#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.