# ISCreate
Creates an index set object. `IS` are objects used to do efficient indexing into other data structures such as `Vec` and `Mat` 
## Synopsis
```
#include "petscis.h"  
PetscErrorCode ISCreate(MPI_Comm comm, IS *is)
```
Collective


## Input Parameters

- ***comm -*** the MPI communicator



## Output Parameter

- ***is -*** the new index set



## Notes
When the communicator is not `MPI_COMM_SELF`, the operations on `IS` are NOT
conceptually the same as `MPI_Group` operations. The `IS` are then
distributed sets of indices and thus certain operations on them are
collective.




## See Also
 [](sec_scatter), `IS`, `ISType()`, `ISSetType()`, `ISCreateGeneral()`, `ISCreateStride()`, `ISCreateBlock()`, `ISAllGather()`

## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/is/is/interface/isreg.c.html#ISCreate">src/vec/is/is/interface/isreg.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex76.c.html">src/ksp/ksp/tutorials/ex76.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex76f.F90.html">src/ksp/ksp/tutorials/ex76f.F90.html</A><BR>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/is/is/impls/block/block.c.html#ISCreate_Block">ISCreate_Block in src/vec/is/is/impls/block/block.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/is/is/impls/general/general.c.html#ISCreate_General">ISCreate_General in src/vec/is/is/impls/general/general.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/is/is/impls/stride/stride.c.html#ISCreate_Stride">ISCreate_Stride in src/vec/is/is/impls/stride/stride.c</A><BR>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/vec/is/is/interface/isreg.c)


[Index of all IS routines](index.md)  
[Table of Contents for all manual pages](/docs/manualpages/index.md)  
[Index of all manual pages](/docs/manualpages/singleindex.md)  
