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int-lq.hpp
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3  * Main authors:
4  * Christian Schulte <schulte@gecode.org>
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6  * Copyright:
7  * Christian Schulte, 2011
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10  * $Date: 2011-08-18 17:41:50 +1000 (Thu, 18 Aug 2011) $ by $Author: tack $
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37 
38 #include <gecode/int/rel.hh>
39 #include <gecode/int/distinct.hh>
40 
41 namespace Gecode { namespace Int { namespace NValues {
42 
43  template<class VY>
46  : IntBase<VY>(home,vs,x,y) {
47  home.notice(*this, AP_WEAKLY);
48  }
49 
50  template<class VY>
51  inline ExecStatus
53  if (x.size() == 0) {
54  GECODE_ME_CHECK(y.eq(home,0));
55  return ES_OK;
56  }
57 
58  x.unique(home);
59 
60  GECODE_ME_CHECK(y.gq(home,1));
61 
62  if (x.size() == 1)
63  return ES_OK;
64 
65  if (y.max() == 1) {
66  assert(y.assigned());
67  return Rel::NaryEqDom<IntView>::post(home,x);
68  }
69 
70  if (y.min() >= x.size())
71  return ES_OK;
72 
73  // Eliminate assigned views and store them into the value set
74  ValSet vs;
75  int n = x.size();
76  for (int i=n; i--; )
77  if (x[i].assigned()) {
78  vs.add(home, x[i].val());
79  x[i] = x[--n];
80  }
81 
82  GECODE_ME_CHECK(y.gq(home,vs.size()));
83 
84  if (n == 0) {
85  assert(y.min() >= vs.size());
86  return ES_OK;
87  }
88 
89  x.size(n);
90 
91  (void) new (home) LqInt<VY>(home, vs, x, y);
92  return ES_OK;
93  }
94 
95  template<class VY>
97  LqInt<VY>::LqInt(Space& home, bool share, LqInt<VY>& p)
98  : IntBase<VY>(home, share, p) {}
99 
100  template<class VY>
101  Propagator*
102  LqInt<VY>::copy(Space& home, bool share) {
103  return new (home) LqInt<VY>(home, share, *this);
104  }
105 
106  template<class VY>
107  forceinline size_t
109  home.ignore(*this, AP_WEAKLY);
110  (void) IntBase<VY>::dispose(home);
111  return sizeof(*this);
112  }
113 
114  template<class VY>
115  ExecStatus
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 
123  if (x.size() == 0)
124  return home.ES_SUBSUMED(*this);
125 
126  // All values must be in the value set
127  if (y.max() == vs.size())
128  return all_in_valset(home);
129 
130  if (x.size() + vs.size() <= y.min())
131  return home.ES_SUBSUMED(*this);
132 
133  // Compute positions of disjoint views
134  Region r(home);
135  int* dis; int n_dis;
136  disjoint(home,r,dis,n_dis);
137 
138  // Some views might have been eliminated as they are subsumed
139  if (x.size() == 0)
140  return home.ES_SUBSUMED(*this);
141 
142  // No lower bound pruning possible
143  if (n_dis == 0)
144  return ES_NOFIX;
145 
146  // Do lower bound-based pruning
147  GECODE_ES_CHECK(prune_lower(home,dis,n_dis));
148 
149  return ES_NOFIX;
150  }
151 
152 }}}
153 
154 // STATISTICS: int-prop