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# MatDiagonalScale
Scales a matrix on the left and right by diagonal matrices that are stored as vectors.  Either of the two scaling matrices can be `NULL`. 
## Synopsis
```
#include "petscmat.h" 
PetscErrorCode MatDiagonalScale(Mat mat, Vec l, Vec r)
```
Collective


## Input Parameters

- ***mat -*** the matrix to be scaled
- ***l -*** the left scaling vector (or `NULL`)
- ***r -*** the right scaling vector (or `NULL`)





## Note
`MatDiagonalScale()` computes A = LAR, where
L = a diagonal matrix (stored as a vector), R = a diagonal matrix (stored as a vector)
The L scales the rows of the matrix, the R scales the columns of the matrix.


## See Also
 [](ch_matrices), `Mat`, `MatScale()`, `MatShift()`, `MatDiagonalSet()`

## Level
intermediate

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

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex70.c.html">src/snes/tutorials/ex70.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/pde_constrained/tutorials/elliptic.c.html">src/tao/pde_constrained/tutorials/elliptic.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/pde_constrained/tutorials/hyperbolic.c.html">src/tao/pde_constrained/tutorials/hyperbolic.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/pde_constrained/tutorials/parabolic.c.html">src/tao/pde_constrained/tutorials/parabolic.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/unconstrained/tutorials/burgers_spectral.c.html">src/tao/unconstrained/tutorials/burgers_spectral.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/unconstrained/tutorials/spectraladjointassimilation.c.html">src/tao/unconstrained/tutorials/spectraladjointassimilation.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex50.c.html">src/ts/tutorials/ex50.c</A><BR>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/aij/mpi/mpiaij.c.html#MatDiagonalScale_MPIAIJ">MatDiagonalScale_MPIAIJ in src/mat/impls/aij/mpi/mpiaij.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/aij/seq/aij.c.html#MatDiagonalScale_SeqAIJ">MatDiagonalScale_SeqAIJ in src/mat/impls/aij/seq/aij.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/baij/mpi/mpibaij.c.html#MatDiagonalScale_MPIBAIJ">MatDiagonalScale_MPIBAIJ in src/mat/impls/baij/mpi/mpibaij.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/baij/seq/baij2.c.html#MatDiagonalScale_SeqBAIJ">MatDiagonalScale_SeqBAIJ in src/mat/impls/baij/seq/baij2.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/baij/seq/baijmkl/baijmkl.c.html#MatDiagonalScale_SeqBAIJMKL">MatDiagonalScale_SeqBAIJMKL in src/mat/impls/baij/seq/baijmkl/baijmkl.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/composite/mcomposite.c.html#MatDiagonalScale_Composite">MatDiagonalScale_Composite in src/mat/impls/composite/mcomposite.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/dense/mpi/mpidense.c.html#MatDiagonalScale_MPIDense">MatDiagonalScale_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#MatDiagonalScale_SeqDense">MatDiagonalScale_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#MatDiagonalScale_Elemental">MatDiagonalScale_Elemental in src/mat/impls/elemental/matelem.cxx</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/is/matis.c.html#MatDiagonalScale_IS">MatDiagonalScale_IS in src/mat/impls/is/matis.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/nest/matnest.c.html#MatDiagonalScale_Nest">MatDiagonalScale_Nest in src/mat/impls/nest/matnest.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/normal/normm.c.html#MatDiagonalScale_Normal">MatDiagonalScale_Normal in src/mat/impls/normal/normm.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/normal/normmh.c.html#MatDiagonalScale_NormalHermitian">MatDiagonalScale_NormalHermitian in src/mat/impls/normal/normmh.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/sbaij/mpi/mpisbaij.c.html#MatDiagonalScale_MPISBAIJ">MatDiagonalScale_MPISBAIJ in src/mat/impls/sbaij/mpi/mpisbaij.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/sbaij/seq/sbaij2.c.html#MatDiagonalScale_SeqSBAIJ">MatDiagonalScale_SeqSBAIJ in src/mat/impls/sbaij/seq/sbaij2.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/scalapack/matscalapack.c.html#MatDiagonalScale_ScaLAPACK">MatDiagonalScale_ScaLAPACK in src/mat/impls/scalapack/matscalapack.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/sell/mpi/mpisell.c.html#MatDiagonalScale_MPISELL">MatDiagonalScale_MPISELL in src/mat/impls/sell/mpi/mpisell.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/sell/seq/sell.c.html#MatDiagonalScale_SeqSELL">MatDiagonalScale_SeqSELL in src/mat/impls/sell/seq/sell.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/shell/shell.c.html#MatDiagonalScale_Shell">MatDiagonalScale_Shell in src/mat/impls/shell/shell.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/submat/submat.c.html#MatDiagonalScale_SubMatrix">MatDiagonalScale_SubMatrix in src/mat/impls/submat/submat.c</A><BR>


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