:orphan:
# PetscDSSetExactSolutionTimeDerivative
Set the pointwise time derivative of the exact solution function for a given test field 
## Synopsis
```
#include "petscds.h" 
PetscErrorCode PetscDSSetExactSolutionTimeDerivative(PetscDS prob, PetscInt f, PetscErrorCode (*sol)(PetscInt dim, PetscReal t, const PetscReal x[], PetscInt Nc, PetscScalar u[], void *ctx), void *ctx)
```
Not Collective


## Input Parameters

- ***prob -*** The `PetscDS`
- ***f    -*** The test field number
- ***sol  -*** time derivative of the solution function for the test fields
- ***ctx  -*** time derivative of the solution context or `NULL`



## Calling sequence of `sol`
```none
  PetscErrorCode sol(PetscInt dim, PetscReal t, const PetscReal x[], PetscInt Nc, PetscScalar u[], void *ctx)
```


- ***dim -*** the spatial dimension
- ***t -*** current time
- ***x -*** coordinates of the current point
- ***Nc -*** the number of field components
- ***u -*** the solution field evaluated at the current point
- ***ctx -*** a user context





## See Also
 `PetscDS`, `PetscDSGetExactSolutionTimeDerivative()`, `PetscDSSetExactSolution()`

## Level
intermediate

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

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


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