Actual source code: ex19.c
1: static char help[] = "Tests DMDA with variable multiple degrees of freedom per node.\n\n";
3: /*
4: This code only compiles with gcc, since it is not ANSI C
5: */
7: #include <petscdm.h>
8: #include <petscdmda.h>
10: PetscErrorCode doit(DM da, Vec global)
11: {
12: PetscInt i, j, k, M, N, dof;
14: PetscCall(DMDAGetInfo(da, 0, &M, &N, 0, 0, 0, 0, &dof, 0, 0, 0, 0, 0));
15: {
16: struct {
17: PetscScalar inside[dof];
18: } **mystruct;
19: PetscCall(DMDAVecGetArrayRead(da, global, (void *)&mystruct));
20: for (i = 0; i < N; i++) {
21: for (j = 0; j < M; j++) {
22: for (k = 0; k < dof; k++) {
23: PetscCall(PetscPrintf(PETSC_COMM_WORLD, "%" PetscInt_FMT " %" PetscInt_FMT " %g\n", i, j, (double)mystruct[i][j].inside[0]));
25: mystruct[i][j].inside[1] = 2.1;
26: }
27: }
28: }
29: PetscCall(DMDAVecRestoreArrayRead(da, global, (void *)&mystruct));
30: }
31: PetscFunctionReturn(PETSC_SUCCESS);
32: }
34: int main(int argc, char **argv)
35: {
36: PetscInt dof = 2, M = 3, N = 3, m = PETSC_DECIDE, n = PETSC_DECIDE;
37: DM da;
38: Vec global, local;
40: PetscFunctionBeginUser;
41: PetscCall(PetscInitialize(&argc, &argv, (char *)0, help));
42: PetscCall(PetscOptionsGetInt(NULL, 0, "-dof", &dof, 0));
43: /* Create distributed array and get vectors */
44: PetscCall(DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE, DMDA_STENCIL_BOX, M, N, m, n, dof, 1, NULL, NULL, &da));
45: PetscCall(DMSetFromOptions(da));
46: PetscCall(DMSetUp(da));
47: PetscCall(DMCreateGlobalVector(da, &global));
48: PetscCall(DMCreateLocalVector(da, &local));
50: PetscCall(doit(da, global));
52: PetscCall(VecView(global, 0));
54: /* Free memory */
55: PetscCall(VecDestroy(&local));
56: PetscCall(VecDestroy(&global));
57: PetscCall(DMDestroy(&da));
58: PetscCall(PetscFinalize());
59: return 0;
60: }