:orphan:
# MatGetDM
Gets the `DM` defining the data layout of the matrix 
## Synopsis
```
#include "petscdm.h"          
#include "petscdmlabel.h"     
#include "petscds.h"     
PetscErrorCode MatGetDM(Mat A, DM *dm)
```
Not Collective


## Input Parameter

- ***A -*** The `Mat`



## Output Parameter

- ***dm -*** The `DM`





## Note
A matrix may not have a `DM` associated with it


## Developer Note
Since the `Mat` class doesn't know about the `DM` class the `DM` object is associated with the `Mat` through a `PetscObjectCompose()` operation


## See Also
 [](ch_dmbase), `DM`, `MatSetDM()`, `DMCreateMatrix()`, `DMSetMatType()`

## Level
intermediate

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


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[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)