#include "petscis.h" PetscErrorCode ISSortPermutation(IS f,PetscBool always,IS *h)Not collective.
|f||- IS to sort|
|always||- build the permutation even when f's indices are nondecreasing.|
|h||- permutation or NULL, if f is nondecreasing and always == PETSC_FALSE.|
Note: Indices in f are unchanged. f[h[i]] is the i-th smallest f index. If always == PETSC_FALSE, an extra check is peformed to see whether the f indices are nondecreasing. h is built on PETSC_COMM_SELF, since the permutation has a local meaning only.