:orphan:
# TSDiscGradSetFormulation
Set the construction method for S, F, and grad F from the formulation u_t = S(u) grad F(u) for `TSDISCGRAD` 
## Synopsis
```
#include "petscts.h"   
PetscErrorCode TSDiscGradSetFormulation(TS ts, PetscErrorCode (*Sfunc)(TS, PetscReal, Vec, Mat, void *), PetscErrorCode (*Ffunc)(TS, PetscReal, Vec, PetscScalar *, void *), PetscErrorCode (*Gfunc)(TS, PetscReal, Vec, Vec, void *), void *ctx)
```
Not Collective


## Input Parameters

- ***ts    -*** timestepping context
- ***Sfunc -*** constructor for the S matrix from the formulation
- ***Ffunc -*** functional F from the formulation
- ***Gfunc -*** constructor for the gradient of F from the formulation
- ***ctx -*** optional context for the functions



## Calling sequence of `Sfunc`
```none
PetscErrorCode Sfunc(TS ts, PetscReal time, Vec u, Mat S, void *ctx)
```


## Calling sequence of `Ffunc`
```none
PetscErrorCode Ffunc(TS ts, PetscReal time, Vec u, PetscScalar *F, void *ctx)
```


## Calling sequence of `Gfunc`
```none
PetscErrorCode Gfunc(TS ts, PetscReal time, Vec u, Vec G, void *ctx)
```




## See Also
 [](ch_ts), `TSDISCGRAD`, `TSDiscGradGetFormulation()`

## Level
Intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/impls/implicit/discgrad/tsdiscgrad.c.html#TSDiscGradSetFormulation">src/ts/impls/implicit/discgrad/tsdiscgrad.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/impls/implicit/discgrad/tsdiscgrad.c.html#TSDiscGradSetFormulation_DiscGrad(TS ts, PetscErrorCode (*Sfunc)(TS, PetscReal, Vec, Mat, void *), PetscErrorCode (*Ffunc)(TS, PetscReal, Vec, PetscScalar *, void *), PetscErrorCode (*Gfunc)">TSDiscGradSetFormulation_DiscGrad(TS ts, PetscErrorCode (*Sfunc)(TS, PetscReal, Vec, Mat, void *), PetscErrorCode (*Ffunc)(TS, PetscReal, Vec, PetscScalar *, void *), PetscErrorCode (*Gfunc) in src/ts/impls/implicit/discgrad/tsdiscgrad.c</A><BR>


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


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