ceph/src/boost/libs/graph/example/undirected_adjacency_list.expected

   1 out_edges(0): (0,1) (0,2)
   2 in_edges(0): (1,0) (2,0)
   3 in a directed graph is (u,v) == (v,u) ? 0
   4 weight[(u,v)] = 1.2
   5 weight[(v,u)] = 2.4
   6 in an undirected graph is (u,v) == (v,u) ? 1
   7 weight[(u,v)] = 3.1
   8 weight[(v,u)] = 3.1
   9 the edges incident to v: (0,1)