1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
* Main authors:
* Christian Schulte <schulte@gecode.org>
*
* Copyright:
* Christian Schulte, 2013
*
* This file is part of Gecode, the generic constraint
* development environment:
* http://www.gecode.org
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
#include <gecode/search/nogoods.hh>
namespace Gecode { namespace Search {
/// Help function to cancel and dispose a no-good literal
forceinline NGL*
disposenext(NGL* ngl, Space& home, Propagator& p, bool c) {
NGL* n = ngl->next();
if (c)
ngl->cancel(home,p);
home.rfree(ngl,ngl->dispose(home));
return n;
}
void
NoNGL::subscribe(Space&, Propagator&) {
GECODE_NEVER;
}
void
NoNGL::cancel(Space&, Propagator&) {
GECODE_NEVER;
}
void
NoNGL::reschedule(Space&, Propagator&) {
GECODE_NEVER;
}
NGL::Status
NoNGL::status(const Space&) const {
GECODE_NEVER;
return NGL::NONE;
}
ExecStatus
NoNGL::prune(Space&) {
GECODE_NEVER;
return ES_OK;
}
NGL*
NoNGL::copy(Space&) {
GECODE_NEVER;
return nullptr;
}
Actor*
NoGoodsProp::copy(Space& home) {
return new (home) NoGoodsProp(home,*this);
}
PropCost
NoGoodsProp::cost(const Space&, const ModEventDelta&) const {
return PropCost::linear(PropCost::LO,n);
}
void
NoGoodsProp::reschedule(Space& home) {
root->reschedule(home,*this);
NGL* l = root->next();
while ((l != nullptr) && l->leaf()) {
l->reschedule(home,*this);
l = l->next();
}
if (l != nullptr)
l->reschedule(home,*this);
}
ExecStatus
NoGoodsProp::propagate(Space& home, const ModEventDelta&) {
restart:
// Start with checking the first literal
switch (root->status(home)) {
case NGL::FAILED:
// All no-goods are dead, let dispose() clean up
return home.ES_SUBSUMED(*this);
case NGL::SUBSUMED:
{
NGL* l = disposenext(root,home,*this,true); n--;
// Prune leaf-literals
while ((l != nullptr) && l->leaf()) {
l->cancel(home,*this); n--;
GECODE_ES_CHECK(l->prune(home));
l = disposenext(l,home,*this,false);
}
root = l;
// Is there anything left?
if (l == nullptr)
return home.ES_SUBSUMED(*this);
// Skip literal that already has a subscription
l = l->next();
// Create subscriptions for leaves
while ((l != nullptr) && l->leaf()) {
l->subscribe(home,*this); n++;
l = l->next();
}
// Create subscription for possible non-leaf literal
if (l != nullptr) {
l->subscribe(home,*this); n++;
}
goto restart;
}
case NGL::NONE:
break;
default: GECODE_NEVER;
}
{
NGL* p = root;
NGL* l = p->next();
// Check the leaves
while ((l != nullptr) && l->leaf()) {
switch (l->status(home)) {
case NGL::SUBSUMED:
l = disposenext(l,home,*this,true); n--;
p->next(l);
GECODE_ES_CHECK(root->prune(home));
if (root->status(home) == NGL::FAILED)
return home.ES_SUBSUMED(*this);
break;
case NGL::FAILED:
l = disposenext(l,home,*this,true); n--;
p->next(l);
break;
case NGL::NONE:
p = l; l = l->next();
break;
default: GECODE_NEVER;
}
}
// Check the next subtree
if (l != nullptr) {
switch (l->status(home)) {
case NGL::FAILED:
(void) disposenext(l,home,*this,true); n--;
// Prune entire subtree
p->next(nullptr);
break;
case NGL::SUBSUMED:
{
// Unlink node
l = disposenext(l,home,*this,true); n--;
p->next(l);
// Create subscriptions
while ((l != nullptr) && l->leaf()) {
l->subscribe(home,*this); n++;
l = l->next();
}
if (l != nullptr) {
l->subscribe(home,*this); n++;
}
}
break;
case NGL::NONE:
break;
default: GECODE_NEVER;
}
}
}
return ES_NOFIX;
}
size_t
NoGoodsProp::dispose(Space& home) {
if (home.failed()) {
// This will be executed when one ngl returned true for notice()
NGL* l = root;
while (l != nullptr) {
NGL* t = l->next();
(void) l->dispose(home);
l = t;
}
} else if (root != nullptr) {
// This will be executed for subsumption
NGL* l = disposenext(root,home,*this,true);
while ((l != nullptr) && l->leaf())
l = disposenext(l,home,*this,true);
if (l != nullptr)
l = disposenext(l,home,*this,true);
while (l != nullptr)
l = disposenext(l,home,*this,false);
}
home.ignore(*this,AP_DISPOSE,true);
(void) Propagator::dispose(home);
return sizeof(*this);
}
}}
// STATISTICS: search-other
|
