1 2 static char help[] = "Tests DMDA with variable multiple degrees of freedom per node.\n\n"; 3 4 /* 5 This code only compiles with gcc, since it is not ANSI C 6 */ 7 8 #include <petscdm.h> 9 #include <petscdmda.h> 10 11 PetscErrorCode doit(DM da, Vec global) 12 { 13 PetscInt i, j, k, M, N, dof; 14 15 PetscCall(DMDAGetInfo(da, 0, &M, &N, 0, 0, 0, 0, &dof, 0, 0, 0, 0, 0)); 16 { 17 struct { 18 PetscScalar inside[dof]; 19 } **mystruct; 20 PetscCall(DMDAVecGetArrayRead(da, global, (void *)&mystruct)); 21 for (i = 0; i < N; i++) { 22 for (j = 0; j < M; j++) { 23 for (k = 0; k < dof; k++) { 24 PetscCall(PetscPrintf(PETSC_COMM_WORLD, "%" PetscInt_FMT " %" PetscInt_FMT " %g\n", i, j, (double)mystruct[i][j].inside[0])); 25 26 mystruct[i][j].inside[1] = 2.1; 27 } 28 } 29 } 30 PetscCall(DMDAVecRestoreArrayRead(da, global, (void *)&mystruct)); 31 } 32 PetscFunctionReturn(PETSC_SUCCESS); 33 } 34 35 int main(int argc, char **argv) 36 { 37 PetscInt dof = 2, M = 3, N = 3, m = PETSC_DECIDE, n = PETSC_DECIDE; 38 DM da; 39 Vec global, local; 40 41 PetscFunctionBeginUser; 42 PetscCall(PetscInitialize(&argc, &argv, (char *)0, help)); 43 PetscCall(PetscOptionsGetInt(NULL, 0, "-dof", &dof, 0)); 44 /* Create distributed array and get vectors */ 45 PetscCall(DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE, DMDA_STENCIL_BOX, M, N, m, n, dof, 1, NULL, NULL, &da)); 46 PetscCall(DMSetFromOptions(da)); 47 PetscCall(DMSetUp(da)); 48 PetscCall(DMCreateGlobalVector(da, &global)); 49 PetscCall(DMCreateLocalVector(da, &local)); 50 51 PetscCall(doit(da, global)); 52 53 PetscCall(VecView(global, 0)); 54 55 /* Free memory */ 56 PetscCall(VecDestroy(&local)); 57 PetscCall(VecDestroy(&global)); 58 PetscCall(DMDestroy(&da)); 59 PetscCall(PetscFinalize()); 60 return 0; 61 } 62