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# DMDASNESSetPicardLocal
set a local right hand side and matrix evaluation function for Picard iteration with `DMDA` 
## Synopsis
```
#include "petscdmda.h" 
#include "petscsnes.h" 
PetscErrorCode DMDASNESSetPicardLocal(DM dm, InsertMode imode, PetscErrorCode (*func)(DMDALocalInfo *, void *, void *, void *), PetscErrorCode (*jac)(DMDALocalInfo *, void *, Mat, Mat, void *), void *ctx)
```
Logically Collective


## Input Parameters

- ***dm -*** `DM` to associate callback with
- ***imode -*** `INSERT_VALUES` if local function computes owned part, `ADD_VALUES` if it contributes to ghosted part
- ***func -*** local residual evaluation
- ***ctx -*** optional context for local residual evaluation



## Calling sequence of `func`
```none
PetscErrorCode func(DMDALocalInfo *info, void *x, void *f, void *ctx);
```

- ***info -*** defines the subdomain to evaluate the residual on
- ***x -*** dimensional pointer to state at which to evaluate residual
- ***f -*** dimensional pointer to residual, write the residual here
- ***ctx -*** optional context passed above





## Note
The user must use `SNESSetFunction`(snes,`NULL`,`SNESPicardComputeFunction`,&user));
in their code before calling this routine.


## See Also
 `DMDA`, `DMSNESSetFunction()`, `DMDASNESSetJacobian()`, `DMDACreate1d()`, `DMDACreate2d()`, `DMDACreate3d()`

## Level
beginner

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

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex15.c.html">src/snes/tutorials/ex15.c</A><BR>


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


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