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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 * Contributing authors:
7 * Mikael Lagerkvist <lagerkvist@gecode.org>
8 *
9 * Copyright:
10 * Guido Tack, 2004
11 * Mikael Lagerkivst, 2017
12 *
13 * This file is part of Gecode, the generic constraint
14 * development environment:
15 * http://www.gecode.org
16 *
17 * Permission is hereby granted, free of charge, to any person obtaining
18 * a copy of this software and associated documentation files (the
19 * "Software"), to deal in the Software without restriction, including
20 * without limitation the rights to use, copy, modify, merge, publish,
21 * distribute, sublicense, and/or sell copies of the Software, and to
22 * permit persons to whom the Software is furnished to do so, subject to
23 * the following conditions:
24 *
25 * The above copyright notice and this permission notice shall be
26 * included in all copies or substantial portions of the Software.
27 *
28 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
29 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
30 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
31 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
32 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
33 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
34 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
35 *
36 */
37
38#include <gecode/driver.hh>
39#include <gecode/int.hh>
40#include <gecode/set.hh>
41
42using namespace Gecode;
43
44/// \brief %Options for %Golf example
45class GolfOptions : public Options {
46protected:
47 Driver::IntOption _w; //< Number of weeks
48 Driver::IntOption _g; //< Number of groups
49 Driver::IntOption _s; //< Number of players per group
50public:
51 /// Constructor
52 GolfOptions(void)
53 : Options("Golf"),
54 _w("w","number of weeks",9),
55 _g("g","number of groups",8),
56 _s("s","number of players per group",4) {
57 add(_w);
58 add(_g);
59 add(_s);
60 }
61 /// Return number of weeks
62 int w(void) const { return _w.value(); }
63 /// Return number of groups
64 int g(void) const { return _g.value(); }
65 /// Return number of players per group
66 int s(void) const { return _s.value(); }
67};
68
69/**
70 * \brief %Example: %Golf tournament
71 *
72 * Schedule a golf tournament. This is problem 010 from csplib.
73 *
74 * Note that "Modeling and Programming with Gecode" uses this example
75 * as a case study.
76 *
77 * \ingroup Example
78 *
79 */
80class Golf : public Script {
81public:
82 /// Model variants
83 enum {
84 MODEL_PLAIN, ///< A simple model
85 MODEL_SYMMETRY ///< Model with symmetry breaking
86 };
87 /// Propagation
88 enum {
89 PROP_SET, ///< Propagation of pair play amount using set variables
90 PROP_INT, ///< Propagation of pair play amount using int variables and distinct
91 PROP_MIXED, ///< Propagation of pair play amount using both set and int variables
92 };
93 int g; ///< Number of groups in a week
94 int s; ///< Number of players in a group
95 int w; ///< Number of weeks
96
97 /// The sets representing the groups
98 SetVarArray groups;
99
100 /// Actual model
101 Golf(const GolfOptions& opt)
102 : Script(opt),
103 g(opt.g()), s(opt.s()), w(opt.w()),
104 groups(*this,g*w,IntSet::empty,0,g*s-1,
105 static_cast<unsigned int>(s),static_cast<unsigned int>(s)) {
106 Matrix<SetVarArray> schedule(groups,g,w);
107
108 // Groups in one week must be disjoint
109 SetVar allPlayers(*this, 0,g*s-1, 0,g*s-1);
110 for (int i=0; i<w; i++)
111 rel(*this, setdunion(schedule.row(i)) == allPlayers);
112
113 // No two golfers play in the same group more than once
114 if (opt.propagation() == PROP_SET || opt.propagation() == PROP_MIXED) {
115 // Cardinality of intersection between two groups is at most one
116 for (int i=0; i<groups.size()-1; i++)
117 for (int j=i+1; j<groups.size(); j++)
118 rel(*this, cardinality(groups[i] & groups[j]) <= 1);
119 }
120 if (opt.propagation() == PROP_INT || opt.propagation() == PROP_MIXED) {
121 // Set up table mapping from pairs (p1,p2) (where p1<p2) of players to
122 // unique integer identifiers
123 int playerCount = g * s;
124 TupleSet ts(3);
125 int pairCount=0;
126 for (int p1=0; p1<playerCount-1; p1++)
127 for (int p2=p1+1; p2<playerCount; p2++)
128 ts.add({p1, p2, pairCount++});
129 ts.finalize();
130
131 // Collect pairs of golfers into pairs
132 IntVarArgs pairs;
133 for (int i=0; i<groups.size()-1; i++) {
134 // Channel sorted will ensure that for i<j, group[i]<group[j],
135 // ensuring that the tuple set has a valid mapping.
136 IntVarArgs group(*this, s, 0, playerCount-1);
137 channelSorted(*this, group, groups[i]);
138 // Collect all pairs in current group
139 for (int p1=0; p1<group.size()-1; ++p1) {
140 for (int p2=p1+1; p2<group.size(); ++p2) {
141 IntVar pair(*this, 0, pairCount);
142
143 IntVarArgs args;
144 args << group[p1] << group[p2] << pair;
145 extensional(*this, args, ts);
146
147 pairs << pair;
148 }
149 }
150 }
151
152 // All pairs of golfers (using the unique identifiers) must be different
153 distinct(*this, pairs, opt.ipl());
154 }
155
156 if (opt.model() == MODEL_SYMMETRY) {
157
158 /*
159 * Redundant constraints and static symmetry breaking from
160 * "Solving Kirkman's Schoolgirl Problem in a Few Seconds"
161 * Nicolas Barnier, Pascal Brisset, Constraints, 10, 7-21, 2005
162 *
163 */
164
165 // Redundant constraint:
166 // in each week, one player plays in only one group
167 for (int j=0; j<w; j++) {
168 for (int p=0; p < g*s; p++) {
169 BoolVarArgs b(g);
170 for (int i=0; i<g; i++)
171 b[i] = expr(*this, (singleton(p) <= schedule(i,j)));
172 linear(*this, b, IRT_EQ, 1);
173 }
174 }
175
176 // Symmetry breaking: order groups
177 for (int j=0; j<w; j++) {
178 IntVarArgs m(g);
179 for (int i=0; i<g; i++)
180 m[i] = expr(*this, min(schedule(i,j)));
181 rel(*this, m, IRT_LE);
182 }
183
184 // Symmetry breaking: order weeks
185 // minElem(group(w,0)\{0}) < minElem(group(w+1,0)\{0})
186 {
187 IntVarArgs m(w);
188 for (int i=0; i<w; i++)
189 m[i] = expr(*this, min(schedule(0,i)-IntSet(0,0)));
190 rel(*this, m, IRT_LE);
191 }
192
193 // Symmetry breaking: value symmetry of player numbers
194 precede(*this, groups, IntArgs::create(groups.size(),0));
195 }
196
197 branch(*this, groups, SET_VAR_MIN_MIN(), SET_VAL_MIN_INC());
198 }
199
200 /// Print solution
201 virtual void
202 print(std::ostream& os) const {
203 os << "Tournament plan" << std::endl;
204 Matrix<SetVarArray> schedule(groups,g,w);
205 for (int j=0; j<w; j++) {
206 os << "Week " << j << ": " << std::endl << " ";
207 os << schedule.row(j) << std::endl;
208 }
209 }
210
211 /// Constructor for copying \a s
212 Golf(Golf& s) : Script(s), g(s.g), s(s.s), w(s.w) {
213 groups.update(*this, s.groups);
214 }
215 /// Copy during cloning
216 virtual Space*
217 copy(void) {
218 return new Golf(*this);
219 }
220};
221
222/** \brief Main-function
223 * \relates Golf
224 */
225int
226main(int argc, char* argv[]) {
227 GolfOptions opt;
228 opt.model(Golf::MODEL_PLAIN);
229 opt.model(Golf::MODEL_PLAIN, "none", "no symmetry breaking");
230 opt.model(Golf::MODEL_SYMMETRY, "symmetry", "static symmetry breaking");
231 opt.propagation(Golf::PROP_SET);
232 opt.propagation(Golf::PROP_SET, "set", "Use set intersection cardinality for pair play constraints");
233 opt.propagation(Golf::PROP_INT, "int", "Use integer distinct for pair play constraints");
234 opt.propagation(Golf::PROP_MIXED, "mixed", "Use set interesection cardinality and integer distinct for pair play constraints");
235 opt.ipl(IPL_DOM);
236 opt.solutions(1);
237 opt.parse(argc,argv);
238 Script::run<Golf,DFS,GolfOptions>(opt);
239 return 0;
240}
241
242// STATISTICS: example-any