remove place_cost_exp and calls to pow()

Author: soheilshahrouz

vpr/src/base/SetupVPR.cpp

@@ -633,8 +633,6 @@ static void SetupPlacerOpts(const t_options& Options, t_placer_opts* PlacerOpts)
     PlacerOpts->inner_loop_recompute_divider = Options.inner_loop_recompute_divider;
     PlacerOpts->quench_recompute_divider = Options.quench_recompute_divider;
 
-    PlacerOpts->place_cost_exp = 1;
-
     PlacerOpts->td_place_exp_first = Options.place_exp_first;
 
     PlacerOpts->td_place_exp_last = Options.place_exp_last;

vpr/src/base/ShowSetup.cpp

@@ -547,8 +547,6 @@ static void ShowPlacerOpts(const t_placer_opts& PlacerOpts,
             VTR_LOG("Using constraints file '%s'\n", PlacerOpts.constraints_file.c_str());
         }
 
-        VTR_LOG("PlacerOpts.place_cost_exp: %f\n", PlacerOpts.place_cost_exp);
-
         VTR_LOG("PlacerOpts.place_chan_width: %d\n", PlacerOpts.place_chan_width);
 
         if (PlacerOpts.place_algorithm.is_timing_driven()) {

vpr/src/base/vpr_types.h

@@ -1065,7 +1065,6 @@ struct t_placer_opts {
     t_place_algorithm place_algorithm;
     t_place_algorithm place_quench_algorithm;
     float timing_tradeoff;
-    float place_cost_exp;
     int place_chan_width;
     enum e_pad_loc_type pad_loc_type;
     std::string constraints_file;

vpr/src/place/net_cost_handler.cpp

@@ -1515,8 +1515,6 @@ double NetCostHandler::get_net_wirelength_from_layer_bb_(ClusterNetId net_id) {
 }
 
 float NetCostHandler::get_chanz_cost_factor_(const t_bb& bb) {
-    float place_cost_exp = placer_opts_.place_cost_exp;
-
     int num_inter_dir_conn;
 
     if (bb.xmin == 0 && bb.ymin == 0) {
@@ -1540,7 +1538,6 @@ float NetCostHandler::get_chanz_cost_factor_(const t_bb& bb) {
     } else {
         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);
     }
 
     return z_cost_factor;

vpr/src/place/net_cost_handler.h

@@ -524,13 +524,11 @@ class NetCostHandler {
     std::pair<double, double> get_chanxy_cost_fac_(const BBT& bb) {
         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 - 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};
+        return {inverse_average_chanx_width, inverse_average_chany_width};
     }
 
     /**