#include "petscsf.h" PetscErrorCode PetscSFGetMultiSF(PetscSF sf,PetscSF *multi)Collective
| sf | - star forest that may contain roots with 0 or with more than 1 vertex |
| multi | - star forest with split roots, such that each root has degree exactly 1 |
In most cases, users should use PetscSFGatherBegin() and PetscSFScatterBegin() instead of manipulating multi directly. Since multi satisfies the stronger condition that each entry in the global space has exactly one incoming edge, it is a candidate for future optimization that might involve its removal.