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eqv.hpp
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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, 2004
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33 
34 namespace Gecode { namespace Int { namespace Bool {
35 
36  template<class BVA, class BVB, class BVC>
38  Eqv<BVA,BVB,BVC>::Eqv(Home home, BVA b0, BVB b1, BVC b2)
39  : BoolTernary<BVA,BVB,BVC>(home,b0,b1,b2) {}
40 
41  template<class BVA, class BVB, class BVC>
44  : BoolTernary<BVA,BVB,BVC>(home,p) {}
45 
46  template<class BVA, class BVB, class BVC>
47  inline ExecStatus
48  Eqv<BVA,BVB,BVC>::post(Home home, BVA b0, BVB b1, BVC b2){
49  switch (bool_test(b0,b1)) {
50  case BT_SAME:
51  GECODE_ME_CHECK(b2.one(home)); break;
52  case BT_COMP:
53  GECODE_ME_CHECK(b2.zero(home)); break;
54  case BT_NONE:
55  if (b2.one())
56  return Eq<BVA,BVB>::post(home,b0,b1);
57  if (b0.one()) {
58  if (b1.one()) {
59  GECODE_ME_CHECK(b2.one(home)); return ES_OK;
60  } else if (b1.zero()) {
61  GECODE_ME_CHECK(b2.zero(home)); return ES_OK;
62  }
63  }
64  if (b0.zero()) {
65  if (b1.one()) {
66  GECODE_ME_CHECK(b2.zero(home)); return ES_OK;
67  } else if (b1.zero()) {
68  GECODE_ME_CHECK(b2.one(home)); return ES_OK;
69  }
70  }
71  (void) new (home) Eqv(home,b0,b1,b2);
72  break;
73  default:
75  }
76  return ES_OK;
77  }
78 
79  template<class BVA, class BVB, class BVC>
80  Actor*
82  return new (home) Eqv<BVA,BVB,BVC>(home,*this);
83  }
84 
85  template<class BVA, class BVB, class BVC>
88 #define GECODE_INT_STATUS(S0,S1,S2) \
89  ((BVA::S0<<(2*BVA::BITS))|(BVB::S1<<(1*BVB::BITS))|(BVC::S2<<(0*BVC::BITS)))
90  switch ((x0.status() << (2*BVA::BITS)) | (x1.status() << (1*BVB::BITS)) |
91  (x2.status() << (0*BVC::BITS))) {
92  case GECODE_INT_STATUS(NONE,NONE,NONE):
94  case GECODE_INT_STATUS(NONE,NONE,ZERO):
95  case GECODE_INT_STATUS(NONE,NONE,ONE):
96  case GECODE_INT_STATUS(NONE,ZERO,NONE):
97  return ES_FIX;
98  case GECODE_INT_STATUS(NONE,ZERO,ZERO):
99  GECODE_ME_CHECK(x0.one_none(home)); break;
100  case GECODE_INT_STATUS(NONE,ZERO,ONE):
101  GECODE_ME_CHECK(x0.zero_none(home)); break;
102  case GECODE_INT_STATUS(NONE,ONE,NONE):
103  return ES_FIX;
104  case GECODE_INT_STATUS(NONE,ONE,ZERO):
105  GECODE_ME_CHECK(x0.zero_none(home)); break;
106  case GECODE_INT_STATUS(NONE,ONE,ONE):
107  GECODE_ME_CHECK(x0.one_none(home)); break;
108  case GECODE_INT_STATUS(ZERO,NONE,NONE):
109  return ES_FIX;
110  case GECODE_INT_STATUS(ZERO,NONE,ZERO):
111  GECODE_ME_CHECK(x1.one_none(home)); break;
112  case GECODE_INT_STATUS(ZERO,NONE,ONE):
113  GECODE_ME_CHECK(x1.zero_none(home)); break;
114  case GECODE_INT_STATUS(ZERO,ZERO,NONE):
115  GECODE_ME_CHECK(x2.one_none(home)); break;
116  case GECODE_INT_STATUS(ZERO,ZERO,ZERO):
117  return ES_FAILED;
118  case GECODE_INT_STATUS(ZERO,ZERO,ONE):
119  break;
120  case GECODE_INT_STATUS(ZERO,ONE,NONE):
121  GECODE_ME_CHECK(x2.zero_none(home)); break;
122  case GECODE_INT_STATUS(ZERO,ONE,ZERO):
123  break;
124  case GECODE_INT_STATUS(ZERO,ONE,ONE):
125  return ES_FAILED;
126  case GECODE_INT_STATUS(ONE,NONE,NONE):
127  return ES_FIX;
128  case GECODE_INT_STATUS(ONE,NONE,ZERO):
129  GECODE_ME_CHECK(x1.zero_none(home)); break;
130  case GECODE_INT_STATUS(ONE,NONE,ONE):
131  GECODE_ME_CHECK(x1.one_none(home)); break;
132  case GECODE_INT_STATUS(ONE,ZERO,NONE):
133  GECODE_ME_CHECK(x2.zero_none(home)); break;
134  case GECODE_INT_STATUS(ONE,ZERO,ZERO):
135  break;
136  case GECODE_INT_STATUS(ONE,ZERO,ONE):
137  return ES_FAILED;
138  case GECODE_INT_STATUS(ONE,ONE,NONE):
139  GECODE_ME_CHECK(x2.one_none(home)); break;
140  case GECODE_INT_STATUS(ONE,ONE,ZERO):
141  return ES_FAILED;
142  case GECODE_INT_STATUS(ONE,ONE,ONE):
143  break;
144  default:
145  GECODE_NEVER;
146  }
147  return home.ES_SUBSUMED(*this);
148 #undef GECODE_INT_STATUS
149  }
150 
151 
152  /*
153  * N-ary Boolean equivalence propagator
154  *
155  */
156 
159  : BinaryPropagator<BoolView,PC_BOOL_VAL>(home,x0[0],x0[1]),
160  x(x0), pm2(pm20) {
161  assert(x.size() >= 2);
162  x.drop_fst(2);
163  }
164 
167  : BinaryPropagator<BoolView,PC_BOOL_VAL>(home,p), pm2(p.pm2) {
168  x.update(home,p.x);
169  }
170 
171  forceinline size_t
174  return sizeof(*this);
175  }
176 
177  forceinline void
179  if (x0.assigned()) {
180  pm2 ^= x0.val();
181  int n = x.size();
182  for (int i=n; i--; )
183  if (x[i].assigned()) {
184  pm2 ^= x[i].val();
185  x[i] = x[--n];
186  } else {
187  // Move to x0 and subscribe
188  x0=x[i]; x[i]=x[--n];
189  x0.subscribe(home,*this,PC_BOOL_VAL,false);
190  break;
191  }
192  x.size(n);
193  }
194  }
195 
196 }}}
197 
198 // STATISTICS: int-prop
BVC x2
Boolean view Constructor for posting.
Definition: bool.hh:81
void update(Space &home, ViewArray< View > &a)
Update array to be a clone of array a.
Definition: array.hpp:1310
ExecStatus ES_SUBSUMED(Propagator &p)
Definition: core.hpp:3490
virtual size_t dispose(Space &home)
Delete propagator and return its size.
Definition: eqv.hpp:172
NaryEqv(Home home, ViewArray< BoolView > &x, int pm2)
Constructor for posting.
Definition: eqv.hpp:158
virtual Actor * copy(Space &home)
Copy propagator during cloning.
Definition: eqv.hpp:81
#define forceinline
Definition: config.hpp:185
Propagation has computed fixpoint.
Definition: core.hpp:476
Computation spaces.
Definition: core.hpp:1701
Base-class for both propagators and branchers.
Definition: core.hpp:627
Same variable.
Definition: view.hpp:1753
void subscribe(Space &home, Propagator &p, PropCond pc, bool schedule=true)
Subscribe propagator p with propagation condition pc to view.
Definition: view.hpp:521
int p
Number of positive literals for node type.
Definition: bool-expr.cpp:232
int n
Number of negative literals for node type.
Definition: bool-expr.cpp:234
Boolean equivalence propagator.
Definition: bool.hh:426
Gecode::IntArgs i({1, 2, 3, 4})
Execution has resulted in failure.
Definition: core.hpp:473
void resubscribe(Space &home, BoolView &x0)
Update subscription.
Definition: eqv.hpp:178
Binary propagator.
Definition: pattern.hpp:84
Boolean equality propagator.
Definition: bool.hh:105
BoolTest bool_test(const BoolView &b0, const BoolView &b1)
Definition: bool-test.hpp:41
void drop_fst(int i)
Drop views from positions 0 to i-1 from array.
Definition: array.hpp:1224
Boolean n-ary equivalence propagator.
Definition: bool.hh:453
virtual ExecStatus propagate(Space &home, const ModEventDelta &med)
Perform propagation.
Definition: eqv.hpp:87
#define GECODE_ME_CHECK(me)
Check whether modification event me is failed, and forward failure.
Definition: macros.hpp:52
static ExecStatus post(Home home, BVA b0, BVB b1, BVC b2)
Post propagator (equivalence)
Definition: eqv.hpp:48
Same variable but complement.
Definition: view.hpp:1754
#define GECODE_INT_STATUS(S0, S1, S2)
BVB x1
Boolean view.
Definition: bool.hh:80
bool assigned(void) const
Test whether view is assigned.
Definition: view.hpp:516
Eqv(Space &home, Eqv &p)
Constructor for cloning p.
Definition: eqv.hpp:43
ExecStatus
Definition: core.hpp:471
bool assigned(View x, int v)
Whether x is assigned to value v.
Definition: single.hpp:43
ViewArray< BoolView > x
Views not yet subscribed to.
Definition: bool.hh:458
Post propagator for SetVar x
Definition: set.hh:767
Execution is okay.
Definition: core.hpp:475
BVA x0
Boolean view.
Definition: bool.hh:79
No sharing.
Definition: view.hpp:1752
Gecode toplevel namespace
Base-class for ternary Boolean propagators.
Definition: bool.hh:77
int size(void) const
Return size of array (number of elements)
Definition: array.hpp:1138
int ModEventDelta
Modification event deltas.
Definition: core.hpp:89
Home class for posting propagators
Definition: core.hpp:853
int pm2
Parity information mod 2.
Definition: bool.hh:460
int val(void) const
Return assigned value (only if assigned)
Definition: bool.hpp:74
#define GECODE_NEVER
Assert that this command is never executed.
Definition: macros.hpp:56
const Gecode::PropCond PC_BOOL_VAL
Propagate when a view becomes assigned (single value)
Definition: var-type.hpp:126
Boolean view for Boolean variables.
Definition: view.hpp:1380