add comments

vpr/src/base/region.cpp

@@ -123,7 +123,7 @@ Region intersection(const Region& r1, const Region& r2) {
         return intersect;
     }
 
-    // subtile are not compatible
+    // subtiles are not compatible
     return {};
 }
 

vpr/src/base/vpr_constraints_serializer.h

@@ -291,7 +291,7 @@ class VprConstraintsSerializer final : public uxsd::VprConstraintsBase<VprConstr
                 report_error_->operator()("The specified region is empty.");
             }
         }
-        
+
         loaded_part_region.add_to_part_region(loaded_region);
 
         Region clear_region;

vpr/src/pack/constraints_report.cpp

@@ -1,6 +1,5 @@
 #include "constraints_report.h"
 
-//To-do: alter this routine to check whether whole PartitionRegions are full instead of individual Regions
 bool floorplan_constraints_regions_overfull() {
     GridTileLookup grid_tiles;
 

vpr/src/pack/constraints_report.h

@@ -9,12 +9,23 @@
 #include "grid_tile_lookup.h"
 #include "place_constraints.h"
 
-/*
- * Check if any constraints regions are overfull,
- * i.e. the region contains more clusters of a certain type
- * than it has room for.
- * If the region is overfull, a message is printed saying which
- * region is overfull, and by how many clusters.
+/**
+ * @brief Check if any constraint partition regions are overfull,
+ * i.e. the partition contains more clusters of a certain type
+ * than it has room for. If the region is overfull, a message is
+ * printed saying which partition is overfull, and by how many clusters.
+ *
+ * To reduce the complexity of this function, several assumptions are made.
+ * 1) Regions of a partition do not overlap, meaning that the capacity of each
+ * partition for accommodating blocks of a specific type can be calculated by
+ * accumulating the capacity of its regions.
+ * 2) Partitions do not overlap. This means that each physical tile is in at most
+ * one partition.
+ *
+ * VPR can still work if these assumptions do not hold true, but for tight overlapping
+ * partitions, the placement engine may fail to find a legal placement.
+ *
+ * @return True if there is at least one overfull partition.
  */
 bool floorplan_constraints_regions_overfull();
 

vpr/src/place/grid_tile_lookup.h

@@ -69,12 +69,13 @@ class GridTileLookup {
    void fill_type_matrix(t_logical_block_type_ptr block_type, vtr::NdMatrix<int, 3>& type_count);
 
    /**
-    * @brief Stores the cumulative total of subtiles available at each location in the grid for each block type.
+    * @brief Stores the cumulative total of subtiles available at each (x, y) location in each layer
+    * for all block types.
     *
     * Therefore, the length of the vector will be the number of logical block types. To access the cumulative
-    * number of subtiles at a location, you would use block_type_matrices[iblock_type][x][y] - this would
-    * give the number of placement locations that are at, or above and to the right of the given [x,y] for
-    * the given block type.
+    * number of subtiles at a location in a specific layer, you would use block_type_matrices[iblock_type][layer][x][y].
+    * This would give the number of placement locations that are at, or above (larger y) and to the right of the given [x,y] for
+    * the given block type in the given layer.
     */
    std::vector<vtr::NdMatrix<int, 3>> block_type_matrices;