#include <deal.II/lac/matrix_block.h>

Inheritance diagram for MatrixBlock< MatrixType >:

Public Types
typedef types::global_dof_index	size_type

typedef MatrixType::value_type	value_type

Public Member Functions
	MatrixBlock ()

	MatrixBlock (const MatrixBlock< MatrixType > &M)

	MatrixBlock (size_type i, size_type j)

void	reinit (const BlockSparsityPattern &sparsity)

void	add (const size_type i, const size_type j, const typename MatrixType::value_type value)

template<typename number >
void	add (const std::vector< size_type > &indices, const FullMatrix< number > &full_matrix, const bool elide_zero_values=true)

template<typename number >
void	add (const std::vector< size_type > &row_indices, const std::vector< size_type > &col_indices, const FullMatrix< number > &full_matrix, const bool elide_zero_values=true)

template<typename number >
void	add (const size_type row_index, const std::vector< size_type > &col_indices, const std::vector< number > &values, const bool elide_zero_values=true)

template<typename number >
void	add (const size_type row, const size_type n_cols, const size_type col_indices, const number values, const bool elide_zero_values=true, const bool col_indices_are_sorted=false)

template<class VectorType >
void	vmult (VectorType &w, const VectorType &v) const

template<class VectorType >
void	vmult_add (VectorType &w, const VectorType &v) const

template<class VectorType >
void	Tvmult (VectorType &w, const VectorType &v) const

template<class VectorType >
void	Tvmult_add (VectorType &w, const VectorType &v) const

std::size_t	memory_consumption () const

Public Member Functions inherited from Subscriptor
	Subscriptor ()

	Subscriptor (const Subscriptor &)

	Subscriptor (Subscriptor &&) noexcept

virtual	~Subscriptor ()

Subscriptor &	operator= (const Subscriptor &)

Subscriptor &	operator= (Subscriptor &&) noexcept

void	subscribe (const char *identifier=nullptr) const

void	unsubscribe (const char *identifier=nullptr) const

unsigned int	n_subscriptions () const

void	list_subscribers () const

template<class Archive >
void	serialize (Archive &ar, const unsigned int version)

Static Public Member Functions
static ::ExceptionBase &	ExcBlockIndexMismatch (size_type arg1, size_type arg2)

Static Public Member Functions inherited from Subscriptor
static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)

static ::ExceptionBase &	ExcNoSubscriber (std::string arg1, std::string arg2)

Public Attributes
size_type	row

size_type	column

MatrixType	matrix

Private Attributes
BlockIndices	row_indices

BlockIndices	column_indices

Detailed Description

template<typename MatrixType>
class MatrixBlock< MatrixType >

A wrapper around a matrix object, storing the coordinates in a block matrix as well.

This class is an alternative to BlockMatrixBase, if you only want to generate a single block of the system, not the whole system. Using the add() functions of this class, it is possible to use the standard assembling functions used for block matrices, but only enter in one of the blocks and still avoiding the index computations involved. The reason for this class is, that we may need a different number of matrices for different blocks in a block system. For example, a preconditioner for the Oseen system can be built as a block system, where the pressure block is of the form M^-1FA^-1 with M the pressure mass matrix, A the pressure Laplacian and F the advection diffusion operator applied to the pressure space. Since only a single matrix is needed for the other blocks, using BlockSparseMatrix or similar would be a waste of memory.

While the add() functions make a MatrixBlock appear like a block matrix for assembling, the functions vmult(), Tvmult(), vmult_add(), and Tvmult_add() make it behave like a MatrixType, when it comes to applying it to a vector. This behavior allows us to store MatrixBlock objects in vectors, for instance in MGLevelObject without extracting the matrix first.

MatrixBlock comes handy when using BlockMatrixArray. Once the MatrixBlock has been properly initialized and filled, it can be used in the simplest case as:

MatrixBlockVector<SparseMatrix<double> > > blocks;
...
BlockMatrixArray matrix (n_blocks, n_blocks);
for (size_type i=0;i<blocks.size;++i)
  matrix.enter(blocks.block(i).row, blocks.block(i).column, blocks.matrix(i));

Here, we have not gained very much, except that we do not need to set up empty blocks in the block system.

Note: This class expects, that the row and column BlockIndices objects for the system are equal. If they are not, some functions will throw ExcNotImplemented.

Todo:: Example for the product preconditioner of the pressure Schur complement.

See also: Block (linear algebra)

Author: Guido Kanschat, 2006

Definition at line 34 of file matrix_block.h.

Member Typedef Documentation

◆ size_type

template<typename MatrixType>

typedef types::global_dof_index MatrixBlock< MatrixType >::size_type

Declare type for container size.

Definition at line 112 of file matrix_block.h.

◆ value_type

template<typename MatrixType>

typedef MatrixType::value_type MatrixBlock< MatrixType >::value_type

Declare a type for matrix entries.

Definition at line 117 of file matrix_block.h.

Constructor & Destructor Documentation

◆ MatrixBlock() [1/3]

template<typename MatrixType >

MatrixBlock< MatrixType >::MatrixBlock ( )

inline

Constructor rendering an uninitialized object.

Definition at line 595 of file matrix_block.h.

◆ MatrixBlock() [2/3]

template<typename MatrixType>

MatrixBlock< MatrixType >::MatrixBlock ( const MatrixBlock< MatrixType > & M )

inline

Copy constructor.

Definition at line 604 of file matrix_block.h.

◆ MatrixBlock() [3/3]

template<typename MatrixType>

MatrixBlock< MatrixType >::MatrixBlock	(	size_type	i,
		size_type	j
	)

inline

Constructor setting block coordinates, but not initializing the matrix.

Definition at line 617 of file matrix_block.h.

Member Function Documentation

◆ reinit()

template<typename MatrixType >

void MatrixBlock< MatrixType >::reinit ( const BlockSparsityPattern & sparsity )

inline

Reinitialize the matrix for a new BlockSparsityPattern. This adjusts the matrix as well as the row_indices and column_indices.

Note: The row and column block structure of the sparsity pattern must be equal.

Definition at line 626 of file matrix_block.h.

◆ add() [1/5]

template<typename MatrixType>

void MatrixBlock< MatrixType >::add	(	const size_type	i,
		const size_type	j,
		const typename MatrixType::value_type	value
	)

inline

Add value to the element (i,j). Throws an error if the entry does not exist or if it is in a different block.

Definition at line 650 of file matrix_block.h.

◆ add() [2/5]

template<typename MatrixType >

template<typename number >

void MatrixBlock< MatrixType >::add	(	const std::vector< size_type > &	indices,
		const FullMatrix< number > &	full_matrix,
		const bool	elide_zero_values = `true`
	)

inline

Add all elements in a FullMatrix into sparse matrix locations given by indices. This function assumes a quadratic sparse matrix and a quadratic full_matrix. The global locations are translated into locations in this block and ExcBlockIndexMismatch is thrown, if the global index does not point into the block referred to by row and column.

Todo:: elide_zero_values is currently ignored.

The optional parameter elide_zero_values can be used to specify whether zero values should be added anyway or these should be filtered away and only non-zero data is added. The default value is true, i.e., zero values won't be added into the matrix.

Definition at line 734 of file matrix_block.h.

◆ add() [3/5]

template<typename MatrixType >

template<typename number >

void MatrixBlock< MatrixType >::add	(	const std::vector< size_type > &	row_indices,
		const std::vector< size_type > &	col_indices,
		const FullMatrix< number > &	full_matrix,
		const bool	elide_zero_values = `true`
	)

inline

Add all elements in a FullMatrix into global locations given by row_indices and col_indices, respectively. The global locations are translated into locations in this block and ExcBlockIndexMismatch is thrown, if the global index does not point into the block referred to by row and column.

Todo:: elide_zero_values is currently ignored.

The optional parameter elide_zero_values can be used to specify whether zero values should be added anyway or these should be filtered away and only non-zero data is added. The default value is true, i.e., zero values won't be added into the matrix.

Definition at line 673 of file matrix_block.h.

◆ add() [4/5]

template<typename MatrixType >

template<typename number >

void MatrixBlock< MatrixType >::add	(	const size_type	row_index,
		const std::vector< size_type > &	col_indices,
		const std::vector< number > &	values,
		const bool	elide_zero_values = `true`
	)

inline

Set several elements in the specified row of the matrix with column indices as given by col_indices to the respective value. This is the function doing the actual work for the ones adding full matrices. The global locations row_index and col_indices are translated into locations in this block and ExcBlockIndexMismatch is thrown, if the global index does not point into the block referred to by row and column.

Todo:: elide_zero_values is currently ignored.

The optional parameter elide_zero_values can be used to specify whether zero values should be added anyway or these should be filtered away and only non-zero data is added. The default value is true, i.e., zero values won't be added into the matrix.

Definition at line 755 of file matrix_block.h.

◆ add() [5/5]

template<typename MatrixType >

template<typename number >

void MatrixBlock< MatrixType >::add	(	const size_type	row,
		const size_type	n_cols,
		const size_type *	col_indices,
		const number *	values,
		const bool	elide_zero_values = `true`,
		const bool	col_indices_are_sorted = `false`
	)

inline

Add an array of values given by values in the given global matrix row at columns specified by col_indices in the sparse matrix.

The optional parameter elide_zero_values can be used to specify whether zero values should be added anyway or these should be filtered away and only non-zero data is added. The default value is true, i.e., zero values won't be added into the matrix.

Definition at line 694 of file matrix_block.h.

◆ vmult()

template<typename MatrixType >

template<class VectorType >

void MatrixBlock< MatrixType >::vmult	(	VectorType &	w,
		const VectorType &	v
	)		const

inline

Matrix-vector-multiplication, forwarding to the same function in MatrixType. No index computations are done, thus, the vectors need to have sizes matching matrix.

Definition at line 773 of file matrix_block.h.

◆ vmult_add()

template<typename MatrixType >

template<class VectorType >

void MatrixBlock< MatrixType >::vmult_add	(	VectorType &	w,
		const VectorType &	v
	)		const

inline

Matrix-vector-multiplication, forwarding to the same function in MatrixType. No index computations are done, thus, the vectors need to have sizes matching matrix.

Definition at line 783 of file matrix_block.h.

◆ Tvmult()

template<typename MatrixType >

template<class VectorType >

void MatrixBlock< MatrixType >::Tvmult	(	VectorType &	w,
		const VectorType &	v
	)		const

inline

Matrix-vector-multiplication, forwarding to the same function in MatrixType. No index computations are done, thus, the vectors need to have sizes matching matrix.

Definition at line 793 of file matrix_block.h.

◆ Tvmult_add()

template<typename MatrixType >

template<class VectorType >

void MatrixBlock< MatrixType >::Tvmult_add	(	VectorType &	w,
		const VectorType &	v
	)		const

inline

Matrix-vector-multiplication, forwarding to the same function in MatrixType. No index computations are done, thus, the vectors need to have sizes matching matrix.

Definition at line 803 of file matrix_block.h.

◆ memory_consumption()

template<typename MatrixType >

std::size_t MatrixBlock< MatrixType >::memory_consumption ( ) const

inline

The memory used by this object.

Definition at line 812 of file matrix_block.h.

Member Data Documentation

◆ row

template<typename MatrixType>

size_type MatrixBlock< MatrixType >::row

Row coordinate. This is the position of the data member matrix on the global matrix.

Definition at line 282 of file matrix_block.h.

◆ column

template<typename MatrixType>

size_type MatrixBlock< MatrixType >::column

Column coordinate. This is the position of the data member matrix on the global matrix.

Definition at line 287 of file matrix_block.h.

◆ matrix

template<typename MatrixType>

MatrixType MatrixBlock< MatrixType >::matrix

The matrix itself

Definition at line 292 of file matrix_block.h.

◆ row_indices

template<typename MatrixType>

BlockIndices MatrixBlock< MatrixType >::row_indices

private

The row BlockIndices of the whole system. Using row(), this allows us to find the index of the first row degree of freedom for this block.

Definition at line 299 of file matrix_block.h.

◆ column_indices

template<typename MatrixType>

BlockIndices MatrixBlock< MatrixType >::column_indices

private

The column BlockIndices of the whole system. Using column(), this allows us to find the index of the first column degree of freedom for this block.

Definition at line 305 of file matrix_block.h.

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

deal.II/lac/matrix_block.h

Public Types

Public Member Functions

Static Public Member Functions

Public Attributes

Private Attributes

Detailed Description

template<typename MatrixType> class MatrixBlock< MatrixType >

Member Typedef Documentation

◆ size_type

◆ value_type

Constructor & Destructor Documentation

◆ MatrixBlock() [1/3]

◆ MatrixBlock() [2/3]

◆ MatrixBlock() [3/3]

Member Function Documentation

◆ reinit()

◆ add() [1/5]

◆ add() [2/5]

◆ add() [3/5]

◆ add() [4/5]

◆ add() [5/5]

◆ vmult()

◆ vmult_add()

◆ Tvmult()

◆ Tvmult_add()

◆ memory_consumption()

Member Data Documentation

◆ row

◆ column

◆ matrix

◆ row_indices

◆ column_indices

template<typename MatrixType>
class MatrixBlock< MatrixType >