In the code below, using listS to store vertices results in vertex instantiation order changing the amount of flow computed by boykov_kolmogorov_max_flow. As given, it computes a flow of 0. If I move the instantiation of "T-" to be before "t-" or switch the VertexList parameter of adjacency_list to vecS, it computes the correct flow of 1000. Stepping through the code, it looks like when the max_flow function iterates over vertices that are targets of out-edges from the source, the call to get(m_in_active_list_map, v) at boykov_kolmogorov_max_flow.hpp:528 returns true for the second vertex, preventing it from getting added to m_active_nodes. I tested this using g++ 4.4.7 and with Boost 1.55 and 1.56. Has anybody else seen anything like this? Code follows: #include #include #include #include #include <iostream> #include <limits> using namespace boost; typedef adjacency_list_traits Traits; typedef Traits::vertex_descriptor Vertex; typedef Traits::edge_descriptor Edge; typedef adjacency_list > > > >, property > > > > Graph; void addEdge(Graph& g, const Vertex& source, const Vertex& target, const double capacity, const double reverseCapacity) { property_map::type rev = get(edge_reverse, g); Edge e1 = add_edge(source, target, g).first; Edge e2 = add_edge(target, source, g).first; put(edge_capacity, g, e1, capacity); put(edge_capacity, g, e2, reverseCapacity); rev[e1] = e2; rev[e2] = e1; } int main(void) { Graph g; property_map::type nameMap = get(vertex_name, g); Vertex source = add_vertex(g); nameMap[source] = "source"; Vertex sink = add_vertex(g); nameMap[sink] = "sink"; Vertex tminus = add_vertex(g); nameMap[tminus] = "t-"; addEdge(g, source, tminus, 1, 0); Vertex Tminus = add_vertex(g); nameMap[Tminus] = "T-"; addEdge(g, source, Tminus, 1000, 0); Vertex Tplus = add_vertex(g); nameMap[Tplus] = "T+"; addEdge(g, Tplus, sink, 1000, 0); addEdge(g, Tplus, Tminus, 0, std::numeric_limits<int>::max()); double flow = boykov_kolmogorov_max_flow(g, source, sink); std::cout << flow << std::endl; return 0; } -- ------------------ Michael J. Iatauro Software Engineer QTS, Inc. NASA Ames Research Center Office: 650-604-0662 Mail stop: 269-2 P.O. Box 1 Moffett Field, CA 94035-0001