Re: [Boost-users] graph cut compilation error

On Tue, Sep 8, 2009 at 2:42 PM, David Doria

wrote:

On Tue, Sep 8, 2009 at 1:17 PM, Jeremiah Willcock 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 #include

using namespace boost;

typedef adjacency_list_traits Traits;

typedef property EdgeReverseProperty; typedef property EdgeResidualCapacityProperty; typedef property EdgeCapacityProperty;

typedef adjacency_list 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

Any clues as to what I've done wrong? Maybe a simple example like this could be put on the kolmogorov documentation page? Thanks, David