Hi Olivier, please post an example, which compiles. For example with all necessary #include directives. Olivier Tournaire <olitour@gmail.com> writes:
std::pair< graph_traits<Graph>::edge_descriptor, bool > p = add_edge (*vertices(g).first, *vertices(g).second, g);
The function vertices returns an iterator range. In my understanding an iterator range is a pair of iterators [first, second) so that second can be reached from first with increment operations, _but_ is not part of the iterator range itself. It could be an iterator like one returned by the end-function of a stl-vector. It shall not be dereferenced! Therefore If I alter your code to read the following, everything is ok. #include <iostream> #include <boost/property_map/property_map.hpp> #include <boost/graph/graph_concepts.hpp> #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/kolmogorov_max_flow.hpp> using namespace boost; typedef adjacency_list_traits < vecS, vecS, directedS > Traits; typedef adjacency_list < vecS, vecS, directedS, property < vertex_index_t, long, property < vertex_color_t, boost::default_color_type, property < vertex_distance_t, long, property < vertex_potential_t, long, // stores the unary energy associated to //each vertex property < vertex_predecessor_t, Traits::edge_descriptor > > > > >, property < edge_capacity_t, long, // stores the binary energy associated to //each edge property < edge_residual_capacity_t, long, property < edge_reverse_t, Traits::edge_descriptor > > > > Graph; int main(int argc, char** argv) { Graph g; //property_map<Graph, edge_capacity_t>::type capacity = get(edge_capacity, //g); //property_map<Graph, edge_reverse_t>::type rev = get(edge_reverse, g); add_vertex(g); add_vertex(g); graph_traits<Graph>::vertex_iterator v_first, v_second; v_first = vertices(g).first; v_second = v_first; ++v_second; std::pair< graph_traits<Graph>::edge_descriptor, bool > p = add_edge (*v_first, *v_second, g); std::pair< graph_traits<Graph>::edge_descriptor, bool > p_reverse = add_edge(*v_second, *v_first, g); std::cout << "num_vertices = " << num_vertices(g) << std::endl; // output: //3!!!! std::cout << "num_edges = " << num_edges(g) << std::endl; // output: 2 return 0; } Yours sincerely, Eric