Creates a sparse symmetric matrix in (block compressed row) MATSEQSBAIJ format. For good matrix assembly performance the user should preallocate the matrix storage by setting the parameter nz (or the array nnz).


#include "petscmat.h" 
PetscErrorCode MatCreateSeqSBAIJ(MPI_Comm comm, PetscInt bs, PetscInt m, PetscInt n, PetscInt nz, const PetscInt nnz[], Mat *A)


Input Parameters#

  • comm - MPI communicator, set to PETSC_COMM_SELF

  • bs - 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 with MatCreateVecs()

  • m - number of rows

  • n - number of columns

  • nz - number of block nonzeros per block row (same for all rows)

  • nnz - array containing the number of block nonzeros in the upper triangular plus diagonal portion of each block (possibly different for each block row) or NULL

Output Parameter#

  • A - the symmetric 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


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. This matrix type does not support complex Hermitian operation.

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.

If the nnz parameter is given then the nz parameter is ignored

See Also#

Matrices, Mat, Sparse Matrices, MATSEQSBAIJ, MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatCreateSBAIJ()





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