SparsityPattern Class Reference

This class provides a sparsity pattern data structure that can be used to initialize sparse matrices. After assembly, column indices are always sorted in increasing order. Ghost entries are kept after assembly. More...

#include <SparsityPattern.h>

Public Member Functions
	SparsityPattern (MPI_Comm comm, const std::array< std::shared_ptr< const common::IndexMap >, 2 > &maps, const std::array< int, 2 > &bs)
	Create an empty sparsity pattern with specified dimensions. More...
	SparsityPattern (MPI_Comm comm, const std::vector< std::vector< const SparsityPattern * >> &patterns, const std::array< std::vector< std::pair< std::reference_wrapper< const common::IndexMap >, int >>, 2 > &maps, const std::array< std::vector< int >, 2 > &bs)
	Create a new sparsity pattern by concatenating sub-patterns, e.g. pattern =[ pattern00 ][ pattern 01] [ pattern10 ][ pattern 11]. More...
	SparsityPattern (const SparsityPattern &pattern)=delete
	SparsityPattern (SparsityPattern &&pattern)=default
	Move constructor.
	~SparsityPattern ()=default
	Destructor.
SparsityPattern &	operator= (SparsityPattern &&pattern)=default
	Move assignment.
void	insert (const std::span< const std::int32_t > &rows, const std::span< const std::int32_t > &cols)
	Insert non-zero locations using local (process-wise) indices.
void	insert_diagonal (const std::span< const std::int32_t > &rows)
	Insert non-zero locations on the diagonal. More...
void	assemble ()
	Finalize sparsity pattern and communicate off-process entries.
std::shared_ptr< const common::IndexMap >	index_map (int dim) const
	Index map for given dimension dimension. Returns the index map for rows and columns that will be set by the current MPI rank. More...
std::vector< std::int64_t >	column_indices () const
	Global indices of non-zero columns on owned rows. More...
common::IndexMap	column_index_map () const
	Builds the index map for columns after assembly of the sparsity pattern. More...
int	block_size (int dim) const
	Return index map block size for dimension dim.
std::int64_t	num_nonzeros () const
	Number of nonzeros on this rank after assembly, including ghost rows.
std::int32_t	nnz_diag (std::int32_t row) const
	Number of non-zeros in owned columns (diagonal block) on a given row. More...
std::int32_t	nnz_off_diag (std::int32_t row) const
	Number of non-zeros in unowned columns (off-diagonal block) on a given row. More...
const graph::AdjacencyList< std::int32_t > &	graph () const
	Sparsity pattern graph after assembly. Uses local indices for the columns. More...
std::span< const int >	off_diagonal_offset () const
	Row-wise start of off-diagonal (unowned columns) on each row. More...
MPI_Comm	comm () const
	Return MPI communicator.

Detailed Description

This class provides a sparsity pattern data structure that can be used to initialize sparse matrices. After assembly, column indices are always sorted in increasing order. Ghost entries are kept after assembly.

Constructor & Destructor Documentation

SparsityPattern() [1/2]

SparsityPattern	(	MPI_Comm	comm,
		const std::array< std::shared_ptr< const common::IndexMap >, 2 > &	maps,
		const std::array< int, 2 > &	bs
	)

Create an empty sparsity pattern with specified dimensions.

Parameters

[in]	comm	The communicator that the pattenr is defined on
[in]	maps	The index maps describing the [0] row and [1] column index ranges (up to a block size)
[in]	bs	The block sizes for the [0] row and [1] column maps

SparsityPattern() [2/2]

SparsityPattern	(	MPI_Comm	comm,
		const std::vector< std::vector< const SparsityPattern * >> &	patterns,
		const std::array< std::vector< std::pair< std::reference_wrapper< const common::IndexMap >, int >>, 2 > &	maps,
		const std::array< std::vector< int >, 2 > &	bs
	)

Create a new sparsity pattern by concatenating sub-patterns, e.g. pattern =[ pattern00 ][ pattern 01] [ pattern10 ][ pattern 11].

Parameters

[in]	comm	The MPI communicator
[in]	patterns	Rectangular array of sparsity pattern. The patterns must not be finalised. Null block are permited
[in]	maps	Pairs of (index map, block size) for each row block (maps[0]) and column blocks (maps[1])
[in]	bs	Block sizes for the sparsity pattern entries

Member Function Documentation

column_index_map()

common::IndexMap column_index_map

(

)

const

Builds the index map for columns after assembly of the sparsity pattern.

Returns

Map for all non-zero columns on this process, including ghosts

Todo:

Should this be compted and stored when finalising the SparsityPattern?

column_indices()

std::vector< std::int64_t > column_indices

(

)

const

Global indices of non-zero columns on owned rows.

Note

The ghosts are computed only once SparsityPattern::assemble has been called

Returns

The global index non-zero columns on this process, including ghosts

graph()

const graph::AdjacencyList< std::int32_t > & graph

(

)

const

Sparsity pattern graph after assembly. Uses local indices for the columns.

Note

Column global indices can be obtained from SparsityPattern::column_index_map()

Includes ghost rows

index_map()

std::shared_ptr< const common::IndexMap > index_map

(

int

dim

)

const

Index map for given dimension dimension. Returns the index map for rows and columns that will be set by the current MPI rank.

Parameters

[in]

dim

The requested map, row (0) or column (1)

Returns

The index map

insert_diagonal()

void insert_diagonal

(

const std::span< const std::int32_t > &

rows

)

Insert non-zero locations on the diagonal.

Parameters

[in]

rows

The rows in local (process-wise) indices. The indices must exist in the row IndexMap.

nnz_diag()

std::int32_t nnz_diag

(

std::int32_t

row

)

const

Number of non-zeros in owned columns (diagonal block) on a given row.

Note

Can also be used on ghost rows

nnz_off_diag()

std::int32_t nnz_off_diag

(

std::int32_t

row

)

const

Number of non-zeros in unowned columns (off-diagonal block) on a given row.

Note

Can also be used on ghost rows

off_diagonal_offset()

std::span< const int > off_diagonal_offset

(

)

const

Row-wise start of off-diagonal (unowned columns) on each row.

Note

Includes ghost rows

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

• /__w/dolfinx/dolfinx/cpp/dolfinx/la/SparsityPattern.h
• /__w/dolfinx/dolfinx/cpp/dolfinx/la/SparsityPattern.cpp