add: leverage centrality

comparison.py

@@ -8,6 +8,23 @@ from src import centrality
 from src import plot
 from src import fitting
 
+def leverage(g, weight):
+    # VertexPropertyMap
+    vp = g.new_vertex_property("double")
+    for v in g.vertices():
+        li = 0.0
+        neighbours = g.get_all_neighbours(v)
+        ki = len(neighbours)
+        # sum
+        for nv, props in neighbours:
+            other_neighbours = g.get_all_neighbours(nv)
+            kj = len(other_neighbours)
+            li += (ki - kj) / (ki + kj)
+        li /= ki
+        vp[v] = li
+    return vp
+
+
 def random_graph(n=5000, seed=None):
     """
     Uniformly random point cloud generation.