petsc-3.7.5 2017-01-01

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  VecScatterCreateToZero(Vec vin,VecScatter *ctx,Vec *vout)

Collective on Vec

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 NULL [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(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);