# VecSet
Sets all components of a vector to a single scalar value. 
## Synopsis
```
#include "petscvec.h"   
PetscErrorCode VecSet(Vec x, PetscScalar alpha)
```
Logically Collective on Vec


## Input Parameters

- ***x  -*** the vector
- ***alpha -*** the scalar



## Output Parameter

- ***x  -*** the vector



## Note
For a vector of dimension n, VecSet() computes
```none
x[i] = alpha, for i=1,...,n,
```
so that all vector entries then equal the identical
scalar value, alpha.  Use the more general routine
VecSetValues() to set different vector entries.

You CANNOT call this after you have called VecSetValues() but before you call
VecAssemblyBegin/End().




## See Also
`VecSetValues()`, `VecSetValuesBlocked()`, `VecSetRandom()`


## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/interface/rvector.c.html#VecSet">src/vec/vec/interface/rvector.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/tutorials/ex1.c.html">src/vec/vec/tutorials/ex1.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/tutorials/ex11.c.html">src/vec/vec/tutorials/ex11.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/tutorials/ex11f.F90.html">src/vec/vec/tutorials/ex11f.F90.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/tutorials/ex11f90.F90.html">src/vec/vec/tutorials/ex11f90.F90.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/tutorials/ex12.c.html">src/vec/vec/tutorials/ex12.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/tutorials/ex12f.F90.html">src/vec/vec/tutorials/ex12f.F90.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/tutorials/ex13.c.html">src/vec/vec/tutorials/ex13.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/tutorials/ex15.c.html">src/vec/vec/tutorials/ex15.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/tutorials/ex18.c.html">src/vec/vec/tutorials/ex18.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/tutorials/ex18f.F90.html">src/vec/vec/tutorials/ex18f.F90.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/tutorials/ex1f.F90.html">src/vec/vec/tutorials/ex1f.F90.html</A><BR>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/impls/nest/vecnest.c.html#VecSet_Nest">VecSet_Nest in src/vec/vec/impls/nest/vecnest.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/impls/seq/dvec2.c.html#VecSet_Seq">VecSet_Seq in src/vec/vec/impls/seq/dvec2.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/impls/seq/kokkos/veckok.kokkos.cxx.html#VecSet_SeqKokkos">VecSet_SeqKokkos in src/vec/vec/impls/seq/kokkos/veckok.kokkos.cxx</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/impls/seq/seqcuda/veccuda2.cu.html#VecSet_SeqCUDA">VecSet_SeqCUDA in src/vec/vec/impls/seq/seqcuda/veccuda2.cu</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/impls/seq/seqhip/vechip2.hip.c.html#VecSet_SeqHIP">VecSet_SeqHIP in src/vec/vec/impls/seq/seqhip/vechip2.hip.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/impls/seq/seqviennacl/vecviennacl.cxx.html#VecSet_SeqViennaCL">VecSet_SeqViennaCL in src/vec/vec/impls/seq/seqviennacl/vecviennacl.cxx</A><BR>


---
[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/vec/vec/interface/rvector.c)


[Index of all Vec routines](index.md)  
[Table of Contents for all manual pages](/docs/manualpages/index.md)  
[Index of all manual pages](/docs/manualpages/singleindex.md)  
