# TSComputeRHSJacobianConstant
Reuses a Jacobian that is time-independent. 
## Synopsis
```
#include "petscts.h"  
PetscErrorCode TSComputeRHSJacobianConstant(TS ts, PetscReal t, Vec U, Mat A, Mat B, void *ctx)
```
Collective on ts


## Input Parameters

- ***ts -*** time stepping context
- ***t -*** time at which to evaluate
- ***U -*** state at which to evaluate
- ***ctx -*** context



## Output Parameters

- ***A -*** pointer to operator
- ***B -*** pointer to preconditioning matrix





## Note
This function is intended to be passed to `TSSetRHSJacobian()` to evaluate the Jacobian for linear time-independent problems.


## See Also
 [](chapter_ts), `TS`, `TSSetRHSFunction()`, `TSSetRHSJacobian()`, `TSComputeRHSFunctionLinear()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/interface/ts.c.html#TSComputeRHSJacobianConstant">src/ts/interface/ts.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex3.c.html">src/ts/tutorials/ex3.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex4.c.html">src/ts/tutorials/ex4.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex5.c.html">src/ts/tutorials/ex5.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex6.c.html">src/ts/tutorials/ex6.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex74.c.html">src/ts/tutorials/ex74.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/unconstrained/tutorials/spectraladjointassimilation.c.html">src/tao/unconstrained/tutorials/spectraladjointassimilation.c.html</A><BR>


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


[Index of all TS routines](index.md)  
[Table of Contents for all manual pages](/docs/manualpages/index.md)  
[Index of all manual pages](/docs/manualpages/singleindex.md)  
