retrieves the global indices of the graph's vertices of nonzero outdegree (i.e., the global indices of this processor's nonzero rows). If the graph is regarded as a multivalued map on integers, this is the support of the map (i.e., the set of indices with nonempty images).
Synopsis
#undef __FUNCT__
#define __FUNCT__ "MatIJGetSupportIS"
PetscErrorCode MatIJGetSupportIS(Mat A, IS *supp)