/*$Id: ex1.c,v 1.16 2001/08/07 03:04:45 balay Exp $*/

static char help[] = "Tests VecView() contour plotting for 2d DAs.\n\n";

#include "petscda.h"
#include "petscsys.h"

#undef __FUNCT__
#define __FUNCT__ "main"
int main(int argc,char **argv)
{
  int            rank,M = 10,N = 8,m = PETSC_DECIDE,n = PETSC_DECIDE,ierr;
  PetscTruth     flg;
  DA             da;
  PetscViewer    viewer;
  Vec            local,global;
  PetscScalar    value;
  DAPeriodicType ptype = DA_NONPERIODIC;
  DAStencilType  stype = DA_STENCIL_BOX;

  ierr = PetscInitialize(&argc,&argv,(char*)0,help);CHKERRQ(ierr); 
  ierr = PetscViewerDrawOpen(PETSC_COMM_WORLD,0,"",300,0,300,300,&viewer);CHKERRQ(ierr);

  /* Read options */
  ierr = PetscOptionsGetInt(PETSC_NULL,"-M",&M,PETSC_NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(PETSC_NULL,"-N",&N,PETSC_NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(PETSC_NULL,"-m",&m,PETSC_NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(PETSC_NULL,"-n",&n,PETSC_NULL);CHKERRQ(ierr);
  ierr = PetscOptionsHasName(PETSC_NULL,"-star_stencil",&flg);CHKERRQ(ierr);
  if (flg) stype = DA_STENCIL_STAR;

  /* Create distributed array and get vectors */
  ierr = DACreate2d(PETSC_COMM_WORLD,ptype,stype,
                    M,N,m,n,1,1,PETSC_NULL,PETSC_NULL,&da);CHKERRQ(ierr);
  ierr = DACreateGlobalVector(da,&global);CHKERRQ(ierr);
  ierr = DACreateLocalVector(da,&local);CHKERRQ(ierr);

  value = -3.0;
  ierr = VecSet(&value,global);CHKERRQ(ierr);
  ierr = DAGlobalToLocalBegin(da,global,INSERT_VALUES,local);CHKERRQ(ierr);
  ierr = DAGlobalToLocalEnd(da,global,INSERT_VALUES,local);CHKERRQ(ierr);

  ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRQ(ierr);
  value = rank+1;
  ierr = VecScale(&value,local);CHKERRQ(ierr);
  ierr = DALocalToGlobal(da,local,ADD_VALUES,global);CHKERRQ(ierr);

  ierr = DAView(da,viewer);CHKERRQ(ierr);
  ierr = VecView(global,viewer);CHKERRQ(ierr);

  /* Free memory */
  ierr = PetscViewerDestroy(viewer);CHKERRQ(ierr);
  ierr = VecDestroy(local);CHKERRQ(ierr);
  ierr = VecDestroy(global);CHKERRQ(ierr);
  ierr = DADestroy(da);CHKERRQ(ierr);
  ierr = PetscFinalize();CHKERRQ(ierr);
  return 0;
}