# DMComputeExactSolution
Compute the exact solution for a given `DM`, using the `PetscDS` information. 
## Synopsis
```
#include "petscdm.h"          
#include "petscdmlabel.h"     
#include "petscds.h"     
PetscErrorCode DMComputeExactSolution(DM dm, PetscReal time, Vec u, Vec u_t)
```
Collective on `DM`


## Input Parameters

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



## Output Parameters

- ***u    -*** The vector will be filled with exact solution values, or NULL
- ***u_t  -*** The vector will be filled with the time derivative of exact solution values, or NULL



## Note
The user must call `PetscDSSetExactSolution()` before using this routine




## See Also
 `PetscDSSetExactSolution()`

## Level
developer

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

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex36.c.html">src/snes/tutorials/ex36.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex45.c.html">src/ts/tutorials/ex45.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex53.c.html">src/ts/tutorials/ex53.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex76.c.html">src/ts/tutorials/ex76.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex77.c.html">src/ts/tutorials/ex77.c.html</A><BR>


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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)  
