# AOPetscToApplication
Maps a set of integers in the PETSc ordering to the application-defined ordering. 
## Synopsis
```
#include "petscao.h" 
PetscErrorCode AOPetscToApplication(AO ao, PetscInt n, PetscInt ia[])
```
Collective


## Input Parameters

- ***ao -*** the application ordering context
- ***n -*** the number of integers
- ***ia -*** the integers; these are replaced with their mapped value



## Output Parameter

- ***ia -*** the mapped integers





## Note
Any integers in ia[] that are negative are left unchanged. This
allows one to convert, for example, neighbor lists that use negative
entries to indicate nonexistent neighbors due to boundary conditions, etc.

Integers that are out of range are mapped to -1


## See Also
 [](sec_ao), `AO`, `AOCreateBasic()`, `AOView()`, `AOApplicationToPetsc()`,
`AOPetscToApplicationIS()`, `AOApplicationToPetsc()`

## Level
beginner

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

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/is/ao/impls/basic/aobasic.c.html#AOPetscToApplication_Basic">AOPetscToApplication_Basic in src/vec/is/ao/impls/basic/aobasic.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/is/ao/impls/mapping/aomapping.c.html#AOPetscToApplication_Mapping">AOPetscToApplication_Mapping in src/vec/is/ao/impls/mapping/aomapping.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/is/ao/impls/memscalable/aomemscalable.c.html#AOPetscToApplication_MemoryScalable">AOPetscToApplication_MemoryScalable in src/vec/is/ao/impls/memscalable/aomemscalable.c</A><BR>


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


[Index of all AO routines](index.md)  
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