Actual source code: ex19.c


  2: static char help[] = "Tests DMDA with variable multiple degrees of freedom per node.\n\n";

  4: /*
  5:    This code only compiles with gcc, since it is not ANSI C
  6: */

  8: #include <petscdm.h>
  9: #include <petscdmda.h>

 11: PetscErrorCode doit(DM da, Vec global)
 12: {
 13:   PetscInt i, j, k, M, N, dof;

 15:   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:     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:           PetscPrintf(PETSC_COMM_WORLD, "%" PetscInt_FMT " %" PetscInt_FMT " %g\n", i, j, (double)mystruct[i][j].inside[0]);

 26:           mystruct[i][j].inside[1] = 2.1;
 27:         }
 28:       }
 29:     }
 30:     DMDAVecRestoreArrayRead(da, global, (void *)&mystruct);
 31:   }
 32:   return 0;
 33: }

 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;

 42:   PetscInitialize(&argc, &argv, (char *)0, help);
 43:   PetscOptionsGetInt(NULL, 0, "-dof", &dof, 0);
 44:   /* Create distributed array and get vectors */
 45:   DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE, DMDA_STENCIL_BOX, M, N, m, n, dof, 1, NULL, NULL, &da);
 46:   DMSetFromOptions(da);
 47:   DMSetUp(da);
 48:   DMCreateGlobalVector(da, &global);
 49:   DMCreateLocalVector(da, &local);

 51:   doit(da, global);

 53:   VecView(global, 0);

 55:   /* Free memory */
 56:   VecDestroy(&local);
 57:   VecDestroy(&global);
 58:   DMDestroy(&da);
 59:   PetscFinalize();
 60:   return 0;
 61: }