PETScWrappers::BlockSparseMatrix Class Reference
[PETScWrappersBasic matrices]

Inheritance diagram for PETScWrappers::BlockSparseMatrix:
Inheritance graph
[legend]

List of all members.

Classes

class  ExcIncompatibleColNumbers
class  ExcIncompatibleRowNumbers

Public Types

typedef BlockMatrixBase
< SparseMatrix
BaseClass
typedef BaseClass::BlockType BlockType
typedef BaseClass::value_type value_type
typedef BaseClass::pointer pointer
typedef BaseClass::const_pointer const_pointer
typedef BaseClass::reference reference
typedef BaseClass::const_reference const_reference
typedef BaseClass::size_type size_type
typedef BaseClass::iterator iterator
typedef BaseClass::const_iterator const_iterator

Public Member Functions

 BlockSparseMatrix ()
 ~BlockSparseMatrix ()
BlockSparseMatrixoperator= (const BlockSparseMatrix &)
BlockSparseMatrixoperator= (const double d)
void reinit (const unsigned int n_block_rows, const unsigned int n_block_columns)
void collect_sizes ()
void vmult (BlockVector &dst, const BlockVector &src) const
void vmult (BlockVector &dst, const Vector &src) const
void vmult (Vector &dst, const BlockVector &src) const
void vmult (Vector &dst, const Vector &src) const
void Tvmult (BlockVector &dst, const BlockVector &src) const
void Tvmult (BlockVector &dst, const Vector &src) const
void Tvmult (Vector &dst, const BlockVector &src) const
void Tvmult (Vector &dst, const Vector &src) const

Detailed Description

Blocked sparse matrix based on the PETScWrappers::SparseMatrix class. This class implements the functions that are specific to the PETSc SparseMatrix base objects for a blocked sparse matrix, and leaves the actual work relaying most of the calls to the individual blocks to the functions implemented in the base class. See there also for a description of when this class is useful.

In contrast to the deal.II-type SparseMatrix class, the PETSc matrices do not have external objects for the sparsity patterns. Thus, one does not determine the size of the individual blocks of a block matrix of this type by attaching a block sparsity pattern, but by calling reinit() to set the number of blocks and then by setting the size of each block separately. In order to fix the data structures of the block matrix, it is then necessary to let it know that we have changed the sizes of the underlying matrices. For this, one has to call the collect_sizes() function, for much the same reason as is documented with the BlockSparsityPattern class.

Author:
Wolfgang Bangerth, 2004

Member Typedef Documentation

Typedef the base class for simpler access to its own typedefs.

Typedef the type of the underlying matrix.

Reimplemented from BlockMatrixBase< PETScWrappers::SparseMatrix >.

Import the typedefs from the base class.

Reimplemented from BlockMatrixBase< PETScWrappers::SparseMatrix >.


Constructor & Destructor Documentation

PETScWrappers::BlockSparseMatrix::BlockSparseMatrix (  ) 

Constructor; initializes the matrix to be empty, without any structure, i.e. the matrix is not usable at all. This constructor is therefore only useful for matrices which are members of a class. All other matrices should be created at a point in the data flow where all necessary information is available.

You have to initialize the matrix before usage with reinit(BlockSparsityPattern). The number of blocks per row and column are then determined by that function.

PETScWrappers::BlockSparseMatrix::~BlockSparseMatrix (  ) 

Destructor.


Member Function Documentation

BlockSparseMatrix& PETScWrappers::BlockSparseMatrix::operator= ( const BlockSparseMatrix  ) 

Pseudo copy operator only copying empty objects. The sizes of the block matrices need to be the same.

Reimplemented from Subscriptor.

BlockSparseMatrix& PETScWrappers::BlockSparseMatrix::operator= ( const double  d  ) 

This operator assigns a scalar to a matrix. Since this does usually not make much sense (should we set all matrix entries to this value? Only the nonzero entries of the sparsity pattern?), this operation is only allowed if the actual value to be assigned is zero. This operator only exists to allow for the obvious notation matrix=0, which sets all elements of the matrix to zero, but keep the sparsity pattern previously used.

void PETScWrappers::BlockSparseMatrix::reinit ( const unsigned int  n_block_rows,
const unsigned int  n_block_columns 
)

Resize the matrix, by setting the number of block rows and columns. This deletes all blocks and replaces them by unitialized ones, i.e. ones for which also the sizes are not yet set. You have to do that by calling the reinit functions of the blocks themselves. Do not forget to call collect_sizes() after that on this object.

The reason that you have to set sizes of the blocks yourself is that the sizes may be varying, the maximum number of elements per row may be varying, etc. It is simpler not to reproduce the interface of the SparsityPattern class here but rather let the user call whatever function she desires.

void PETScWrappers::BlockSparseMatrix::collect_sizes (  ) 

This function collects the sizes of the sub-objects and stores them in internal arrays, in order to be able to relay global indices into the matrix to indices into the subobjects. You *must* call this function each time after you have changed the size of the sub-objects.

Reimplemented from BlockMatrixBase< PETScWrappers::SparseMatrix >.

void BlockSparseMatrix< number >::vmult ( BlockVector dst,
const BlockVector src 
) const [inline]

Matrix-vector multiplication: let $dst = M*src$ with $M$ being this matrix.

References BlockMatrixBase< SparseMatrix >::vmult_block_block().

void BlockSparseMatrix< number >::vmult ( BlockVector dst,
const Vector src 
) const [inline]

Matrix-vector multiplication. Just like the previous function, but only applicable if the matrix has only one block column.

References BlockMatrixBase< SparseMatrix >::vmult_block_nonblock().

void BlockSparseMatrix< number >::vmult ( Vector dst,
const BlockVector src 
) const [inline]

Matrix-vector multiplication. Just like the previous function, but only applicable if the matrix has only one block row.

References BlockMatrixBase< SparseMatrix >::vmult_nonblock_block().

void BlockSparseMatrix< number >::vmult ( Vector dst,
const Vector src 
) const [inline]

Matrix-vector multiplication. Just like the previous function, but only applicable if the matrix has only one block.

References BlockMatrixBase< SparseMatrix >::vmult_nonblock_nonblock().

void BlockSparseMatrix< number >::Tvmult ( BlockVector dst,
const BlockVector src 
) const [inline]

Matrix-vector multiplication: let $dst = M^T*src$ with $M$ being this matrix. This function does the same as vmult() but takes the transposed matrix.

References BlockMatrixBase< SparseMatrix >::Tvmult_block_block().

void BlockSparseMatrix< number >::Tvmult ( BlockVector dst,
const Vector src 
) const [inline]

Matrix-vector multiplication. Just like the previous function, but only applicable if the matrix has only one block row.

References BlockMatrixBase< SparseMatrix >::Tvmult_block_nonblock().

void BlockSparseMatrix< number >::Tvmult ( Vector dst,
const BlockVector src 
) const [inline]

Matrix-vector multiplication. Just like the previous function, but only applicable if the matrix has only one block column.

References BlockMatrixBase< SparseMatrix >::Tvmult_nonblock_block().

void BlockSparseMatrix< number >::Tvmult ( Vector dst,
const Vector src 
) const [inline]

Matrix-vector multiplication. Just like the previous function, but only applicable if the matrix has only one block.

References BlockMatrixBase< SparseMatrix >::Tvmult_nonblock_nonblock().


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

deal.II documentation generated on Mon Nov 23 22:58:28 2009 by doxygen 1.6.1