# DMFindRegionNum
Find the region number for a given PetscDS, or -1 if it is not found. 
## Synopsis
```
#include "petscdm.h"          
#include "petscdmlabel.h"     
#include "petscds.h"     
PetscErrorCode DMFindRegionNum(DM dm, PetscDS ds, PetscInt *num)
```
Not collective


## Input Parameters

- ***dm  -*** The DM
- ***ds  -*** The PetscDS defined on the given region



## Output Parameter

- ***num -*** The region number, in [0, Nds), or -1 if not found





## See Also
 `DMGetRegionNumDS()`, `DMGetRegionDS()`, `DMSetRegionDS()`, `DMGetDS()`, `DMGetCellDS()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/interface/dm.c.html#DMFindRegionNum">src/dm/interface/dm.c</A>


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