petsc-3.14.5 2021-03-03
Report Typos and Errors

# ISInvertPermutation

Creates a new permutation that is the inverse of a given permutation.

### Synopsis

    #include "petscis.h"
    PetscErrorCode  ISInvertPermutation(IS is,PetscInt nlocal,IS *isout)

Collective on IS

### Input Parameter

| is | - the index set
| nlocal | - number of indices on this processor in result (ignored for 1 proccessor) or use PETSC_DECIDE

### Output Parameter

| isout | - the inverse permutation

### Notes

For parallel index sets this does the complete parallel permutation, but the code is not efficient for huge index sets (10,000,000 indices).

### Level

intermediate

### Location

src/vec/is/is/interface/index.c

### Implementations

ISInvertPermutation_Block in src/vec/is/is/impls/block/block.c
ISInvertPermutation_General in src/vec/is/is/impls/general/general.c
ISInvertPermutation_Stride in src/vec/is/is/impls/stride/stride.c
Index of all IS routines
Table of Contents for all manual pages
Index of all manual pages