VecScatterCreateToZero

Creates an output vector and a scatter context used to copy all vector values into the output vector on the zeroth processor

#include "petscvec.h" 
PetscErrorCode PETSCVEC_DLLEXPORT VecScatterCreateToZero(Vec vin,VecScatter *ctx,Vec *vout)

Collective

vin -input MPIVEC

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

Note: vout may be PETSC_NULL [PETSC_NULL_OBJECT from fortran] if you do not need to have it created

       VecScatterCreateToZero(vin,&ctx,&vout);

       // scatter as many times as you need

       VecScatterBegin(vin,vout,INSERT_VALUES,SCATTER_FORWARD,ctx);

       VecScatterEnd(vin,vout,INSERT_VALUES,SCATTER_FORWARD,ctx);

       // destroy scatter context and local vector when no longer needed

       VecScatterDestroy(ctx);

       VecDestroy(vout);