# 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#

        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).

Low-level Vector Communication, VecScatter, VecScatterCreate(), VecScatterCreateToAll(), VecScatterBegin(), VecScatterEnd()

intermediate

## Location#

src/vec/is/sf/interface/vscat.c

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