:orphan:
# DMForestSetAdaptivityPurpose
During the pre-setup phase, set whether the current `DM` is being adapted from its source (set with `DMForestSetAdaptivityForest()`) for the purpose of refinement (`DM_ADAPT_REFINE`), coarsening (`DM_ADAPT_COARSEN`), or undefined (`DM_ADAPT_DETERMINE`).  This only matters for the purposes of reference counting: during `DMDestroy()`, cyclic references can be found between `DM`s only if the cyclic reference is due to a fine/coarse relationship (see `DMSetFineDM()`/`DMSetCoarseDM()`).  If the purpose is not refinement or coarsening, and the user does not maintain a reference to the post-adaptation forest (i.e., the one created by `DMForestTemplate()`), then this can cause a memory leak.  This method is used by subtypes of `DMFOREST` when automatically constructing mesh hierarchies. 
## Synopsis
```
#include "petscdmforest.h" 
#include "petscdm.h" 
#include "petscdmlabel.h" 
PetscErrorCode DMForestSetAdaptivityPurpose(DM dm, DMAdaptFlag purpose)
```
Logically Collective


## Input Parameters

- ***dm -*** the forest
- ***purpose -*** the adaptivity purpose





## See Also
 `DM`, `DMFOREST`, `DMForestTemplate()`, `DMForestSetAdaptivityForest()`, `DMForestGetAdaptivityForest()`, `DMAdaptFlag`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/forest/forest.c.html#DMForestSetAdaptivityPurpose">src/dm/impls/forest/forest.c</A>


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


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