Ejemplo n.º 1
0
HYPRE_Int
hypre_BoxBoundaryIntersect( hypre_Box *box,
                            hypre_StructGrid *grid,
                            HYPRE_Int d,
                            HYPRE_Int dir,
                            hypre_BoxArray *boundary )
{
   HYPRE_Int           ndim = hypre_BoxNDim(box);
   hypre_BoxManager   *boxman;
   hypre_BoxManEntry **entries;
   hypre_BoxArray     *int_boxes, *tmp_boxes;
   hypre_Box          *bbox, *ibox;
   HYPRE_Int           nentries, i;

   /* set bbox to the box surface of interest */
   hypre_BoxArraySetSize(boundary, 1);
   bbox = hypre_BoxArrayBox(boundary, 0);
   hypre_CopyBox(box, bbox);
   if (dir > 0)
   {
      hypre_BoxIMinD(bbox, d) = hypre_BoxIMaxD(bbox, d);
   }
   else if (dir < 0)
   {
      hypre_BoxIMaxD(bbox, d) = hypre_BoxIMinD(bbox, d);
   }

   /* temporarily shift bbox in direction dir and intersect with the grid */
   hypre_BoxIMinD(bbox, d) += dir;
   hypre_BoxIMaxD(bbox, d) += dir;
   boxman = hypre_StructGridBoxMan(grid);
   hypre_BoxManIntersect(boxman, hypre_BoxIMin(bbox), hypre_BoxIMax(bbox),
                         &entries, &nentries);
   hypre_BoxIMinD(bbox, d) -= dir;
   hypre_BoxIMaxD(bbox, d) -= dir;

   /* shift intersected boxes in direction -dir and subtract from bbox */
   int_boxes  = hypre_BoxArrayCreate(nentries, ndim);
   tmp_boxes  = hypre_BoxArrayCreate(0, ndim);
   for (i = 0; i < nentries; i++)
   {
      ibox = hypre_BoxArrayBox(int_boxes, i);
      hypre_BoxManEntryGetExtents(
         entries[i], hypre_BoxIMin(ibox), hypre_BoxIMax(ibox));
      hypre_BoxIMinD(ibox, d) -= dir;
      hypre_BoxIMaxD(ibox, d) -= dir;
   }
   hypre_SubtractBoxArrays(boundary, int_boxes, tmp_boxes);

   hypre_BoxArrayDestroy(int_boxes);
   hypre_BoxArrayDestroy(tmp_boxes);
   hypre_TFree(entries);

   return hypre_error_flag;
}
Ejemplo n.º 2
0
Archivo: grow.c Proyecto: 8l/insieme
hypre_BoxArray *
hypre_GrowBoxByStencil( hypre_Box           *box,
                        hypre_StructStencil *stencil,
                        int                  transpose )
{
   hypre_BoxArray   *grow_box_array;
                  
   hypre_BoxArray   *shift_box_array;
   hypre_Box        *shift_box;

   hypre_Index      *stencil_shape;

   int               s, d;

   stencil_shape = hypre_StructStencilShape(stencil);

   shift_box_array = hypre_BoxArrayCreate(hypre_StructStencilSize(stencil));
   shift_box = hypre_BoxCreate();
   for (s = 0; s < hypre_StructStencilSize(stencil); s++)
   {
      if (transpose)
         for (d = 0; d < 3; d++)
         {
            hypre_BoxIMinD(shift_box, d) =
               hypre_BoxIMinD(box, d) - hypre_IndexD(stencil_shape[s], d);
            hypre_BoxIMaxD(shift_box, d) =
               hypre_BoxIMaxD(box, d) - hypre_IndexD(stencil_shape[s], d);
         }
      else
         for (d = 0; d < 3; d++)
         {
            hypre_BoxIMinD(shift_box, d) =
               hypre_BoxIMinD(box, d) + hypre_IndexD(stencil_shape[s], d);
            hypre_BoxIMaxD(shift_box, d) =
               hypre_BoxIMaxD(box, d) + hypre_IndexD(stencil_shape[s], d);
         }

      hypre_CopyBox(shift_box, hypre_BoxArrayBox(shift_box_array, s));
   }
   hypre_BoxDestroy(shift_box);

   hypre_UnionBoxes(shift_box_array);
   grow_box_array = shift_box_array;

   return grow_box_array;
}
Ejemplo n.º 3
0
HYPRE_Int
hypre_IntersectBoxes( hypre_Box *box1,
                      hypre_Box *box2,
                      hypre_Box *ibox )
{
   HYPRE_Int d;

   /* find x, y, and z bounds */
   for (d = 0; d < 3; d++)
   {
      hypre_BoxIMinD(ibox, d) =
         hypre_max(hypre_BoxIMinD(box1, d), hypre_BoxIMinD(box2, d));
      hypre_BoxIMaxD(ibox, d) =
         hypre_min(hypre_BoxIMaxD(box1, d), hypre_BoxIMaxD(box2, d));
   }

   return hypre_error_flag;
}
Ejemplo n.º 4
0
int
hypre_IntersectBoxes( hypre_Box *box1,
                      hypre_Box *box2,
                      hypre_Box *ibox )
{
   int ierr = 0;
   int d;

   /* find x, y, and z bounds */
   for (d = 0; d < 3; d++)
   {
      hypre_BoxIMinD(ibox, d) =
         hypre_max(hypre_BoxIMinD(box1, d), hypre_BoxIMinD(box2, d));
      hypre_BoxIMaxD(ibox, d) =
         hypre_min(hypre_BoxIMaxD(box1, d), hypre_BoxIMaxD(box2, d));
   }

   return ierr;
}
Ejemplo n.º 5
0
int
hypre_ProjectBox( hypre_Box    *box,
                  hypre_Index   index,
                  hypre_Index   stride )
{
   int  i, s, d, hl, hu, kl, ku;
   int  ierr = 0;

   /*------------------------------------------------------
    * project in all 3 dimensions
    *------------------------------------------------------*/

   for (d = 0; d < 3; d++)
   {

      i = hypre_IndexD(index, d);
      s = hypre_IndexD(stride, d);

      hl = hypre_BoxIMinD(box, d) - i;
      hu = hypre_BoxIMaxD(box, d) - i;

      if ( hl <= 0 )
         kl = (int) (hl / s);
      else
         kl = (int) ((hl + (s-1)) / s);

      if ( hu >= 0 )
         ku = (int) (hu / s);
      else
         ku = (int) ((hu - (s-1)) / s);

      hypre_BoxIMinD(box, d) = i + kl * s;
      hypre_BoxIMaxD(box, d) = i + ku * s;

   }

   return ierr;
}
Ejemplo n.º 6
0
int 
hypre_StructVectorInitializeShell( hypre_StructVector *vector )
{
   int    ierr = 0;

   hypre_StructGrid     *grid;

   int                  *num_ghost;
 
   hypre_BoxArray       *data_space;
   hypre_BoxArray       *boxes;
   hypre_Box            *box;
   hypre_Box            *data_box;

   int                  *data_indices;
   int                   data_size;
                     
   int                   i, d;
 
   /*-----------------------------------------------------------------------
    * Set up data_space
    *-----------------------------------------------------------------------*/

   grid = hypre_StructVectorGrid(vector);

   if (hypre_StructVectorDataSpace(vector) == NULL)
   {
      num_ghost = hypre_StructVectorNumGhost(vector);

      boxes = hypre_StructGridBoxes(grid);
      data_space = hypre_BoxArrayCreate(hypre_BoxArraySize(boxes));

      hypre_ForBoxI(i, boxes)
         {
            box = hypre_BoxArrayBox(boxes, i);
            data_box = hypre_BoxArrayBox(data_space, i);

            hypre_CopyBox(box, data_box);
            for (d = 0; d < 3; d++)
            {
               hypre_BoxIMinD(data_box, d) -= num_ghost[2*d];
               hypre_BoxIMaxD(data_box, d) += num_ghost[2*d + 1];
            }
         }
Ejemplo n.º 7
0
   hypre_ForBoxI(i, boxes)
      {
         cbox_array = hypre_BoxArrayArrayBoxArray(indt_boxes, i);
         hypre_BoxArraySetSize(cbox_array, 1);
         cbox = hypre_BoxArrayBox(cbox_array, 0);
         hypre_CopyBox(hypre_BoxArrayBox(boxes, i), cbox);

         for (d = 0; d < 3; d++)
         {
            if ( (border[d][0]) )
            {
               hypre_BoxIMinD(cbox, d) += border[d][0];
            }
            if ( (border[d][1]) )
            {
               hypre_BoxIMaxD(cbox, d) -= border[d][1];
            }
         }
      }
Ejemplo n.º 8
0
int
hypre_CreateComputeInfo( hypre_StructGrid      *grid,
                         hypre_StructStencil   *stencil,
                         hypre_ComputeInfo    **compute_info_ptr )
{
   int                      ierr = 0;

   hypre_CommInfo          *comm_info;
   hypre_BoxArrayArray     *indt_boxes;
   hypre_BoxArrayArray     *dept_boxes;

   hypre_BoxArray          *boxes;

   hypre_BoxArray          *cbox_array;
   hypre_Box               *cbox;

   int                      i;

#ifdef HYPRE_OVERLAP_COMM_COMP
   hypre_Box               *rembox;
   hypre_Index             *stencil_shape;
   int                      border[3][2] = {{0, 0}, {0, 0}, {0, 0}};
   int                      cbox_array_size;
   int                      s, d;
#endif

   /*------------------------------------------------------
    * Extract needed grid info
    *------------------------------------------------------*/

   boxes = hypre_StructGridBoxes(grid);

   /*------------------------------------------------------
    * Get communication info
    *------------------------------------------------------*/

   hypre_CreateCommInfoFromStencil(grid, stencil, &comm_info);

#ifdef HYPRE_OVERLAP_COMM_COMP

   /*------------------------------------------------------
    * Compute border info
    *------------------------------------------------------*/

   stencil_shape = hypre_StructStencilShape(stencil);
   for (s = 0; s < hypre_StructStencilSize(stencil); s++)
   {
      for (d = 0; d < 3; d++)
      {
         i = hypre_IndexD(stencil_shape[s], d);
         if (i < 0)
         {
            border[d][0] = hypre_max(border[d][0], -i);
         }
         else if (i > 0)
         {
            border[d][1] = hypre_max(border[d][1], i);
         }
      }
   }

   /*------------------------------------------------------
    * Set up the dependent boxes
    *------------------------------------------------------*/

   dept_boxes = hypre_BoxArrayArrayCreate(hypre_BoxArraySize(boxes));

   rembox = hypre_BoxCreate();
   hypre_ForBoxI(i, boxes)
      {
         cbox_array = hypre_BoxArrayArrayBoxArray(dept_boxes, i);
         hypre_BoxArraySetSize(cbox_array, 6);

         hypre_CopyBox(hypre_BoxArrayBox(boxes, i), rembox);
         cbox_array_size = 0;
         for (d = 0; d < 3; d++)
         {
            if ( (hypre_BoxVolume(rembox)) && (border[d][0]) )
            {
               cbox = hypre_BoxArrayBox(cbox_array, cbox_array_size);
               hypre_CopyBox(rembox, cbox);
               hypre_BoxIMaxD(cbox, d) =
                  hypre_BoxIMinD(cbox, d) + border[d][0] - 1;
               hypre_BoxIMinD(rembox, d) =
                  hypre_BoxIMinD(cbox, d) + border[d][0];
               cbox_array_size++;
            }
            if ( (hypre_BoxVolume(rembox)) && (border[d][1]) )
            {
               cbox = hypre_BoxArrayBox(cbox_array, cbox_array_size);
               hypre_CopyBox(rembox, cbox);
               hypre_BoxIMinD(cbox, d) =
                  hypre_BoxIMaxD(cbox, d) - border[d][1] + 1;
               hypre_BoxIMaxD(rembox, d) =
                  hypre_BoxIMaxD(cbox, d) - border[d][1];
               cbox_array_size++;
            }
         }
         hypre_BoxArraySetSize(cbox_array, cbox_array_size);
      }
Ejemplo n.º 9
0
int
hypre_StructMatrixInitializeShell( hypre_StructMatrix *matrix )
{
    int    ierr = 0;

    hypre_StructGrid     *grid;

    hypre_StructStencil  *user_stencil;
    hypre_StructStencil  *stencil;
    hypre_Index          *stencil_shape;
    int                   stencil_size;
    int                   num_values;
    int                  *symm_elements;

    int                  *num_ghost;
    int                   extra_ghost[] = {0, 0, 0, 0, 0, 0};

    hypre_BoxArray       *data_space;
    hypre_BoxArray       *boxes;
    hypre_Box            *box;
    hypre_Box            *data_box;

    int                 **data_indices;
    int                   data_size;
    int                   data_box_volume;

    int                   i, j, d;

    grid = hypre_StructMatrixGrid(matrix);

    /*-----------------------------------------------------------------------
     * Set up stencil and num_values:
     *    The stencil is a "symmetrized" version of the user's stencil
     *    as computed by hypre_StructStencilSymmetrize.
     *
     *    The `symm_elements' array is used to determine what data is
     *    explicitely stored (symm_elements[i] < 0) and what data does is
     *    not explicitely stored (symm_elements[i] >= 0), but is instead
     *    stored as the transpose coefficient at a neighboring grid point.
     *-----------------------------------------------------------------------*/

    if (hypre_StructMatrixStencil(matrix) == NULL)
    {
        user_stencil = hypre_StructMatrixUserStencil(matrix);

        hypre_StructStencilSymmetrize(user_stencil, &stencil, &symm_elements);

        stencil_shape = hypre_StructStencilShape(stencil);
        stencil_size  = hypre_StructStencilSize(stencil);

        if (!hypre_StructMatrixSymmetric(matrix))
        {
            /* store all element data */
            for (i = 0; i < stencil_size; i++)
                symm_elements[i] = -1;
            num_values = stencil_size;
        }
        else
        {
            num_values = (stencil_size + 1) / 2;
        }

        hypre_StructMatrixStencil(matrix)   = stencil;
        hypre_StructMatrixSymmElements(matrix) = symm_elements;
        hypre_StructMatrixNumValues(matrix) = num_values;
    }

    /*-----------------------------------------------------------------------
     * Set ghost-layer size for symmetric storage
     *   - All stencil coeffs are to be available at each point in the
     *     grid, as well as in the user-specified ghost layer.
     *-----------------------------------------------------------------------*/

    num_ghost     = hypre_StructMatrixNumGhost(matrix);
    stencil       = hypre_StructMatrixStencil(matrix);
    stencil_shape = hypre_StructStencilShape(stencil);
    stencil_size  = hypre_StructStencilSize(stencil);
    symm_elements = hypre_StructMatrixSymmElements(matrix);

    for (i = 0; i < stencil_size; i++)
    {
        if (symm_elements[i] >= 0)
        {
            for (d = 0; d < 3; d++)
            {
                extra_ghost[2*d] =
                    hypre_max(extra_ghost[2*d], -hypre_IndexD(stencil_shape[i], d));
                extra_ghost[2*d + 1] =
                    hypre_max(extra_ghost[2*d + 1],  hypre_IndexD(stencil_shape[i], d));
            }
        }
    }

    for (d = 0; d < 3; d++)
    {
        num_ghost[2*d]     += extra_ghost[2*d];
        num_ghost[2*d + 1] += extra_ghost[2*d + 1];
    }

    /*-----------------------------------------------------------------------
     * Set up data_space
     *-----------------------------------------------------------------------*/

    if (hypre_StructMatrixDataSpace(matrix) == NULL)
    {
        boxes = hypre_StructGridBoxes(grid);
        data_space = hypre_BoxArrayCreate(hypre_BoxArraySize(boxes));

        hypre_ForBoxI(i, boxes)
        {
            box = hypre_BoxArrayBox(boxes, i);
            data_box = hypre_BoxArrayBox(data_space, i);

            hypre_CopyBox(box, data_box);
            for (d = 0; d < 3; d++)
            {
                hypre_BoxIMinD(data_box, d) -= num_ghost[2*d];
                hypre_BoxIMaxD(data_box, d) += num_ghost[2*d + 1];
            }
        }
Ejemplo n.º 10
0
int
hypre_SubtractBoxes( hypre_Box      *box1,
                     hypre_Box      *box2,
                     hypre_BoxArray *box_array )
{
   int ierr = 0;
              
   hypre_Box  *box;
   hypre_Box  *rembox;
   int         d, size;

   /*------------------------------------------------------
    * Set the box array size to the maximum possible,
    * plus one, to have space for the remainder box.
    *------------------------------------------------------*/

   size = hypre_BoxArraySize(box_array);
   hypre_BoxArraySetSize(box_array, (size + 7));

   /*------------------------------------------------------
    * Subtract the boxes by cutting box1 in x, y, then z
    *------------------------------------------------------*/

   rembox = hypre_BoxArrayBox(box_array, (size + 6));
   hypre_CopyBox(box1, rembox);

   for (d = 0; d < 3; d++)
   {
      /* if the boxes do not intersect, the subtraction is trivial */
      if ( (hypre_BoxIMinD(box2, d) > hypre_BoxIMaxD(rembox, d)) ||
           (hypre_BoxIMaxD(box2, d) < hypre_BoxIMinD(rembox, d)) )
      {
         size = hypre_BoxArraySize(box_array) - 7;
         hypre_CopyBox(box1, hypre_BoxArrayBox(box_array, size));
         size++;
         break;
      }

      /* update the box array */
      else
      {
         if ( hypre_BoxIMinD(box2, d) > hypre_BoxIMinD(rembox, d) )
         {
            box = hypre_BoxArrayBox(box_array, size);
            hypre_CopyBox(rembox, box);
            hypre_BoxIMaxD(box, d) = hypre_BoxIMinD(box2, d) - 1;
            hypre_BoxIMinD(rembox, d) = hypre_BoxIMinD(box2, d);
            if ( hypre_BoxVolume(box)>0 ) size++;
         }
         if ( hypre_BoxIMaxD(box2, d) < hypre_BoxIMaxD(rembox, d) )
         {
            box = hypre_BoxArrayBox(box_array, size);
            hypre_CopyBox(rembox, box);
            hypre_BoxIMinD(box, d) = hypre_BoxIMaxD(box2, d) + 1;
            hypre_BoxIMaxD(rembox, d) = hypre_BoxIMaxD(box2, d);
            if ( hypre_BoxVolume(box)>0 ) size++;
         }
      }
   }
   hypre_BoxArraySetSize(box_array, size);

   return ierr;
}
Ejemplo n.º 11
0
int
hypre_BoxNeighborsAssemble( hypre_BoxNeighbors *neighbors,
                            int                 max_distance,
                            int                 prune )
{
   hypre_BoxArray      *boxes;
   int                 *procs;
   int                 *ids;
   int                  first_local;
   int                  num_local;
   int                  num_periodic;

   int                  keep_box;
   int                  num_boxes;

   hypre_RankLink      *rank_link;

   hypre_Box           *local_box;
   hypre_Box           *neighbor_box;

   int                  distance;
   int                  distance_index[3];

   int                  diff;
   int                  i, j, d, ilocal, inew;

   int                  ierr = 0;

   /*---------------------------------------------
    * Find neighboring boxes
    *---------------------------------------------*/

   boxes           = hypre_BoxNeighborsBoxes(neighbors);
   procs           = hypre_BoxNeighborsProcs(neighbors);
   ids             = hypre_BoxNeighborsIDs(neighbors);
   first_local     = hypre_BoxNeighborsFirstLocal(neighbors);
   num_local       = hypre_BoxNeighborsNumLocal(neighbors);
   num_periodic    = hypre_BoxNeighborsNumPeriodic(neighbors);

   /*---------------------------------------------
    * Find neighboring boxes
    *---------------------------------------------*/

   inew = 0;
   num_boxes = 0;
   hypre_ForBoxI(i, boxes)
      {
         keep_box = 0;
         for (j = 0; j < num_local + num_periodic; j++)
         {
            ilocal = first_local + j;
            if (i != ilocal)
            {
               local_box = hypre_BoxArrayBox(boxes, ilocal);
               neighbor_box = hypre_BoxArrayBox(boxes, i);

               /* compute distance info */
               distance = 0;
               for (d = 0; d < 3; d++)
               {
                  distance_index[d] = 0;

                  diff = hypre_BoxIMinD(neighbor_box, d) -
                     hypre_BoxIMaxD(local_box, d);
                  if (diff > 0)
                  {
                     distance_index[d] = 1;
                     distance = hypre_max(distance, diff);
                  }

                  diff = hypre_BoxIMinD(local_box, d) -
                     hypre_BoxIMaxD(neighbor_box, d);
                  if (diff > 0)
                  {
                     distance_index[d] = -1;
                     distance = hypre_max(distance, diff);
                  }
               }

               /* create new rank_link */
               if (distance <= max_distance)
               {
                  keep_box = 1;

                  if (j < num_local)
                  {
                     hypre_RankLinkCreate(num_boxes, &rank_link);
                     hypre_RankLinkNext(rank_link) =
                        hypre_BoxNeighborsRankLink(neighbors, j,
                                                   distance_index[0],
                                                   distance_index[1],
                                                   distance_index[2]);
                     hypre_BoxNeighborsRankLink(neighbors, j,
                                                distance_index[0],
                                                distance_index[1],
                                                distance_index[2]) = rank_link;
                  }
               }
            }
            else
            {
               keep_box = 1;
            }
         }

         if (prune)
         {
            /* use procs array to store which boxes to keep */
            if (keep_box)
            {
               procs[i] = -procs[i];
               if (inew < i)
               {
                  procs[inew] = i;
               }
               inew = i + 1;
               
               num_boxes++;
            }
         }
         else
         {
            /* keep all of the boxes */
            num_boxes++;
         }
      }
Ejemplo n.º 12
0
HYPRE_Int
hypre_CreateCommInfoFromStencil( hypre_StructGrid      *grid,
                                 hypre_StructStencil   *stencil,
                                 hypre_CommInfo       **comm_info_ptr )
{
   HYPRE_Int              i,j,k, d, m, s;   

   hypre_BoxArrayArray   *send_boxes;
   hypre_BoxArrayArray   *recv_boxes;

   HYPRE_Int            **send_procs;
   HYPRE_Int            **recv_procs;
   HYPRE_Int            **send_rboxnums;
   HYPRE_Int            **recv_rboxnums;
   hypre_BoxArrayArray   *send_rboxes;
   hypre_BoxArrayArray   *recv_rboxes;

   hypre_BoxArray        *local_boxes;
   HYPRE_Int              num_boxes;

   HYPRE_Int             *local_ids;

   hypre_BoxManager      *boxman;
                       
   hypre_Index           *stencil_shape;
   hypre_IndexRef         stencil_offset;
   hypre_IndexRef         pshift;
                          
   hypre_Box             *box;
   hypre_Box             *hood_box;
   hypre_Box             *grow_box;
   hypre_Box             *extend_box;
   hypre_Box             *int_box;
   hypre_Box             *periodic_box;
   
   HYPRE_Int              stencil_grid[3][3][3];
   HYPRE_Int              grow[3][2];
                       
   hypre_BoxManEntry    **entries;
   hypre_BoxManEntry     *entry;
   
   HYPRE_Int              num_entries;
   hypre_BoxArray        *neighbor_boxes = NULL;
   HYPRE_Int             *neighbor_procs = NULL;
   HYPRE_Int             *neighbor_ids = NULL;
   HYPRE_Int             *neighbor_shifts = NULL;
   HYPRE_Int              neighbor_count;
   HYPRE_Int              neighbor_alloc;

   hypre_Index            ilower, iupper;

   hypre_BoxArray        *send_box_array;
   hypre_BoxArray        *recv_box_array;
   hypre_BoxArray        *send_rbox_array;
   hypre_BoxArray        *recv_rbox_array;
                       
   hypre_Box            **cboxes;
   hypre_Box             *cboxes_mem;
   HYPRE_Int             *cboxes_neighbor_location;
   HYPRE_Int              num_cboxes, cbox_alloc;
                       
   HYPRE_Int              istart[3], istop[3];
   HYPRE_Int              sgindex[3];               

   HYPRE_Int              num_periods, loc, box_id, id, proc_id;
   HYPRE_Int              myid;
   
   MPI_Comm               comm;

   /*------------------------------------------------------
    * Initializations
    *------------------------------------------------------*/

   local_boxes  = hypre_StructGridBoxes(grid);
   local_ids    = hypre_StructGridIDs(grid);
   num_boxes    = hypre_BoxArraySize(local_boxes);
   num_periods  = hypre_StructGridNumPeriods(grid);
   
   boxman    = hypre_StructGridBoxMan(grid);
   comm      =  hypre_StructGridComm(grid);
   
   hypre_MPI_Comm_rank(comm, &myid);
  
   for (k = 0; k < 3; k++)
   {
      for (j = 0; j < 3; j++)
      {
         for (i = 0; i < 3; i++)
         {
            stencil_grid[i][j][k] = 0;
         }
      }
   }

   /*------------------------------------------------------
    * Compute the "grow" information from the stencil
    *------------------------------------------------------*/

   stencil_shape = hypre_StructStencilShape(stencil);

   for (d = 0; d < 3; d++)
   {
      grow[d][0] = 0;
      grow[d][1] = 0;
   }

   for (s = 0; s < hypre_StructStencilSize(stencil); s++)
   {
      stencil_offset = stencil_shape[s];

      for (d = 0; d < 3; d++)
      {
         m = stencil_offset[d];

         istart[d] = 1;
         istop[d]  = 1;

         if (m < 0)
         {
            istart[d] = 0;
            grow[d][0] = hypre_max(grow[d][0], -m);
         }
         else if (m > 0)
         {
            istop[d] = 2;
            grow[d][1] = hypre_max(grow[d][1],  m);
         }
      }

      /* update stencil grid from the grow_stencil */
      for (k = istart[2]; k <= istop[2]; k++)
      {
         for (j = istart[1]; j <= istop[1]; j++)
         {
            for (i = istart[0]; i <= istop[0]; i++)
            {
               stencil_grid[i][j][k] = 1;
            }
         }
      }
   }

   /*------------------------------------------------------
    * Compute send/recv boxes and procs for each local box
    *------------------------------------------------------*/

   /* initialize: for each local box, we create an array of send/recv info */

   send_boxes = hypre_BoxArrayArrayCreate(num_boxes);
   recv_boxes = hypre_BoxArrayArrayCreate(num_boxes);
   send_procs = hypre_CTAlloc(HYPRE_Int *, num_boxes);
   recv_procs = hypre_CTAlloc(HYPRE_Int *, num_boxes);

   /* Remote boxnums and boxes describe data on the opposing processor, so some
      shifting of boxes is needed below for periodic neighbor boxes.  Remote box
      info is also needed for receives to allow for reverse communication. */
   send_rboxnums = hypre_CTAlloc(HYPRE_Int *, num_boxes);
   send_rboxes   = hypre_BoxArrayArrayCreate(num_boxes);
   recv_rboxnums = hypre_CTAlloc(HYPRE_Int *, num_boxes);
   recv_rboxes   = hypre_BoxArrayArrayCreate(num_boxes);

   grow_box = hypre_BoxCreate();
   extend_box = hypre_BoxCreate();
   int_box  = hypre_BoxCreate();
   periodic_box =  hypre_BoxCreate();
 
   /* storage we will use and keep track of the neighbors */
   neighbor_alloc = 30; /* initial guess at max size */
   neighbor_boxes = hypre_BoxArrayCreate(neighbor_alloc);
   neighbor_procs = hypre_CTAlloc(HYPRE_Int, neighbor_alloc);
   neighbor_ids = hypre_CTAlloc(HYPRE_Int, neighbor_alloc);
   neighbor_shifts = hypre_CTAlloc(HYPRE_Int, neighbor_alloc);

   /* storage we will use to collect all of the intersected boxes (the send and
      recv regions for box i (this may not be enough in the case of periodic
      boxes, so we will have to check) */
   cbox_alloc =  hypre_BoxManNEntries(boxman);

   cboxes_neighbor_location = hypre_CTAlloc(HYPRE_Int, cbox_alloc);
   cboxes = hypre_CTAlloc(hypre_Box *, cbox_alloc);
   cboxes_mem = hypre_CTAlloc(hypre_Box, cbox_alloc);

   /******* loop through each local box **************/

   for (i = 0; i < num_boxes; i++)
   {
      /* get the box */
      box = hypre_BoxArrayBox(local_boxes, i);
      /* box_id = local_ids[i]; the box id in the Box Manager is the box number,
       * and we use this to find out if a box has intersected with itself */
      box_id = i;
      
      /* grow box local i according to the stencil*/
      hypre_CopyBox(box, grow_box);
      for (d = 0; d < 3; d++)
      {
         hypre_BoxIMinD(grow_box, d) -= grow[d][0];
         hypre_BoxIMaxD(grow_box, d) += grow[d][1];
      }

      /* extend_box - to find the list of potential neighbors, we need to grow
         the local box a bit differently in case, for example, the stencil grows
         in one dimension [0] and not the other [1] */
      hypre_CopyBox(box, extend_box);
      for (d = 0; d < 3; d++)
      { 
         hypre_BoxIMinD(extend_box, d) -= hypre_max(grow[d][0],grow[d][1]);
         hypre_BoxIMaxD(extend_box, d) += hypre_max(grow[d][0],grow[d][1]);
      }

      /*------------------------------------------------
       * Determine the neighbors of box i
       *------------------------------------------------*/
     
      /* Do this by intersecting the extend box with the BoxManager. 
         We must also check for periodic neighbors. */

      neighbor_count = 0;
      hypre_BoxArraySetSize(neighbor_boxes, 0);
      /* shift the box by each period (k=0 is original box) */
      for (k = 0; k < num_periods; k++)
      {
         hypre_CopyBox(extend_box, periodic_box);
         pshift = hypre_StructGridPShift(grid, k);
         hypre_BoxShiftPos(periodic_box, pshift);
         
         /* get the intersections */
         hypre_BoxManIntersect(boxman, hypre_BoxIMin(periodic_box) , 
                               hypre_BoxIMax(periodic_box) , 
                               &entries , &num_entries);
      
         /* note: do we need to remove the intersection with our original box?
            no if periodic, yes if non-periodic (k=0) */ 

         /* unpack entries (first check storage) */
         if (neighbor_count + num_entries > neighbor_alloc)
         {
            neighbor_alloc = neighbor_count + num_entries + 5;
            neighbor_procs = hypre_TReAlloc(neighbor_procs, HYPRE_Int,
                                            neighbor_alloc);
            neighbor_ids = hypre_TReAlloc(neighbor_ids, HYPRE_Int, neighbor_alloc);
            neighbor_shifts = hypre_TReAlloc(neighbor_shifts, HYPRE_Int,
                                             neighbor_alloc);
         }
         /* check storage for the array */
         hypre_BoxArraySetSize(neighbor_boxes, neighbor_count + num_entries);
         /* now unpack */
         for (j = 0; j < num_entries; j++)
         {
            entry = entries[j];
            proc_id = hypre_BoxManEntryProc(entry);        
            id = hypre_BoxManEntryId(entry); 
            /* don't keep box i in the non-periodic case*/  
            if (!k)
            {
               if((myid == proc_id) && (box_id == id))
               {
                  continue;
               }
            }

            hypre_BoxManEntryGetExtents(entry, ilower, iupper);        
            hypre_BoxSetExtents(hypre_BoxArrayBox(neighbor_boxes, neighbor_count),
                                ilower, iupper);
            /* shift the periodic boxes (needs to be the opposite of above) */
            if (k)
            {
               hypre_BoxShiftNeg(
                  hypre_BoxArrayBox(neighbor_boxes, neighbor_count), pshift);
            }
            
            neighbor_procs[neighbor_count] = proc_id;
            neighbor_ids[neighbor_count] = id;
            neighbor_shifts[neighbor_count] = k;
            neighbor_count++;
         }
         hypre_BoxArraySetSize(neighbor_boxes, neighbor_count);

         hypre_TFree(entries);
  
      } /* end of loop through periods k */

      /* Now we have a list of all of the neighbors for box i! */

      /* note: we don't want/need to remove duplicates - they should have
         different intersections (TO DO: put more thought into if there are ever
         any exceptions to this? - the intersection routine already eliminates
         duplicates - so what i mean is eliminating duplicates from multiple
         intersection calls in periodic case)  */  
    
      /*------------------------------------------------
       * Compute recv_box_array for box i
       *------------------------------------------------*/

      /* check size of storage for cboxes */
      /* let's make sure that we have enough storage in case each neighbor
         produces a send/recv region */
      if (neighbor_count > cbox_alloc)
      {
         cbox_alloc = neighbor_count;
         cboxes_neighbor_location = hypre_TReAlloc(cboxes_neighbor_location, 
                                                   HYPRE_Int, cbox_alloc);
         cboxes = hypre_TReAlloc(cboxes, hypre_Box *, cbox_alloc);
         cboxes_mem = hypre_TReAlloc(cboxes_mem, hypre_Box, cbox_alloc);
      }

      /* Loop through each neighbor box.  If the neighbor box intersects the
         grown box i (grown according to our stencil), then the intersection is
         a recv region.  If the neighbor box was shifted to handle periodicity,
         we need to (positive) shift it back. */

      num_cboxes = 0;
      
      for (k = 0; k < neighbor_count; k++)
      {
         hood_box = hypre_BoxArrayBox(neighbor_boxes, k);
         /* check the stencil grid to see if it makes sense to intersect */
         for (d = 0; d < 3; d++)
         {
            sgindex[d] = 1;
               
            s = hypre_BoxIMinD(hood_box, d) - hypre_BoxIMaxD(box, d);
            if (s > 0)
            {
               sgindex[d] = 2;
            }
            s = hypre_BoxIMinD(box, d) - hypre_BoxIMaxD(hood_box, d);
            if (s > 0)
            {
               sgindex[d] = 0;
            }
         }
         /* it makes sense only if we have at least one non-zero entry */   
         if (stencil_grid[sgindex[0]][sgindex[1]][sgindex[2]])
         {
            /* intersect - result is int_box */
            hypre_IntersectBoxes(grow_box, hood_box, int_box);
            /* if we have a positive volume box, this is a recv region */
            if (hypre_BoxVolume(int_box))
            {
               /* keep track of which neighbor: k... */
               cboxes_neighbor_location[num_cboxes] = k;
               cboxes[num_cboxes] = &cboxes_mem[num_cboxes];
               /* keep the intersected box */
               hypre_CopyBox(int_box, cboxes[num_cboxes]);
               num_cboxes++;
            }
         }
      } /* end of loop through each neighbor */

      /* create recv_box_array and recv_procs for box i */
      recv_box_array = hypre_BoxArrayArrayBoxArray(recv_boxes, i);
      hypre_BoxArraySetSize(recv_box_array, num_cboxes);
      recv_procs[i] = hypre_CTAlloc(HYPRE_Int, num_cboxes);
      recv_rboxnums[i] = hypre_CTAlloc(HYPRE_Int, num_cboxes);
      recv_rbox_array = hypre_BoxArrayArrayBoxArray(recv_rboxes, i);
      hypre_BoxArraySetSize(recv_rbox_array, num_cboxes);

      for (m = 0; m < num_cboxes; m++)
      {
         loc = cboxes_neighbor_location[m];
         recv_procs[i][m] = neighbor_procs[loc];
         recv_rboxnums[i][m] = neighbor_ids[loc];
         hypre_CopyBox(cboxes[m], hypre_BoxArrayBox(recv_box_array, m));

         /* if periodic, positive shift before copying to the rbox_array */
         if (neighbor_shifts[loc]) /* periodic if shift != 0 */
         {
            pshift = hypre_StructGridPShift(grid, neighbor_shifts[loc]);
            hypre_BoxShiftPos(cboxes[m], pshift);
         }
         hypre_CopyBox(cboxes[m], hypre_BoxArrayBox(recv_rbox_array, m));

         cboxes[m] = NULL;
      }

      /*------------------------------------------------
       * Compute send_box_array for box i
       *------------------------------------------------*/

      /* Loop through each neighbor box.  If the grown neighbor box intersects
         box i, then the intersection is a send region.  If the neighbor box was
         shifted to handle periodicity, we need to (positive) shift it back. */

      num_cboxes = 0;

      for (k = 0; k < neighbor_count; k++)
      {
         hood_box = hypre_BoxArrayBox(neighbor_boxes, k);
         /* check the stencil grid to see if it makes sense to intersect */
         for (d = 0; d < 3; d++)
         {
            sgindex[d] = 1;
            
            s = hypre_BoxIMinD(box, d) - hypre_BoxIMaxD(hood_box, d);
            if (s > 0)
            {
               sgindex[d] = 2;
            }
            s = hypre_BoxIMinD(hood_box, d) - hypre_BoxIMaxD(box, d);
            if (s > 0)
            {
               sgindex[d] = 0;
            }
         }
         /* it makes sense only if we have at least one non-zero entry */   
         if (stencil_grid[sgindex[0]][sgindex[1]][sgindex[2]])
         {
            /* grow the neighbor box and intersect */
            hypre_CopyBox(hood_box, grow_box);
            for (d = 0; d < 3; d++)
            {
               hypre_BoxIMinD(grow_box, d) -= grow[d][0];
               hypre_BoxIMaxD(grow_box, d) += grow[d][1];
            }
            hypre_IntersectBoxes(box, grow_box, int_box);
            /* if we have a positive volume box, this is a send region */
            if (hypre_BoxVolume(int_box))
            {
               /* keep track of which neighbor: k... */
               cboxes_neighbor_location[num_cboxes] = k;
               cboxes[num_cboxes] = &cboxes_mem[num_cboxes];
               /* keep the intersected box */
               hypre_CopyBox(int_box, cboxes[num_cboxes]);
               num_cboxes++;
            }
         }
      }/* end of loop through neighbors */

      /* create send_box_array and send_procs for box i */
      send_box_array = hypre_BoxArrayArrayBoxArray(send_boxes, i);
      hypre_BoxArraySetSize(send_box_array, num_cboxes);
      send_procs[i] = hypre_CTAlloc(HYPRE_Int, num_cboxes);
      send_rboxnums[i] = hypre_CTAlloc(HYPRE_Int, num_cboxes);
      send_rbox_array = hypre_BoxArrayArrayBoxArray(send_rboxes, i);
      hypre_BoxArraySetSize(send_rbox_array, num_cboxes);

      for (m = 0; m < num_cboxes; m++)
      {
         loc = cboxes_neighbor_location[m];
         send_procs[i][m] = neighbor_procs[loc];
         send_rboxnums[i][m] = neighbor_ids[loc];
         hypre_CopyBox(cboxes[m], hypre_BoxArrayBox(send_box_array, m));

         /* if periodic, positive shift before copying to the rbox_array */
         if (neighbor_shifts[loc]) /* periodic if shift != 0 */
         {
            pshift = hypre_StructGridPShift(grid, neighbor_shifts[loc]);
            hypre_BoxShiftPos(cboxes[m], pshift);
         }
         hypre_CopyBox(cboxes[m], hypre_BoxArrayBox(send_rbox_array, m));

         cboxes[m] = NULL;
      }
   } /* end of loop through each local box */
Ejemplo n.º 13
0
int hypre_StructGridAssembleWithAP( hypre_StructGrid *grid )
{
 


   int                  ierr = 0;
   int                  tmp_i;
   
   int                  size, global_num_boxes, num_local_boxes;
   int                  i, j, d, k, index;
   int                  num_procs, myid;
   int                  *sendbuf8, *recvbuf8, *sendbuf2, *recvbuf2;
   int                  min_box_size, max_box_size;
   int                  global_min_box_size, global_max_box_size;
   int                 *ids;
   int                  max_regions, max_refinements, ologp;
   double               gamma;
   hypre_Index          min_index, max_index;
   
  
   int                  prune;
       
   hypre_Box           *box;
   

   MPI_Comm             comm         = hypre_StructGridComm(grid);
   hypre_Box           *bounding_box = hypre_StructGridBoundingBox(grid);
   hypre_BoxArray      *local_boxes  = hypre_StructGridBoxes(grid);
   int                  dim          = hypre_StructGridDim(grid);
   hypre_BoxNeighbors  *neighbors    = hypre_StructGridNeighbors(grid);
   int                  max_distance = hypre_StructGridMaxDistance(grid);
   hypre_IndexRef       periodic     = hypre_StructGridPeriodic(grid);

   int                 *local_boxnums;

   double               dbl_global_size, tmp_dbl;
   
   hypre_BoxArray       *my_partition;
   int                  *part_ids, *part_boxnums;
     
   int                  *proc_array, proc_count, proc_alloc, count;
   int                  *tmp_proc_ids = NULL;
   
   int                  max_response_size;
   int                  *ap_proc_ids, *send_buf, *send_buf_starts;
   int                  *response_buf, *response_buf_starts;

   hypre_BoxArray      *neighbor_boxes, *n_boxes_copy;
   int                 *neighbor_proc_ids, *neighbor_boxnums;

   int                 *order_index, *delete_array;
   int                 tmp_id, start, first_local;
   
   int                 grow, grow_array[6];
   hypre_Box           *grow_box;
   
   
   int                  *numghost;
   int                   ghostsize;
   hypre_Box            *ghostbox;

   hypre_StructAssumedPart     *assumed_part;
   hypre_DataExchangeResponse  response_obj;
 
   int                  px = hypre_IndexX(periodic);
   int                  py = hypre_IndexY(periodic);
   int                  pz = hypre_IndexZ(periodic);

   int                  i_periodic = px ? 1 : 0;
   int                  j_periodic = py ? 1 : 0;
   int                  k_periodic = pz ? 1 : 0;

   int                  num_periods, multiple_ap, p;
   hypre_Box           *result_box, *period_box;
   hypre_Index         *pshifts;

   hypre_IndexRef       pshift;

#if NEIGH_PRINT
   double               start_time, end_time;
   
#endif



/*---------------------------------------------
  Step 1:  Initializations
  -----------------------------------------------*/

   prune = 1; /* default is to prune */ 
   
   num_local_boxes = hypre_BoxArraySize(local_boxes);
  
   num_periods = (1+2*i_periodic) * (1+2*j_periodic) * (1+2*k_periodic);


   MPI_Comm_size(comm, &num_procs);
   MPI_Comm_rank(comm, &myid);


 
/*---------------------------------------------
  Step 2:  Determine the global size, total number of boxes,
           and global bounding box.
           Also get the min and max box sizes
           since it is convenient to do so.
  -----------------------------------------------*/

   if (neighbors == NULL) 
   {
    
      /*these may not be needed - check later */
      ids =   hypre_TAlloc(int, num_local_boxes);
    
      /* for the vol and number of boxes */
      sendbuf2 = hypre_CTAlloc(int, 2);
      recvbuf2 = hypre_CTAlloc(int, 2);
      size = 0;
     
      bounding_box = hypre_BoxCreate();
      grow_box = hypre_BoxCreate();
      

      if (num_local_boxes) 
      {
         
         min_box_size = hypre_BoxVolume( hypre_BoxArrayBox(local_boxes, 0));
         max_box_size = hypre_BoxVolume( hypre_BoxArrayBox(local_boxes, 0));


         /* initialize min and max */
         for (d=0; d<3; d++)
         {
            hypre_IndexD(min_index, d) = pow(2,30); 
            hypre_IndexD(max_index, d) = -pow(2,30);
         }
         

         hypre_ForBoxI(i, local_boxes)
         {
            box = hypre_BoxArrayBox(local_boxes, i);
            /* get global size and number of boxes */ 
            tmp_i = hypre_BoxVolume(box);
            size += tmp_i;
            min_box_size = hypre_min(min_box_size, tmp_i);
            max_box_size = hypre_max(max_box_size, tmp_i);


            /* set id */  
            ids[i] = i;


            /* 1/3/05 we need this for the case of holes in the domain. (I had
               commented
               it out on 12/04 - as I thought this was not necessary. */
            
            
            /* zero volume boxes - still look at for getting the bounding box */
            if (hypre_BoxVolume(box) == 0) /* zero volume boxes - still count */
            {
               hypre_CopyBox(box, grow_box);
               for (d = 0; d < 3; d++)
               {
                  if(!hypre_BoxSizeD(box, d))
                  {
                     grow = (hypre_BoxIMinD(box, d) - hypre_BoxIMaxD(box, d) + 1)/2;
                     grow_array[2*d] = grow;
                     grow_array[2*d+1] = grow;
                  }
                  else
                  {
                     grow_array[2*d] = 0;
                     grow_array[2*d+1] = 0;
                  }
               }   
               /* expand the box */
               hypre_BoxExpand(grow_box, grow_array);
               box = grow_box; /*pointer copy*/
            }     
            /*now we have a vol > 0 box */
    
         
            for (d = 0; d < dim; d++) /* for each dimension */
            {
               hypre_IndexD(min_index, d) = hypre_min( hypre_IndexD(min_index, d), 
                                                       hypre_BoxIMinD(box, d));
               hypre_IndexD(max_index, d) = hypre_max( hypre_IndexD(max_index, d), 
                                                       hypre_BoxIMaxD(box, d));
            }
                        
         }/*end for each box loop */

         /* bounding box extents */ 
         hypre_BoxSetExtents(bounding_box, min_index, max_index);
   
      }
Ejemplo n.º 14
0
HYPRE_Int
hypre_GeneralBoxBoundaryIntersect( hypre_Box *box,
                            hypre_StructGrid *grid,
                            hypre_Index stencil_element,
                            hypre_BoxArray *boundary )
{
   hypre_BoxManager   *boxman;
   hypre_BoxManEntry **entries;
   hypre_BoxArray     *int_boxes, *tmp_boxes;
   hypre_Box          *bbox, *ibox;
   HYPRE_Int           nentries, i, j;
   HYPRE_Int          *dd;
   HYPRE_Int           ndim;

   ndim = hypre_StructGridNDim(grid);
   dd = hypre_CTAlloc(HYPRE_Int, ndim);

   for (i=0; i < ndim; i++)
     dd[i] = hypre_IndexD(stencil_element, i);

   /* set bbox to the box surface of interest */
   hypre_BoxArraySetSize(boundary, 1);
   bbox = hypre_BoxArrayBox(boundary, 0);
   hypre_CopyBox(box, bbox);

   /* temporarily shift bbox in direction dir and intersect with the grid */
   for (i=0; i < ndim; i++)
   {
      hypre_BoxIMinD(bbox, i) += dd[i];
      hypre_BoxIMaxD(bbox, i) += dd[i];
   }

   boxman = hypre_StructGridBoxMan(grid);
   hypre_BoxManIntersect(boxman, hypre_BoxIMin(bbox), hypre_BoxIMax(bbox),
                         &entries, &nentries);
   for (i=0; i < ndim; i++)
   {
      hypre_BoxIMinD(bbox, i) -= dd[i];
      hypre_BoxIMaxD(bbox, i) -= dd[i];
   }

   /* shift intersected boxes in direction -dir and subtract from bbox */
   int_boxes  = hypre_BoxArrayCreate(nentries, ndim);
   tmp_boxes  = hypre_BoxArrayCreate(0, ndim);
   for (i = 0; i < nentries; i++)
   {
      ibox = hypre_BoxArrayBox(int_boxes, i);
      hypre_BoxManEntryGetExtents(
         entries[i], hypre_BoxIMin(ibox), hypre_BoxIMax(ibox));
      for (j=0; j < ndim; j++)
      {
         hypre_BoxIMinD(ibox, j) -= dd[j];
         hypre_BoxIMaxD(ibox, j) -= dd[j];
      }
   }
   hypre_SubtractBoxArrays(boundary, int_boxes, tmp_boxes);

   hypre_BoxArrayDestroy(int_boxes);
   hypre_BoxArrayDestroy(tmp_boxes);
   hypre_TFree(entries);
   hypre_TFree(dd);

   return hypre_error_flag;
}
Ejemplo n.º 15
0
int
hypre_StructCoarsen( hypre_StructGrid  *fgrid,
                     hypre_Index        index,
                     hypre_Index        stride,
                     int                prune,
                     hypre_StructGrid **cgrid_ptr )
{
   int ierr = 0;

   hypre_StructGrid   *cgrid;
                      
   MPI_Comm            comm;
   int                 dim;
   hypre_BoxNeighbors *neighbors;
   hypre_BoxArray     *hood_boxes;
   int                 num_hood;
   int                *hood_procs;
   int                *hood_ids;
   int                 first_local;
   int                 num_local;
   int                 num_periodic;
   int                 max_distance;
   hypre_Box          *bounding_box;
   hypre_Index         periodic;

   MPI_Request        *send_requests;
   MPI_Status         *send_status;
   int                *send_buffer;
   int                 send_size;
   MPI_Request        *recv_requests;
   MPI_Status         *recv_status;
   int               **recv_buffers;
   int                *recv_sizes;
   int                 my_rank;

   int                *send_procs;
   int                *recv_procs;
   int                 num_sends;
   int                 num_recvs;
                      
   hypre_BoxArray     *new_hood_boxes;
   int                 new_num_hood;
   int                *new_hood_procs;
   int                *new_hood_ids;
   int                 new_first_local;
   int                 new_num_local;
   int                 new_num_periodic;

   hypre_Box          *box;
   hypre_Box          *local_box;
   hypre_Box          *neighbor_box;
   hypre_Box          *local_cbox;
   hypre_Box          *neighbor_cbox;
   hypre_Index         imin;
   hypre_Index         imax;
   int                 alloc_size;

   double              perimeter_count, cperimeter_count;
   /*double              diff, distance, perimeter_count, cperimeter_count;*/
                      
   int                *iarray;
   int                *jrecv;
   int                 i, j, d, ilocal;
   int                 data_id, min_id, jj;

   /*-----------------------------------------
    * Copy needed info from fgrid
    *-----------------------------------------*/

   comm         = hypre_StructGridComm(fgrid);
   dim          = hypre_StructGridDim(fgrid);
   neighbors    = hypre_StructGridNeighbors(fgrid);
   hood_boxes   = hypre_BoxArrayDuplicate(hypre_BoxNeighborsBoxes(neighbors));
   num_hood     = hypre_BoxArraySize(hood_boxes);

   iarray  = hypre_BoxNeighborsProcs(neighbors);
   hood_procs = hypre_TAlloc(int, num_hood);
   for (i = 0; i < num_hood; i++)
   {
      hood_procs[i] = iarray[i];
   }

   iarray = hypre_BoxNeighborsIDs(neighbors);
   hood_ids  = hypre_TAlloc(int, num_hood);
   for (i = 0; i < num_hood; i++)
   {
      hood_ids[i] = iarray[i];
   }

   first_local  = hypre_BoxNeighborsFirstLocal(neighbors);
   num_local    = hypre_BoxNeighborsNumLocal(neighbors);
   num_periodic = hypre_BoxNeighborsNumPeriodic(neighbors);

   max_distance = hypre_StructGridMaxDistance(fgrid);
   bounding_box = hypre_BoxDuplicate(hypre_StructGridBoundingBox(fgrid));
   hypre_CopyIndex(hypre_StructGridPeriodic(fgrid), periodic);

   MPI_Comm_rank(comm, &my_rank);

#if DEBUG
   sprintf(filename, "zcoarsen.%05d", my_rank);

   if ((file = fopen(filename, "a")) == NULL)
   {
      printf("Error: can't open output file %s\n", filename);
      exit(1);
   }

   fprintf(file, "\n\n============================\n\n");
   fprintf(file, "\n\n%d\n\n", debug_count++);
   fprintf(file, "num_hood = %d\n", num_hood);
   for (i = 0; i < num_hood; i++)
   {
      box = hypre_BoxArrayBox(hood_boxes, i);
      fprintf(file, "(%d,%d,%d) X (%d,%d,%d) ; (%d,%d); %d\n",
              hypre_BoxIMinX(box),hypre_BoxIMinY(box),hypre_BoxIMinZ(box),
              hypre_BoxIMaxX(box),hypre_BoxIMaxY(box),hypre_BoxIMaxZ(box),
              hood_procs[i], hood_ids[i], hypre_BoxVolume(box));
   }
   fprintf(file, "first_local  = %d\n", first_local);
   fprintf(file, "num_local    = %d\n", num_local);
   fprintf(file, "num_periodic = %d\n", num_periodic);
#endif

   /*-----------------------------------------
    * Coarsen bounding box
    *-----------------------------------------*/

   hypre_StructCoarsenBox(bounding_box, index, stride);

   /*-----------------------------------------
    * Coarsen neighborhood boxes & determine
    * send / recv procs
    *
    * NOTE: Currently, this always communicates
    * with all neighboring processes.
    *-----------------------------------------*/

   local_cbox = hypre_BoxCreate();
   neighbor_cbox = hypre_BoxCreate();

   num_recvs = 0;
   num_sends = 0;
   recv_procs = NULL;
   send_procs = NULL;
   for (i = 0; i < num_hood; i++)
   {
      if (hood_procs[i] != my_rank)
      {
         for (j = 0; j < num_local; j++)
         {
            ilocal = first_local + j;

            local_box    = hypre_BoxArrayBox(hood_boxes, ilocal);
            neighbor_box = hypre_BoxArrayBox(hood_boxes, i);

            /* coarsen boxes being considered */
            hypre_CopyBox(local_box, local_cbox);
            hypre_StructCoarsenBox(local_cbox, index, stride);
            hypre_CopyBox(neighbor_box, neighbor_cbox);
            hypre_StructCoarsenBox(neighbor_cbox, index, stride);

            /*-----------------------
             * Receive info?
             *-----------------------*/

/* always communicate */
#if 0
            perimeter_count = 0;
            cperimeter_count = 0;
            for (d = 0; d < 3; d++)
            {
               distance = max_distance;
               diff = hypre_BoxIMaxD(neighbor_box, d) -
                  hypre_BoxIMaxD(local_box, d);
               if (diff > 0)
               {
                  distance = hypre_min(distance, diff);
               }
               diff = hypre_BoxIMinD(local_box, d) -
                  hypre_BoxIMinD(neighbor_box, d);
               if (diff > 0)
               {
                  distance = hypre_min(distance, diff);
               }
               if (distance < max_distance)
               {
                  perimeter_count++;
               }

               distance = max_distance;
               diff = hypre_BoxIMaxD(neighbor_cbox, d) -
                  hypre_BoxIMaxD(local_cbox, d);
               if (diff > 0)
               {
                  distance = hypre_min(distance, diff);
               }
               diff = hypre_BoxIMinD(local_cbox, d) -
                  hypre_BoxIMinD(neighbor_cbox, d);
               if (diff > 0)
               {
                  distance = hypre_min(distance, diff);
               }
               if (distance < max_distance)
               {
                  cperimeter_count++;
               }
            }
#else
            perimeter_count = 0;
            cperimeter_count = 1;
#endif
            if (cperimeter_count > perimeter_count)
            {
               if (num_recvs == 0)
               {
                  recv_procs = hypre_TAlloc(int, num_hood);
                  recv_procs[num_recvs] = hood_procs[i];
                  num_recvs++;
               }
               else if (hood_procs[i] != recv_procs[num_recvs-1])
               {
                  recv_procs[num_recvs] = hood_procs[i];
                  num_recvs++;
               }
            }

            /*-----------------------
             * Send info?
             *-----------------------*/

/* always communicate */
#if 0
            perimeter_count = 0;
            cperimeter_count = 0;
            for (d = 0; d < 3; d++)
            {
               distance = max_distance;
               diff = hypre_BoxIMaxD(local_box, d) -
                  hypre_BoxIMaxD(neighbor_box, d);
               if (diff > 0)
               {
                  distance = hypre_min(distance, diff);
               }
               diff = hypre_BoxIMinD(neighbor_box, d) -
                  hypre_BoxIMinD(local_box, d);
               if (diff > 0)
               {
                  distance = hypre_min(distance, diff);
               }
               if (distance < max_distance)
               {
                  perimeter_count++;
               }

               distance = max_distance;
               diff = hypre_BoxIMaxD(local_cbox, d) -
                  hypre_BoxIMaxD(neighbor_cbox, d);
               if (diff > 0)
               {
                  distance = hypre_min(distance, diff);
               }
               diff = hypre_BoxIMinD(neighbor_cbox, d) -
                  hypre_BoxIMinD(local_cbox, d);
               if (diff > 0)
               {
                  distance = hypre_min(distance, diff);
               }
               if (distance < max_distance)
               {
                  cperimeter_count++;
               }
            }
#else
            perimeter_count = 0;
            cperimeter_count = 1;
#endif
            if (cperimeter_count > perimeter_count)
            {
               if (num_sends == 0)
               {
                  send_procs = hypre_TAlloc(int, num_hood);
                  send_procs[num_sends] = hood_procs[i];
                  num_sends++;
               }
               else if (hood_procs[i] != send_procs[num_sends-1])
               {
                  send_procs[num_sends] = hood_procs[i];
                  num_sends++;
               }
            }