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int-eq.hpp
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2 /*
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  if (x.size() == 1) {
61  GECODE_ME_CHECK(y.eq(home,1));
62  return ES_OK;
63  }
64 
65  GECODE_ME_CHECK(y.gq(home,1));
66  GECODE_ME_CHECK(y.lq(home,x.size()));
67 
68  if (y.max() == 1) {
69  assert(y.assigned());
70  return Rel::NaryEqDom<IntView>::post(home,x);
71  }
72 
73  if (y.min() == x.size()) {
74  assert(y.assigned());
75  return Distinct::Dom<IntView>::post(home,x);
76  }
77 
78  // Eliminate assigned views and store them into the value set
79  ValSet vs;
80  int n = x.size();
81  for (int i=n; i--; )
82  if (x[i].assigned()) {
83  vs.add(home, x[i].val());
84  x[i] = x[--n];
85  }
86 
87  GECODE_ME_CHECK(y.gq(home,vs.size()));
88  GECODE_ME_CHECK(y.lq(home,n + vs.size()));
89 
90  if (n == 0) {
91  assert(y.val() == vs.size());
92  return ES_OK;
93  }
94  x.size(n);
95  (void) new (home) EqInt<VY>(home, vs, x, y);
96  return ES_OK;
97  }
98 
99  template<class VY>
101  EqInt<VY>::EqInt(Space& home, bool share, EqInt<VY>& p)
102  : IntBase<VY>(home, share, p) {}
103 
104  template<class VY>
105  Propagator*
106  EqInt<VY>::copy(Space& home, bool share) {
107  return new (home) EqInt<VY>(home, share, *this);
108  }
109 
110  template<class VY>
111  forceinline size_t
113  home.ignore(*this, AP_WEAKLY);
114  (void) IntBase<VY>::dispose(home);
115  return sizeof(*this);
116  }
117 
118  template<class VY>
119  ExecStatus
121  // Add assigned views to value set
122  if (IntView::me(med) == ME_INT_VAL)
123  add(home);
124 
125  GECODE_ME_CHECK(y.gq(home, vs.size()));
126  GECODE_ME_CHECK(y.lq(home, x.size() + vs.size()));
127 
128  if (x.size() == 0)
129  return home.ES_SUBSUMED(*this);
130 
131  // All values must be in the value set
132  if (y.max() == vs.size())
133  return all_in_valset(home);
134 
135  // Compute positions of disjoint views and eliminate subsumed views
136  Region r(home);
137  int* dis; int n_dis;
138  disjoint(home,r,dis,n_dis);
139 
140  // The number might have changed due to elimination of subsumed views
141  GECODE_ME_CHECK(y.lq(home, x.size() + vs.size()));
142 
143  if (x.size() == 0) {
144  assert(y.val() == vs.size());
145  return home.ES_SUBSUMED(*this);
146  }
147 
148  GECODE_ES_CHECK(prune_upper(home,g));
149 
150  // No lower bound pruning possible
151  if (n_dis == 0)
152  return ES_NOFIX;
153 
154  // Only if the propagator is at fixpoint here, continue with
155  // propagating the lower bound
157  return ES_NOFIX;
158 
159  // Do lower bound-based pruning
160  GECODE_ES_CHECK(prune_lower(home,dis,n_dis));
161 
162  return ES_NOFIX;
163  }
164 
165 }}}
166 
167 // STATISTICS: int-prop