[petsc-users] VecRestoreSubVector can't change value of original vector

[mailinglist]

Hello,

I have a vector(v). I use VecRestoreSubVector to get a sub vector(subv). 
I change the value of the sub vector and want to give the new value back 
to v using VecRestoreSubVector, but it only works for seqential 
case(mpirun -np 1 ...). This is my code. Thank you very much.

#include "petsc.h"
#include "mpi.h"

int main(int argc, char** argv){

  PetscInitialize(&argc,&argv,0,0);

  int commSize;
  int commRank;
  MPI_Comm_rank(MPI_COMM_WORLD,&commRank);
  MPI_Comm_size(MPI_COMM_WORLD,&commSize);

  Vec v;
  VecCreateMPI(PETSC_COMM_WORLD,5,5*commSize,&v);
  VecSet(v,0.0);
  VecAssemblyBegin(v);
  VecAssemblyEnd(v);

  // is
  IS is;
  int index[1], Nindex = 1;
  index[0] = 0;
ISCreateGeneral(PETSC_COMM_WORLD,Nindex,index,PETSC_COPY_VALUES,&is);

  Vec vsub;
  VecGetSubVector(v,is,&vsub);
  VecSet(vsub,1);
  VecAssemblyBegin(vsub);
  VecAssemblyEnd(vsub);

  // VecView(vsub,PETSC_VIEWER_STDOUT_WORLD);

  VecRestoreSubVector(v,is,&vsub);
  // VecAssemblyBegin(v);
  // VecAssemblyEnd(v);

  VecView(v,PETSC_VIEWER_STDOUT_WORLD);

  PetscFinalize();

  return 0;
}

Regards,

fxing