/*$Id: ex16.c,v 1.17 2001/09/11 16:32:10 bsmith Exp $*/

static char help[] = "Tests VecSetValuesBlocked() on MPI vectors.\n\n";

#include "petscvec.h"
#include "petscsys.h"

#undef __FUNCT__
#define __FUNCT__ "main"
int main(int argc,char **argv)
{
  int          i,n = 8,ierr,size,rank,bs = 2,indices[2];
  PetscScalar  values[4];
  Vec          x;

  ierr = PetscInitialize(&argc,&argv,(char*)0,help);CHKERRQ(ierr); 
  ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRQ(ierr);
  ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRQ(ierr);

  if (size != 2) SETERRQ(1,"Must be run with two processors");

  /* create vector */
  ierr = VecCreateMPI(PETSC_COMM_WORLD,PETSC_DECIDE,n,&x);CHKERRQ(ierr);
  ierr = VecSetFromOptions(x);CHKERRQ(ierr);
  ierr = VecSetBlockSize(x,bs);CHKERRQ(ierr);

  if (!rank) {
    for (i=0; i<4; i++) values[i] = i+1;
    indices[0] = 0; indices[1] = 2;
    ierr = VecSetValuesBlocked(x,2,indices,values,INSERT_VALUES);CHKERRQ(ierr);
  }
  ierr = VecAssemblyBegin(x);CHKERRQ(ierr);
  ierr = VecAssemblyEnd(x);CHKERRQ(ierr);

  /* 
      Resulting vector should be 1 2 0 0 3 4 0 0
  */
  ierr = VecView(x,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);

  ierr = VecDestroy(x);CHKERRQ(ierr);

  ierr = PetscFinalize();CHKERRQ(ierr);
  return 0;
}