# MatDenseGetColumnVecRead
Gives read-only access to a column of a dense matrix, represented as a Vec. 
## Synopsis
```
#include "petscmat.h" 
PetscErrorCode MatDenseGetColumnVecRead(Mat A, PetscInt col, Vec *v)
```
Collective


## Input Parameters

- ***mat -*** the Mat object
- ***col -*** the column index



## Output Parameter

- ***v -*** the vector



## Notes
The vector is owned by PETSc and users cannot modify it.

Users need to call MatDenseRestoreColumnVecRead() when the vector is no longer needed.

Use MatDenseGetColumnVec() to obtain read-write access or MatDenseGetColumnVecWrite() for write-only access.




## See Also
 `MATDENSE`, `MATDENSECUDA`, `MATDENSEHIP`, `MatDenseGetColumnVec()`, `MatDenseGetColumnVecWrite()`, `MatDenseRestoreColumnVec()`, `MatDenseRestoreColumnVecRead()`, `MatDenseRestoreColumnVecWrite()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/dense/seq/dense.c.html#MatDenseGetColumnVecRead">src/mat/impls/dense/seq/dense.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/dense/mpi/mpidense.c.html#MatDenseGetColumnVecRead_MPIDenseCUDA">MatDenseGetColumnVecRead_MPIDenseCUDA in src/mat/impls/dense/mpi/mpidense.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/dense/mpi/mpidense.c.html#MatDenseGetColumnVecRead_MPIDenseHIP">MatDenseGetColumnVecRead_MPIDenseHIP in src/mat/impls/dense/mpi/mpidense.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/dense/mpi/mpidense.c.html#MatDenseGetColumnVecRead_MPIDense">MatDenseGetColumnVecRead_MPIDense in src/mat/impls/dense/mpi/mpidense.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/dense/seq/cuda/densecuda.cu.html#MatDenseGetColumnVecRead_SeqDenseCUDA">MatDenseGetColumnVecRead_SeqDenseCUDA in src/mat/impls/dense/seq/cuda/densecuda.cu</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/dense/seq/dense.c.html#MatDenseGetColumnVecRead_SeqDense">MatDenseGetColumnVecRead_SeqDense in src/mat/impls/dense/seq/dense.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/mat/impls/dense/seq/hip/densehip.hip.c.html#MatDenseGetColumnVecRead_SeqDenseHIP">MatDenseGetColumnVecRead_SeqDenseHIP in src/mat/impls/dense/seq/hip/densehip.hip.c</A><BR>


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


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