# DMSetAdjacency
Set the flags for determining variable influence 
## Synopsis
```
#include "petscdm.h"          
#include "petscdmlabel.h"     
#include "petscds.h"     
PetscErrorCode DMSetAdjacency(DM dm, PetscInt f, PetscBool useCone, PetscBool useClosure)
```
Not collective


## Input Parameters

- ***dm         -*** The DM object
- ***f          -*** The field number
- ***useCone    -*** Flag for variable influence starting with the cone operation
- ***useClosure -*** Flag for variable influence using transitive closure



## Notes
```none
FEM:   Two points p and q are adjacent if q \in closure(star(p)),   useCone = PETSC_FALSE, useClosure = PETSC_TRUE
```
```none
FVM:   Two points p and q are adjacent if q \in support(p+cone(p)), useCone = PETSC_TRUE,  useClosure = PETSC_FALSE
```
```none
FVM++: Two points p and q are adjacent if q \in star(closure(p)),   useCone = PETSC_TRUE,  useClosure = PETSC_TRUE
```
Further explanation can be found in the User's Manual Section on the Influence of Variables on One Another.




## See Also
 `DMGetAdjacency()`, `DMGetField()`, `DMSetField()`

## Level
developer

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


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