avoid a division by zero when the timing cost is zero

Author: soheilshahrouz

vpr/src/place/placer.cpp

@@ -118,18 +118,17 @@ Placer::Placer(const Netlist<>& net_list,
 
     // Gets initial cost and loads bounding boxes.
     costs_.bb_cost = net_cost_handler_.comp_bb_cost(e_cost_methods::NORMAL).first;
-    costs_.bb_cost_norm = 1 / costs_.bb_cost;
 
     if (placer_opts.place_algorithm.is_timing_driven()) {
         alloc_and_init_timing_objects_(net_list, analysis_opts);
     } else {
         VTR_ASSERT(placer_opts.place_algorithm == e_place_algorithm::BOUNDING_BOX_PLACE);
-        // Timing cost and normalization factors are not used
-        constexpr double INVALID_COST = std::numeric_limits<double>::quiet_NaN();
-        costs_.timing_cost = INVALID_COST;
-        costs_.timing_cost_norm = INVALID_COST;
+        // Timing cost is not used
+        costs_.timing_cost = std::numeric_limits<double>::quiet_NaN();
     }
 
+    costs_.update_norm_factors();
+
     if (noc_opts.noc) {
         VTR_ASSERT(noc_cost_handler_.has_value());
 
@@ -215,8 +214,6 @@ void Placer::alloc_and_init_timing_objects_(const Netlist<>& net_list,
         write_setup_timing_graph_dot(getEchoFileName(E_ECHO_INITIAL_PLACEMENT_TIMING_GRAPH) + std::string(".dot"),
                                      *timing_info_, debug_tnode);
     }
-
-    costs_.timing_cost_norm = 1 / costs_.timing_cost;
 }
 
 void Placer::check_place_() {