1 | //
|
---|
2 | //=======================================================================
|
---|
3 | // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
|
---|
4 | // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
|
---|
5 | //
|
---|
6 | // Distributed under the Boost Software License, Version 1.0. (See
|
---|
7 | // accompanying file LICENSE_1_0.txt or copy at
|
---|
8 | // http://www.boost.org/LICENSE_1_0.txt)
|
---|
9 | //=======================================================================
|
---|
10 | //
|
---|
11 |
|
---|
12 | /*
|
---|
13 | This file implements the function
|
---|
14 |
|
---|
15 | template <class EdgeListGraph, class Size, class P, class T, class R>
|
---|
16 | bool bellman_ford_shortest_paths(EdgeListGraph& g, Size N,
|
---|
17 | const bgl_named_params<P, T, R>& params)
|
---|
18 |
|
---|
19 | */
|
---|
20 |
|
---|
21 |
|
---|
22 | #ifndef BOOST_GRAPH_BELLMAN_FORD_SHORTEST_PATHS_HPP
|
---|
23 | #define BOOST_GRAPH_BELLMAN_FORD_SHORTEST_PATHS_HPP
|
---|
24 |
|
---|
25 | #include <boost/config.hpp>
|
---|
26 | #include <boost/graph/graph_traits.hpp>
|
---|
27 | #include <boost/graph/graph_concepts.hpp>
|
---|
28 | #include <boost/graph/properties.hpp>
|
---|
29 | #include <boost/graph/relax.hpp>
|
---|
30 | #include <boost/graph/visitors.hpp>
|
---|
31 | #include <boost/graph/named_function_params.hpp>
|
---|
32 |
|
---|
33 | namespace boost {
|
---|
34 |
|
---|
35 | template <class Visitor, class Graph>
|
---|
36 | struct BellmanFordVisitorConcept {
|
---|
37 | void constraints() {
|
---|
38 | function_requires< CopyConstructibleConcept<Visitor> >();
|
---|
39 | vis.examine_edge(e, g);
|
---|
40 | vis.edge_relaxed(e, g);
|
---|
41 | vis.edge_not_relaxed(e, g);
|
---|
42 | vis.edge_minimized(e, g);
|
---|
43 | vis.edge_not_minimized(e, g);
|
---|
44 | }
|
---|
45 | Visitor vis;
|
---|
46 | Graph g;
|
---|
47 | typename graph_traits<Graph>::edge_descriptor e;
|
---|
48 | };
|
---|
49 |
|
---|
50 | template <class Visitors = null_visitor>
|
---|
51 | class bellman_visitor {
|
---|
52 | public:
|
---|
53 | bellman_visitor() { }
|
---|
54 | bellman_visitor(Visitors vis) : m_vis(vis) { }
|
---|
55 |
|
---|
56 | template <class Edge, class Graph>
|
---|
57 | void examine_edge(Edge u, Graph& g) {
|
---|
58 | invoke_visitors(m_vis, u, g, on_examine_edge());
|
---|
59 | }
|
---|
60 | template <class Edge, class Graph>
|
---|
61 | void edge_relaxed(Edge u, Graph& g) {
|
---|
62 | invoke_visitors(m_vis, u, g, on_edge_relaxed());
|
---|
63 | }
|
---|
64 | template <class Edge, class Graph>
|
---|
65 | void edge_not_relaxed(Edge u, Graph& g) {
|
---|
66 | invoke_visitors(m_vis, u, g, on_edge_not_relaxed());
|
---|
67 | }
|
---|
68 | template <class Edge, class Graph>
|
---|
69 | void edge_minimized(Edge u, Graph& g) {
|
---|
70 | invoke_visitors(m_vis, u, g, on_edge_minimized());
|
---|
71 | }
|
---|
72 | template <class Edge, class Graph>
|
---|
73 | void edge_not_minimized(Edge u, Graph& g) {
|
---|
74 | invoke_visitors(m_vis, u, g, on_edge_not_minimized());
|
---|
75 | }
|
---|
76 | protected:
|
---|
77 | Visitors m_vis;
|
---|
78 | };
|
---|
79 | template <class Visitors>
|
---|
80 | bellman_visitor<Visitors>
|
---|
81 | make_bellman_visitor(Visitors vis) {
|
---|
82 | return bellman_visitor<Visitors>(vis);
|
---|
83 | }
|
---|
84 | typedef bellman_visitor<> default_bellman_visitor;
|
---|
85 |
|
---|
86 | template <class EdgeListGraph, class Size, class WeightMap,
|
---|
87 | class PredecessorMap, class DistanceMap,
|
---|
88 | class BinaryFunction, class BinaryPredicate,
|
---|
89 | class BellmanFordVisitor>
|
---|
90 | bool bellman_ford_shortest_paths(EdgeListGraph& g, Size N,
|
---|
91 | WeightMap weight,
|
---|
92 | PredecessorMap pred,
|
---|
93 | DistanceMap distance,
|
---|
94 | BinaryFunction combine,
|
---|
95 | BinaryPredicate compare,
|
---|
96 | BellmanFordVisitor v)
|
---|
97 | {
|
---|
98 | function_requires<EdgeListGraphConcept<EdgeListGraph> >();
|
---|
99 | typedef graph_traits<EdgeListGraph> GTraits;
|
---|
100 | typedef typename GTraits::edge_descriptor Edge;
|
---|
101 | typedef typename GTraits::vertex_descriptor Vertex;
|
---|
102 | function_requires<ReadWritePropertyMapConcept<DistanceMap, Vertex> >();
|
---|
103 | function_requires<ReadablePropertyMapConcept<WeightMap, Edge> >();
|
---|
104 | typedef typename property_traits<DistanceMap>::value_type D_value;
|
---|
105 | typedef typename property_traits<WeightMap>::value_type W_value;
|
---|
106 |
|
---|
107 | typename GTraits::edge_iterator i, end;
|
---|
108 |
|
---|
109 | for (Size k = 0; k < N; ++k) {
|
---|
110 | bool at_least_one_edge_relaxed = false;
|
---|
111 | for (tie(i, end) = edges(g); i != end; ++i) {
|
---|
112 | v.examine_edge(*i, g);
|
---|
113 | if (relax(*i, g, weight, pred, distance, combine, compare)) {
|
---|
114 | at_least_one_edge_relaxed = true;
|
---|
115 | v.edge_relaxed(*i, g);
|
---|
116 | } else
|
---|
117 | v.edge_not_relaxed(*i, g);
|
---|
118 | }
|
---|
119 | if (!at_least_one_edge_relaxed)
|
---|
120 | break;
|
---|
121 | }
|
---|
122 |
|
---|
123 | for (tie(i, end) = edges(g); i != end; ++i)
|
---|
124 | if (compare(combine(get(distance, source(*i, g)), get(weight, *i)),
|
---|
125 | get(distance, target(*i,g))))
|
---|
126 | {
|
---|
127 | v.edge_not_minimized(*i, g);
|
---|
128 | return false;
|
---|
129 | } else
|
---|
130 | v.edge_minimized(*i, g);
|
---|
131 |
|
---|
132 | return true;
|
---|
133 | }
|
---|
134 |
|
---|
135 | namespace detail {
|
---|
136 |
|
---|
137 | template<typename VertexAndEdgeListGraph, typename Size,
|
---|
138 | typename WeightMap, typename PredecessorMap, typename DistanceMap,
|
---|
139 | typename P, typename T, typename R>
|
---|
140 | bool
|
---|
141 | bellman_dispatch2
|
---|
142 | (VertexAndEdgeListGraph& g,
|
---|
143 | typename graph_traits<VertexAndEdgeListGraph>::vertex_descriptor s,
|
---|
144 | Size N, WeightMap weight, PredecessorMap pred, DistanceMap distance,
|
---|
145 | const bgl_named_params<P, T, R>& params)
|
---|
146 | {
|
---|
147 | typedef typename property_traits<DistanceMap>::value_type D;
|
---|
148 | bellman_visitor<> null_vis;
|
---|
149 | typedef typename property_traits<WeightMap>::value_type weight_type;
|
---|
150 | typename graph_traits<VertexAndEdgeListGraph>::vertex_iterator v, v_end;
|
---|
151 | for (tie(v, v_end) = vertices(g); v != v_end; ++v) {
|
---|
152 | put(distance, *v, (std::numeric_limits<weight_type>::max)());
|
---|
153 | put(pred, *v, *v);
|
---|
154 | }
|
---|
155 | put(distance, s, weight_type(0));
|
---|
156 | return bellman_ford_shortest_paths
|
---|
157 | (g, N, weight, pred, distance,
|
---|
158 | choose_param(get_param(params, distance_combine_t()),
|
---|
159 | closed_plus<D>()),
|
---|
160 | choose_param(get_param(params, distance_compare_t()),
|
---|
161 | std::less<D>()),
|
---|
162 | choose_param(get_param(params, graph_visitor),
|
---|
163 | null_vis)
|
---|
164 | );
|
---|
165 | }
|
---|
166 |
|
---|
167 | template<typename VertexAndEdgeListGraph, typename Size,
|
---|
168 | typename WeightMap, typename PredecessorMap, typename DistanceMap,
|
---|
169 | typename P, typename T, typename R>
|
---|
170 | bool
|
---|
171 | bellman_dispatch2
|
---|
172 | (VertexAndEdgeListGraph& g,
|
---|
173 | detail::error_property_not_found,
|
---|
174 | Size N, WeightMap weight, PredecessorMap pred, DistanceMap distance,
|
---|
175 | const bgl_named_params<P, T, R>& params)
|
---|
176 | {
|
---|
177 | typedef typename property_traits<DistanceMap>::value_type D;
|
---|
178 | bellman_visitor<> null_vis;
|
---|
179 | return bellman_ford_shortest_paths
|
---|
180 | (g, N, weight, pred, distance,
|
---|
181 | choose_param(get_param(params, distance_combine_t()),
|
---|
182 | closed_plus<D>()),
|
---|
183 | choose_param(get_param(params, distance_compare_t()),
|
---|
184 | std::less<D>()),
|
---|
185 | choose_param(get_param(params, graph_visitor),
|
---|
186 | null_vis)
|
---|
187 | );
|
---|
188 | }
|
---|
189 |
|
---|
190 | template <class EdgeListGraph, class Size, class WeightMap,
|
---|
191 | class DistanceMap, class P, class T, class R>
|
---|
192 | bool bellman_dispatch(EdgeListGraph& g, Size N,
|
---|
193 | WeightMap weight, DistanceMap distance,
|
---|
194 | const bgl_named_params<P, T, R>& params)
|
---|
195 | {
|
---|
196 | dummy_property_map dummy_pred;
|
---|
197 | return
|
---|
198 | detail::bellman_dispatch2
|
---|
199 | (g,
|
---|
200 | get_param(params, root_vertex_t()),
|
---|
201 | N, weight,
|
---|
202 | choose_param(get_param(params, vertex_predecessor), dummy_pred),
|
---|
203 | distance,
|
---|
204 | params);
|
---|
205 | }
|
---|
206 | } // namespace detail
|
---|
207 |
|
---|
208 | template <class EdgeListGraph, class Size, class P, class T, class R>
|
---|
209 | bool bellman_ford_shortest_paths
|
---|
210 | (EdgeListGraph& g, Size N,
|
---|
211 | const bgl_named_params<P, T, R>& params)
|
---|
212 | {
|
---|
213 | return detail::bellman_dispatch
|
---|
214 | (g, N,
|
---|
215 | choose_const_pmap(get_param(params, edge_weight), g, edge_weight),
|
---|
216 | choose_pmap(get_param(params, vertex_distance), g, vertex_distance),
|
---|
217 | params);
|
---|
218 | }
|
---|
219 |
|
---|
220 | template <class EdgeListGraph, class Size>
|
---|
221 | bool bellman_ford_shortest_paths(EdgeListGraph& g, Size N)
|
---|
222 | {
|
---|
223 | bgl_named_params<int,int> params(0);
|
---|
224 | return bellman_ford_shortest_paths(g, N, params);
|
---|
225 | }
|
---|
226 |
|
---|
227 | template <class VertexAndEdgeListGraph, class P, class T, class R>
|
---|
228 | bool bellman_ford_shortest_paths
|
---|
229 | (VertexAndEdgeListGraph& g,
|
---|
230 | const bgl_named_params<P, T, R>& params)
|
---|
231 | {
|
---|
232 | function_requires<VertexListGraphConcept<VertexAndEdgeListGraph> >();
|
---|
233 | return detail::bellman_dispatch
|
---|
234 | (g, num_vertices(g),
|
---|
235 | choose_const_pmap(get_param(params, edge_weight), g, edge_weight),
|
---|
236 | choose_pmap(get_param(params, vertex_distance), g, vertex_distance),
|
---|
237 | params);
|
---|
238 | }
|
---|
239 | } // namespace boost
|
---|
240 |
|
---|
241 | #endif // BOOST_GRAPH_BELLMAN_FORD_SHORTEST_PATHS_HPP
|
---|