lookahead: additional comments and assertions

Signed-off-by: Alessandro Comodi <[email protected]>

Author: acomodi

vpr/src/route/route_timing.cpp

@@ -69,9 +69,14 @@ struct RoutingMetrics {
  * File-scope variables
  */
 
-//Run-time flag to control when router debug information is printed
-//Note only enables debug output if compiled with VTR_ENABLE_DEBUG_LOGGING defined
-//f_router_debug is used to stop the router when a breakpoint is reached. When a breakpoint is reached, this flag is set to true.
+/**
+ * @brief Run-time flag to control when router debug information is printed
+ * Note only enables debug output if compiled with VTR_ENABLE_DEBUG_LOGGING defined
+ * f_router_debug is used to stop the router when a breakpoint is reached. When a breakpoint is reached, this flag is set to true.
+ *
+ * In addition f_router_debug is used to print additional debug information during routing, for instance lookahead expected costs
+ * information.
+ */
 bool f_router_debug = false;
 
 //Count the number of times the router has failed

vpr/src/route/router_lookahead_extended_map.cpp

@@ -143,6 +143,9 @@ float ExtendedMapLookahead::get_chan_ipin_delays(RRNodeId to_node) const {
     auto& device_ctx = g_vpr_ctx.device();
     auto& rr_graph = device_ctx.rr_nodes;
 
+    e_rr_type to_type = rr_graph.node_type(to_node);
+    VTR_ASSERT(to_type == SINK);
+
     auto to_tile_type = device_ctx.grid[rr_graph.node_xlow(to_node)][rr_graph.node_ylow(to_node)].type;
     auto to_tile_index = to_tile_type->index;
 

vpr/src/route/router_lookahead_map_utils.cpp

@@ -198,6 +198,10 @@ util::Cost_Entry util::Expansion_Cost_Entry::get_median_entry() const {
     /* find median by binning the delays of all entries and then chosing the bin
      * with the largest number of entries */
 
+    // This is code that needs to be revisited. For the time being, if the median entry
+    // method calculation is used an assertion is thrown.
+    VTR_ASSERT_MSG(false, "Get median entry calculation method is not implemented!");
+
     int num_bins = 10;
 
     /* find entries with smallest and largest delays */