# MatCreateMPICRL

Creates a sparse matrix of type MPICRL. This type inherits from AIJ, but stores some additional information that is used to allow better vectorization of the matrix-vector product. 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 PETSCMAT_DLLEXPORT MatCreateMPICRL(MPI_Comm comm,PetscInt m,PetscInt n,PetscInt nz,const PetscInt nnz[],PetscInt onz,const PetscInt onnz[],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 PETSC_NULL

### Output Parameter

A -the matrix

### Notes

If nnz is given then nz is ignored

### Keywords

matrix, cray, sparse, parallel

### See Also

MatCreate(), MatCreateMPICSRPERM(), MatSetValues()

Level:intermediate
Location:src/mat/impls/aij/mpi/crl/mcrl.c
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages