# DMSetMatrixStructureOnly
When `DMCreateMatrix()` is called, the matrix structure will be created but the array for numerical values will not be allocated. 
## Synopsis
```
#include "petscdm.h"          
#include "petscdmlabel.h"     
#include "petscds.h"     
PetscErrorCode DMSetMatrixStructureOnly(DM dm, PetscBool only)
```
Logically Collective on dm


## Input Parameters

- ***dm -*** the `DM`
- ***only -*** `PETSC_TRUE` if you only want matrix stucture





## See Also
 `DMCreateMatrix()`, `DMSetMatrixPreallocateOnly()`, `DMSetMatrixPreallocateSkip()`

## Level
developer

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/interface/dm.c.html#DMSetMatrixStructureOnly">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](/docs/manualpages/index.md)  
[Index of all manual pages](/docs/manualpages/singleindex.md)  
