:orphan:
# AOCreateBasicIS
Creates a basic application ordering using two `IS` index sets. 
## Synopsis
```
#include "petscao.h"   
PetscErrorCode AOCreateBasicIS(IS isapp, IS ispetsc, AO *aoout)
```
Collective


## Input Parameters

- ***isapp -*** index set that defines an ordering
- ***ispetsc -*** index set that defines another ordering (may be NULL to use the
natural ordering)



## Output Parameter

- ***aoout -*** the new application ordering





## Note
The index sets isapp and ispetsc must contain the all the integers 0 to napp-1 (where napp is the length of the index sets) with no duplicates;
that is there cannot be any "holes"


## See Also
 [](sec_ao), [](sec_scatter), `IS`, `AO`, `AOCreateBasic()`, `AODestroy()`

## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/is/ao/impls/basic/aobasic.c.html#AOCreateBasicIS">src/vec/is/ao/impls/basic/aobasic.c</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/vec/is/ao/impls/basic/aobasic.c)


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