[vpr][place][net_cost] use bb

Author: amin1377

vpr/src/place/net_cost_handler.cpp

@@ -1595,35 +1595,31 @@ double NetCostHandler::get_net_wirelength_from_layer_bb_(ClusterNetId net_id) {
     return ncost;
 }
 
-float NetCostHandler::get_chanz_cost_factor_(const t_bb& bounding_box) {
+float NetCostHandler::get_chanz_cost_factor_(const t_bb& bb) {
     float place_cost_exp = placer_opts_.place_cost_exp;
-    int x_high = bounding_box.xmax;
-    int x_low = bounding_box.xmin;
-    int y_high = bounding_box.ymax;
-    int y_low = bounding_box.ymin;
 
     int num_inter_dir_conn;
 
-    if (x_low == 0 && y_low == 0) {
-        num_inter_dir_conn = acc_tile_num_inter_die_conn_[x_high][y_high];
-    } else if (x_low == 0) {
-        num_inter_dir_conn = acc_tile_num_inter_die_conn_[x_high][y_high] -
-                             acc_tile_num_inter_die_conn_[x_high][y_low-1];
-    } else if (y_low == 0) {
-        num_inter_dir_conn = acc_tile_num_inter_die_conn_[x_high][y_high] -
-                             acc_tile_num_inter_die_conn_[x_low-1][y_high];
+    if (bb.xmin == 0 && bb.ymin == 0) {
+        num_inter_dir_conn = acc_tile_num_inter_die_conn_[bb.xmax][bb.ymax];
+    } else if (bb.xmin == 0) {
+        num_inter_dir_conn = acc_tile_num_inter_die_conn_[bb.xmax][bb.ymax] -
+                             acc_tile_num_inter_die_conn_[bb.xmax][bb.ymin-1];
+    } else if (bb.ymin == 0) {
+        num_inter_dir_conn = acc_tile_num_inter_die_conn_[bb.xmax][bb.ymax] -
+                             acc_tile_num_inter_die_conn_[bb.xmin-1][bb.ymax];
     } else {
-        num_inter_dir_conn = acc_tile_num_inter_die_conn_[x_high][y_high] -
-                             acc_tile_num_inter_die_conn_[x_low-1][y_high] -
-                             acc_tile_num_inter_die_conn_[x_high][y_low-1] +
-                             acc_tile_num_inter_die_conn_[x_low-1][y_low-1];
+        num_inter_dir_conn = acc_tile_num_inter_die_conn_[bb.xmax][bb.ymax] -
+                             acc_tile_num_inter_die_conn_[bb.xmin-1][bb.ymax] -
+                             acc_tile_num_inter_die_conn_[bb.xmax][bb.ymin-1] +
+                             acc_tile_num_inter_die_conn_[bb.xmin-1][bb.ymin-1];
     }
 
     float z_cost_factor;
     if (num_inter_dir_conn == 0) {
         return 1.0f;
     } else {
-        int bb_num_tiles = (x_high - x_low + 1) * (y_high - y_low + 1);
+        int bb_num_tiles = (bb.xmax - bb.xmin + 1) * (bb.ymax - bb.ymin + 1);
         z_cost_factor = bb_num_tiles / static_cast<float>(num_inter_dir_conn);
         z_cost_factor = pow((double)z_cost_factor, (double)place_cost_exp);
     }

vpr/src/place/net_cost_handler.h

@@ -256,8 +256,8 @@ class NetCostHandler {
     void alloc_and_load_chan_w_factors_for_place_cost_();
 
     /**
-    * @brief Allocates and loads the chanz_place_cost_fac array with the inverse of
-    * the average number of inter-die connections between [subhigh] and [sublow].
+    * @brief Allocates and loads acc_tile_num_inter_die_conn_ which contains the accumulative number of inter-die
+    * conntections.
     *
     * @details This is only useful for multi-die FPGAs. The place_cost_exp factor specifies to
     * what power the average number of inter-die connections should be take -- larger numbers make narrower channels more expensive.
@@ -511,7 +511,9 @@ class NetCostHandler {
      * @brief Calculate the chanz cost factor based on the inverse of the average number of inter-die connections 
      * in the given bounding box. This cost factor increases the placement cost for blocks that require inter-layer 
      * connections in areas with, on average, fewer inter-die connections. If inter-die connections are evenly 
-     * distributed across tiles, the cost factor will be the same for all bounding boxes.
+     * distributed across tiles, the cost factor will be the same for all bounding boxes, but it will still 
+     * weight z-directed vs. x- and y-directed connections appropriately.
+     *
      * @param bounding_box Bounding box of the net which chanz cost factor is to be calculated
      * @return ChanZ cost factor
      */