# DMShellGetCoarsen
Get the routine used to coarsen the shell DM 
## Synopsis
```
#include "petscdmshell.h"  
PetscErrorCode DMShellGetCoarsen(DM dm, PetscErrorCode (**coarsen)(DM, MPI_Comm, DM *))
```
Logically Collective on dm


## Input Parameter

- ***dm -*** the shell DM



## Output Parameter

- ***coarsen -*** the routine that coarsens the DM





## See Also
 `DMShellSetCoarsen()`, `DMCoarsen()`, `DMShellSetRefine()`, `DMRefine()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/shell/dmshell.c.html#DMShellGetCoarsen">src/dm/impls/shell/dmshell.c</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/dm/impls/shell/dmshell.c)


[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)  
