator
	This class is a base class for matrices that can be used in PETScKrylovSolver. More...
class	PETScOptions
	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. More...
class	PETScVector
	A simple wrapper for a PETSc vector pointer (Vec). Its main purpose is to assist with memory/lifetime management of PETSc Vec objects. More...
class	SparsityPattern
	This class provides a sparsity pattern data structure that can be used to initialize sparse matrices. More...
class	Vector
	Distributed vector. More...
class	VectorSpaceBasis
	This class defines a basis for vector spaces, typically used for expressing nullspaces of singular operators and 'near nullspaces' used in smoothed aggregation algebraic multigrid. More...

Enumerations
enum class	Norm { l1 , l2 , linf , frobenius }
	Norm types.

Functions
Mat	create_petsc_matrix (MPI_Comm comm, const SparsityPattern &sparsity_pattern, const std::string &type=std::string())
	Create a PETSc Mat. Caller is responsible for destroying the returned object.
MatNullSpace	create_petsc_nullspace (MPI_Comm comm, const VectorSpaceBasis &nullspace)
	Create PETSc MatNullSpace. Caller is responsible for destruction returned object.
Vec	create_ghosted_vector (const common::IndexMap &map, int bs, xtl::span< PetscScalar > x)
	Create a PETSc Vec that wraps the data in an array. More...
void	petsc_error (int error_code, std::string filename, std::string petsc_function)
	Print error message for PETSc calls that return an error.
std::vector< IS >	create_petsc_index_sets (const std::vector< std::pair< std::reference_wrapper< const common::IndexMap >, int >> &maps)
Vec	create_petsc_vector (const common::IndexMap &map, int bs)
	Create a ghosted PETSc Vec. More...
Vec	create_petsc_vector (MPI_Comm comm, std::array< std::int64_t, 2 > range, const std::vector< std::int64_t > &ghosts, int bs)
	Create a ghosted PETSc Vec from a local range and ghost indices. More...
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< xtl::span< const PetscScalar >> &x_b, const std::vector< std::pair< std::reference_wrapper< const common::IndexMap >, int >> &maps)
	Scatter local vectors to Vec.
template<typename T , class Allocator = std::allocator<T>>
T	inner_product (const Vector< T, Allocator > &a, const Vector< T, Allocator > &b)
	Compute the inner product of two vectors. The two vectors must have the same parallel layout. More...

Detailed Description

Linear algebra interface.

Interface to linear algebra data structures and solvers

Function Documentation

create_ghosted_vector()

Vec dolfinx::la::create_ghosted_vector	(	const common::IndexMap &	map,
		int	bs,
		xtl::span< 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. The caller is responsible for destroying the Vec.

create_petsc_index_sets()

std::vector< IS > dolfinx::la::create_petsc_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}.

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_petsc_vector() [1/2]

Vec dolfinx::la::create_petsc_vector	(	const common::IndexMap &	map,
		int	bs
	)

Create a ghosted PETSc Vec.

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_petsc_vector() [2/2]

Vec dolfinx::la::create_petsc_vector	(	MPI_Comm	comm,
		std::array< std::int64_t, 2 >	range,
		const std::vector< std::int64_t > &	ghosts,
		int	bs
	)

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

Caller is responsible for destroying 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

inner_product()

template<typename T , class Allocator = std::allocator<T>>

T dolfinx::la::inner_product	(	const Vector< T, Allocator > &	a,
		const Vector< T, Allocator > &	b
	)

Compute the inner product of two vectors. The two vectors must have the same parallel layout.

Note

Collective

Parameters

a	A vector
b	A vector

Returns

Returns a^{H} b (a^{T} b if a and b are real)