# DMSNESGetJacobian
get `SNES` Jacobian evaluation function 
## Synopsis
```
#include "petscsnes.h" 
#include "petscdm.h" 
PetscErrorCode DMSNESGetJacobian(DM dm, PetscErrorCode (**J)(SNES, Vec, Mat, Mat, void *), void **ctx)
```
Not Collective


## Input Parameter

- ***dm -*** `DM` to be used with `SNES`



## Output Parameters

- ***J -*** Jacobian evaluation function; see `SNESJacobianFunction` for all calling sequence
- ***ctx -*** context for residual evaluation





## Note
`SNESGetJacobian()` is normally used, but it calls this function internally because the user context is actually
associated with the `DM`.  This makes the interface consistent regardless of whether the user interacts with a `DM` or
not.


## Developer Note
If `DM` took a more central role at some later date, this could become the primary method of setting the Jacobian.


## See Also
 `DMSNESSetContext()`, `SNESSetFunction()`, `DMSNESSetJacobian()`, `SNESJacobianFunction`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/utils/dmsnes.c.html#DMSNESGetJacobian">src/snes/utils/dmsnes.c</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/snes/utils/dmsnes.c)


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