:orphan:
# VecScatterCreateToZero
Creates an output vector and a scatter context used to copy all vector values into the output vector on the zeroth processor 
## Synopsis
```
#include "petscsf.h" 
PetscErrorCode VecScatterCreateToZero(Vec vin, VecScatter *ctx, Vec *vout)
```
Collective


## Input Parameter

- ***vin  -*** `Vec` of type `MPIVEC`



## Output Parameters

- ***ctx -*** scatter context
- ***vout -*** output `SEQVEC` that is large enough to scatter into on processor 0 and
of length zero on all other processors





## Usage
```none
        VecScatterCreateToZero(vin,&ctx,&vout);

        // scatter as many times as you need
        VecScatterBegin(ctx,vin,vout,INSERT_VALUES,SCATTER_FORWARD);
        VecScatterEnd(ctx,vin,vout,INSERT_VALUES,SCATTER_FORWARD);

        // destroy scatter context and local vector when no longer needed
        VecScatterDestroy(&ctx);
        VecDestroy(&vout);
```



## Notes
vout may be `NULL` [`PETSC_NULL_VEC` from fortran] if you do not
need to have it created

Do NOT create a vector and then pass it in as the final argument `vout`! `vout` is created by this routine
automatically (unless you pass `NULL` in for that argument if you do not need it).


## See Also
 [](sec_scatter), `VecScatter`, `VecScatterCreate()`, `VecScatterCreateToAll()`, `VecScatterBegin()`, `VecScatterEnd()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/is/sf/interface/vscat.c.html#VecScatterCreateToZero">src/vec/is/sf/interface/vscat.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/constrained/tutorials/ex1.c.html">src/tao/constrained/tutorials/ex1.c</A><BR>


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


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