:orphan:
# PetscDSGetExactSolutionTimeDerivative
Get the pointwise time derivative of the exact solution function for a given test field 
## Synopsis
```
#include "petscds.h" 
PetscErrorCode PetscDSGetExactSolutionTimeDerivative(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



## Output Parameters

- ***exactSol -*** time derivative of the exact solution for the test field
- ***exactCtx -*** time derivative of the exact solution context



## Calling sequence of `exactSol`
```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`, `PetscDSSetExactSolutionTimeDerivative()`, `PetscDSGetExactSolution()`

## Level
intermediate

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


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/dm/dt/interface/dtds.c)


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