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# MatProductSetFromOptions
Sets the options for the computation of a matrix-matrix product operation where the type, the algorithm etc are determined from the options database. 
## Synopsis
```
#include "petscmat.h" 
PetscErrorCode MatProductSetFromOptions(Mat mat)
```
Logically Collective


## Input Parameter

- ***mat -*** the matrix whose values are computed via a matrix-matrix product operation



## Options Database Keys

- ***-mat_product_clear -*** Clear intermediate data structures after `MatProductNumeric()` has been called
- ***-mat_product_algorithm <algorithm> -*** Sets the algorithm, see `MatProductAlgorithm` for possible values
- ***-mat_product_algorithm_backend_cpu -*** Use the CPU to perform the computation even if the matrix is a GPU matrix





## Note
The `-mat_product_clear` option reduces memory usage but means that the matrix cannot be re-used for a matrix-matrix product operation


## See Also
 [](ch_matrices), `MatProduct`, `Mat`, `MatSetFromOptions()`, `MatProductCreate()`, `MatProductCreateWithMat()`, `MatProductNumeric()`,
`MatProductSetType()`, `MatProductSetAlgorithm()`, `MatProductAlgorithm`

## Level
intermediate

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

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/aij/mpi/kokkos/mpiaijkok.kokkos.cxx.html#MatProductSetFromOptions_MPIAIJKokkos">MatProductSetFromOptions_MPIAIJKokkos in src/mat/impls/aij/mpi/kokkos/mpiaijkok.kokkos.cxx</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/aij/mpi/mpiaij.c.html#MatProductSetFromOptions_MPIAIJBACKEND">MatProductSetFromOptions_MPIAIJBACKEND in src/mat/impls/aij/mpi/mpiaij.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/aij/mpi/mpimatmatmult.c.html#MatProductSetFromOptions_MPIAIJ">MatProductSetFromOptions_MPIAIJ in src/mat/impls/aij/mpi/mpimatmatmult.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/aij/seq/aijmkl/aijmkl.c.html#MatProductSetFromOptions_SeqAIJMKL">MatProductSetFromOptions_SeqAIJMKL in src/mat/impls/aij/seq/aijmkl/aijmkl.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/aij/seq/kokkos/aijkok.kokkos.cxx.html#MatProductSetFromOptions_SeqAIJKokkos">MatProductSetFromOptions_SeqAIJKokkos in src/mat/impls/aij/seq/kokkos/aijkok.kokkos.cxx</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/aij/seq/matmatmult.c.html#MatProductSetFromOptions_SeqAIJ">MatProductSetFromOptions_SeqAIJ in src/mat/impls/aij/seq/matmatmult.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/aij/seq/seqcusparse/aijcusparse.cu.html#MatProductSetFromOptions_SeqAIJCUSPARSE">MatProductSetFromOptions_SeqAIJCUSPARSE in src/mat/impls/aij/seq/seqcusparse/aijcusparse.cu</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/aij/seq/seqhipsparse/aijhipsparse.hip.c.html#MatProductSetFromOptions_SeqAIJHIPSPARSE">MatProductSetFromOptions_SeqAIJHIPSPARSE in src/mat/impls/aij/seq/seqhipsparse/aijhipsparse.hip.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/dense/mpi/mpidense.c.html#MatProductSetFromOptions_MPIDense">MatProductSetFromOptions_MPIDense in src/mat/impls/dense/mpi/mpidense.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/dense/seq/dense.c.html#MatProductSetFromOptions_SeqDense">MatProductSetFromOptions_SeqDense in src/mat/impls/dense/seq/dense.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/elemental/matelem.cxx.html#MatProductSetFromOptions_Elemental">MatProductSetFromOptions_Elemental in src/mat/impls/elemental/matelem.cxx</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/h2opus/cuda/math2opus.cu.html#MatProductSetFromOptions_H2OPUS">MatProductSetFromOptions_H2OPUS in src/mat/impls/h2opus/cuda/math2opus.cu</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/htool/htool.cxx.html#MatProductSetFromOptions_Htool">MatProductSetFromOptions_Htool in src/mat/impls/htool/htool.cxx</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/hypre/mhypre.c.html#MatProductSetFromOptions_HYPRE">MatProductSetFromOptions_HYPRE in src/mat/impls/hypre/mhypre.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/scalapack/matscalapack.c.html#MatProductSetFromOptions_ScaLAPACK">MatProductSetFromOptions_ScaLAPACK in src/mat/impls/scalapack/matscalapack.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/shell/shellcnv.c.html#MatProductSetFromOptions_CF">MatProductSetFromOptions_CF in src/mat/impls/shell/shellcnv.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/transpose/htransm.c.html#MatProductSetFromOptions_HermitianTranspose">MatProductSetFromOptions_HermitianTranspose in src/mat/impls/transpose/htransm.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/transpose/transm.c.html#MatProductSetFromOptions_Transpose">MatProductSetFromOptions_Transpose in src/mat/impls/transpose/transm.c</A><BR>


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