static char help[] = "Make a 2D grid of patches and view them\n\n";

/*
Serial Test
Parallel Test where all zooms are serials
Parallel Test where zooms are parallel

Return DMPatch from Zoom
Override refine from DMPatch to split cells
 */
#include <petscdmpatch.h>

typedef struct {
  PetscInt   debug;     /* The debugging level */
  PetscInt   dim;       /* The spatial dimension */
  MatStencil patchSize; /* Size of patches */
  MatStencil gridSize;  /* Size of patch grid */
  MatStencil commSize;  /* Size of patch comm */
} AppCtx;

PetscErrorCode ProcessOptions(MPI_Comm comm, AppCtx *options)
{
  PetscInt       patchSize, commSize, gridSize;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  options->debug = 0;
  options->dim   = 2;
  patchSize      = 0;
  commSize       = 0;
  gridSize       = 0;

  ierr = PetscOptionsBegin(comm, "", "Patch Test Options", "DMPATCH");CHKERRQ(ierr);
  ierr = PetscOptionsBoundedInt("-debug", "The debugging level", "ex1.c", options->debug, &options->debug, NULL,0);CHKERRQ(ierr);
  ierr = PetscOptionsRangeInt("-dim", "The spatial dimension", "ex1.c", options->dim, &options->dim, NULL,1,3);CHKERRQ(ierr);
  ierr = PetscOptionsBoundedInt("-patch_size", "The patch size in each dimension", "ex1.c", patchSize, &patchSize, NULL,0);CHKERRQ(ierr);
  ierr = PetscOptionsBoundedInt("-comm_size", "The comm size in each dimension", "ex1.c", commSize, &commSize, NULL,0);CHKERRQ(ierr);
  ierr = PetscOptionsBoundedInt("-grid_size", "The grid size in each dimension", "ex1.c", gridSize, &gridSize, NULL,1);CHKERRQ(ierr);
  ierr = PetscOptionsEnd();

  options->patchSize.i = options->patchSize.j = options->patchSize.k = 1;
  options->commSize.i  = options->commSize.j  = options->commSize.k = 1;
  options->gridSize.i  = options->gridSize.j  = options->gridSize.k = 1;
  if (options->dim > 0) {options->patchSize.i = patchSize; options->commSize.i = commSize; options->gridSize.i = gridSize;}
  if (options->dim > 1) {options->patchSize.j = patchSize; options->commSize.j = commSize; options->gridSize.j = gridSize;}
  if (options->dim > 2) {options->patchSize.k = patchSize; options->commSize.k = commSize; options->gridSize.k = gridSize;}
  PetscFunctionReturn(0);
};

int main(int argc, char **argv)
{
  DM             dm;
  AppCtx         user;                 /* user-defined work context */
  PetscErrorCode ierr;

  ierr = PetscInitialize(&argc, &argv, NULL, help);if (ierr) return ierr;
  ierr = ProcessOptions(PETSC_COMM_WORLD, &user);CHKERRQ(ierr);
  ierr = DMPatchCreateGrid(PETSC_COMM_WORLD, user.dim, user.patchSize, user.commSize, user.gridSize, &dm);CHKERRQ(ierr);
  ierr = PetscObjectSetName((PetscObject) dm, "Patch Mesh");CHKERRQ(ierr);
  ierr = DMSetFromOptions(dm);CHKERRQ(ierr);
  ierr = DMSetUp(dm);CHKERRQ(ierr);
  ierr = DMView(dm, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
  ierr = DMPatchSolve(dm);CHKERRQ(ierr);
  ierr = DMDestroy(&dm);CHKERRQ(ierr);
  ierr = PetscFinalize();
  return ierr;
}