MatCreateSeqBAIJ#
Creates a sparse matrix in MATSEQAIJ (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).
Synopsis#
#include "petscmat.h"
PetscErrorCode MatCreateSeqBAIJ(MPI_Comm comm, PetscInt bs, PetscInt m, PetscInt n, PetscInt nz, const PetscInt nnz[], Mat *A)
Collective
Input Parameters#
comm - MPI communicator, set to
PETSC_COMM_SELFbs - size of block, the blocks are ALWAYS square. One can use
MatSetBlockSizes()to set a different row and column blocksize but the row blocksize always defines the size of the blocks. The column blocksize sets the blocksize of the vectors obtained withMatCreateVecs()m - number of rows
n - number of columns
nz - number of nonzero blocks per block row (same for all rows)
nnz - array containing the number of nonzero blocks in the various block rows (possibly different for each block row) or
NULL
Output Parameter#
A - the 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#
It is recommended that one use MatCreateFromOptions() or the MatCreate(), MatSetType() and/or MatSetFromOptions(),
MatXXXXSetPreallocation() paradigm instead of this routine directly.
[MatXXXXSetPreallocation() is, for example, MatSeqAIJSetPreallocation()]
The number of rows and columns must be divisible by blocksize.
If the nnz parameter is given then the nz parameter is ignored
A nonzero block is any block that as 1 or more nonzeros in it
The MATSEQBAIJ format is fully compatible with standard Fortran
storage. That is, the stored row and column indices can begin at
either one (as in Fortran) or zero.
Specify the preallocated storage with either nz or nnz (not both).
Set nz = PETSC_DEFAULT and nnz = NULL for PETSc to control dynamic memory
allocation. See Sparse Matrices for details.
matrices.
See Also#
Matrices, Mat, Sparse Matrices, MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatCreateBAIJ()
Level#
intermediate
Location#
Examples#
src/tao/unconstrained/tutorials/rosenbrock3.c
src/tao/unconstrained/tutorials/rosenbrock1f.F90
src/tao/unconstrained/tutorials/rosenbrock1.c
src/tao/unconstrained/tutorials/rosenbrock2.c
src/ksp/ksp/tutorials/ex74.c
Index of all Mat routines
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Index of all manual pages