Dear boost-users: I just start learning boost graph library and have a basic problem on using the remove_edge function in boost graph library. I would like to remove an edge in a multigraph. For a graph with two edges connect vertice 0 and 1, I would like to remove one of them, but kept the other. According to the user guide, remove_edge(u ,v , g) removes all occurrences of (u ,v). So I should use remove_edge(e ,g) instead. Here, e is a valid edge descriptor. For a single graph, g, I am able to perform both remove_edge(u ,v , g) and remove_edge(e ,g) operation. However, when I want to generalize the implementation to fit my need by putting graphs in a vector container, I got segmentation fault for remove_edge(e ,graph_list[0]). I really want to make remove_edge(e,g) and vector container work at the same time. So any suggestion that can help my bypass this difficulty is appreciated. Thanks a lot!! Yi-Ping *************************Here is the complete code************************* #include <iostream> #include <utility> #include <algorithm> #include <vector> #include "boost/graph/graph_traits.hpp" #include "boost/graph/adjacency_list.hpp" using namespace boost; typedef adjacency_list UndirectedGraph; typedef boost::graph_traits<UndirectedGraph>::edge_iterator edge_iterator; int graph_show(UndirectedGraph &g); int main(int argc, char *argv[]) { UndirectedGraph g; typedef boost::graph_traits<UndirectedGraph>::edge_descriptor edge_descriptor; edge_descriptor ed; std::vector edge_list; std::vector > graph_edge_list; std::vector<UndirectedGraph> graph_list; int nb=0; int Nl=4; bool inserted; while(nb ei=edges(g); for (edge_iterator edge_iter = ei.first; edge_iter!=ei.second; ++edge_iter) { std::cout<<"("<< boost::source(*edge_iter,g)<<","< p = vertices(g); p.first != p.second; ++p.first) { std::cout<< *p.first; std::cout<<" "; } std::cout<<"}"<