**petsc-3.10.4 2019-02-26**

# VecWhichEqual

Creates an index set containing the indices where the vectors Vec1 and Vec2 have identical elements.
### Synopsis

#include "petscvec.h"
PetscErrorCode VecWhichEqual(Vec Vec1, Vec Vec2, IS *S)

Collective on Vec

### Input Parameters

**Vec1, Vec2 ** -the two vectors to compare

### OutputParameter

**S ** -The index set containing the indices i where vec1[i] == vec2[i]

### Notes

the two vectors must have the same parallel layout

### Level

advanced

### Location

src/vec/vec/utils/projection.c

Index of all Vec routines

Table of Contents for all manual pages

Index of all manual pages