Edit: /usr/include/boost/graph/bellman_ford_shortest_paths.hpp (8229B)
//
//=======================================================================
// 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)
//=======================================================================
//
/*
This file implements the function
template
bool bellman_ford_shortest_paths(EdgeListGraph& g, Size N,
const bgl_named_params& params)
*/
#ifndef BOOST_GRAPH_BELLMAN_FORD_SHORTEST_PATHS_HPP
#define BOOST_GRAPH_BELLMAN_FORD_SHORTEST_PATHS_HPP
#include
#include
#include
#include
#include
#include
#include
#include
namespace boost
{
template < class Visitor, class Graph > struct BellmanFordVisitorConcept
{
void constraints()
{
BOOST_CONCEPT_ASSERT((CopyConstructibleConcept< Visitor >));
vis.examine_edge(e, g);
vis.edge_relaxed(e, g);
vis.edge_not_relaxed(e, g);
vis.edge_minimized(e, g);
vis.edge_not_minimized(e, g);
}
Visitor vis;
Graph g;
typename graph_traits< Graph >::edge_descriptor e;
};
template < class Visitors = null_visitor > class bellman_visitor
{
public:
bellman_visitor() {}
bellman_visitor(Visitors vis) : m_vis(vis) {}
template < class Edge, class Graph > void examine_edge(Edge u, Graph& g)
{
invoke_visitors(m_vis, u, g, on_examine_edge());
}
template < class Edge, class Graph > void edge_relaxed(Edge u, Graph& g)
{
invoke_visitors(m_vis, u, g, on_edge_relaxed());
}
template < class Edge, class Graph > void edge_not_relaxed(Edge u, Graph& g)
{
invoke_visitors(m_vis, u, g, on_edge_not_relaxed());
}
template < class Edge, class Graph > void edge_minimized(Edge u, Graph& g)
{
invoke_visitors(m_vis, u, g, on_edge_minimized());
}
template < class Edge, class Graph >
void edge_not_minimized(Edge u, Graph& g)
{
invoke_visitors(m_vis, u, g, on_edge_not_minimized());
}
protected:
Visitors m_vis;
};
template < class Visitors >
bellman_visitor< Visitors > make_bellman_visitor(Visitors vis)
{
return bellman_visitor< Visitors >(vis);
}
typedef bellman_visitor<> default_bellman_visitor;
template < class EdgeListGraph, class Size, class WeightMap,
class PredecessorMap, class DistanceMap, class BinaryFunction,
class BinaryPredicate, class BellmanFordVisitor >
bool bellman_ford_shortest_paths(EdgeListGraph& g, Size N, WeightMap weight,
PredecessorMap pred, DistanceMap distance, BinaryFunction combine,
BinaryPredicate compare, BellmanFordVisitor v)
{
BOOST_CONCEPT_ASSERT((EdgeListGraphConcept< EdgeListGraph >));
typedef graph_traits< EdgeListGraph > GTraits;
typedef typename GTraits::edge_descriptor Edge;
typedef typename GTraits::vertex_descriptor Vertex;
BOOST_CONCEPT_ASSERT((ReadWritePropertyMapConcept< DistanceMap, Vertex >));
BOOST_CONCEPT_ASSERT((ReadablePropertyMapConcept< WeightMap, Edge >));
typename GTraits::edge_iterator i, end;
for (Size k = 0; k < N; ++k)
{
bool at_least_one_edge_relaxed = false;
for (boost::tie(i, end) = edges(g); i != end; ++i)
{
v.examine_edge(*i, g);
if (relax(*i, g, weight, pred, distance, combine, compare))
{
at_least_one_edge_relaxed = true;
v.edge_relaxed(*i, g);
}
else
v.edge_not_relaxed(*i, g);
}
if (!at_least_one_edge_relaxed)
break;
}
for (boost::tie(i, end) = edges(g); i != end; ++i)
if (compare(combine(get(distance, source(*i, g)), get(weight, *i)),
get(distance, target(*i, g))))
{
v.edge_not_minimized(*i, g);
return false;
}
else
v.edge_minimized(*i, g);
return true;
}
namespace detail
{
template < typename VertexAndEdgeListGraph, typename Size,
typename WeightMap, typename PredecessorMap, typename DistanceMap,
typename P, typename T, typename R >
bool bellman_dispatch2(VertexAndEdgeListGraph& g,
typename graph_traits< VertexAndEdgeListGraph >::vertex_descriptor s,
Size N, WeightMap weight, PredecessorMap pred, DistanceMap distance,
const bgl_named_params< P, T, R >& params)
{
typedef typename property_traits< DistanceMap >::value_type D;
bellman_visitor<> null_vis;
typedef typename property_traits< WeightMap >::value_type weight_type;
typename graph_traits< VertexAndEdgeListGraph >::vertex_iterator v,
v_end;
for (boost::tie(v, v_end) = vertices(g); v != v_end; ++v)
{
put(distance, *v, (std::numeric_limits< weight_type >::max)());
put(pred, *v, *v);
}
put(distance, s, weight_type(0));
return bellman_ford_shortest_paths(g, N, weight, pred, distance,
choose_param(
get_param(params, distance_combine_t()), closed_plus< D >()),
choose_param(
get_param(params, distance_compare_t()), std::less< D >()),
choose_param(get_param(params, graph_visitor), null_vis));
}
template < typename VertexAndEdgeListGraph, typename Size,
typename WeightMap, typename PredecessorMap, typename DistanceMap,
typename P, typename T, typename R >
bool bellman_dispatch2(VertexAndEdgeListGraph& g, param_not_found, Size N,
WeightMap weight, PredecessorMap pred, DistanceMap distance,
const bgl_named_params< P, T, R >& params)
{
typedef typename property_traits< DistanceMap >::value_type D;
bellman_visitor<> null_vis;
return bellman_ford_shortest_paths(g, N, weight, pred, distance,
choose_param(
get_param(params, distance_combine_t()), closed_plus< D >()),
choose_param(
get_param(params, distance_compare_t()), std::less< D >()),
choose_param(get_param(params, graph_visitor), null_vis));
}
template < class EdgeListGraph, class Size, class WeightMap,
class DistanceMap, class P, class T, class R >
bool bellman_dispatch(EdgeListGraph& g, Size N, WeightMap weight,
DistanceMap distance, const bgl_named_params< P, T, R >& params)
{
dummy_property_map dummy_pred;
return detail::bellman_dispatch2(g, get_param(params, root_vertex_t()),
N, weight,
choose_param(get_param(params, vertex_predecessor), dummy_pred),
distance, params);
}
} // namespace detail
template < class EdgeListGraph, class Size, class P, class T, class R >
bool bellman_ford_shortest_paths(
EdgeListGraph& g, Size N, const bgl_named_params< P, T, R >& params)
{
return detail::bellman_dispatch(g, N,
choose_const_pmap(get_param(params, edge_weight), g, edge_weight),
choose_pmap(get_param(params, vertex_distance), g, vertex_distance),
params);
}
template < class EdgeListGraph, class Size >
bool bellman_ford_shortest_paths(EdgeListGraph& g, Size N)
{
bgl_named_params< int, int > params(0);
return bellman_ford_shortest_paths(g, N, params);
}
template < class VertexAndEdgeListGraph, class P, class T, class R >
bool bellman_ford_shortest_paths(
VertexAndEdgeListGraph& g, const bgl_named_params< P, T, R >& params)
{
BOOST_CONCEPT_ASSERT((VertexListGraphConcept< VertexAndEdgeListGraph >));
return detail::bellman_dispatch(g, num_vertices(g),
choose_const_pmap(get_param(params, edge_weight), g, edge_weight),
choose_pmap(get_param(params, vertex_distance), g, vertex_distance),
params);
}
} // namespace boost
#endif // BOOST_GRAPH_BELLMAN_FORD_SHORTEST_PATHS_HPP