Ok... getting even closer... I looked at read_dimacs a little bit and the kolmogorov example again and came up with this: I put a comment in where I added the reverse edge - this stops the segfault. It seems like there should be a way to do this automatically though - when you add an edge - have it add the reverse edge automatically - is this possible? Also, the cut weight seems to be only 4.3 (the weight of the first edge - where I am expecting it to be 4.3 + 5.1 = 9.4 (the sum of the edge weights). I actually do not need a directional graph, but it seems to be what the cut function is expecting, so I guess I can just use the 2-edge method and divide the weight I actually want by 2 and put it on both edges. Does anyone have any comments on this code / know what the cut weight should be? Can this example (once we get it working) be added to the documentation? I feel like it is extremely useful... #include <iostream> #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_name_t, std::string, property < vertex_index_t, long, property < vertex_color_t, boost::default_color_type, property < vertex_distance_t, long, property < vertex_predecessor_t, Traits::edge_descriptor > > > > >, property < edge_capacity_t, double, property < edge_residual_capacity_t, double, property < edge_reverse_t, Traits::edge_descriptor > > > > Graph; int main(int,char*[]) { Graph g; //a graph with 0 vertices property_map < Graph, edge_reverse_t >::type rev = get(edge_reverse, g); //add a source and sink node, and store them in s and t, respectively Traits::vertex_descriptor s = add_vertex(g); Traits::vertex_descriptor t = add_vertex(g); //add an edge between node s and node t with weight (capacity) 2.3 Traits::edge_descriptor e1 = add_edge(s, t, g).first; Traits::edge_descriptor e2 = add_edge(t, s, g).first; put(edge_capacity, g, e1, 4.3); put(edge_capacity, g, e2, 5.1); * //adding these two lines makes the segmentation fault stop!* rev[e1] = e2; rev[e2] = e1; //find min cut double flow = kolmogorov_max_flow(g, s, t); // a list of sources will be returned in s, and a list of sinks will be returned in t std::cout << "Max flow is: " << flow << std::endl; return 0; } Thanks, David