# MatMFFDSetPeriod
Sets how often h is recomputed for a `MATMFFD` matrix, by default it is every time 
## Synopsis
```
#include "petscmat.h"   
PetscErrorCode MatMFFDSetPeriod(Mat mat, PetscInt period)
```
Logically Collective on mat


## Input Parameters

- ***mat -*** the `MATMFFD` matrix free matrix
- ***period -*** 1 for every time, 2 for every second etc



## Options Database Keys

- ***-mat_mffd_period <period> -*** Sets how often h is recomputed





## See Also
 `MATMFFD`, `MatCreateSNESMF()`, `MatMFFDGetH()`,
`MatMFFDSetHHistory()`, `MatMFFDResetHHistory()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/mffd/mffd.c.html#MatMFFDSetPeriod">src/mat/impls/mffd/mffd.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/mffd/mffd.c.html#MatMFFDSetPeriod_MFFD">MatMFFDSetPeriod_MFFD in src/mat/impls/mffd/mffd.c</A><BR>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/mat/impls/mffd/mffd.c)


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