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pow-nroot.hpp
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1/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
2/*
3 * Main authors:
4 * Vincent Barichard <Vincent.Barichard@univ-angers.fr>
5 *
6 * Copyright:
7 * Vincent Barichard, 2012
8 *
9 * This file is part of Gecode, the generic constraint
10 * development environment:
11 * http://www.gecode.org
12 *
13 * Permission is hereby granted, free of charge, to any person obtaining
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18 * permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
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31 *
32 */
33
34namespace Gecode { namespace Float { namespace Arithmetic {
35
36
37 /*
38 * Bounds consistent square operator
39 *
40 */
41
42 template<class A, class B>
44 Pow<A,B>::Pow(Home home, A x0, B x1, int n)
46
47 template<class A, class B>
49 Pow<A,B>::post(Home home, A x0, B x1, int n) {
50 if (n == 0) {
51 if ((x0.min() == 0.0) && (x0.max() == 0.0)) return ES_FAILED;
52 GECODE_ME_CHECK(x1.eq(home,1.0));
53 return ES_OK;
54 }
55
56 GECODE_ME_CHECK(x1.eq(home,pow(x0.domain(),n)));
57 if ((x1.min() == 0.0) && (x1.max() == 0.0)) {
58 GECODE_ME_CHECK(x1.eq(home,0.0));
59 return ES_OK;
60 }
61
62 if ((n % 2) == 0) {
63 if (x0.min() >= 0)
64 GECODE_ME_CHECK(x0.eq(home,nroot(x1.domain(),n)));
65 else if (x0.max() <= 0)
66 GECODE_ME_CHECK(x0.eq(home,-nroot(x1.domain(),n)));
67 else
68 GECODE_ME_CHECK(x0.eq(home,
69 hull(
70 nroot(x1.domain(),n),
71 -nroot(x1.domain(),n)
72 )
73 ));
74 } else {
75 GECODE_ME_CHECK(x0.eq(home,nroot(x1.domain(),n)));
76 }
77
78 if (!x0.assigned()) (void) new (home) Pow<A,B>(home,x0,x1,n);
79 return ES_OK;
80 }
81
82 template<class A, class B>
86
87 template<class A, class B>
88 Actor*
90 return new (home) Pow<A,B>(home,*this);
91 }
92
93 template<class A, class B>
96 if ((x0.min() == 0.0) && (x0.max() == 0.0)) return ES_FAILED;
97 GECODE_ME_CHECK(x1.eq(home,pow(x0.domain(),m_n)));
98
99 if ((x1.min() == 0.0) && (x1.max() == 0.0)) {
100 GECODE_ME_CHECK(x1.eq(home,0.0));
101 return home.ES_SUBSUMED(*this);
102 }
103
104 if ((m_n % 2) == 0) {
105 if (x0.min() >= 0)
106 GECODE_ME_CHECK(x0.eq(home,nroot(x1.domain(),m_n)));
107 else if (x0.max() <= 0)
108 GECODE_ME_CHECK(x0.eq(home,-nroot(x1.domain(),m_n)));
109 else
110 GECODE_ME_CHECK(x0.eq(home,
111 hull(
112 nroot(x1.domain(),m_n),
113 -nroot(x1.domain(),m_n)
114 )
115 ));
116 } else {
117 GECODE_ME_CHECK(x0.eq(home,nroot(x1.domain(),m_n)));
118 }
119 return x0.assigned() ? home.ES_SUBSUMED(*this) : ES_FIX;
120 }
121
122 /*
123 * Bounds consistent square root operator
124 *
125 */
126
127 template<class A, class B>
131
132 template<class A, class B>
134 NthRoot<A,B>::post(Home home, A x0, B x1, int n) {
135 if (n == 0) return ES_FAILED;
136 GECODE_ME_CHECK(x0.gq(home,0.0));
137 GECODE_ME_CHECK(x1.eq(home,nroot(x0.domain(),n)));
138 GECODE_ME_CHECK(x0.eq(home,pow(x1.domain(),n)));
139 (void) new (home) NthRoot<A,B>(home,x0,x1,n);
140 return ES_OK;
141 }
142
143 template<class A, class B>
147
148 template<class A, class B>
149 Actor*
151 return new (home) NthRoot<A,B>(home,*this);
152 }
153
154 template<class A, class B>
157 GECODE_ME_CHECK(x1.eq(home,nroot(x0.domain(),m_n)));
158 GECODE_ME_CHECK(x0.eq(home,pow(x1.domain(),m_n)));
159 return x0.assigned() ? home.ES_SUBSUMED(*this) : ES_FIX;
160 }
161
162
163}}}
164
165// STATISTICS: float-prop
166
Base-class for both propagators and branchers.
Definition core.hpp:628
NthRoot(Space &home, NthRoot &p)
Constructor for cloning p.
virtual ExecStatus propagate(Space &home, const ModEventDelta &med)
Perform propagation.
virtual Actor * copy(Space &home)
Create copy during cloning.
static ExecStatus post(Home home, A x0, B x1, int n)
Post propagator for .
static ExecStatus post(Home home, A x0, B x1, int n)
Post propagator for .
Definition pow-nroot.hpp:49
virtual ExecStatus propagate(Space &home, const ModEventDelta &med)
Perform propagation.
Definition pow-nroot.hpp:95
virtual Actor * copy(Space &home)
Create copy during cloning.
Definition pow-nroot.hpp:89
Pow(Space &home, Pow &p)
Constructor for cloning p.
Definition pow-nroot.hpp:84
Home class for posting propagators
Definition core.hpp:856
MixBinaryPropagator(Space &home, MixBinaryPropagator &p)
Definition pattern.hpp:597
friend class Space
Definition core.hpp:1068
ExecStatus ES_SUBSUMED(Propagator &p)
Propagator p is subsumed
Definition core.hpp:3570
int ModEventDelta
Modification event deltas.
Definition core.hpp:89
#define GECODE_ME_CHECK(me)
Check whether modification event me is failed, and forward failure.
Definition macros.hpp:52
Arithmetic propagators
Floating point numbers.
FloatVal hull(const FloatVal &x, const FloatVal &y)
Definition val.hpp:507
const Gecode::PropCond PC_FLOAT_BND
Propagate when minimum or maximum of a view changes.
Definition var-type.hpp:292
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
void pow(Home home, FloatVar x0, int n, FloatVar x1)
Post propagator for for $n\geq 0$.
void nroot(Home home, FloatVar x0, int n, FloatVar x1)
Post propagator for for $n\geq 0$.
#define forceinline
Definition config.hpp:194