--- Loïc Joly wrote:
Hello,
There is a bug in the boost graph library in depth_first_search. When we look at the implementation, we can see in file boost/graph/depth_first_search.hpp):
detail::dfs_dispatch<C>::apply (g, choose_param(get_param(params, graph_visitor),
make_dfs_visitor(null_visitor())), choose_param(get_param(params, root_vertex_t()), *vertices(g).first), params, get_param(params, vertex_color) );
This code makes the assumption the the graph is non-empty, since it calls *vertices(g).first. For empty graphs, this call fails.
Why not just request that the corresponding documentation be amended to reflect the fact that both depth_first_search and topological_sort require non-empty graphs? It's a simple matter of adding (0 < num_vertices(g)) as a precondition. I'd rather not pay for extra runtime checks if my graphs are already guaranteed to contain vertices. Cromwell D. Enage __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com