Edit: /usr/include/boost/graph/dag_shortest_paths.hpp (6064B)
//=======================================================================
// Copyright 2002 Indiana University.
// 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)
//=======================================================================
#ifndef BOOST_GRAPH_DAG_SHORTEST_PATHS_HPP
#define BOOST_GRAPH_DAG_SHORTEST_PATHS_HPP
#include
#include
// single-source shortest paths for a Directed Acyclic Graph (DAG)
namespace boost
{
// Initalize distances and call depth first search
template < class VertexListGraph, class DijkstraVisitor, class DistanceMap,
class WeightMap, class ColorMap, class PredecessorMap, class Compare,
class Combine, class DistInf, class DistZero >
inline void dag_shortest_paths(const VertexListGraph& g,
typename graph_traits< VertexListGraph >::vertex_descriptor s,
DistanceMap distance, WeightMap weight, ColorMap color, PredecessorMap pred,
DijkstraVisitor vis, Compare compare, Combine combine, DistInf inf,
DistZero zero)
{
typedef typename graph_traits< VertexListGraph >::vertex_descriptor Vertex;
std::vector< Vertex > rev_topo_order;
rev_topo_order.reserve(num_vertices(g));
// Call 'depth_first_visit', not 'topological_sort', because we don't
// want to traverse the entire graph, only vertices reachable from 's',
// and 'topological_sort' will traverse everything. The logic below
// is the same as for 'topological_sort', only we call 'depth_first_visit'
// and 'topological_sort' calls 'depth_first_search'.
topo_sort_visitor< std::back_insert_iterator< std::vector< Vertex > > >
topo_visitor(std::back_inserter(rev_topo_order));
depth_first_visit(g, s, topo_visitor, color);
typename graph_traits< VertexListGraph >::vertex_iterator ui, ui_end;
for (boost::tie(ui, ui_end) = vertices(g); ui != ui_end; ++ui)
{
put(distance, *ui, inf);
put(pred, *ui, *ui);
}
put(distance, s, zero);
vis.discover_vertex(s, g);
typename std::vector< Vertex >::reverse_iterator i;
for (i = rev_topo_order.rbegin(); i != rev_topo_order.rend(); ++i)
{
Vertex u = *i;
vis.examine_vertex(u, g);
typename graph_traits< VertexListGraph >::out_edge_iterator e, e_end;
for (boost::tie(e, e_end) = out_edges(u, g); e != e_end; ++e)
{
vis.discover_vertex(target(*e, g), g);
bool decreased
= relax(*e, g, weight, pred, distance, combine, compare);
if (decreased)
vis.edge_relaxed(*e, g);
else
vis.edge_not_relaxed(*e, g);
}
vis.finish_vertex(u, g);
}
}
namespace detail
{
// Defaults are the same as Dijkstra's algorithm
// Handle Distance Compare, Combine, Inf and Zero defaults
template < class VertexListGraph, class DijkstraVisitor, class DistanceMap,
class WeightMap, class ColorMap, class IndexMap, class Params >
inline void dag_sp_dispatch2(const VertexListGraph& g,
typename graph_traits< VertexListGraph >::vertex_descriptor s,
DistanceMap distance, WeightMap weight, ColorMap color, IndexMap /*id*/,
DijkstraVisitor vis, const Params& params)
{
typedef typename property_traits< DistanceMap >::value_type D;
dummy_property_map p_map;
D inf = choose_param(get_param(params, distance_inf_t()),
(std::numeric_limits< D >::max)());
dag_shortest_paths(g, s, distance, weight, color,
choose_param(get_param(params, vertex_predecessor), p_map), vis,
choose_param(
get_param(params, distance_compare_t()), std::less< D >()),
choose_param(
get_param(params, distance_combine_t()), closed_plus< D >(inf)),
inf, choose_param(get_param(params, distance_zero_t()), D()));
}
// Handle DistanceMap and ColorMap defaults
template < class VertexListGraph, class DijkstraVisitor, class DistanceMap,
class WeightMap, class ColorMap, class IndexMap, class Params >
inline void dag_sp_dispatch1(const VertexListGraph& g,
typename graph_traits< VertexListGraph >::vertex_descriptor s,
DistanceMap distance, WeightMap weight, ColorMap color, IndexMap id,
DijkstraVisitor vis, const Params& params)
{
typedef typename property_traits< WeightMap >::value_type T;
typename std::vector< T >::size_type n;
n = is_default_param(distance) ? num_vertices(g) : 1;
std::vector< T > distance_map(n);
n = is_default_param(color) ? num_vertices(g) : 1;
std::vector< default_color_type > color_map(n);
dag_sp_dispatch2(g, s,
choose_param(distance,
make_iterator_property_map(
distance_map.begin(), id, distance_map[0])),
weight,
choose_param(color,
make_iterator_property_map(
color_map.begin(), id, color_map[0])),
id, vis, params);
}
} // namespace detail
template < class VertexListGraph, class Param, class Tag, class Rest >
inline void dag_shortest_paths(const VertexListGraph& g,
typename graph_traits< VertexListGraph >::vertex_descriptor s,
const bgl_named_params< Param, Tag, Rest >& params)
{
// assert that the graph is directed...
null_visitor null_vis;
detail::dag_sp_dispatch1(g, s, get_param(params, vertex_distance),
choose_const_pmap(get_param(params, edge_weight), g, edge_weight),
get_param(params, vertex_color),
choose_const_pmap(get_param(params, vertex_index), g, vertex_index),
choose_param(
get_param(params, graph_visitor), make_dijkstra_visitor(null_vis)),
params);
}
} // namespace boost
#endif // BOOST_GRAPH_DAG_SHORTEST_PATHS_HPP