# SNESGetJacobian
Returns the Jacobian matrix and optionally the user provided context for evaluating the Jacobian. 
## Synopsis
```
#include "petscsnes.h"  
PetscErrorCode SNESGetJacobian(SNES snes, Mat *Amat, Mat *Pmat, PetscErrorCode (**J)(SNES, Vec, Mat, Mat, void *), void **ctx)
```
Not Collective, but `Mat` object will be parallel if `SNES` object is


## Input Parameter

- ***snes -*** the nonlinear solver context



## Output Parameters

- ***Amat -*** location to stash (approximate) Jacobian matrix (or NULL)
- ***Pmat -*** location to stash matrix used to compute the preconditioner (or NULL)
- ***J -*** location to put Jacobian function (or NULL), see SNESJacobianFunction for details on its calling sequence
- ***ctx -*** location to stash Jacobian ctx (or NULL)





## See Also
 `SNES`, `Mat`, `SNESSetJacobian()`, `SNESComputeJacobian()`, `SNESJacobianFunction`, `SNESGetFunction()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/interface/snes.c.html#SNESGetJacobian">src/snes/interface/snes.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex62.c.html">src/snes/tutorials/ex62.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex69.c.html">src/snes/tutorials/ex69.c.html</A><BR>


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[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)