Actual source code: ex43.c

  1: static char help[] = "Demonstrates the DMLocalToLocal bug in PETSc 3.6.\n\n";

  3: /*
  4: Use the options
  5:      -da_grid_x <nx> - number of grid points in x direction, if M < 0
  6:      -da_grid_y <ny> - number of grid points in y direction, if N < 0
  7:      -da_processors_x <MX> number of processors in x directio
  8:      -da_processors_y <MY> number of processors in x direction

 10:   Contributed by Constantine Khroulev
 11: */

 13: #include <petscdm.h>
 14: #include <petscdmda.h>

 16: PetscErrorCode PrintVecWithGhosts(DM da, Vec v)
 17: {
 18:   PetscScalar    **p;
 19:   PetscInt       i, j;
 20:   MPI_Comm       com;
 21:   PetscMPIInt    rank;
 22:   DMDALocalInfo  info;

 24:   com = PetscObjectComm((PetscObject)da);
 25:   MPI_Comm_rank(com, &rank);
 26:   DMDAGetLocalInfo(da, &info);
 27:   PetscSynchronizedPrintf(com, "begin rank %d portion (with ghosts, %D x %D)\n",rank, info.gxm, info.gym);
 28:   DMDAVecGetArray(da, v, &p);
 29:   for (i = info.gxs; i < info.gxs + info.gxm; i++) {
 30:     for (j = info.gys; j < info.gys + info.gym; j++) {
 31:       PetscSynchronizedPrintf(com, "%g, ", (double) PetscRealPart(p[j][i]));
 32:     }
 33:     PetscSynchronizedPrintf(com, "\n");
 34:   }
 35:   DMDAVecRestoreArray(da, v, &p);
 36:   PetscSynchronizedPrintf(com, "end rank %d portion\n", rank);
 37:   PetscSynchronizedFlush(com, PETSC_STDOUT);
 38:   return 0;
 39: }

 41: /* Set a Vec v to value, but do not touch ghosts. */
 42: PetscErrorCode VecSetOwned(DM da, Vec v, PetscScalar value)
 43: {
 44:   PetscScalar    **p;
 45:   PetscInt         i, j, xs, xm, ys, ym;

 47:   DMDAGetCorners(da, &xs, &ys, 0, &xm, &ym, 0);
 48:   DMDAVecGetArray(da, v, &p);
 49:   for (i = xs; i < xs + xm; i++) {
 50:     for (j = ys; j < ys + ym; j++) {
 51:       p[j][i] = value;
 52:     }
 53:   }
 54:   DMDAVecRestoreArray(da, v, &p);
 55:   return 0;
 56: }

 58: int main(int argc, char **argv)
 59: {
 60:   PetscInt         M = 4, N = 3;
 61:   DM               da;
 62:   Vec              local;
 63:   PetscScalar      value = 0.0;
 64:   DMBoundaryType   bx    = DM_BOUNDARY_PERIODIC, by = DM_BOUNDARY_PERIODIC;
 65:   DMDAStencilType  stype = DMDA_STENCIL_BOX;

 67:   PetscInitialize(&argc, &argv, (char*)0, help);
 68:   DMDACreate2d(PETSC_COMM_WORLD,bx,by,stype,M,N,PETSC_DECIDE,PETSC_DECIDE,1,1,NULL,NULL,&da);
 69:   DMSetFromOptions(da);
 70:   DMSetUp(da);
 71:   DMCreateLocalVector(da, &local);

 73:   VecSet(local, value);
 74:   PetscPrintf(PETSC_COMM_WORLD, "\nAfter setting all values to %d:\n", (int)PetscRealPart(value));
 75:   PrintVecWithGhosts(da, local);
 76:   PetscPrintf(PETSC_COMM_WORLD, "done\n");

 78:   value += 1.0;
 79:   /* set values owned by a process, leaving ghosts alone */
 80:   VecSetOwned(da, local, value);

 82:   /* print after re-setting interior values again */
 83:   PetscPrintf(PETSC_COMM_WORLD, "\nAfter setting interior values to %d:\n", (int)PetscRealPart(value));
 84:   PrintVecWithGhosts(da, local);
 85:   PetscPrintf(PETSC_COMM_WORLD, "done\n");

 87:   /* communicate ghosts */
 88:   DMLocalToLocalBegin(da, local, INSERT_VALUES, local);
 89:   DMLocalToLocalEnd(da, local, INSERT_VALUES, local);

 91:   /* print again */
 92:   PetscPrintf(PETSC_COMM_WORLD, "\nAfter local-to-local communication:\n");
 93:   PrintVecWithGhosts(da, local);
 94:   PetscPrintf(PETSC_COMM_WORLD, "done\n");

 96:   /* Free memory */
 97:   VecDestroy(&local);
 98:   DMDestroy(&da);
 99:   PetscFinalize();
100:   return 0;
101: }

103: /*TEST

105:    test:
106:       nsize: 2

108: TEST*/