Actual source code: ex5.c
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;
21: PetscFunctionBeginUser;
22: PetscCall(PetscInitialize(&argc, &argv, (char *)0, help));
23: PetscCall(PetscViewerDrawOpen(PETSC_COMM_WORLD, 0, "", 300, 0, 300, 300, &viewer));
25: /* Read options */
26: PetscCall(PetscOptionsGetInt(NULL, NULL, "-M", &M, NULL));
27: PetscCall(PetscOptionsGetInt(NULL, NULL, "-N", &N, NULL));
28: PetscCall(PetscOptionsGetBool(NULL, NULL, "-star_stencil", &flg, NULL));
29: if (flg) stype = DMDA_STENCIL_STAR;
31: /* Create distributed array and get vectors */
32: PetscCall(DMDACreate2d(PETSC_COMM_WORLD, bx, by, stype, M, N, PETSC_DECIDE, PETSC_DECIDE, 1, 1, NULL, NULL, &da));
33: PetscCall(DMSetFromOptions(da));
34: PetscCall(DMSetUp(da));
35: PetscCall(DMCreateGlobalVector(da, &global));
36: PetscCall(DMCreateLocalVector(da, &local));
38: value = -3.0;
39: PetscCall(VecSet(global, value));
40: PetscCall(DMGlobalToLocalBegin(da, global, INSERT_VALUES, local));
41: PetscCall(DMGlobalToLocalEnd(da, global, INSERT_VALUES, local));
43: PetscCall(DMDASetElementType(da, DMDA_ELEMENT_P1));
44: PetscCall(DMDAGetElements(da, &ne, &nc, &e));
45: PetscCall(VecGetArray(local, &lv));
46: for (i = 0; i < ne; i++) {
47: PetscCall(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: PetscCall(PetscSynchronizedFlush(PETSC_COMM_WORLD, stdout));
51: PetscCall(VecRestoreArray(local, &lv));
52: PetscCall(DMDARestoreElements(da, &ne, &nc, &e));
54: PetscCall(DMLocalToGlobalBegin(da, local, ADD_VALUES, global));
55: PetscCall(DMLocalToGlobalEnd(da, local, ADD_VALUES, global));
57: PetscCall(DMView(da, viewer));
58: PetscCall(VecView(global, viewer));
60: /* Free memory */
61: PetscCall(PetscViewerDestroy(&viewer));
62: PetscCall(VecDestroy(&local));
63: PetscCall(VecDestroy(&global));
64: PetscCall(DMDestroy(&da));
65: PetscCall(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*/