petsc-3.14.5 2021-03-03
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# 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

### 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

### See Also

MatCreate(), MatCreateMPIAIJPERM(), MatSetValues()

### Level

intermediate

### Location

src/mat/impls/aij/seq/aijperm/aijperm.c
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages