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#############################################################################
##
#W matblock.gd GAP Library Alexander Hulpke
##
#H @(#)$Id: matblock.gd,v 4.8 2002/04/15 10:05:00 sal Exp $
##
#Y Copyright (C) 1997, Lehrstuhl D fuer Mathematik, RWTH Aachen, Germany
#Y (C) 1998 School Math and Comp. Sci., University of St. Andrews, Scotland
#Y Copyright (C) 2002 The GAP Group
##
## This file contains the declarations for block matrices.
##
Revision.matblock_gd :=
"@(#)$Id: matblock.gd,v 4.8 2002/04/15 10:05:00 sal Exp $";
#1
## Block matrices are a special representation of matrices which can save a
## lot of memory if large matrices have a block structure with lots of zero
## blocks. {\GAP} uses the representation `IsBlockMatrixRep' to store block
## matrices.
## \indextt{IsBlockMatrixRep}
#############################################################################
##
#F BlockMatrix( <blocks>, <nrb>, <ncb> )
#F BlockMatrix( <blocks>, <nrb>, <ncb>, <rpb>, <cpb>, <zero> )
##
## `BlockMatrix' returns an immutable matrix in the sparse representation
## `IsBlockMatrixRep'.
## The nonzero blocks are described by the list <blocks> of triples,
## the matrix has <nrb> row blocks and <ncb> column blocks.
##
## If <blocks> is empty (i.e., if the matrix is a zero matrix) then
## the dimensions of the blocks must be entered as <rpb> and <cpb>,
## and the zero element as <zero>.
##
## Note that all blocks must be ordinary matrices (see~"IsOrdinaryMatrix"),
## and also the block matrix is an ordinary matrix.
##
DeclareGlobalFunction( "BlockMatrix" );
#############################################################################
##
#A MatrixByBlockMatrix( <blockmat> ) . . . create matrix from (block) matrix
##
## returns a plain ordinary matrix that is equal to the block matrix
## <blockmat>.
##
DeclareAttribute( "MatrixByBlockMatrix", IsMatrix );
#T ConvertToPlistRep?
#############################################################################
##
#F AsBlockMatrix( <m>, <nrb>, <ncb> ) . . . create block matrix from matrix
##
## returns a block matrix with <nrb> row blocks and <ncb> column blocks
## which is equal to the ordinary matrix <m>.
##
DeclareGlobalFunction( "AsBlockMatrix" );
#T ConvertToBlockMatrixRep?
#############################################################################
##
#E
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