petsc-3.7.1 2016-05-15
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MatCreateSeqSBAIJ

Creates a sparse symmetric matrix in block AIJ (block compressed row) format. For good matrix assembly performance the user should preallocate the matrix storage by setting the parameter nz (or the array nnz). By setting these parameters accurately, performance during matrix assembly can be increased by more than a factor of 50.

Synopsis

#include "petscmat.h" 
PetscErrorCode  MatCreateSeqSBAIJ(MPI_Comm comm,PetscInt bs,PetscInt m,PetscInt n,PetscInt nz,const PetscInt nnz[],Mat *A)
Collective on MPI_Comm Many br

Input Parameters

comm - MPI communicator, set to PETSC_COMM_SELF Many br
bs - size of block, the blocks are ALWAYS square. One can use MatSetBlockSizes() to set a different row and column blocksize but the row Many brblocksize always defines the size of the blocks. The column blocksize sets the blocksize of the vectors obtained with MatCreateVecs() Many br
m - number of rows, or number of columns Many br
nz - number of block nonzeros per block row (same for all rows) Many br
nnz - array containing the number of block nonzeros in the upper triangular plus Many brdiagonal portion of each block (possibly different for each block row) or NULL Many br

Output Parameter

A -the symmetric matrix Many br

Options Database Keys

-mat_no_unroll -uses code that does not unroll the loops in the Many brblock calculations (much slower) Many br
-mat_block_size -size of the blocks to use Many br

Many br

It is recommended that one use the MatCreate(), MatSetType() and/or MatSetFromOptions(), Many brMatXXXXSetPreallocation() paradgm instead of this routine directly. Many br[MatXXXXSetPreallocation() is, for example, MatSeqAIJSetPreallocation] Many br

Notes

The number of rows and columns must be divisible by blocksize. Many brThis matrix type does not support complex Hermitian operation. Many br

Specify the preallocated storage with either nz or nnz (not both). Many brSet nz=PETSC_DEFAULT and nnz=NULL for PETSc to control dynamic memory Many brallocation. See Users-Manual: ch_mat for details. Many br

If the nnz parameter is given then the nz parameter is ignored Many br

See Also

MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatCreateSBAIJ()

Level:intermediate
Location:
src/mat/impls/sbaij/seq/sbaij.c
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages