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dekker.one
1/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
2/*
3 * Main authors:
4 * Guido Tack <tack@gecode.org>
5 *
6 * Copyright:
7 * Guido Tack, 2012
8 *
9 * This file is part of Gecode, the generic constraint
10 * development environment:
11 * http://www.gecode.org
12 *
13 * Permission is hereby granted, free of charge, to any person obtaining
14 * a copy of this software and associated documentation files (the
15 * "Software"), to deal in the Software without restriction, including
16 * without limitation the rights to use, copy, modify, merge, publish,
17 * distribute, sublicense, and/or sell copies of the Software, and to
18 * permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
20 *
21 * The above copyright notice and this permission notice shall be
22 * included in all copies or substantial portions of the Software.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
28 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
29 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
30 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
31 *
32 */
33
34#ifndef GECODE_SEARCH_SEQ_RBS_HH
35#define GECODE_SEARCH_SEQ_RBS_HH
36
37#include <gecode/search.hh>
38
39namespace Gecode { namespace Search { namespace Seq {
40
41 class RBS;
42
43 /// %Stop-object for restart engine
44 class GECODE_SEARCH_EXPORT RestartStop : public Stop {
45 template<class,template<class>class> friend class ::Gecode::RBS;
46 friend class ::Gecode::Search::Seq::RBS;
47 private:
48 /// The failure limit for the engine
49 unsigned long long int l;
50 /// The stop object for the meta engine
51 Stop* m_stop;
52 /// Whether the engine was stopped
53 bool e_stopped;
54 /// Accumulated statistics for the meta engine
55 Statistics m_stat;
56 public:
57 /// Stop the meta engine if indicated by the stop object \a s
58 RestartStop(Stop* s);
59 /// Return true if meta engine must be stopped
60 virtual bool stop(const Statistics& s, const Options& o);
61 /// Set current limit for the engine to \a l fails
62 void limit(const Statistics& s, unsigned long long int l);
63 /// Update statistics
64 void update(const Search::Statistics& s);
65 /// Return whether the engine has been stopped
66 bool enginestopped(void) const;
67 /// Return statistics for the meta engine
68 Statistics metastatistics(void) const;
69 };
70
71 /// Engine for restart-based search
72 class GECODE_SEARCH_EXPORT RBS : public Engine {
73 protected:
74 /// The actual engine
75 Engine* e;
76 /// The master space to restart from
77 Space* master;
78 /// The last solution space (possibly nullptr)
79 Space* last;
80 /// The cutoff object
81 Cutoff* co;
82 /// The stop control object
83 RestartStop* stop;
84 /// How many solutions since the last restart
85 unsigned long int sslr;
86 /// Whether the slave can share info (AFC) with the master
87 bool shared_info;
88 /// Whether search for the next solution will be complete
89 bool complete;
90 /// Whether a restart must be performed when next is called
91 bool restart;
92 /// Whether the engine performs best solution search
93 bool best;
94 public:
95 /// Constructor
96 RBS(Space* s, RestartStop* stop0, Engine* e0,
97 const Search::Statistics& stat, const Options& o, bool best);
98 /// Return next solution (nullptr, if none exists or search has been stopped)
99 virtual Space* next(void);
100 /// Return statistics
101 virtual Statistics statistics(void) const;
102 /// Check whether engine has been stopped
103 virtual bool stopped(void) const;
104 /// Constrain future solutions to be better than \a b
105 virtual void constrain(const Space& b);
106 /// Destructor
107 virtual ~RBS(void);
108 };
109
110}}}
111
112#include <gecode/search/seq/rbs.hpp>
113
114#endif
115
116// STATISTICS: search-seq