On Tue, Sep 8, 2009 at 1:17 PM, Jeremiah Willcock <jewillco@osl.iu.edu>wrote:
On Tue, 8 Sep 2009, David Doria wrote:
I made a super simple example: A graph with 2 nodes and an edge between
them. On trying to call kolmogorov_max_flow, I am getting: error: cannot convert 'boost::detail::error_property_not_found' to 'long int' in initialization
You are missing the edge weights and other property maps described in the documentation for kolmogorov_max_flow; you can supply them either as parameters to the kolmogorov_max_flow function or as particular property maps in your graph. You can add properties as template parameters to the adjacency_list class (see the documentation for how to do that), or use external properties. Once you have properties, you can use add_edge(source, target, prop, g) to add edges with properties.
-- Jeremiah Willcock __
Jeremiah, Thanks for the response. I am very new to boost, so I am not quite getting the Property Map idea. It seems like you can just provide a whole list of template arguments that are of type property<> to the adjacency_list object. It the kolmogorov example ( http://www.boost.org/doc/libs/1_39_0/libs/graph/doc/kolmogorov_max_flow.html) , it looks like the only property that is needed is edge_capacity, so I defined EdgeCapacityProperty (it was actually quite a complicated property, depending on edge_reverse as well as edge_residual_capacity). However, I am still getting "conversion from error_property_not_found to EdgeCapacityProperty requested" when I try to call the maxflow function. Is this getting closer? I guess I am following the property<> stuff, but not the property_map<> idea? Here is the latest attempt: #include <iostream> // for std::cout #include <boost/graph/adjacency_list.hpp> #include <boost/graph/kolmogorov_max_flow.hpp> using namespace boost; typedef adjacency_list_traits<vecS, vecS, bidirectionalS> Traits; typedef property<edge_reverse_t, Traits::edge_descriptor> EdgeReverseProperty; typedef property<edge_residual_capacity_t, long, EdgeReverseProperty> EdgeResidualCapacityProperty; typedef property<edge_capacity_t, double, EdgeResidualCapacityProperty> EdgeCapacityProperty; typedef adjacency_list<vecS, vecS, bidirectionalS, EdgeCapacityProperty> Graph; //simple int main(int,char*[]) { // declare a graph object Graph g(2); //a graph with 2 vertices //add an edge between node 0 and node 1 with weight (capacity) 2.3 EdgeCapacityProperty e = 2.3; add_edge(0, 1, e, g); //find min cut Traits::vertex_descriptor s, t; //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 EdgeCapacityProperty 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