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//=======================================================================
// Copyright 2001 Jeremy G. Siek, Andrew Lumsdaine, Lie-Quan Lee,
//
// 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)
//=======================================================================
#include <iostream>
#include <boost/graph/edge_list.hpp>
#include <boost/graph/bellman_ford_shortest_paths.hpp>
int main()
{
using namespace boost;
// ID numbers for the routers (vertices).
enum
{
A,
B,
C,
D,
E,
F,
G,
H,
n_vertices
};
const int n_edges = 11;
typedef std::pair< int, int > Edge;
// The list of connections between routers stored in an array.
Edge edges[] = { Edge(A, B), Edge(A, C), Edge(B, D), Edge(B, E), Edge(C, E),
Edge(C, F), Edge(D, H), Edge(D, E), Edge(E, H), Edge(F, G),
Edge(G, H) };
// Specify the graph type and declare a graph object
typedef edge_list< Edge*, Edge, std::ptrdiff_t,
std::random_access_iterator_tag >
Graph;
Graph g(edges, edges + n_edges);
// The transmission delay values for each edge.
float delay[] = { 5.0, 1.0, 1.3, 3.0, 10.0, 2.0, 6.3, 0.4, 1.3, 1.2, 0.5 };
// Declare some storage for some "external" vertex properties.
char name[] = "ABCDEFGH";
int parent[n_vertices];
for (int i = 0; i < n_vertices; ++i)
parent[i] = i;
float distance[n_vertices];
std::fill(
distance, distance + n_vertices, (std::numeric_limits< float >::max)());
// Specify A as the source vertex
distance[A] = 0;
bool r = bellman_ford_shortest_paths(g, int(n_vertices),
weight_map(
make_iterator_property_map(&delay[0], get(edge_index, g), delay[0]))
.distance_map(&distance[0])
.predecessor_map(&parent[0]));
if (r)
for (int i = 0; i < n_vertices; ++i)
std::cout << name[i] << ": " << distance[i] << " "
<< name[parent[i]] << std::endl;
else
std::cout << "negative cycle" << std::endl;
return EXIT_SUCCESS;
}
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