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int-eq.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, 2006
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33
34namespace Gecode { namespace Int { namespace Count {
35
36 template<class VX, class VY>
39 : IntBase<VX,VY>(home,x,n_s,y,c) {}
40
41 template<class VX, class VY>
44 // Eliminate decided views
45 int n_x = x.size();
46 for (int i=n_x; i--; )
47 switch (holds(x[i],y)) {
48 case RT_FALSE:
49 x[i] = x[--n_x]; break;
50 case RT_TRUE:
51 x[i] = x[--n_x]; c--; break;
52 case RT_MAYBE:
53 break;
54 default:
56 }
57 x.size(n_x);
58 // RHS too small or too large
59 if ((c < 0) || (c > n_x))
60 return ES_FAILED;
61 // All views must be different
62 if (c == 0)
63 return post_false(home,x,y);
64 // All views must be equal
65 if (c == n_x)
66 return post_true(home,x,y);
67 // Compute how many subscriptions must be created
68 int n_s = std::max(c,n_x-c)+1;
69 assert(n_s <= n_x);
70 (void) new (home) EqInt<VX,VY>(home,x,n_s,y,c);
71 return ES_OK;
72 }
73
74 template<class VX, class VY>
77 : IntBase<VX,VY>(home,p) {}
78
79 template<class VX, class VY>
80 Actor*
82 return new (home) EqInt<VX,VY>(home,*this);
83 }
84
85 template<class VX, class VY>
88 // Eliminate decided views from subscribed views
89 int n_x = x.size();
90 for (int i=n_s; i--; )
91 switch (holds(x[i],y)) {
92 case RT_FALSE:
93 x[i].cancel(home,*this,PC_INT_DOM);
94 x[i]=x[--n_s]; x[n_s]=x[--n_x];
95 break;
96 case RT_TRUE:
97 x[i].cancel(home,*this,PC_INT_DOM);
98 x[i]=x[--n_s]; x[n_s]=x[--n_x]; c--;
99 break;
100 case RT_MAYBE:
101 break;
102 default:
104 }
105 x.size(n_x);
106 if ((c < 0) || (c > n_x))
107 return ES_FAILED;
108 // Eliminate decided views from unsubscribed views
109 for (int i=n_x; i-- > n_s; )
110 switch (holds(x[i],y)) {
111 case RT_FALSE: x[i]=x[--n_x]; break;
112 case RT_TRUE: x[i]=x[--n_x]; c--; break;
113 case RT_MAYBE: break;
114 default: GECODE_NEVER;
115 }
116 x.size(n_x);
117 if ((c < 0) || (c > n_x))
118 return ES_FAILED;
119 if (c == 0) {
120 // All views must be different
122 return home.ES_SUBSUMED(*this);
123 }
124 if (c == n_x) {
125 // All views must be equal
127 return home.ES_SUBSUMED(*this);
128 }
129 int m = std::max(c,n_x-c)+1;
130 assert(m <= n_x);
131 // Now, there must be new subscriptions from x[n_s] up to x[m-1]
132 while (n_s < m)
133 x[n_s++].subscribe(home,*this,PC_INT_DOM,false);
134 return ES_FIX;
135 }
136
137}}}
138
139// STATISTICS: int-prop
Base-class for both propagators and branchers.
Definition core.hpp:628
Home class for posting propagators
Definition core.hpp:856
virtual ExecStatus propagate(Space &home, const ModEventDelta &med)
Perform propagation.
Definition int-eq.hpp:87
virtual Actor * copy(Space &home)
Create copy during cloning.
Definition int-eq.hpp:81
EqInt(Space &home, EqInt &p)
Constructor for cloning p.
Definition int-eq.hpp:76
static ExecStatus post(Home home, ViewArray< VX > &x, VY y, int c)
Post propagator for .
Definition int-eq.hpp:43
IntBase(Space &home, IntBase &p)
Constructor for cloning p.
Definition int-base.hpp:62
int n_s
Views from x[0] ... x[n_s-1] have subscriptions.
Definition count.hh:143
ViewArray< VX > x
Views still to count.
Definition count.hh:141
int c
Number of views which are equal and have been eliminated.
Definition count.hh:147
VY y
View to compare to.
Definition count.hh:145
friend class Space
Definition core.hpp:1068
View arrays.
Definition array.hpp:253
ExecStatus ES_SUBSUMED(Propagator &p)
Propagator p is subsumed
Definition core.hpp:3570
int ModEventDelta
Modification event deltas.
Definition core.hpp:89
#define GECODE_ES_CHECK(es)
Check whether execution status es is failed or subsumed, and forward failure or subsumption.
Definition macros.hpp:91
Counting propagators.
ExecStatus post_false(Home home, ViewArray< VX > &x, VX y)
Post that all views in x are not equal to y.
Definition rel.hpp:251
ExecStatus post_true(Home home, ViewArray< VX > &x, VX y)
Post that all views in x are equal to y.
Definition rel.hpp:237
RelTest holds(VX x, VX y)
Test whether x and y are equal.
Definition rel.hpp:145
Finite domain integers.
const Gecode::PropCond PC_INT_DOM
Propagate when domain changes.
Definition var-type.hpp:100
@ RT_TRUE
Relation does hold.
Definition view.hpp:1737
@ RT_MAYBE
Relation may hold or not.
Definition view.hpp:1736
@ RT_FALSE
Relation does not hold.
Definition view.hpp:1735
Gecode toplevel namespace
ExecStatus
Definition core.hpp:472
@ ES_OK
Execution is okay.
Definition core.hpp:476
@ ES_FIX
Propagation has computed fixpoint.
Definition core.hpp:477
@ ES_FAILED
Execution has resulted in failure.
Definition core.hpp:474
#define forceinline
Definition config.hpp:194
#define GECODE_NEVER
Assert that this command is never executed.
Definition macros.hpp:56