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 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(0); 32 } 33 34 int main(int argc, char **argv) { 35 PetscInt dof = 2, M = 3, N = 3, m = PETSC_DECIDE, n = PETSC_DECIDE; 36 DM da; 37 Vec global, local; 38 39 PetscFunctionBeginUser; 40 PetscCall(PetscInitialize(&argc, &argv, (char *)0, help)); 41 PetscCall(PetscOptionsGetInt(NULL, 0, "-dof", &dof, 0)); 42 /* Create distributed array and get vectors */ 43 PetscCall(DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE, DMDA_STENCIL_BOX, M, N, m, n, dof, 1, NULL, NULL, &da)); 44 PetscCall(DMSetFromOptions(da)); 45 PetscCall(DMSetUp(da)); 46 PetscCall(DMCreateGlobalVector(da, &global)); 47 PetscCall(DMCreateLocalVector(da, &local)); 48 49 PetscCall(doit(da, global)); 50 51 PetscCall(VecView(global, 0)); 52 53 /* Free memory */ 54 PetscCall(VecDestroy(&local)); 55 PetscCall(VecDestroy(&global)); 56 PetscCall(DMDestroy(&da)); 57 PetscCall(PetscFinalize()); 58 return 0; 59 } 60