# TSRHSSplitSetRHSFunction
Set the split right-hand-side functions. 
## Synopsis
```
#include "petscts.h"  
PetscErrorCode TSRHSSplitSetRHSFunction(TS ts, const char splitname[], Vec r, TSRHSFunction rhsfunc, void *ctx)
```
Logically Collective


## Input Parameters

- ***ts        -*** the `TS` context obtained from `TSCreate()`
- ***splitname -*** name of this split
- ***r         -*** vector to hold the residual (or NULL to have it created internally)
- ***rhsfunc   -*** the RHS function evaluation routine
- ***ctx       -*** user-defined context for private data for the split function evaluation routine (may be NULL)



## Calling sequence of fun
```none
rhsfunc(TS ts,PetscReal t,Vec u,Vec f,ctx);
```


- ***t    -*** time at step/stage being solved
- ***u    -*** state vector
- ***f    -*** function vector
- ***ctx  -*** [optional] user-defined context for matrix evaluation routine (may be NULL)





## See Also
 [](chapter_ts), `TS`, `IS`, `TSRHSSplitSetIS()`

## Level
beginner

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


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


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