Fixed code to find cliques in graph

Nodes should be rejected based on the existence of an edge, not based on
whether that edge has already been visited or not.

Mesh/mwis.hpp

@@ -1051,29 +1051,27 @@ public:
 };
 
 /**
- * Function object that checks if the edge between a fixed vertex (passed as a
- * parameter to the constructor) and its argument has already been visited by
- * the algorithm.
+ * Function object that checks if there exisits an edge between a fixed vertex
+ * (passed as a parameter to the constructor) and its argument.
  *
  * This is used in find_cliques.
  */
 template<typename Graph>
-class edge_visited_test {
+class has_no_edge_test {
   typedef typename boost::graph_traits<Graph>::vertex_descriptor vertex;
 
-  const std::set<std::pair<vertex, vertex>> &_visited_edges;
+  const Graph &_graph;
   vertex _v;
 public:
   typedef vertex argument_type;
   typedef bool result_type;
 
-  edge_visited_test(const std::set<std::pair<vertex, vertex>> &visited_edges,
-                    vertex v): _visited_edges(visited_edges), _v(v)
+  has_no_edge_test(const Graph &graph, vertex v):
+    _graph(graph), _v(v)
     {}
 
   bool operator()(vertex w) const {
-    return _visited_edges.find(std::make_pair(_v, w)) ==
-      _visited_edges.end();
+    return !edge(_v, w, _graph).second;
   }
 };
 
@@ -1111,12 +1109,11 @@ void find_cliques(const Graph &graph, OutputIterator out) {
       while (!candidates.empty()) {
         vertex v = candidates.back();
         candidates.pop_back();
-
         contents.push_back(v);
 
         candidates.erase(
           std::remove_if(candidates.begin(), candidates.end(),
-                         edge_visited_test<Graph>(visited_edges, v)),
+                         has_no_edge_test<Graph>(graph, v)),
           candidates.end());
       }