File: strong_components.hpp

package info (click to toggle)
boost1.62 1.62.0+dfsg-4
  • links: PTS, VCS
  • area: main
  • in suites: stretch
  • size: 686,420 kB
  • sloc: cpp: 2,609,004; xml: 972,558; ansic: 53,674; python: 32,437; sh: 8,829; asm: 3,071; cs: 2,121; makefile: 964; perl: 859; yacc: 472; php: 132; ruby: 94; f90: 55; sql: 13; csh: 6
file content (343 lines) | stat: -rw-r--r-- 12,850 bytes parent folder | download | duplicates (7)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
//
//=======================================================================
// 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)
//=======================================================================
//

#ifndef BOOST_GRAPH_STRONG_COMPONENTS_HPP
#define BOOST_GRAPH_STRONG_COMPONENTS_HPP

#include <stack>
#include <boost/config.hpp>
#include <boost/graph/depth_first_search.hpp>
#include <boost/type_traits/conversion_traits.hpp>
#include <boost/static_assert.hpp>
#include <boost/graph/overloading.hpp>
#include <boost/concept/assert.hpp>

namespace boost {

  //==========================================================================
  // This is Tarjan's algorithm for strongly connected components
  // from his paper "Depth first search and linear graph algorithms".
  // It calculates the components in a single application of DFS.
  // We implement the algorithm as a dfs-visitor.

  namespace detail {
    
    template <typename ComponentMap, typename RootMap, typename DiscoverTime,
              typename Stack>
    class tarjan_scc_visitor : public dfs_visitor<> 
    {
      typedef typename property_traits<ComponentMap>::value_type comp_type;
      typedef typename property_traits<DiscoverTime>::value_type time_type;
    public:
      tarjan_scc_visitor(ComponentMap comp_map, RootMap r, DiscoverTime d, 
                         comp_type& c_, Stack& s_)
        : c(c_), comp(comp_map), root(r), discover_time(d),
          dfs_time(time_type()), s(s_) { }

      template <typename Graph>
      void discover_vertex(typename graph_traits<Graph>::vertex_descriptor v,
                           const Graph&) {
        put(root, v, v);
        put(comp, v, (std::numeric_limits<comp_type>::max)());
        put(discover_time, v, dfs_time++);
        s.push(v);
      }
      template <typename Graph>
      void finish_vertex(typename graph_traits<Graph>::vertex_descriptor v,
                         const Graph& g) {
        typename graph_traits<Graph>::vertex_descriptor w;
        typename graph_traits<Graph>::out_edge_iterator ei, ei_end;
        for (boost::tie(ei, ei_end) = out_edges(v, g); ei != ei_end; ++ei) {
          w = target(*ei, g);
          if (get(comp, w) == (std::numeric_limits<comp_type>::max)())
            put(root, v, this->min_discover_time(get(root,v), get(root,w)));
        }
        if (get(root, v) == v) {
          do {
            w = s.top(); s.pop();
            put(comp, w, c);
	    put(root, w, v);
          } while (w != v);
          ++c;
        }
      }
    private:
      template <typename Vertex>
      Vertex min_discover_time(Vertex u, Vertex v) {
        return get(discover_time, u) < get(discover_time,v) ? u : v;
      }

      comp_type& c;
      ComponentMap comp;
      RootMap root;
      DiscoverTime discover_time;
      time_type dfs_time;
      Stack& s;
    };
    
    template <class Graph, class ComponentMap, class RootMap,
              class DiscoverTime, class P, class T, class R>
    typename property_traits<ComponentMap>::value_type
    strong_components_impl
      (const Graph& g,    // Input
       ComponentMap comp, // Output
       // Internal record keeping
       RootMap root, 
       DiscoverTime discover_time,
       const bgl_named_params<P, T, R>& params)
    {
      typedef typename graph_traits<Graph>::vertex_descriptor Vertex;
      BOOST_CONCEPT_ASSERT(( ReadWritePropertyMapConcept<ComponentMap, Vertex> ));
      BOOST_CONCEPT_ASSERT(( ReadWritePropertyMapConcept<RootMap, Vertex> ));
      typedef typename property_traits<RootMap>::value_type RootV;
      BOOST_CONCEPT_ASSERT(( ConvertibleConcept<RootV, Vertex> ));
      BOOST_CONCEPT_ASSERT(( ReadWritePropertyMapConcept<DiscoverTime, Vertex> ));

      typename property_traits<ComponentMap>::value_type total = 0;

      std::stack<Vertex> s;
      detail::tarjan_scc_visitor<ComponentMap, RootMap, DiscoverTime, 
        std::stack<Vertex> > 
        vis(comp, root, discover_time, total, s);
      depth_first_search(g, params.visitor(vis));
      return total;
    }

    //-------------------------------------------------------------------------
    // The dispatch functions handle the defaults for the rank and discover
    // time property maps.
    // dispatch with class specialization to avoid VC++ bug

    template <class DiscoverTimeMap>
    struct strong_comp_dispatch2 {
      template <class Graph, class ComponentMap, class RootMap, class P, class T, class R>
      inline static typename property_traits<ComponentMap>::value_type
      apply(const Graph& g,
            ComponentMap comp,
            RootMap r_map,
            const bgl_named_params<P, T, R>& params,
            DiscoverTimeMap time_map)
      {
        return strong_components_impl(g, comp, r_map, time_map, params);
      }
    };


    template <>
    struct strong_comp_dispatch2<param_not_found> {
      template <class Graph, class ComponentMap, class RootMap,
                class P, class T, class R>
      inline static typename property_traits<ComponentMap>::value_type
      apply(const Graph& g,
            ComponentMap comp,
            RootMap r_map,
            const bgl_named_params<P, T, R>& params,
            param_not_found)
      {
        typedef typename graph_traits<Graph>::vertices_size_type size_type;
        size_type       n = num_vertices(g) > 0 ? num_vertices(g) : 1;
        std::vector<size_type> time_vec(n);
        return strong_components_impl
          (g, comp, r_map,
           make_iterator_property_map(time_vec.begin(), choose_const_pmap
                                      (get_param(params, vertex_index),
                                       g, vertex_index), time_vec[0]),
           params);
      }
    };

    template <class Graph, class ComponentMap, class RootMap,
              class P, class T, class R, class DiscoverTimeMap>
    inline typename property_traits<ComponentMap>::value_type
    scc_helper2(const Graph& g,
                ComponentMap comp,
                RootMap r_map,
                const bgl_named_params<P, T, R>& params,
                DiscoverTimeMap time_map)
    {
      return strong_comp_dispatch2<DiscoverTimeMap>::apply(g, comp, r_map, params, time_map);
    }

    template <class RootMap>
    struct strong_comp_dispatch1 {

      template <class Graph, class ComponentMap, class P, class T, class R>
      inline static typename property_traits<ComponentMap>::value_type
      apply(const Graph& g,
            ComponentMap comp,
            const bgl_named_params<P, T, R>& params,
            RootMap r_map)
      {
        return scc_helper2(g, comp, r_map, params, get_param(params, vertex_discover_time));
      }
    };
    template <>
    struct strong_comp_dispatch1<param_not_found> {

      template <class Graph, class ComponentMap, 
                class P, class T, class R>
      inline static typename property_traits<ComponentMap>::value_type
      apply(const Graph& g,
            ComponentMap comp,
            const bgl_named_params<P, T, R>& params,
            param_not_found)
      {
        typedef typename graph_traits<Graph>::vertex_descriptor Vertex;
        typename std::vector<Vertex>::size_type
          n = num_vertices(g) > 0 ? num_vertices(g) : 1;
        std::vector<Vertex> root_vec(n);
        return scc_helper2
          (g, comp, 
           make_iterator_property_map(root_vec.begin(), choose_const_pmap
                                      (get_param(params, vertex_index),
                                       g, vertex_index), root_vec[0]),
           params, 
           get_param(params, vertex_discover_time));
      }
    };

    template <class Graph, class ComponentMap, class RootMap,
              class P, class T, class R>
    inline typename property_traits<ComponentMap>::value_type
    scc_helper1(const Graph& g,
               ComponentMap comp,
               const bgl_named_params<P, T, R>& params,
               RootMap r_map)
    {
      return detail::strong_comp_dispatch1<RootMap>::apply(g, comp, params,
                                                           r_map);
    }

  } // namespace detail 

  template <class Graph, class ComponentMap, 
            class P, class T, class R>
  inline typename property_traits<ComponentMap>::value_type
  strong_components(const Graph& g, ComponentMap comp,
                    const bgl_named_params<P, T, R>& params
                    BOOST_GRAPH_ENABLE_IF_MODELS_PARM(Graph, vertex_list_graph_tag))
  {
    typedef typename graph_traits<Graph>::directed_category DirCat;
    BOOST_STATIC_ASSERT((is_convertible<DirCat*, directed_tag*>::value == true));
    return detail::scc_helper1(g, comp, params, 
                               get_param(params, vertex_root_t()));
  }

  template <class Graph, class ComponentMap>
  inline typename property_traits<ComponentMap>::value_type
  strong_components(const Graph& g, ComponentMap comp
                    BOOST_GRAPH_ENABLE_IF_MODELS_PARM(Graph, vertex_list_graph_tag))
  {
    typedef typename graph_traits<Graph>::directed_category DirCat;
    BOOST_STATIC_ASSERT((is_convertible<DirCat*, directed_tag*>::value == true));
    bgl_named_params<int, int> params(0);
    return strong_components(g, comp, params);
  }

  template <typename Graph, typename ComponentMap, typename ComponentLists>
  void build_component_lists
    (const Graph& g,
     typename graph_traits<Graph>::vertices_size_type num_scc,
     ComponentMap component_number,
     ComponentLists& components)
  {
    components.resize(num_scc);
    typename graph_traits<Graph>::vertex_iterator vi, vi_end;
    for (boost::tie(vi, vi_end) = vertices(g); vi != vi_end; ++vi)
      components[component_number[*vi]].push_back(*vi);
  }


} // namespace boost

#include <queue>
#include <vector>
#include <boost/graph/transpose_graph.hpp>
#include <boost/pending/indirect_cmp.hpp>
#include <boost/graph/connected_components.hpp> // for components_recorder

namespace boost {

  //==========================================================================
  // This is the version of strongly connected components from
  // "Intro. to Algorithms" by Cormen, Leiserson, Rivest, which was
  // adapted from "Data Structure and Algorithms" by Aho, Hopcroft,
  // and Ullman, who credit the algorithm to S.R. Kosaraju and M. Sharir.
  // The algorithm is based on computing DFS forests the graph
  // and its transpose.

  // This algorithm is slower than Tarjan's by a constant factor, uses
  // more memory, and puts more requirements on the graph type.

  template <class Graph, class DFSVisitor, class ComponentsMap,
            class DiscoverTime, class FinishTime,
            class ColorMap>
  typename property_traits<ComponentsMap>::value_type
  kosaraju_strong_components(Graph& G, ComponentsMap c,
                             FinishTime finish_time, ColorMap color)
  {
    BOOST_CONCEPT_ASSERT(( MutableGraphConcept<Graph> ));
    // ...
    
    typedef typename graph_traits<Graph>::vertex_descriptor Vertex;
    typedef typename property_traits<ColorMap>::value_type ColorValue;
    typedef color_traits<ColorValue> Color;
    typename property_traits<FinishTime>::value_type time = 0;
    depth_first_search
     (G, make_dfs_visitor(stamp_times(finish_time, time, on_finish_vertex())),
      color);

    Graph G_T(num_vertices(G));
    transpose_graph(G, G_T);

    typedef typename property_traits<ComponentsMap>::value_type count_type;

    count_type c_count(0);
    detail::components_recorder<ComponentsMap>
      vis(c, c_count);

    // initialize G_T
    typename graph_traits<Graph>::vertex_iterator ui, ui_end;
    for (boost::tie(ui, ui_end) = vertices(G_T); ui != ui_end; ++ui)
      put(color, *ui, Color::white());

    typedef typename property_traits<FinishTime>::value_type D;
    typedef indirect_cmp< FinishTime, std::less<D> > Compare;

    Compare fl(finish_time);
    std::priority_queue<Vertex, std::vector<Vertex>, Compare > Q(fl);

    typename graph_traits<Graph>::vertex_iterator i, j, iend, jend;
    boost::tie(i, iend) = vertices(G_T);
    boost::tie(j, jend) = vertices(G);
    for ( ; i != iend; ++i, ++j) {
      put(finish_time, *i, get(finish_time, *j));
       Q.push(*i);
    }

    while ( !Q.empty() ) {
      Vertex u = Q.top();
      Q.pop();
      if  (get(color, u) == Color::white()) {
        depth_first_visit(G_T, u, vis, color);
        ++c_count; 
      }
    }
    return c_count;
  }

} // namespace boost

#ifdef BOOST_GRAPH_USE_MPI
#  include <boost/graph/distributed/strong_components.hpp>
#endif

#endif // BOOST_GRAPH_STRONG_COMPONENTS_HPP