clustering.local_clustering(): Fix bug with directed graphs

src/graph/clustering/graph_clustering.cc

@@ -34,25 +34,19 @@ using namespace graph_tool;
 boost::python::tuple global_clustering(GraphInterface& g)
 {
     double c, c_err;
-    bool directed = g.get_directed();
-    g.set_directed(false);
     run_action<graph_tool::detail::never_directed>()
         (g, std::bind(get_global_clustering(), std::placeholders::_1,
                       std::ref(c), std::ref(c_err)))();
-    g.set_directed(directed);
     return boost::python::make_tuple(c, c_err);
 }
 
 void local_clustering(GraphInterface& g, boost::any prop)
 {
-    bool directed = g.get_directed();
-    g.set_directed(false);
-    run_action<graph_tool::detail::never_directed>()
+    run_action<>()
         (g, std::bind(set_clustering_to_property(),
                       std::placeholders::_1,
                       std::placeholders::_2),
          writable_vertex_scalar_properties())(prop);
-    g.set_directed(directed);
 }
 
 using namespace boost::python;

src/graph/clustering/graph_clustering.hh

@@ -46,7 +46,7 @@ using namespace boost;
 template <class Graph, class VProp>
 pair<int,int>
 get_triangles(typename graph_traits<Graph>::vertex_descriptor v, VProp& mark,
-              const Graph &g)
+              const Graph& g)
 {
     size_t triangles = 0;
 
@@ -74,7 +74,10 @@ get_triangles(typename graph_traits<Graph>::vertex_descriptor v, VProp& mark,
         mark[n] = false;
 
     size_t k = out_degree(v, g);
-    return make_pair(triangles / 2, (k * (k - 1)) / 2);
+    if (is_directed::apply<Graph>::type::value)
+        return make_pair(triangles, (k * (k - 1)));
+    else
+        return make_pair(triangles / 2, (k * (k - 1)) / 2);
 }
 
 
@@ -124,7 +127,6 @@ struct set_clustering_to_property
     void operator()(const Graph& g, ClustMap clust_map) const
     {
         typedef typename property_traits<ClustMap>::value_type c_type;
-        typename get_undirected_graph<Graph>::type ug(g);
         vector<bool> mask(num_vertices(g), false);
 
         #pragma omp parallel if (num_vertices(g) > OPENMP_MIN_THRESH) \
@@ -133,7 +135,7 @@ struct set_clustering_to_property
             (g,
              [&](auto v)
              {
-                 auto triangles = get_triangles(v, mask, ug); // get from ug
+                 auto triangles = get_triangles(v, mask, g);
                  double clustering = (triangles.second > 0) ?
                      double(triangles.first)/triangles.second :
                      0.0;

src/graph_tool/clustering/__init__.py

@@ -130,10 +130,10 @@ def local_clustering(g, prop=None, undirected=True):
        :doi:`10.1038/30918`
     """
 
-    if prop == None:
+    if prop is None:
         prop = g.new_vertex_property("double")
     if g.is_directed() and undirected:
-        g = GraphView(g, directed=False)
+        g = GraphView(g, directed=False, skip_properties=True)
     _gt.local_clustering(g._Graph__graph, _prop("v", g, prop))
     return prop
 
@@ -191,6 +191,8 @@ def global_clustering(g):
        :doi:`10.1137/S003614450342480`
     """
 
+    if g.is_directed():
+        g = GraphView(g, directed=False, skip_properties=True)
     c = _gt.global_clustering(g._Graph__graph)
     return c