Dune::BCRSMatrix

Dune::BCRSMatrix< B, A > Class Template Reference
[Sparse Matrix and Vector classes]

#include <bcrsmatrix.hh>

Inheritance diagram for Dune::BCRSMatrix< B, A >:

Dune::BDMatrix< B, A > List of all members.

Detailed Description

template<class B, class A = ISTLAllocator>
class Dune::BCRSMatrix< B, A >

A sparse block matrix with compressed row storage.

Implements a block compressed row storage scheme. The block type B can be any type implementing the matrix interface.

Different ways to build up a compressed row storage matrix are supported:

1. Row-wise scheme 2. Random scheme

Error checking: no error checking is provided normally. Setting the compile time switch DUNE_ISTL_WITH_CHECKING enables error checking.

Details:

1. Row-wise scheme

Rows are built up in sequential order. Size of the row and the column indices are defined. A row can be used as soon as it is initialized. With respect to memory there are two variants of this scheme: (a) number of non-zeroes known in advance (application finite difference schemes), (b) number of non-zeroes not known in advance (application: Sparse LU, ILU(n)).

2. Random scheme

For general finite element implementations the number of rows n is known, the number of non-zeroes might also be known (e.g. #edges + #nodes for P1) but the size of a row and the indices of a row can not be defined in sequential order.

     #include<dune/common/fmatrix.hh>
     #include<dune/istl/bcrsmatrix.hh>

     ...
       
     typedef FieldMatrix<double,2,2> M;
     BCRSMatrix<M> B(4,4,BCRSMatrix<M>::random);

     // initially set row size for each row
     B.setrowsize(0,1);
     B.setrowsize(3,4);
     B.setrowsize(2,1);
     B.setrowsize(1,1);
     // increase row size for row 2
     B.incrementrowsize(2)

     // finalize row setup phase
     B.endrowsizes();

     // add column entries to rows
     B.addindex(0,0);
     B.addindex(3,1);
     B.addindex(2,2);
     B.addindex(1,1);
     B.addindex(2,0);
     B.addindex(3,2);
     B.addindex(3,0);
     B.addindex(3,3);
       
     // finalize column setup phase
     B.endindices();

     // set entries using the random access operator
     B[0][0] = 1;
     B[1][1] = 2;
     B[2][0] = 3;
     B[2][2] = 4;
     B[3][1] = 5;
     B[3][2] = 6;
     B[3][0] = 7;
     B[3][3] = 8;


Public Types

enum  { blocklevel = B::blocklevel+1 }
 increment block level counter More...
enum  BuildMode { row_wise, random, unknown }
 we support two modes More...
typedef B::field_type field_type
 export the type representing the field
typedef B block_type
 export the type representing the components
typedef A allocator_type
 export the allocator type
typedef CompressedBlockVectorWindow<
B, A > 		row_type
 implement row_type with compressed vector
typedef A::size_type size_type
 The type for the index access and the size.
typedef RealRowIterator< row_type > iterator
 The iterator over the (mutable matrix rows.
typedef Iterator RowIterator
 rename the iterators for easier access
typedef row_type::Iterator ColIterator
 Iterator for the entries of each row.
typedef RealRowIterator< const
row_type > 		const_iterator
 The const iterator over the matrix rows.
typedef ConstIterator ConstRowIterator
 rename the const row iterator for easier access
typedef row_type::ConstIterator ConstColIterator
 Const iterator to the entries of a row.

Public Member Functions

row_type & operator[] (size_type i)
 random access to the rows
const row_type & operator[] (size_type i) const
 same for read only access
Iterator begin ()
 Get iterator to first row.
Iterator end ()
 Get iterator to one beyond last row.
Iterator rbegin ()
 Get iterator to last row.
Iterator rend ()
 Get iterator to one before first row.
ConstIterator begin () const
 Get const iterator to first row.
ConstIterator end () const
 Get const iterator to one beyond last row.
ConstIterator rbegin () const
 Get const iterator to last row.
ConstIterator rend () const
 Get const iterator to one before first row.
 BCRSMatrix ()
 an empty matrix
 BCRSMatrix (size_type _n, size_type _m, size_type _nnz, BuildMode bm)
 matrix with known number of nonzeroes
 BCRSMatrix (size_type _n, size_type _m, BuildMode bm)
 matrix with unknown number of nonzeroes
 BCRSMatrix (const BCRSMatrix &Mat)
 copy constructor
 ~BCRSMatrix ()
 destructor
void setBuildMode (BuildMode bm)
 Sets the build mode of the matrix.
void setSize (size_type rows, size_type columns, size_type nnz=0)
 Set the size of the matrix.
BCRSMatrix & operator= (const BCRSMatrix &Mat)
 assignment
BCRSMatrix & operator= (const field_type &k)
 Assignment from a scalar.
CreateIterator createbegin ()
 get initial create iterator
CreateIterator createend ()
 get create iterator pointing to one after the last block
void setrowsize (size_type i, size_type s)
 set number of indices in row i to s
size_type getrowsize (size_type i) const
 get current number of indices in row i
void incrementrowsize (size_type i, size_type s=1)
 increment size of row i by s (1 by default)
void endrowsizes ()
 indicate that size of all rows is defined
void addindex (size_type row, size_type col)
 add index (row,col) to the matrix
void endindices ()
 indicate that all indices are defined, check consistency
BCRSMatrix & operator *= (const field_type &k)
 vector space multiplication with scalar
BCRSMatrix & operator/= (const field_type &k)
 vector space division by scalar
BCRSMatrix & operator+= (const BCRSMatrix &b)
 Add the entries of another matrix to this one.
BCRSMatrix & operator-= (const BCRSMatrix &b)
 Substract the entries of another matrix to this one.
template<class X, class Y>
void mv (const X &x, Y &y) const
 y = A x
template<class X, class Y>
void umv (const X &x, Y &y) const
 y += A x
template<class X, class Y>
void mmv (const X &x, Y &y) const
 y -= A x
template<class X, class Y>
void usmv (const field_type &alpha, const X &x, Y &y) const
 y += alpha A x
template<class X, class Y>
void umtv (const X &x, Y &y) const
 y += A^T x
template<class X, class Y>
void mmtv (const X &x, Y &y) const
 y -= A^T x
template<class X, class Y>
void usmtv (const field_type &alpha, const X &x, Y &y) const
 y += alpha A^T x
template<class X, class Y>
void umhv (const X &x, Y &y) const
 y += A^H x
template<class X, class Y>
void mmhv (const X &x, Y &y) const
 y -= A^H x
template<class X, class Y>
void usmhv (const field_type &alpha, const X &x, Y &y) const
 y += alpha A^H x
double frobenius_norm2 () const
 square of frobenius norm, need for block recursion
double frobenius_norm () const
 frobenius norm: sqrt(sum over squared values of entries)
double infinity_norm () const
 infinity norm (row sum norm, how to generalize for blocks?)
double infinity_norm_real () const
 simplified infinity norm (uses Manhattan norm for complex values)
size_type N () const
 number of rows (counted in blocks)
size_type M () const
 number of columns (counted in blocks)
size_type nonzeroes () const
 number of blocks that are stored (the number of blocks that possibly are nonzero)
bool exists (size_type i, size_type j) const
 return true if (i,j) is in pattern

Classes

class  CreateIterator
 Iterator class for sequential creation of blocks More...
class  RealRowIterator
 Iterator access to matrix rows More...

Member Enumeration Documentation

template<class B, class A = ISTLAllocator>
anonymous enum

increment block level counter

Enumerator:
blocklevel  The number of blocklevels the matrix contains.

template<class B, class A = ISTLAllocator>
enum Dune::BCRSMatrix::BuildMode

we support two modes

Enumerator:
row_wise  Build in a row-wise manner.

Rows are built up in sequential order. Size of the row and the column indices are defined. A row can be used as soon as it is initialized. With respect to memory there are two variants of this scheme: (a) number of non-zeroes known in advance (application finite difference schemes), (b) number of non-zeroes not known in advance (application: Sparse LU, ILU(n)).

random  Build entries randomly.

For general finite element implementations the number of rows n is known, the number of non-zeroes might also be known (e.g. #edges + #nodes for P1) but the size of a row and the indices of a row can not be defined in sequential order.

unknown  Build mode not set!

Member Function Documentation

template<class B, class A = ISTLAllocator>
void Dune::BCRSMatrix< B, A >::setBuildMode ( BuildMode  bm  )  [inline]

Sets the build mode of the matrix.

Parameters:
bm The build mode to use.

template<class B, class A = ISTLAllocator>
void Dune::BCRSMatrix< B, A >::setSize ( size_type  rows,
size_type  columns,
size_type  nnz = 0 
) [inline]

Set the size of the matrix.

Sets the number of rows and columns of the matrix and allocates the memory needed for the storage of the matrix entries.

Warning:
After calling this methods on an already allocated (and probably setup matrix) results in all the structure and data being deleted. I.~e. one has to setup the matrix again.
Parameters:
rows The number of rows the matrix should contain.
columns the number of columns the matrix should contain.
nnz The number of nonzero entries the matrix should hold (if omitted defaults to 0).

template<class B, class A = ISTLAllocator>
void Dune::BCRSMatrix< B, A >::addindex ( size_type  row,
size_type  col 
) [inline]

add index (row,col) to the matrix

This method can only be used when building the BCRSMatrix in random mode.

addindex adds a new column entry to the row. If this column entry already exists, nothing is done.

Don't call addindex after the setup phase is finished (after endindices is called).

template<class B, class A = ISTLAllocator>
BCRSMatrix& Dune::BCRSMatrix< B, A >::operator+= ( const BCRSMatrix< B, A > &  b  )  [inline]

Add the entries of another matrix to this one.

Parameters:
b The matrix to add to this one. Its sparsity pattern has to be subset of the sparsity pattern of this matrix.

template<class B, class A = ISTLAllocator>
BCRSMatrix& Dune::BCRSMatrix< B, A >::operator-= ( const BCRSMatrix< B, A > &  b  )  [inline]

Substract the entries of another matrix to this one.

Parameters:
b The matrix to add to this one. Its sparsity pattern has to be subset of the sparsity pattern of this matrix.

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

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