petsc-3.7.5 2017-01-01

MatCreateSeqAIJPERM

Creates a sparse matrix of type SEQAIJPERM. This type inherits from AIJ, but calculates some additional permutation information that is used to allow better vectorization of some operations. At the cost of increased storage, the AIJ formatted matrix can be copied to a format in which pieces of the matrix are stored in ELLPACK format, allowing the vectorized matrix multiply routine to use stride-1 memory accesses. As with the AIJ type, it is important to preallocate matrix storage in order to get good assembly performance.

Synopsis

PetscErrorCode  MatCreateSeqAIJPERM(MPI_Comm comm,PetscInt m,PetscInt n,PetscInt nz,const PetscInt nnz[],Mat *A)

Collective on MPI_Comm

Input Parameters

	comm	- MPI communicator, set to PETSC_COMM_SELF
	m	- number of rows
	n	- number of columns
	nz	- number of nonzeros per row (same for all rows)
	nnz	- array containing the number of nonzeros in the various rows (possibly different for each row) or NULL

Output Parameter

A -the matrix

Notes

If nnz is given then nz is ignored

Keywords