# VecSetSizes
Sets the local and global sizes, and checks to determine compatibility 
## Synopsis
```
#include "petscvec.h"   
PetscErrorCode VecSetSizes(Vec v, PetscInt n, PetscInt N)
```
Collective on Vec


## Input Parameters

- ***v -*** the vector
- ***n -*** the local size (or PETSC_DECIDE to have it set)
- ***N -*** the global size (or PETSC_DECIDE)



## Notes
n and N cannot be both PETSC_DECIDE
If one processor calls this with N of PETSC_DECIDE then all processors must, otherwise the program will hang.




## See Also
 `VecGetSize()`, `PetscSplitOwnership()`

## Level
intermediate

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

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/utils/tagger/tutorials/ex1.c.html">src/vec/vec/utils/tagger/tutorials/ex1.c.html</A><BR>
<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/ex10.c.html">src/vec/vec/tutorials/ex10.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/ex16.c.html">src/vec/vec/tutorials/ex16.c.html</A><BR>


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