Fix problem with sfdp_layout() and the clang compiler

src/graph/layout/graph_sfdp.cc

@@ -99,9 +99,10 @@ struct do_propagate_pos
             any_cast<typename VertexMap::checked_t>(acvmap);
         typedef typename property_traits<VertexMap>::value_type c_t;
         typedef typename property_traits<PosMap>::value_type pos_t;
+        typedef typename pos_t::value_type val_t;
 
-        tr1::variate_generator<RNG&, tr1::uniform_real<> >
-            noise(rng, tr1::uniform_real<>(-delta, delta));
+        tr1::variate_generator<RNG&, tr1::uniform_real<val_t> >
+            noise(rng, tr1::uniform_real<val_t>(-delta, delta));
 
         tr1::unordered_map<c_t, pos_t, boost::hash<c_t> >
             cmap(num_vertices(*cg));
@@ -126,9 +127,12 @@ struct do_propagate_pos
                 continue;
             pos[v] = cmap[vmap[v]];
             {
-                #pragma omp critical
-                for (size_t j = 0; j < pos[v].size(); ++j)
-                    pos[v][j] += noise();
+                if (delta > 0)
+                {
+                    #pragma omp critical
+                    for (size_t j = 0; j < pos[v].size(); ++j)
+                        pos[v][j] += noise();
+                }
             }
         }
     }
@@ -171,9 +175,10 @@ struct do_propagate_pos_mivs
     void operator()(Graph& g, MIVSMap mivs, PosMap pos, double delta, RNG& rng) const
     {
         typedef typename property_traits<PosMap>::value_type pos_t;
+        typedef typename pos_t::value_type val_t;
 
-        tr1::variate_generator<RNG&, tr1::uniform_real<> >
-            noise(rng, tr1::uniform_real<>(-delta, delta));
+        tr1::variate_generator<RNG&, tr1::uniform_real<val_t> >
+            noise(rng, tr1::uniform_real<val_t>(-delta, delta));
 
         int i, N = num_vertices(g);
         #pragma omp parallel for default(shared) private(i)
@@ -204,9 +209,12 @@ struct do_propagate_pos_mivs
 
             if (count == 1)
             {
-                #pragma omp critical
-                for (size_t j = 0; j < pos[v].size(); ++j)
-                    pos[v][j] += noise();
+                if (delta > 0)
+                {
+                    #pragma omp critical
+                    for (size_t j = 0; j < pos[v].size(); ++j)
+                        pos[v][j] += noise();
+                }
             }
             else
             {

src/graph_tool/draw/__init__.py

@@ -395,6 +395,8 @@ def coarse_graphs(g, method="hybrid", mivs_thres=0.9, ec_thres=0.75,
         if i == 0:
             u = cg[i][0]
             K = _avg_edge_distance(u, pos)
+            if K == 0:
+                K = 1.
             Ks.append(K)
             continue
         if weighted_coarse:
@@ -420,7 +422,7 @@ def coarse_graphs(g, method="hybrid", mivs_thres=0.9, ec_thres=0.75,
                 print("propagating...", end=' ')
                 print(mivs.a.sum() if mivs is not None else "")
             pos = _propagate_pos(cg[i + 1][0], u, c, cc, pos,
-                                 Ks[i] / 1000, mivs)
+                                 Ks[i] / 1000., mivs)
 
 
 def sfdp_layout(g, vweight=None, eweight=None, pin=None, C=0.2, K=None, p=2.,