Commented ClusterAtomsLookup class

Author: sfkhalid

vpr/src/base/clustered_netlist_utils.h

@@ -27,6 +27,12 @@ class ClusteredPinAtomPinsLookup {
     vtr::vector<AtomPinId, ClusterPinId> atom_pin_connected_cluster_pin_;
 };
 
+/*
+ * This lookup is used to see which atoms are in each cluster block.
+ * Getting the atoms inside of a cluster is an order k lookup.
+ * The data is initialized automatically upon creation of the object.
+ * The class should only be used after the clustered netlist is created.
+ */
 class ClusterAtomsLookup {
   public:
     ClusterAtomsLookup();
@@ -36,6 +42,7 @@ class ClusterAtomsLookup {
     void init_lookup();
 
   private:
+    //Store the atom ids of the atoms inside each cluster
     vtr::vector<ClusterBlockId, std::vector<AtomBlockId>> cluster_atoms;
 };
 #endif