1 static char help[] = "Tests DMDA with variable multiple degrees of freedom per node.\n\n"; 2 3 /* 4 This code only compiles with gcc, since it is not ANSI C 5 */ 6 7 #include <petscdm.h> 8 #include <petscdmda.h> 9 10 PetscErrorCode doit(DM da, Vec global) 11 { 12 PetscInt i, j, k, M, N, dof; 13 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])); 24 25 mystruct[i][j].inside[1] = 2.1; 26 } 27 } 28 } 29 PetscCall(DMDAVecRestoreArrayRead(da, global, (void *)&mystruct)); 30 } 31 PetscFunctionReturn(PETSC_SUCCESS); 32 } 33 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; 39 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)); 49 50 PetscCall(doit(da, global)); 51 52 PetscCall(VecView(global, 0)); 53 54 /* Free memory */ 55 PetscCall(VecDestroy(&local)); 56 PetscCall(VecDestroy(&global)); 57 PetscCall(DMDestroy(&da)); 58 PetscCall(PetscFinalize()); 59 return 0; 60 } 61