Sorry for the Doble posting, wast'nt yet register to the mailing list. Cheers! hi Folks, I've played around with the following example: struct detect_loops : public boost::dfs_visitor<> { template <class Edge, class Graph> void back_edge(Edge e, const Graph& g) { std::cout << source(e, g) << " -- " << target(e, g) << "\n"; } }; int main(int,char*[]) { typedef std::pair<int,int> Edge; std::vector<Edge> edges; edges.push_back(Edge(0,1)); edges.push_back(Edge(1,2)); edges.push_back(Edge(2,3)); edges.push_back(Edge(3,1)); edges.push_back(Edge(4,5)); edges.push_back(Edge(5,0)); edges.push_back(Edge(4,0)); edges.push_back(Edge(5,6)); edges.push_back(Edge(2,6)); typedef adjacency_list< vecS, vecS, undirectedS, no_property, property<edge_color_t, default_color_type> > graph_t; typedef graph_traits<graph_t>::vertex_descriptor vertex_t; graph_t g(edges.begin(), edges.end(), 7); std::cout << "back edges:\n"; detect_loops vis; undirected_dfs(g, root_vertex(vertex_t(0)).visitor(vis).edge_color_map(get(edge_color, g))); std::cout << std::endl; return 0; } However, I donot know how and where to place the predeccesor recorder. Secondly, I actually need but all the cycles, i.e. these may not have only distinct verterces. i.e some vertices may occur repeated in certain circles. My example above has 3 distinct cycles I guess and thats wha t the the back_edge() gives. But, I'll like to have all the hamiltonian cycles (hope they call it like that ;)). Thanks in advance for the tipps. Daniel -- View this message in context: http://boost.2283326.n4.nabble.com/Identify-cycles-in-a-undirected-graph-tp4... Sent from the Boost - Users mailing list archive at Nabble.com.