Boost C++ Libraries

libs/graph/example/miles_span.cpp

//=======================================================================
// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================

// Sample output:
//
//  The graph miles(100,0,0,0,0,10,0) has 405 edges,
//   and its minimum spanning tree has length 14467.
//

#include <boost/config.hpp>
#include <string.h>
#include <stdio.h>
#include <boost/graph/stanford_graph.hpp>
#include <boost/graph/prim_minimum_spanning_tree.hpp>

// A visitor class for accumulating the total length of the minimum
// spanning tree. The Distance template parameter is for a
// PropertyMap.
template < class Distance >
struct total_length_visitor : public boost::dijkstra_visitor<>
{
    typedef typename boost::property_traits< Distance >::value_type D;
    total_length_visitor(D& len, Distance d) : _total_length(len), _distance(d)
    {
    }
    template < class Vertex, class Graph >
    inline void finish_vertex(Vertex s, Graph& g)
    {
        _total_length += boost::get(_distance, s);
    }
    D& _total_length;
    Distance _distance;
};

int main(int argc, char* argv[])
{
    using namespace boost;
    Graph* g;

    unsigned long n = 100;
    unsigned long n_weight = 0;
    unsigned long w_weight = 0;
    unsigned long p_weight = 0;
    unsigned long d = 10;
    long s = 0;
    unsigned long r = 1;
    char* file_name = NULL;

    while (--argc)
    {
        if (sscanf(argv[argc], "-n%lu", &n) == 1)
            ;
        else if (sscanf(argv[argc], "-N%lu", &n_weight) == 1)
            ;
        else if (sscanf(argv[argc], "-W%lu", &w_weight) == 1)
            ;
        else if (sscanf(argv[argc], "-P%lu", &p_weight) == 1)
            ;
        else if (sscanf(argv[argc], "-d%lu", &d) == 1)
            ;
        else if (sscanf(argv[argc], "-r%lu", &r) == 1)
            ;
        else if (sscanf(argv[argc], "-s%ld", &s) == 1)
            ;
        else if (strcmp(argv[argc], "-v") == 0)
            verbose = 1;
        else if (strncmp(argv[argc], "-g", 2) == 0)
            file_name = argv[argc] + 2;
        else
        {
            fprintf(stderr,
                "Usage: %s [-nN][-dN][-rN][-sN][-NN][-WN][-PN][-v][-gfoo]\n",
                argv[0]);
            return -2;
        }
    }
    if (file_name)
        r = 1;

    while (r--)
    {
        if (file_name)
            g = restore_graph(file_name);
        else
            g = miles(n, n_weight, w_weight, p_weight, 0L, d, s);

        if (g == NULL || g->n <= 1)
        {
            fprintf(stderr, "Sorry, can't create the graph! (error code %ld)\n",
                panic_code);
            return -1;
        }

        printf("The graph %s has %ld edges,\n", g->id, g->m / 2);

        long sp_length = 0;

        // Use the "z" utility field for distance.
        typedef property_map< Graph*, z_property< long > >::type Distance;
        Distance d = get(z_property< long >(), g);
        // Use the "w" property for parent
        typedef property_map< Graph*, w_property< Vertex* > >::type Parent;
        Parent p = get(w_property< Vertex* >(), g);
        total_length_visitor< Distance > length_vis(sp_length, d);

        prim_minimum_spanning_tree(g, p,
            distance_map(get(z_property< long >(), g))
                .weight_map(get(edge_length_t(), g))
                .
            // Use the "y" utility field for color
            color_map(get(y_property< long >(), g))
                .visitor(length_vis));

        printf("  and its minimum spanning tree has length %ld.\n", sp_length);

        gb_recycle(g);
        s++;
    }
    return 0;
}