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# MatSolve
Solves A x = b, given a factored matrix.
## Synopsis
```
#include "petscmat.h"
PetscErrorCode MatSolve(Mat mat, Vec b, Vec x)
```
Neighbor-wise Collective
## Input Parameters
- ***mat -*** the factored matrix
- ***b -*** the right-hand-side vector
## Output Parameter
- ***x -*** the result vector
## Notes
The vectors `b` and `x` cannot be the same. I.e., one cannot
call `MatSolve`(A,x,x).
Most users should employ the `KSP` interface for linear solvers
instead of working directly with matrix algebra routines such as this.
See, e.g., `KSPCreate()`.
## See Also
[](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatLUFactor()`, `MatSolveAdd()`, `MatSolveTranspose()`, `MatSolveTransposeAdd()`
## Level
developer
## Location
src/mat/interface/matrix.c
## Examples
src/tao/unconstrained/tutorials/eptorsion1.c
src/tao/unconstrained/tutorials/eptorsion3.c
src/tao/unconstrained/tutorials/rosenbrock1.c
## Implementations
MatSolve_SparseElemental in src/mat/impls/aij/mpi/clique/clique.cxx
MatSolve_MUMPS in src/mat/impls/aij/mpi/mumps/mumps.c
MatSolve_PaStiX in src/mat/impls/aij/mpi/pastix/pastix.c
MatSolve_STRUMPACK in src/mat/impls/aij/mpi/strumpack/strumpack.c
MatSolve_SeqAIJ in src/mat/impls/aij/seq/aijfact.c
MatSolve_Essl in src/mat/impls/aij/seq/essl/essl.c
MatSolve_KLU in src/mat/impls/aij/seq/klu/klu.c
MatSolve_SeqAIJKokkos in src/mat/impls/aij/seq/kokkos/aijkok.kokkos.cxx
MatSolve_LUSOL in src/mat/impls/aij/seq/lusol/lusol.c
MatSolve_Matlab in src/mat/impls/aij/seq/matlab/aijmatlab.c
MatSolve_SeqAIJCUSPARSE in src/mat/impls/aij/seq/seqcusparse/aijcusparse.cu
MatSolve_SeqAIJCUSPARSEBAND in src/mat/impls/aij/seq/seqcusparse/aijcusparseband.cu
MatSolve_SeqAIJHIPSPARSE in src/mat/impls/aij/seq/seqhipsparse/aijhipsparse.hip.c
MatSolve_SeqAIJHIPSPARSEBAND in src/mat/impls/aij/seq/seqhipsparse/aijhipsparseband.hip.c
MatSolve_SPQR in src/mat/impls/aij/seq/spqr/aijspqr.c
MatSolve_SuperLU in src/mat/impls/aij/seq/superlu/superlu.c
MatSolve_UMFPACK in src/mat/impls/aij/seq/umfpack/umfpack.c
MatSolve_Elemental in src/mat/impls/elemental/matelem.cxx
MatSolve_CHOLMOD in src/mat/impls/sbaij/seq/cholmod/sbaijcholmod.c
MatSolve_ScaLAPACK in src/mat/impls/scalapack/matscalapack.c
---
[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/mat/interface/matrix.c)
[Index of all Mat routines](index.md)
[Table of Contents for all manual pages](/manualpages/index.md)
[Index of all manual pages](/manualpages/singleindex.md)