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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
35#include <gecode/search/seq/rbs.hh>
36
37namespace Gecode { namespace Search { namespace Seq {
38
39 bool
40 RestartStop::stop(const Statistics& s, const Options& o) {
41 // Stop if the fail limit for the engine says so
42 if (s.fail > l) {
43 e_stopped = true;
44 m_stat.restart++;
45 return true;
46 }
47 // Stop if the stop object for the meta engine says so
48 if ((m_stop != nullptr) && m_stop->stop(m_stat+s,o)) {
49 e_stopped = false;
50 return true;
51 }
52 return false;
53 }
54
55 Space*
56 RBS::next(void) {
57 if (restart) {
58 restart = false;
59 sslr++;
60 NoGoods& ng = e->nogoods();
61 // Reset number of no-goods found
62 ng.ng(0);
63 MetaInfo mi(stop->m_stat.restart,sslr,e->statistics().fail,last,ng);
64 bool r = master->master(mi);
65 stop->m_stat.nogood += ng.ng();
66 if (master->status(stop->m_stat) == SS_FAILED) {
67 stop->update(e->statistics());
68 delete master;
69 master = nullptr;
70 e->reset(nullptr);
71 return nullptr;
72 } else if (r) {
73 stop->update(e->statistics());
74 Space* slave = master;
75 master = master->clone();
76 complete = slave->slave(mi);
77 e->reset(slave);
78 sslr = 0;
79 stop->m_stat.restart++;
80 }
81 }
82 while (true) {
83 Space* n = e->next();
84 if (n != nullptr) {
85 // The engine found a solution
86 restart = true;
87 delete last;
88 last = n->clone();
89 return n;
90 } else if ( (!complete && !e->stopped()) ||
91 (e->stopped() && stop->enginestopped()) ) {
92 // The engine must perform a true restart
93 // The number of the restart has been incremented in the stop object
94 sslr = 0;
95 NoGoods& ng = e->nogoods();
96 ng.ng(0);
97 MetaInfo mi(stop->m_stat.restart,sslr,e->statistics().fail,last,ng);
98 (void) master->master(mi);
99 stop->m_stat.nogood += ng.ng();
100 unsigned long long int nl = ++(*co);
101 stop->limit(e->statistics(),nl);
102 if (master->status(stop->m_stat) == SS_FAILED)
103 return nullptr;
104 Space* slave = master;
105 master = master->clone();
106 complete = slave->slave(mi);
107 e->reset(slave);
108 } else {
109 return nullptr;
110 }
111 }
112 GECODE_NEVER;
113 return nullptr;
114 }
115
116 Search::Statistics
117 RBS::statistics(void) const {
118 return stop->metastatistics()+e->statistics();
119 }
120
121 void
122 RBS::constrain(const Space& b) {
123 if (!best)
124 throw NoBest("RBS::constrain");
125 if (last != nullptr) {
126 last->constrain(b);
127 if (last->status() == SS_FAILED) {
128 delete last;
129 } else {
130 return;
131 }
132 }
133 last = b.clone();
134 master->constrain(b);
135 e->constrain(b);
136 }
137
138 bool
139 RBS::stopped(void) const {
140 /*
141 * What might happen during parallel search is that the
142 * engine has been stopped but the meta engine has not, so
143 * the meta engine does not perform a restart. However the
144 * invocation of next will do so and no restart will be
145 * missed.
146 */
147 return e->stopped();
148 }
149
150 RBS::~RBS(void) {
151 delete e;
152 delete master;
153 delete last;
154 delete co;
155 delete stop;
156 }
157
158}}}
159
160// STATISTICS: search-seq