fix extended clustering when graph has parallel edges

git-svn-id: https://svn.forked.de/graph-tool/trunk@37 d4600afd-f417-0410-95de-beed9576f240

src/graph/graph_extended_clustering.cc

@@ -42,10 +42,7 @@ struct single_vertex_filter
     single_vertex_filter() {}
     single_vertex_filter(Vertex v):_v(v) {}
 
-    bool operator()(Vertex v) const 
-    {
-	return v != _v;
-    }
+    bool operator()(Vertex v) const { return v != _v; }
 
     Vertex _v;
 };
@@ -101,9 +98,7 @@ public:
 	typename Container::iterator val;
 	val = _base_map->find(k);
 	if (val == _base_map->end())
-	{
 	    val = _base_map->insert(make_pair(k, _default)).first;
-	}
 	return val->second;
     }
 
@@ -147,17 +142,23 @@ struct get_extended_clustering
 	    typedef DescriptorHash<IndexMap> hasher_t;
 	    typedef tr1::unordered_set<typename graph_traits<Graph>::vertex_descriptor,hasher_t> neighbour_set_t;
 	    neighbour_set_t neighbours(0, hasher_t(vertex_index));
+	    neighbour_set_t neighbours2(0, hasher_t(vertex_index));
+	    neighbour_set_t targets(0, hasher_t(vertex_index));
 	    
-	    // collect the neighbours
+	    // collect the targets
 	    typename graph_traits<Graph>::adjacency_iterator a, a_end;
 	    for(tie(a, a_end) = adjacent_vertices(*v, g); a != a_end; ++a)
 		if (*a != *v) // no self-loops
-		    neighbours.insert(*a);
-	    size_t k = neighbours.size();
+		    targets.insert(*a);
+	    size_t k = targets.size();
 
 	    // And now we setup and start the BFS bonanza
 	    for(tie(a, a_end) = adjacent_vertices(*v, g); a != a_end; ++a)
 	    {
+		if (neighbours.find(*a) != neighbours.end()) // avoid parallel edges
+		    continue;
+		neighbours.insert(*a);
+
 		typedef tr1::unordered_map<typename graph_traits<Graph>::vertex_descriptor,size_t,DescriptorHash<IndexMap> > dmap_t;
 		dmap_t dmap(0, DescriptorHash<IndexMap>(vertex_index));
 		InitializedPropertyMap<dmap_t> distance_map(dmap, numeric_limits<size_t>::max());
@@ -168,21 +169,23 @@ struct get_extended_clustering
 		
 		try
 		{
-		    bfs_max_depth_watcher<neighbour_set_t,InitializedPropertyMap<dmap_t> > watcher(neighbours, cmaps.size(), distance_map);
+		    bfs_max_depth_watcher<neighbour_set_t,InitializedPropertyMap<dmap_t> > watcher(targets, cmaps.size(), distance_map);
 		    breadth_first_visit(fg, *a, visitor(make_bfs_visitor(make_pair(record_distances(distance_map, boost::on_tree_edge()),watcher))).
 					color_map(color_map));
 		}
 		catch(bfs_stop_exception) {}
 
+		neighbours2.clear();
 		typename graph_traits<Graph>::adjacency_iterator a2;
 		for(a2 = adjacent_vertices(*v, g).first ; a2 != a_end ; ++a2) 
 		{
 		    if (*a2 == *v) // no self-loops
 			continue;
+		    if (neighbours2.find(*a2) != neighbours2.end()) // avoid parallel edges
+			continue;
+		    neighbours2.insert(*a2);
 		    if (distance_map[*a2] < cmaps.size())
-		    {
 			cmaps[distance_map[*a2]][*v] += 1.0/(k*(k-1));
-		    }
 		}
 	    }
 	}