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

  4: #include <petscdm.h>
  5: #include <petscdmda.h>
  6: #include <petscdraw.h>

  8: int main(int argc, char **argv)
  9: {
 10:   PetscInt        M = 10, N = 8, ne, nc, i;
 11:   const PetscInt *e;
 12:   PetscBool       flg = PETSC_FALSE;
 13:   DM              da;
 14:   PetscViewer     viewer;
 15:   Vec             local, global;
 16:   PetscScalar     value;
 17:   DMBoundaryType  bx = DM_BOUNDARY_NONE, by = DM_BOUNDARY_NONE;
 18:   DMDAStencilType stype = DMDA_STENCIL_BOX;
 19:   PetscScalar    *lv;

 22:   PetscInitialize(&argc, &argv, (char *)0, help);
 23:   PetscViewerDrawOpen(PETSC_COMM_WORLD, 0, "", 300, 0, 300, 300, &viewer);

 25:   /* Read options */
 26:   PetscOptionsGetInt(NULL, NULL, "-M", &M, NULL);
 27:   PetscOptionsGetInt(NULL, NULL, "-N", &N, NULL);
 28:   PetscOptionsGetBool(NULL, NULL, "-star_stencil", &flg, NULL);
 29:   if (flg) stype = DMDA_STENCIL_STAR;

 31:   /* Create distributed array and get vectors */
 32:   DMDACreate2d(PETSC_COMM_WORLD, bx, by, stype, M, N, PETSC_DECIDE, PETSC_DECIDE, 1, 1, NULL, NULL, &da);
 33:   DMSetFromOptions(da);
 34:   DMSetUp(da);
 35:   DMCreateGlobalVector(da, &global);
 36:   DMCreateLocalVector(da, &local);

 38:   value = -3.0;
 39:   VecSet(global, value);
 40:   DMGlobalToLocalBegin(da, global, INSERT_VALUES, local);
 41:   DMGlobalToLocalEnd(da, global, INSERT_VALUES, local);

 43:   DMDASetElementType(da, DMDA_ELEMENT_P1);
 44:   DMDAGetElements(da, &ne, &nc, &e);
 45:   VecGetArray(local, &lv);
 46:   for (i = 0; i < ne; i++) {
 47:     PetscSynchronizedPrintf(PETSC_COMM_WORLD, "i %" PetscInt_FMT " e[3*i] %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT "\n", i, e[3 * i], e[3 * i + 1], e[3 * i + 2]);
 48:     lv[e[3 * i]] = i;
 49:   }
 50:   PetscSynchronizedFlush(PETSC_COMM_WORLD, stdout);
 51:   VecRestoreArray(local, &lv);
 52:   DMDARestoreElements(da, &ne, &nc, &e);

 54:   DMLocalToGlobalBegin(da, local, ADD_VALUES, global);
 55:   DMLocalToGlobalEnd(da, local, ADD_VALUES, global);

 57:   DMView(da, viewer);
 58:   VecView(global, viewer);

 60:   /* Free memory */
 61:   PetscViewerDestroy(&viewer);
 62:   VecDestroy(&local);
 63:   VecDestroy(&global);
 64:   DMDestroy(&da);
 65:   PetscFinalize();
 66:   return 0;
 67: }

 69: /*TEST

 71:    test:
 72:      requires: x

 74:    test:
 75:      suffix: 2
 76:      nsize: 2
 77:      requires: x

 79: TEST*/