MatCreateScaLAPACK#

Creates a dense parallel matrix in ScaLAPACK format (2D block cyclic distribution) for a MATSCALAPACK matrix

Synopsis#

#include "petscmat.h" 
PetscErrorCode MatCreateScaLAPACK(MPI_Comm comm, PetscInt mb, PetscInt nb, PetscInt M, PetscInt N, PetscInt rsrc, PetscInt csrc, Mat *A)

Collective

Input Parameters#

comm - MPI communicator
mb - row block size (or PETSC_DECIDE to have it set)
nb - column block size (or PETSC_DECIDE to have it set)
M - number of global rows
N - number of global columns
rsrc - coordinate of process that owns the first row of the distributed matrix
csrc - coordinate of process that owns the first column of the distributed matrix

Output Parameter#

A - the matrix

Options Database Key#

-mat_scalapack_block_sizes - size of the blocks to use (one or two integers separated by comma)

Notes#

If PETSC_DECIDE is used for the block sizes, then an appropriate value is chosen

It is recommended that one use the MatCreate(), MatSetType() and/or MatSetFromOptions(), MatXXXXSetPreallocation() paradigm instead of this routine directly. [MatXXXXSetPreallocation() is, for example, MatSeqAIJSetPreallocation()]

Storate is completely managed by ScaLAPACK, so this requires PETSc to be configured with ScaLAPACK. In particular, PETSc’s local sizes lose significance and are thus ignored. The block sizes refer to the values used for the distributed matrix, not the same meaning as in MATBAIJ.