petsc-3.8.4 2018-03-24

MatMPIAdjCreateNonemptySubcommMat

create the same MPIAdj matrix on a subcommunicator containing only processes owning a positive number of rows

#include "petscmat.h" 
PetscErrorCode MatMPIAdjCreateNonemptySubcommMat(Mat A,Mat *B)

Collective

A -original MPIAdj matrix

B -matrix on subcommunicator, NULL on ranks that owned zero rows of A

This function is mostly useful for internal use by mesh partitioning packages that require that every process owns at least one row.

The matrix B should be destroyed with MatDestroy(). The arrays are not copied, so B should be destroyed before A is destroyed.