MatCreateSeqBAIJ
Creates a sparse matrix in block AIJ (block compressed row) format. For good matrix assembly performance the user should preallocate the matrix storage by setting the parameter nz (or the array nzz). By setting these parameters accurately, performance during matrix assembly can be increased by more than a factor of 50.
Synopsis
int MatCreateSeqBAIJ(MPI_Comm comm,int bs,int m,int n,int nz,int *nnz, Mat *A)
Collective on
MPI_Comm
Input Parameters
comm | - MPI communicator, set to PETSC_COMM_SELF
|
bs | - size of block
|
m | - number of rows
|
n | - number of columns
|
nz | - number of block nonzeros per block row (same for all rows)
|
nzz | - array containing the number of block nonzeros in the various block rows
(possibly different for each block row) or PETSC_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
The block AIJ format is fully compatible with standard Fortran
77storage. That is, the stored row and column indices can begin
ateither one (as in Fortran) or zero. See the users' manual for details.
Specify the preallocated storage with either nz or nnz (not both).
Set nz=PETSC_DEFAULT and nnz=PETSC_NULL for PETSc to control dynamic
memoryallocation. For additional details, see the users manual chapter
onmatrices.
See Also
MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatCreateMPIBAIJ()
Location: src/mat/impls/baij/seq/baij.c
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