petsc-3.10.5 2019-03-28
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# PetscSFGetMultiSF

gets the inner SF implemeting gathers and scatters

### Synopsis

    #include "petscsf.h"
    PetscErrorCode PetscSFGetMultiSF(PetscSF sf,PetscSF *multi)

Collective

### Input Argument

sf -star forest that may contain roots with 0 or with more than 1 vertex

### Output Arguments

multi -star forest with split roots, such that each root has degree exactly 1

### Notes

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.

### See Also

PetscSFSetGraph(), PetscSFGatherBegin(), PetscSFScatterBegin()

### Level

developer

### Location

src/vec/is/sf/interface/sf.c

### Examples

src/vec/is/sf/examples/tutorials/ex1.c.html
Index of all PetscSF routines
Table of Contents for all manual pages
Index of all manual pages