**petsc-3.8.3 2017-12-09**

# ISEqual

Compares if two index sets have the same set of indices.
### Synopsis

#include "petscis.h"
PetscErrorCode ISEqual(IS is1,IS is2,PetscBool *flg)

Collective on IS

### Input Parameters

**is1, is2 ** -The index sets being compared

### Output Parameters

**flg ** -output flag, either PETSC_TRUE (if both index sets have the
same indices), or PETSC_FALSE if the index sets differ by size
or by the set of indices)

### Note

This routine sorts the contents of the index sets before
the comparision is made, so the order of the indices on a processor is immaterial.
Each processor has to have the same indices in the two sets, for example,

Processor

0 1

is1 = {0, 1} {2, 3}

is2 = {2, 3} {0, 1}

will return false.

**Level:**intermediate

Location:src/vec/is/is/utils/iscomp.c

Index of all IS routines

Table of Contents for all manual pages

Index of all manual pages