# MatMultHermitianTranspose
Computes matrix Hermitian transpose times a vector. 
## Synopsis
```
#include "petscmat.h" 
PetscErrorCode MatMultHermitianTranspose(Mat mat, Vec x, Vec y)
```
Neighbor-wise Collective


## Input Parameters

- ***mat -*** the matrix
- ***x   -*** the vector to be multilplied



## Output Parameters

- ***y -*** the result



## Notes
The vectors x and y cannot be the same.  I.e., one cannot
call `MatMultHermitianTranspose`(A,y,y).

Also called the conjugate transpose, complex conjugate transpose, or adjoint.

For real numbers `MatMultTranspose()` and `MatMultHermitianTranspose()` are identical.




## See Also
 `Mat`, `MatMult()`, `MatMultAdd()`, `MatMultHermitianTransposeAdd()`, `MatMultTranspose()`

## Level
beginner

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

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex27.c.html">src/ksp/ksp/tutorials/ex27.c.html</A><BR>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/aij/seq/kokkos/aijkok.kokkos.cxx.html#MatMultHermitianTranspose_SeqAIJKokkos">MatMultHermitianTranspose_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/seqcusparse/aijcusparse.cu.html#MatMultHermitianTranspose_SeqAIJCUSPARSE">MatMultHermitianTranspose_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#MatMultHermitianTranspose_SeqAIJHIPSPARSE">MatMultHermitianTranspose_SeqAIJHIPSPARSE in src/mat/impls/aij/seq/seqhipsparse/aijhipsparse.hip.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/baij/seq/baij2.c.html#MatMultHermitianTranspose_SeqBAIJ">MatMultHermitianTranspose_SeqBAIJ in src/mat/impls/baij/seq/baij2.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/normal/normmh.c.html#MatMultHermitianTranspose_Normal">MatMultHermitianTranspose_Normal in src/mat/impls/normal/normmh.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/transpose/htransm.c.html#MatMultHermitianTranspose_HT">MatMultHermitianTranspose_HT in src/mat/impls/transpose/htransm.c</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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