[Boost-users] [BGL] assert( source(* (out_edges(v, undigraph).first), undigraph) == v )

Hello, When I have an undirected graph, for edge_descriptor source and target still are defined. That is stated here: http://www.boost.org/doc/libs/1_53_0/libs/graph/doc/graph_concepts.html My question. Is edge_descriptor ed = * out_edges(v,undigraph).first; Is there a requirement for graph implementations that source(ed,g) == v ? best regards, andreas -- Andreas Fabri, PhD Chief Officer, GeometryFactory Editor, The CGAL Project phone: +33.492.954.912 skype: andreas.fabri