:orphan:
# DMGetNeighbors
Gets an array containing the MPI ranks of all the processes neighbors
## Synopsis
```
#include "petscdm.h"
#include "petscdmlabel.h"
#include "petscds.h"
PetscErrorCode DMGetNeighbors(DM dm, PetscInt *nranks, const PetscMPIInt *ranks[])
```
Not Collective
## Input Parameter
- ***dm -*** The `DM`
## Output Parameters
- ***nranks -*** the number of neighbours
- ***ranks -*** the neighbors ranks
## Note
Do not free the array, it is freed when the `DM` is destroyed.
## See Also
[](ch_dmbase), `DM`, `DMDAGetNeighbors()`, `PetscSFGetRootRanks()`
## Level
beginner
## Location
src/dm/interface/dm.c
## Examples
src/dm/tutorials/swarm_ex3.c
## Implementations
DMGetNeighbors_DA in src/dm/impls/da/dacreate.c
DMGetNeighbors_Plex in src/dm/impls/plex/plexcreate.c
DMGetNeighbors_Stag in src/dm/impls/stag/stag.c
---
[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/dm/interface/dm.c)
[Index of all DM routines](index.md)
[Table of Contents for all manual pages](/manualpages/index.md)
[Index of all manual pages](/manualpages/singleindex.md)