Hi Considering the example that comes with BGL i.e examples/dijkstra-example.cpp. I have already a graph which is undirected now i want to apply dijkstra algorithm on it. My vertex discriptor is "Vertex_name" and edge discriptor is "edge_value". The following is the code provided in the example. :- std::vector<vertex_descriptor> p(num_vertices(g)); std::vector<int> d(num_vertices(g)); vertex_descriptor s = vertex(A, g); #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300 // VC++ has trouble with the named parameters mechanism property_map<graph_t, vertex_index_t>::type indexmap = get(vertex_index, g); dijkstra_shortest_paths(g, s, &p[0], &d[0], weightmap, indexmap, std::less<int>(), closed_plus<int>(), (std::numeric_limits<int>::max)(), 0, default_dijkstra_visitor()); #else dijkstra_shortest_paths(g, s, predecessor_map(&p[0]).distance_map(&d[0])); #endif My code for the corresponding code is as follows :- std::vector<vertex_descriptor> p(num_vertices(g)); std::vector<int> d(num_vertices(g)); vertex_descriptor s = vertex(L1, g); //Giving error Undeclared identifier L1. Here L1 is the name of my vertex. Also i tried Vertex_name(u) to this parameter but it is giving compilation error. What parameter need to be passed for this. Secondly i m not defining BOOST_MSVC so i'm elimination the IF BLock and directly writing the code as dijkstra_shortest_paths(g, s, predecessor_map(&p[0]).distance_map(&d[0])); Here kindly explain what the distance_map signifies and where it is being defined. Thanks Abhishek Vyas Tata Consultancy Services Mailto: abhishek.v@tcs.com Website: http://www.tcs.com ____________________________________________ Experience certainty. IT Services Business Solutions Outsourcing ____________________________________________ =====-----=====-----===== Notice: The information contained in this e-mail message and/or attachments to it may contain confidential or privileged information. If you are not the intended recipient, any dissemination, use, review, distribution, printing or copying of the information contained in this e-mail message and/or attachments to it are strictly prohibited. If you have received this communication in error, please notify us by reply e-mail or telephone and immediately and permanently delete the message and any attachments. Thank you