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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 * Christian Schulte <schulte@gecode.org>
6 * Gabor Szokoli <szokoli@gecode.org>
7 *
8 * Copyright:
9 * Guido Tack, 2004
10 * Christian Schulte, 2004
11 * Gabor Szokoli, 2004
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
39
40#include <gecode/set.hh>
41#include <gecode/int.hh>
42#include <gecode/set/rel.hh>
43
44namespace Gecode { namespace Set { namespace Channel {
45
46 template<class View>
47 forceinline
48 ChannelSorted<View>::ChannelSorted(Home home, View y0,
49 ViewArray< Gecode::Int::IntView >& ys)
50 : Propagator(home), x0(y0), xs(ys) {
51 x0.subscribe(home,*this, PC_SET_ANY);
52 xs.subscribe(home,*this, Gecode::Int::PC_INT_BND);
53 }
54
55 template<class View>
56 forceinline
57 ChannelSorted<View>::ChannelSorted(Space& home, ChannelSorted& p)
58 : Propagator(home,p) {
59 x0.update(home,p.x0);
60 xs.update(home,p.xs);
61 }
62
63 template<class View>
64 forceinline ExecStatus
65 ChannelSorted<View>::post(Home home, View x0,
66 ViewArray<Gecode::Int::IntView>& xs) {
67 unsigned int xs_size = static_cast<unsigned int>(xs.size());
68 GECODE_ME_CHECK(x0.cardMin(home,xs_size));
69 GECODE_ME_CHECK(x0.cardMax(home,xs_size));
70 if (xs_size == 1) {
71 SingletonView sv(xs[0]);
72 GECODE_ES_CHECK((Rel::Eq<View,
73 SingletonView>::post(home,x0, sv)));
74 } else {
75 // Sharing in xs is handled correctly in the propagator:
76 // if two views in xs are shared, this leads to failure.
77 (void) new (home) ChannelSorted(home,x0,xs);
78 }
79 return ES_OK;
80 }
81
82 template<class View>
83 PropCost
84 ChannelSorted<View>::cost(const Space&, const ModEventDelta&) const {
85 return PropCost::linear(PropCost::LO, xs.size()+1);
86 }
87
88 template<class View>
89 void
90 ChannelSorted<View>::reschedule(Space& home) {
91 x0.reschedule(home,*this, PC_SET_ANY);
92 xs.reschedule(home,*this, Gecode::Int::PC_INT_BND);
93 }
94
95 template<class View>
96 forceinline size_t
97 ChannelSorted<View>::dispose(Space& home) {
98 x0.cancel(home,*this, PC_SET_ANY);
99 xs.cancel(home,*this, Gecode::Int::PC_INT_BND);
100 (void) Propagator::dispose(home);
101 return sizeof(*this);
102 }
103
104 template<class View>
105 Actor*
106 ChannelSorted<View>::copy(Space& home) {
107 return new (home) ChannelSorted(home,*this);
108 }
109
110 template<class View>
111 ExecStatus
112 ChannelSorted<View>::propagate(Space& home, const ModEventDelta&) {
113
114 int xs_size = xs.size();
115
116 bool loopFlag;
117
118 do {
119 loopFlag = false;
120
121 // Order int vars in xs
122 GECODE_ME_CHECK(xs[0].gq(home,x0.lubMin()));
123 for (int i=xs_size-1; i--; ) {
124 GECODE_ME_CHECK_MODIFIED(loopFlag, xs[i+1].gq(home,xs[i].min() + 1));
125 }
126
127 GECODE_ME_CHECK_MODIFIED(loopFlag, xs[xs_size-1].lq(home,x0.lubMax()));
128 for (int i=xs_size-2; i--; ) {
129 GECODE_ME_CHECK_MODIFIED(loopFlag, xs[i].lq(home,xs[i+1].max() - 1));
130 }
131
132 // if y from xs is assigned, add to glb(x0)
133 for (int i=xs_size; i--; ) {
134 if (xs[i].assigned()) {
135 GECODE_ME_CHECK_MODIFIED(loopFlag, x0.include(home,xs[i].val()));
136 }
137 }
138
139 // intersect every y in xs with lub(x0)
140 for (int i=xs_size; i--; ) {
141 LubRanges<View> ub(x0);
142 GECODE_ME_CHECK_MODIFIED(loopFlag, xs[i].inter_r(home,ub,false));
143 }
144
145 // remove gaps between vars in xs from lub(x0)
146 GECODE_ME_CHECK_MODIFIED(loopFlag,
147 x0.exclude(home,Limits::min,xs[0].min()-1));
148 GECODE_ME_CHECK_MODIFIED(loopFlag,
149 x0.exclude(home,xs[xs_size-1].max()+1,
150 Limits::max));
151
152 for (int i=xs_size-1; i--; ) {
153 int start = xs[i].max() + 1;
154 int end = xs[i+1].min() - 1;
155 if (start<=end) {
156 GECODE_ME_CHECK_MODIFIED(loopFlag, x0.exclude(home,start,end));
157 }
158 }
159
160 // try to assign vars in xs from glb(x0)
161 if (x0.glbSize()>0) {
162
163 LubRanges<View> ub(x0);
164 Iter::Ranges::ToValues<LubRanges<View> > ubv(ub);
165 GlbRanges<View> lb(x0);
166 Iter::Ranges::ToValues<GlbRanges<View> > lbv(lb);
167
168 int i=0;
169 for (; ubv() && lbv() && ubv.val()==lbv.val();
170 ++ubv, ++lbv, i++) {
171 GECODE_ME_CHECK_MODIFIED(loopFlag, xs[i].eq(home,lbv.val()));
172 }
173
174 if (i<xs_size-1 && x0.lubMax()==x0.glbMax()) {
175 LubRanges<View> lbx0(x0);
176 GlbRanges<View> ubx0(x0);
177 Iter::Ranges::Inter<LubRanges<View>,GlbRanges<View> >
178 inter(lbx0, ubx0);
179
180 int to = x0.glbMax();
181 int from = to;
182 while (inter()) {
183 from = inter.min();
184 ++inter;
185 }
186
187 int k=xs_size-1;
188 for (int j=to; j>=from;j--,k--) {
189 GECODE_ME_CHECK_MODIFIED(loopFlag, xs[k].eq(home,j));
190 }
191 }
192 }
193
194 } while (loopFlag);
195
196 for (int i=xs_size; i--; )
197 if (!xs[i].assigned())
198 return ES_FIX;
199 return home.ES_SUBSUMED(*this);
200 }
201
202}}}
203
204// STATISTICS: set-prop