MatHYPRESetPreallocation#
Preallocates memory for a sparse parallel matrix in HYPRE IJ format
Synopsis#
PetscErrorCode MatHYPRESetPreallocation(Mat A, PetscInt dnz, const PetscInt dnnz[], PetscInt onz, const PetscInt onnz[])
Collective
Input Parameters#
A - the matrix
dnz - number of nonzeros per row in DIAGONAL portion of local submatrix (same value is used for all local rows)
dnnz - array containing the number of nonzeros in the various rows of the DIAGONAL portion of the local submatrix (possibly different for each row) or
NULL
(PETSC_NULL_INTEGER
in Fortran), ifd_nz
is used to specify the nonzero structure. The size of this array is equal to the number of local rows, i.em
. For matrices that will be factored, you must leave room for (and set) the diagonal entry even if it is zero.onz - number of nonzeros per row in the OFF-DIAGONAL portion of local submatrix (same value is used for all local rows).
onnz - array containing the number of nonzeros in the various rows of the OFF-DIAGONAL portion of the local submatrix (possibly different for each row) or
NULL
(PETSC_NULL_INTEGER
in Fortran), ifo_nz
is used to specify the nonzero structure. The size of this array is equal to the number of local rows, i.em
.
Note#
If the *nnz parameter is given then the *nz parameter is ignored; for sequential matrices, onz
and onnz
are ignored.
See Also#
Matrices, Mat
, MatCreate()
, MatMPIAIJSetPreallocation()
, MATHYPRE
, MATAIJ
Level#
intermediate
Location#
Examples#
Implementations#
MatHYPRESetPreallocation_HYPRE() in src/mat/impls/hypre/mhypre.c
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