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# PCFactorSetReuseOrdering
When similar matrices are factored, this causes the ordering computed in the first factor to be used for all following factors. 
## Synopsis
```
#include "petscpc.h" 
PetscErrorCode PCFactorSetReuseOrdering(PC pc, PetscBool flag)
```
Logically Collective


## Input Parameters

- ***pc -*** the preconditioner context
- ***flag -*** `PETSC_TRUE` to reuse else `PETSC_FALSE`



## Options Database Key

- ***-pc_factor_reuse_ordering -*** Activate `PCFactorSetReuseOrdering()`





## See Also
 `PCLU`, `PCCHOLESKY`, `PCFactorSetReuseFill()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/factor/cholesky/cholesky.c.html#PCFactorSetReuseOrdering">src/ksp/pc/impls/factor/cholesky/cholesky.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/factor/factor.c.html#PCFactorSetReuseOrdering_Factor">PCFactorSetReuseOrdering_Factor in src/ksp/pc/impls/factor/factor.c</A><BR>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/ksp/pc/impls/factor/cholesky/cholesky.c)


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