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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, 2011
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#include <gecode/int/rel.hh>
35#include <gecode/int/distinct.hh>
36
37namespace Gecode { namespace Int { namespace NValues {
38
39 template<class VY>
40 forceinline
41 EqInt<VY>::EqInt(Home home, ValSet& vs, ViewArray<IntView>& x, VY y)
42 : IntBase<VY>(home,vs,x,y) {
43 home.notice(*this, AP_WEAKLY);
44 }
45
46 template<class VY>
47 inline ExecStatus
48 EqInt<VY>::post(Home home, ViewArray<IntView>& x, VY y) {
49 if (x.size() == 0) {
50 GECODE_ME_CHECK(y.eq(home,0));
51 return ES_OK;
52 }
53
54 x.unique();
55
56 if (x.size() == 1) {
57 GECODE_ME_CHECK(y.eq(home,1));
58 return ES_OK;
59 }
60
61 GECODE_ME_CHECK(y.gq(home,1));
62 GECODE_ME_CHECK(y.lq(home,x.size()));
63
64 if (y.max() == 1) {
65 assert(y.assigned());
66 return Rel::NaryEqDom<IntView>::post(home,x);
67 }
68
69 if (y.min() == x.size()) {
70 assert(y.assigned());
71 return Distinct::Dom<IntView>::post(home,x);
72 }
73
74 // Eliminate assigned views and store them into the value set
75 ValSet vs;
76 int n = x.size();
77 for (int i=n; i--; )
78 if (x[i].assigned()) {
79 vs.add(home, x[i].val());
80 x[i] = x[--n];
81 }
82
83 GECODE_ME_CHECK(y.gq(home,vs.size()));
84 GECODE_ME_CHECK(y.lq(home,n + vs.size()));
85
86 if (n == 0) {
87 assert(y.val() == vs.size());
88 return ES_OK;
89 }
90 x.size(n);
91 (void) new (home) EqInt<VY>(home, vs, x, y);
92 return ES_OK;
93 }
94
95 template<class VY>
96 forceinline
97 EqInt<VY>::EqInt(Space& home, EqInt<VY>& p)
98 : IntBase<VY>(home, p) {}
99
100 template<class VY>
101 Propagator*
102 EqInt<VY>::copy(Space& home) {
103 return new (home) EqInt<VY>(home, *this);
104 }
105
106 template<class VY>
107 forceinline size_t
108 EqInt<VY>::dispose(Space& home) {
109 home.ignore(*this, AP_WEAKLY);
110 (void) IntBase<VY>::dispose(home);
111 return sizeof(*this);
112 }
113
114 template<class VY>
115 ExecStatus
116 EqInt<VY>::propagate(Space& home, const ModEventDelta& med) {
117 // Add assigned views to value set
118 if (IntView::me(med) == ME_INT_VAL)
119 add(home);
120
121 GECODE_ME_CHECK(y.gq(home, vs.size()));
122 GECODE_ME_CHECK(y.lq(home, x.size() + vs.size()));
123
124 if (x.size() == 0)
125 return home.ES_SUBSUMED(*this);
126
127 // All values must be in the value set
128 if (y.max() == vs.size())
129 return all_in_valset(home);
130
131 // Compute positions of disjoint views and eliminate subsumed views
132 Region r;
133 int* dis; int n_dis;
134 disjoint(home,r,dis,n_dis);
135
136 // The number might have changed due to elimination of subsumed views
137 GECODE_ME_CHECK(y.lq(home, x.size() + vs.size()));
138
139 if (x.size() == 0) {
140 assert(y.val() == vs.size());
141 return home.ES_SUBSUMED(*this);
142 }
143
144 GECODE_ES_CHECK(prune_upper(home,g));
145
146 // No lower bound pruning possible
147 if (n_dis == 0)
148 return ES_NOFIX;
149
150 // Only if the propagator is at fixpoint here, continue with
151 // propagating the lower bound
152 if (IntView::me(Propagator::modeventdelta()) != ME_INT_NONE)
153 return ES_NOFIX;
154
155 // Do lower bound-based pruning
156 GECODE_ES_CHECK(prune_lower(home,dis,n_dis));
157
158 return ES_NOFIX;
159 }
160
161}}}
162
163// STATISTICS: int-prop