# PCFactorSetFill
Indicate the amount of fill you expect in the factored matrix, fill = number nonzeros in factor/number nonzeros in original matrix. 
## Synopsis
```
#include "petscpc.h" 
PetscErrorCode PCFactorSetFill(PC pc, PetscReal fill)
```
Not Collective, each process can expect a different amount of fill


## Input Parameters

- ***pc -*** the preconditioner context
- ***fill -*** amount of expected fill



## Options Database Key

- ***-pc_factor_fill <fill> -*** Sets fill amount





## Notes
For sparse matrix factorizations it is difficult to predict how much
fill to expect. By running with the option -info PETSc will print the
actual amount of fill used; allowing you to set the value accurately for
future runs. Default PETSc uses a value of 5.0

This is ignored for most solver packages

This parameter has NOTHING to do with the levels-of-fill of ILU(). That is set with `PCFactorSetLevels()` or -pc_factor_levels.


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

## Level
intermediate

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

## Implementations

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


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


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