exclude left and bottom channels in average channel width factor computation

Author: soheilshahrouz

vpr/src/place/net_cost_handler.cpp

@@ -155,27 +155,25 @@ NetCostHandler::NetCostHandler(const t_placer_opts& placer_opts,
 void NetCostHandler::alloc_and_load_chan_w_factors_for_place_cost_(float place_cost_exp) {
     const auto& device_ctx = g_vpr_ctx.device();
 
-    const int grid_height = device_ctx.grid.height();
-    const int grid_width = device_ctx.grid.width();
+    const int grid_height = (int)device_ctx.grid.height();
+    const int grid_width = (int)device_ctx.grid.width();
 
     /* Access arrays below as chan?_place_cost_fac_(subhigh, sublow). Since subhigh must be greater than or
      * equal to sublow, we will only access the lower half of a matrix, but we allocate the whole matrix anyway
      * for simplicity, so we can use the vtr utility matrix functions. */
-    acc_chanx_width_ = vtr::NdOffsetMatrix<int, 1>({{{-2, grid_height}}});
-    acc_chany_width_ = vtr::NdOffsetMatrix<int, 1>({{{-2, grid_width}}});
+    acc_chanx_width_ = vtr::NdOffsetMatrix<int, 1>({{{-1, grid_height}}});
+    acc_chany_width_ = vtr::NdOffsetMatrix<int, 1>({{{-1, grid_width}}});
 
     // First compute the number of tracks between channel high and channel low, inclusive.
-    acc_chanx_width_[-2] = 0;
-    acc_chanx_width_[-1] = 1;
+    acc_chanx_width_[-1] = 0;
     for (int y = 0; y < grid_height; y++) {
         acc_chanx_width_[y] = acc_chanx_width_[y - 1] + device_ctx.chan_width.x_list[y];
         if (acc_chanx_width_[y] == acc_chanx_width_[y - 1]) {
             acc_chanx_width_[y]++;
         }
     }
 
-    acc_chany_width_[-2] = 0;
-    acc_chany_width_[-1] = 1;
+    acc_chany_width_[-1] = 0;
     for (int x = 0; x < grid_width; x++) {
         acc_chany_width_[x] = acc_chany_width_[x - 1] + device_ctx.chan_width.y_list[x];
         if (acc_chany_width_[x] == acc_chany_width_[x - 1]) {

vpr/src/place/net_cost_handler.h

@@ -514,12 +514,12 @@ class NetCostHandler {
 
     template<typename BBT>
     std::pair<double, double> get_chan_place_fac_(const BBT& bb) {
-        const int total_chanx_width = acc_chanx_width_[bb.ymax] - acc_chanx_width_[bb.ymin - 2];
-        const double inverse_average_chanx_width = (bb.ymax - bb.ymin + 2.0) / total_chanx_width;
+        const int total_chanx_width = acc_chanx_width_[bb.ymax] - acc_chanx_width_[bb.ymin - 1];
+        const double inverse_average_chanx_width = (bb.ymax - bb.ymin + 1.0) / total_chanx_width;
         const double inverse_average_chanx_width_sharpened = std::pow(inverse_average_chanx_width, (double)placer_opts_.place_cost_exp);
 
-        const int total_chany_width = acc_chany_width_[bb.xmax] - acc_chany_width_[bb.xmin - 2];
-        const double inverse_average_chany_width = (bb.xmax - bb.xmin + 2.0) / total_chany_width;
+        const int total_chany_width = acc_chany_width_[bb.xmax] - acc_chany_width_[bb.xmin - 1];
+        const double inverse_average_chany_width = (bb.xmax - bb.xmin + 1.0) / total_chany_width;
         const double inverse_average_chany_width_sharpened = std::pow(inverse_average_chany_width, (double)placer_opts_.place_cost_exp);
 
         return {inverse_average_chanx_width_sharpened, inverse_average_chany_width_sharpened};