# DMSNESSetMFFunction
set `SNES` residual evaluation function used in applying the matrix-free Jacobian with -snes_mf_operator 
## Synopsis
```
#include "petscsnes.h" 
#include "petscdm.h" 
PetscErrorCode DMSNESSetMFFunction(DM dm, PetscErrorCode (*f)(SNES, Vec, Vec, void *), void *ctx)
```
Logically Collective


## Input Parameters

- ***dm -*** `DM` to be used with `SNES`
- ***f -*** residual evaluation function; see `SNESFunction` for details





## See Also
 `DMSNESSetContext()`, `SNESSetFunction()`, `DMSNESSetJacobian()`, `SNESFunction`, `DMSNESSetFunction()`

## Level
advanced

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


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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)  
