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dekker.one
1/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
2/*
3 * Main authors:
4 * Christian Schulte <schulte@gecode.org>
5 *
6 * Copyright:
7 * Christian Schulte, 2006
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
34namespace Gecode { namespace Int { namespace Bool {
35
36 /*
37 * Less or equal propagator
38 *
39 */
40
41 template<class BV>
42 forceinline
43 Lq<BV>::Lq(Home home, BV b0, BV b1)
44 : BoolBinary<BV,BV>(home,b0,b1) {}
45
46 template<class BV>
47 forceinline
48 Lq<BV>::Lq(Space& home, Lq<BV>& p)
49 : BoolBinary<BV,BV>(home,p) {}
50
51 template<class BV>
52 Actor*
53 Lq<BV>::copy(Space& home) {
54 return new (home) Lq<BV>(home,*this);
55 }
56
57 template<class BV>
58 inline ExecStatus
59 Lq<BV>::post(Home home, BV b0, BV b1) {
60 if (b0.zero()) {
61 return ES_OK;
62 } else if (b0.one()) {
63 GECODE_ME_CHECK(b1.one(home));
64 } else if (b1.zero()) {
65 GECODE_ME_CHECK(b0.zero(home));
66 } else if (b1.one()) {
67 return ES_OK;
68 } else {
69 (void) new (home) Lq<BV>(home,b0,b1);
70 }
71 return ES_OK;
72 }
73
74 template<class BV>
75 ExecStatus
76 Lq<BV>::propagate(Space& home, const ModEventDelta&) {
77#define GECODE_INT_STATUS(S0,S1) \
78 ((BV::S0<<(1*BV::BITS))|(BV::S1<<(0*BV::BITS)))
79 switch ((x0.status()<<(1*BV::BITS)) | (x1.status()<<(0*BV::BITS))) {
80 case GECODE_INT_STATUS(NONE,NONE):
81 GECODE_NEVER;
82 case GECODE_INT_STATUS(NONE,ZERO):
83 GECODE_ME_CHECK(x0.zero_none(home)); break;
84 case GECODE_INT_STATUS(NONE,ONE):
85 case GECODE_INT_STATUS(ZERO,NONE):
86 case GECODE_INT_STATUS(ZERO,ZERO):
87 case GECODE_INT_STATUS(ZERO,ONE):
88 break;
89 case GECODE_INT_STATUS(ONE,NONE):
90 GECODE_ME_CHECK(x1.one_none(home)); break;
91 case GECODE_INT_STATUS(ONE,ZERO):
92 return ES_FAILED;
93 case GECODE_INT_STATUS(ONE,ONE):
94 break;
95 default:
96 GECODE_NEVER;
97 }
98 return home.ES_SUBSUMED(*this);
99#undef GECODE_INT_STATUS
100 }
101
102
103 /*
104 * N-ary Boolean less or equal propagator
105 *
106 */
107
108 template<class VX>
109 forceinline
110 NaryLq<VX>::NaryLq(Home home, ViewArray<VX>& x)
111 : NaryPropagator<VX,PC_BOOL_NONE>(home,x),
112 run(false), n_zero(0), n_one(0), c(home) {
113 x.subscribe(home,*new (home) Advisor(home,*this,c));
114 }
115
116 template<class VX>
117 forceinline
118 NaryLq<VX>::NaryLq(Space& home, NaryLq<VX>& p)
119 : NaryPropagator<VX,PC_BOOL_NONE>(home,p),
120 run(false), n_zero(0), n_one(0) {
121 c.update(home,p.c);
122 }
123
124 template<class VX>
125 Actor*
126 NaryLq<VX>::copy(Space& home) {
127 return new (home) NaryLq<VX>(home,*this);
128 }
129
130 template<class VX>
131 inline ExecStatus
132 NaryLq<VX>::post(Home home, ViewArray<VX>& x) {
133 int i = 0;
134 while (i < x.size())
135 if (x[i].zero()) {
136 // All x[j] left of i must be zero as well
137 for (int j=0; j<i; j++)
138 GECODE_ME_CHECK(x[j].zero_none(home));
139 x.drop_fst(i+1); i=0;
140 } else if (x[i].one()) {
141 // All x[j] right of i must be one as well
142 for (int j=i+1; j<x.size(); j++)
143 GECODE_ME_CHECK(x[j].one(home));
144 x.drop_lst(i-1); break;
145 } else {
146 i++;
147 }
148
149 if (x.size() == 2)
150 return Lq<VX>::post(home,x[0],x[1]);
151 if (x.size() > 2)
152 (void) new (home) NaryLq(home,x);
153 return ES_OK;
154 }
155
156 template<class VX>
157 PropCost
158 NaryLq<VX>::cost(const Space&, const ModEventDelta&) const {
159 return PropCost::binary(PropCost::LO);
160 }
161
162 template<class VX>
163 ExecStatus
164 NaryLq<VX>::advise(Space&, Advisor&, const Delta& d) {
165 if (VX::zero(d))
166 n_zero++;
167 else
168 n_one++;
169 return run ? ES_FIX : ES_NOFIX;
170 }
171
172 template<class VX>
173 forceinline size_t
174 NaryLq<VX>::dispose(Space& home) {
175 Advisors<Advisor> as(c);
176 x.cancel(home,as.advisor());
177 c.dispose(home);
178 (void) NaryPropagator<VX,PC_BOOL_NONE>::dispose(home);
179 return sizeof(*this);
180 }
181
182 template<class VX>
183 ExecStatus
184 NaryLq<VX>::propagate(Space& home, const ModEventDelta&) {
185 run = true;
186 while (n_zero > 0) {
187 int i = 0;
188 while (x[i].none())
189 i++;
190 if (x[i].one())
191 return ES_FAILED;
192 // As the x[j] might be shared, only zero() but not zero_none()
193 for (int j=0; j<i; j++)
194 GECODE_ME_CHECK(x[j].zero(home));
195 n_zero -= i + 1;
196 assert(n_zero >= 0);
197 x.drop_fst(i+1);
198 }
199
200 while (n_one > 0) {
201 int i = x.size() - 1;
202 while (x[i].none())
203 i--;
204 assert(x[i].one());
205 // As the x[j] might be shared, only one() but not one_none()
206 for (int j=i+1; j<x.size(); j++)
207 GECODE_ME_CHECK(x[j].one(home));
208 n_one -= x.size() - i;
209 assert(n_one >= 0);
210 x.drop_lst(i-1);
211 }
212
213 if (x.size() < 2)
214 return home.ES_SUBSUMED(*this);
215
216 run = false;
217 return ES_FIX;
218 }
219
220
221 /*
222 * Less posting
223 *
224 */
225
226 template<class BV>
227 forceinline ExecStatus
228 Le<BV>::post(Home home, BV b0, BV b1) {
229 GECODE_ME_CHECK(b0.zero(home));
230 GECODE_ME_CHECK(b1.one(home));
231 return ES_OK;
232 }
233
234}}}
235
236// STATISTICS: int-prop
237