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lq.hpp
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3  * Main authors:
4  * Christian Schulte <schulte@gecode.org>
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6  * Copyright:
7  * Christian Schulte, 2006
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10  * $Date: 2011-06-20 19:16:03 +1000 (Mon, 20 Jun 2011) $ by $Author: schulte $
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37 
38 namespace Gecode { namespace Int { namespace Bool {
39 
40  /*
41  * Less or equal propagator
42  *
43  */
44 
45  template<class BV>
47  Lq<BV>::Lq(Home home, BV b0, BV b1)
48  : BoolBinary<BV,BV>(home,b0,b1) {}
49 
50  template<class BV>
52  Lq<BV>::Lq(Space& home, bool share, Lq<BV>& p)
53  : BoolBinary<BV,BV>(home,share,p) {}
54 
55  template<class BV>
56  Actor*
57  Lq<BV>::copy(Space& home, bool share) {
58  return new (home) Lq<BV>(home,share,*this);
59  }
60 
61  template<class BV>
62  inline ExecStatus
63  Lq<BV>::post(Home home, BV b0, BV b1) {
64  if (b0.zero()) {
65  return ES_OK;
66  } else if (b0.one()) {
67  GECODE_ME_CHECK(b1.one(home));
68  } else if (b1.zero()) {
69  GECODE_ME_CHECK(b0.zero(home));
70  } else if (b1.one()) {
71  return ES_OK;
72  } else {
73  (void) new (home) Lq<BV>(home,b0,b1);
74  }
75  return ES_OK;
76  }
77 
78  template<class BV>
81 #define GECODE_INT_STATUS(S0,S1) \
82  ((BV::S0<<(1*BV::BITS))|(BV::S1<<(0*BV::BITS)))
83  switch ((x0.status()<<(1*BV::BITS)) | (x1.status()<<(0*BV::BITS))) {
84  case GECODE_INT_STATUS(NONE,NONE):
86  case GECODE_INT_STATUS(NONE,ZERO):
87  GECODE_ME_CHECK(x0.zero_none(home)); break;
88  case GECODE_INT_STATUS(NONE,ONE):
89  case GECODE_INT_STATUS(ZERO,NONE):
90  case GECODE_INT_STATUS(ZERO,ZERO):
91  case GECODE_INT_STATUS(ZERO,ONE):
92  break;
93  case GECODE_INT_STATUS(ONE,NONE):
94  GECODE_ME_CHECK(x1.one_none(home)); break;
95  case GECODE_INT_STATUS(ONE,ZERO):
96  return ES_FAILED;
97  case GECODE_INT_STATUS(ONE,ONE):
98  break;
99  default:
100  GECODE_NEVER;
101  }
102  return home.ES_SUBSUMED(*this);
103 #undef GECODE_INT_STATUS
104  }
105 
106 
107  /*
108  * N-ary Boolean less or equal propagator
109  *
110  */
111 
112  template<class VX>
115  : NaryPropagator<VX,PC_BOOL_NONE>(home,x),
116  run(false), n_zero(0), n_one(0), c(home) {
117  x.subscribe(home,*new (home) Advisor(home,*this,c));
118  }
119 
120  template<class VX>
122  NaryLq<VX>::NaryLq(Space& home, bool share, NaryLq<VX>& p)
123  : NaryPropagator<VX,PC_BOOL_NONE>(home,share,p),
124  run(false), n_zero(0), n_one(0) {
125  c.update(home,share,p.c);
126  }
127 
128  template<class VX>
129  Actor*
130  NaryLq<VX>::copy(Space& home, bool share) {
131  return new (home) NaryLq<VX>(home,share,*this);
132  }
133 
134  template<class VX>
135  inline ExecStatus
137  int i = 0;
138  while (i < x.size())
139  if (x[i].zero()) {
140  // All x[j] left of i must be zero as well
141  for (int j=i; j--; )
142  GECODE_ME_CHECK(x[j].zero_none(home));
143  x.drop_fst(i+1); i=0;
144  } else if (x[i].one()) {
145  // All x[j] right of i must be one as well
146  for (int j=i+1; j<x.size(); j++)
147  GECODE_ME_CHECK(x[j].one(home));
148  x.drop_lst(i-1); break;
149  } else {
150  i++;
151  }
152 
153  if (x.size() == 2)
154  return Lq<VX>::post(home,x[0],x[1]);
155  if (x.size() > 2)
156  (void) new (home) NaryLq(home,x);
157  return ES_OK;
158  }
159 
160  template<class VX>
161  PropCost
162  NaryLq<VX>::cost(const Space&, const ModEventDelta&) const {
164  }
165 
166  template<class VX>
167  ExecStatus
169  if (VX::zero(d))
170  n_zero++;
171  else
172  n_one++;
173  return run ? ES_FIX : ES_NOFIX;
174  }
175 
176  template<class VX>
177  forceinline size_t
179  Advisors<Advisor> as(c);
180  x.cancel(home,as.advisor());
181  c.dispose(home);
183  return sizeof(*this);
184  }
185 
186  template<class VX>
187  ExecStatus
189  run = true;
190  while (n_zero > 0) {
191  int i = 0;
192  while (x[i].none())
193  i++;
194  if (x[i].one())
195  return ES_FAILED;
196  // As the x[j] might be shared, only zero() but not zero_none()
197  for (int j=i; j--; )
198  GECODE_ME_CHECK(x[j].zero(home));
199  n_zero -= i + 1;
200  assert(n_zero >= 0);
201  x.drop_fst(i+1);
202  }
203 
204  while (n_one > 0) {
205  int i = x.size() - 1;
206  while (x[i].none())
207  i--;
208  assert(x[i].one());
209  // As the x[j] might be shared, only one() but not one_none()
210  for (int j=i+1; j<x.size(); j++)
211  GECODE_ME_CHECK(x[j].one(home));
212  n_one -= x.size() - i;
213  assert(n_one >= 0);
214  x.drop_lst(i-1);
215  }
216 
217  if (x.size() < 2)
218  return home.ES_SUBSUMED(*this);
219 
220  run = false;
221  return ES_FIX;
222  }
223 
224 
225  /*
226  * Less posting
227  *
228  */
229 
230  template<class BV>
232  Le<BV>::post(Home home, BV b0, BV b1) {
233  GECODE_ME_CHECK(b0.zero(home));
234  GECODE_ME_CHECK(b1.one(home));
235  return ES_OK;
236  }
237 
238 }}}
239 
240 // STATISTICS: int-prop
241