# DMDACreateAggregates
Gets the aggregates that map between grids associated with two `DMDA` 
## Synopsis
```
#include "petscdmda.h"   
PetscErrorCode DMDACreateAggregates(DM dac, DM daf, Mat *rest)
```
Collective on dmc


## Input Parameters

- ***dmc -*** the coarse grid `DMDA`
- ***dmf -*** the fine grid `DMDA`



## Output Parameters

- ***rest -*** the restriction matrix (transpose of the projection matrix)





## Note
This routine is not used by PETSc.
It is not clear what its use case is and it may be removed in a future release.
Users should contact petsc-maint@mcs.anl.gov if they plan to use it.


## See Also
 `DMRefine()`, `DMCreateInjection()`, `DMCreateInterpolation()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/da/dainterp.c.html#DMDACreateAggregates">src/dm/impls/da/dainterp.c</A>


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


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