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# DMCoarsen_Moab
Generate a multi-level uniform refinement hierarchy by succesively refining a coarse mesh, already defined in the `DM` object provided by the user. 
## Synopsis
```
PETSC_EXTERN PetscErrorCode DMCoarsen_Moab(DM dm, MPI_Comm comm, DM *dmc)
```
Collective


## Input Parameters

- ***dm  -*** The `DMMOAB` object
- ***comm -*** the communicator to contain the new `DM` object (or `MPI_COMM_NULL`)



## Output Parameter

- ***dmf -*** the coarsened `DM`, or `NULL`





## Note
If no coarsening was done, the return value is `NULL`


## Level
developer

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/moab/dmmbmg.cxx.html#DMCoarsen_Moab">src/dm/impls/moab/dmmbmg.cxx</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/dm/impls/moab/dmmbmg.cxx)


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