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" 
int MatCreateSeqSBAIJ(MPI_Comm comm,int bs,int m,int n,int nz,int *nnz,Mat *A)

Collective on MPI_Comm

Input Parameters

	comm	- MPI communicator, set to PETSC_COMM_SELF
	bs	- size of block
	m	- number of rows, or number of columns
	nz	- number of block nonzeros per block row (same for all rows)
	nnz	- array containing the number of block nonzeros in the upper triangular plus diagonal portion of each block (possibly different for each block row) or PETSC_NULL

Output Parameter

A -the symmetric matrix

Options Database Keys

-mat_no_unroll -uses code that does not unroll the loops in the block calculations (much slower)

-mat_block_size -size of the blocks to use

Notes