# MatGetFactor
Returns a matrix suitable to calls to MatXXFactorSymbolic() 
## Synopsis
```
#include "petscmat.h" 
PetscErrorCode MatGetFactor(Mat mat, MatSolverType type, MatFactorType ftype, Mat *f)
```
Collective on mat


## Input Parameters

- ***mat -*** the matrix
- ***type -*** name of solver type, for example, superlu, petsc (to use PETSc's default)
- ***ftype -*** factor type, `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ICC`, `MAT_FACTOR_ILU`, `MAT_FACTOR_QR`



## Output Parameters

- ***f -*** the factor matrix used with MatXXFactorSymbolic() calls



## Options Database Key

- ***-mat_factor_bind_factorization <host, device> -*** Where to do matrix factorization? Default is device (might consume more device memory.
One can choose host to save device memory). Currently only supported with `MATSEQAIJCUSPARSE` matrices.



## Notes
Users usually access the factorization solvers via `KSP`

Some PETSc matrix formats have alternative solvers available that are contained in alternative packages
such as pastix, superlu, mumps etc.

PETSc must have been ./configure to use the external solver, using the option --download-package

Some of the packages have options for controlling the factorization, these are in the form -prefix_mat_packagename_packageoption
where prefix is normally obtained from the calling `KSP`/`PC`. If `MatGetFactor()` is called directly one can set
call `MatSetOptionsPrefixFactor()` on the originating matrix or  `MatSetOptionsPrefix()` on the resulting factor matrix.


## Developer Note
This should actually be called `MatCreateFactor()` since it creates a new factor object




## See Also
 [Matrix Factorization](sec_matfactor), `KSP`, `MatSolverType`, `MatFactorType`, `MatCopy()`, `MatDuplicate()`, `MatGetFactorAvailable()`, `MatFactorGetCanUseOrdering()`, `MatSolverTypeRegister()`,
`MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ICC`, `MAT_FACTOR_ILU`, `MAT_FACTOR_QR`

## Level
intermediate

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

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex52.c.html">src/ksp/ksp/tutorials/ex52.c.html</A><BR>


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


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