# AO
Abstract PETSc object that manages mapping between different global numbering 
## Synopsis
```
typedef struct _p_AO *AO;
```



## Notes
An application ordering is mapping between an application-centric
ordering (the ordering that is "natural" for the application) and
the parallel ordering that PETSc uses.


## See Also
 `AOCreateBasic()`, `AOCreateBasicIS()`, `AOPetscToApplication()`, `AOView()`, `AOApplicationToPetsc()`, `AOType`, `AOSetType()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/include/petscao.h.html#AO">include/petscao.h</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/is/ao/aoimpl.h.html#_p_AO">_p_AO in src/vec/is/ao/aoimpl.h</A><BR>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/include/petscao.h)


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