Hi Stephan, What you've posted is not a complete program (it is missing at least the #include's). Please post a complete program. Thanks, Jeremy P.S. Sorry to be pedantic about this, but I've wasted a lot of time in the past trying to reconstruct complete programs from incomplete programs. On Wed, 6 Aug 2003, Stephan [iso-8859-1] Höfer wrote: yg-boo> the original graph looks like that yg-boo> yg-boo> 0--1--2--3 yg-boo> | | | | yg-boo> 7--6--5--4 yg-boo> yg-boo> the subgraph looks like that yg-boo> 0--1--2 yg-boo> | | yg-boo> 6--5 yg-boo> yg-boo> typedef boost::property<boost::vertex_color_t, boost::default_color_type, yg-boo> boost::property< boost::vertex_predecessor_t, vertex_descriptor > > yg-boo> VertexProperty; yg-boo> yg-boo> typedef boost::property<boost::edge_color_t, boost::default_color_type, yg-boo> boost::property<boost::edge_weight_t, int, yg-boo> boost::property<boost::edge_index_t, int > > > EdgeProperty; yg-boo> yg-boo> typedef boost::subgraph< boost::adjacency_list<boost::vecS, boost::vecS, yg-boo> boost::undirectedS, yg-boo> VertexProperty, EdgeProperty > > Graph; yg-boo> yg-boo> void main() yg-boo> { yg-boo> Graph g(7); yg-boo> yg-boo> boost::property_map<Graph, boost::edge_weight_t>::type weightmap = yg-boo> boost::get(boost::edge_weight, g); yg-boo> Edge e; bool inserted; yg-boo> yg-boo> boost::tie(e, inserted) = boost::add_edge(0, 1, g); weightmap[e] = 1; yg-boo> boost::tie(e, inserted) = boost::add_edge(1, 2, g); weightmap[e] = 1; yg-boo> boost::tie(e, inserted) = boost::add_edge(2, 3, g); weightmap[e] = 1; yg-boo> boost::tie(e, inserted) = boost::add_edge(3, 4, g); weightmap[e] = 1; yg-boo> boost::tie(e, inserted) = boost::add_edge(4, 5, g); weightmap[e] = 1; yg-boo> boost::tie(e, inserted) = boost::add_edge(5, 2, g); weightmap[e] = 1; yg-boo> boost::tie(e, inserted) = boost::add_edge(5, 6, g); weightmap[e] = 1; yg-boo> boost::tie(e, inserted) = boost::add_edge(6, 1, g); weightmap[e] = 1; yg-boo> boost::tie(e, inserted) = boost::add_edge(6, 7, g); weightmap[e] = 1; yg-boo> boost::tie(e, inserted) = boost::add_edge(7, 0, g); weightmap[e] = 1; yg-boo> yg-boo> Graph& tSubGraph = g.create_subgraph(); yg-boo> yg-boo> add_vertex(0,tSubGraph); add_vertex(1,tSubGraph); add_vertex(2,tSubGraph); yg-boo> add_vertex(5,tSubGraph); add_vertex(6,tSubGraph); yg-boo> yg-boo> std::vector < boost::graph_traits < Graph >::vertex_descriptor> yg-boo> p(boost::num_vertices(tSubGraph)); yg-boo> boost::prim_minimum_spanning_tree(tSubGraph, &p[0]); yg-boo> } yg-boo> yg-boo> The crash happens after having added for instance the 6th point of the Graph yg-boo> g to the subgraph. Before it worked. yg-boo> ---------------------------------------------------------------------- Jeremy Siek http://php.indiana.edu/~jsiek/ Ph.D. Student, Indiana Univ. B'ton email: jsiek@osl.iu.edu C++ Booster (http://www.boost.org) office phone: (812) 855-3608 ----------------------------------------------------------------------