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# DMDASetPreallocationCenterDimension
Determine the topology used to determine adjacency 
## Synopsis
```
#include "petscdmda.h"   
PetscErrorCode DMDASetPreallocationCenterDimension(DM dm, PetscInt preallocCenterDim)
```

## Input Parameters

- ***dm -*** The `DMDA` object
- ***preallocCenterDim -*** The dimension of points which connect adjacent entries





## Notes
```none
     FEM:   Two points p and q are adjacent if q \in closure(star(p)), preallocCenterDim = dim
     FVM:   Two points p and q are adjacent if q \in star(cone(p)),    preallocCenterDim = dim-1
     FVM++: Two points p and q are adjacent if q \in star(closure(p)), preallocCenterDim = 0
```



## See Also
 `DM`, `DMDA`, `DMCreateMatrix()`, `DMDAPreallocateOperator()`

## Level
developer

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


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


[Index of all DMDA routines](index.md)  
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