# MatProductSetFill
Set an expected fill of the matrix product. 
## Synopsis
```
#include "petscmat.h" 
PetscErrorCode MatProductSetFill(Mat mat, PetscReal fill)
```
Collective on Mat


## Input Parameters

- ***mat -*** the matrix product result matrix
- ***fill -*** expected fill as ratio of nnz(mat)/(nnz(A) + nnz(B) + nnz(C)); use `PETSC_DEFAULT` if you do not have a good estimate. If the product is a dense matrix, this value is not used.





## See Also
 `Mat`, `MatProductSetFromOptions()`, `MatProductSetType()`, `MatProductSetAlgorithm()`, `MatProductCreate()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/interface/matproduct.c.html#MatProductSetFill">src/mat/interface/matproduct.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/pde_constrained/tutorials/parabolic.c.html">src/tao/pde_constrained/tutorials/parabolic.c.html</A><BR>


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


[Index of all Mat routines](index.md)  
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[Index of all manual pages](/docs/manualpages/singleindex.md)  
