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gpi.hpp
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3 * Main authors:
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7 * Christian Schulte, 2009
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33
34#include <cmath>
35
36namespace Gecode { namespace Kernel {
37
39 class GPI {
40 public:
42 class Info {
43 public:
45 unsigned int pid;
47 unsigned int gid;
49 double afc;
51 void init(unsigned int pid, unsigned int gid);
52 };
53 private:
55 class Block : public HeapAllocated {
56 public:
58 static const int n_info = 8192;
60 Info info[n_info];
62 Block* next;
64 int free;
66 Block(void);
68 void rescale(void);
69 };
71 Block* b;
73 double invd;
75 unsigned int npid;
77 bool us;
79 Block fst;
82 public:
84 GPI(void);
86 void decay(double d);
88 double decay(void) const;
90 void fail(Info& c);
92 Info* allocate(unsigned int p, unsigned int gid);
94 Info* allocate(unsigned int gid);
96 unsigned int pid(void) const;
98 bool unshare(void);
100 ~GPI(void);
101 };
102
103
104 forceinline void
105 GPI::Info::init(unsigned int pid0, unsigned int gid0) {
106 pid=pid0; gid=gid0; afc=1.0;
107 }
108
109
111 GPI::Block::Block(void)
112 : next(NULL), free(n_info) {}
113
114 forceinline void
115 GPI::Block::rescale(void) {
116 for (int i=free; i < n_info; i++)
117 info[i].afc *= Kernel::Config::rescale;
118 }
119
120
123 : b(&fst), invd(1.0), npid(0U), us(false) {}
124
125 forceinline void
127 m.acquire();
128 c.afc = invd * (c.afc + 1.0);
130 for (Block* i = b; i != NULL; i = i->next)
131 i->rescale();
132 m.release();
133 }
134
135 forceinline double
136 GPI::decay(void) const {
137 double d;
138 const_cast<GPI&>(*this).m.acquire();
139 d = 1.0 / invd;
140 const_cast<GPI&>(*this).m.release();
141 return d;
142 }
143
144 forceinline unsigned int
145 GPI::pid(void) const {
146 unsigned int p;
147 const_cast<GPI&>(*this).m.acquire();
148 p = npid;
149 const_cast<GPI&>(*this).m.release();
150 return p;
151 }
152
153 forceinline bool
155 bool u;
156 m.acquire();
157 u = us; us = true;
158 m.release();
159 return u;
160 }
161
162 forceinline void
163 GPI::decay(double d) {
164 m.acquire();
165 invd = 1.0 / d;
166 m.release();
167 }
168
170 GPI::allocate(unsigned int p, unsigned int gid) {
171 Info* c;
172 m.acquire();
173 if (b->free == 0) {
174 Block* n = new Block;
175 n->next = b; b = n;
176 }
177 c = &b->info[--b->free];
178 m.release();
179 c->init(p,gid);
180 return c;
181 }
182
184 GPI::allocate(unsigned int gid) {
185 Info* c;
186 m.acquire();
187 if (b->free == 0) {
188 Block* n = new Block;
189 n->next = b; b = n;
190 }
191 c = &b->info[--b->free];
192 c->init(npid++,gid);
193 m.release();
194 return c;
195 }
196
198 GPI::~GPI(void) {
199 Block* n = b;
200 while (n != &fst) {
201 Block* d = n;
202 n = n->next;
203 delete d;
204 }
205 }
206
207}}
208
209// STATISTICS: kernel-prop
Base class for heap allocated objects.
Definition heap.hpp:340
Class for storing propagator information.
Definition gpi.hpp:42
void init(unsigned int pid, unsigned int gid)
Initialize.
Definition gpi.hpp:105
unsigned int pid
Propagator identifier.
Definition gpi.hpp:45
unsigned int gid
Group identifier.
Definition gpi.hpp:47
double afc
The afc value.
Definition gpi.hpp:49
GPI(void)
Initialize.
Definition gpi.hpp:122
unsigned int pid(void) const
Return next free propagator id.
Definition gpi.hpp:145
double decay(void) const
Return decay factor.
Definition gpi.hpp:136
void fail(Info &c)
Increment failure count.
Definition gpi.hpp:126
~GPI(void)
Delete.
Definition gpi.hpp:198
bool unshare(void)
Provide access to unshare info and set to true.
Definition gpi.hpp:154
Info * allocate(unsigned int p, unsigned int gid)
Allocate info for existing propagator with pid p.
Definition gpi.hpp:170
A mutex for mutual exclausion among several threads.
Definition thread.hpp:96
#define GECODE_KERNEL_EXPORT
Definition kernel.hh:70
const double rescale_limit
Rescale action and afc values when larger than this.
Definition kernel.hh:101
const double rescale
Rescale factor for action and afc values.
Definition kernel.hh:99
Kernel functionality
Gecode toplevel namespace
#define forceinline
Definition config.hpp:194