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# PCDeflationSetCorrectionFactor
Set coarse problem correction factor. The preconditioner becomes P*M^{-1} + fact*Q. 
## Synopsis
```
#include "petscksp.h" 
PetscErrorCode PCDeflationSetCorrectionFactor(PC pc, PetscScalar fact)
```
Logically Collective


## Input Parameters

- ***pc   -*** the preconditioner context
- ***fact -*** correction factor



## Options Database Keys

- ***-pc_deflation_correction        <false> -*** if true apply coarse problem correction
- ***-pc_deflation_correction_factor <1.0>   -*** sets coarse problem correction factor



## Note
Any non-zero fact enables the coarse problem correction.




## See Also
 `PCDEFLATION`, `PCDeflationSetLevels()`, `PCDeflationSetReductionFactor()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/deflation/deflation.c.html#PCDeflationSetCorrectionFactor">src/ksp/pc/impls/deflation/deflation.c</A>

## Implementations

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


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


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