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int-dom.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
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
14 * a copy of this software and associated documentation files (the
15 * "Software"), to deal in the Software without restriction, including
16 * without limitation the rights to use, copy, modify, merge, publish,
17 * distribute, sublicense, and/or sell copies of the Software, and to
18 * permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
20 *
21 * The above copyright notice and this permission notice shall be
22 * included in all copies or substantial portions of the Software.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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30 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
31 *
32 */
33
34namespace Gecode { namespace Int { namespace Linear {
35
43 class SupportSet {
44 private:
47 public:
49 SupportSet(void);
51 void init(Region& r, unsigned int n);
53 void support(unsigned int i);
55 bool supported(unsigned int i) const;
56
57 private:
59 class ResultIter : public ViewValues<IntView> {
60 protected:
62 const SupportSet& s;
64 unsigned int p;
65 public:
67 ResultIter(const SupportSet& s0, const IntView& x);
69 void operator ++(void);
70 };
71
72 public:
74 ModEvent tell(Space& home, IntView& x) const;
75 };
76
81 template<class Val>
83 protected:
85 int a;
91 int c;
93 unsigned int p;
98 public:
100 void init(Region& r, int a, const IntView& x, Val l, Val u);
102 void support(void);
104 ModEvent tell(Space& home);
105 };
106
107
112 template<class Val>
113 class PosSupportIter : public SupportIter<Val> {
114 private:
116 IntVarImpFwd i;
117 // Using-declarations for dependant names
118 using SupportIter<Val>::a;
119 using SupportIter<Val>::x;
120 using SupportIter<Val>::s;
121 using SupportIter<Val>::c;
122 using SupportIter<Val>::p;
123 using SupportIter<Val>::l;
124 using SupportIter<Val>::u;
125 public:
127 bool reset(Val& d);
129 bool adjust(Val& d);
130 };
131
132
137 template<class Val>
138 class NegSupportIter : public SupportIter<Val> {
139 private:
141 IntVarImpBwd i;
142 // Using-declarations for dependant names
143 using SupportIter<Val>::a;
144 using SupportIter<Val>::x;
145 using SupportIter<Val>::s;
146 using SupportIter<Val>::c;
147 using SupportIter<Val>::p;
148 using SupportIter<Val>::l;
149 using SupportIter<Val>::u;
150 public:
152 bool reset(Val& d);
154 bool adjust(Val& d);
155 };
156
157
158 /*
159 * Support set
160 *
161 */
164 forceinline void
165 SupportSet::init(Region& r, unsigned int n) {
166 bs.init(r,n);
167 }
168 forceinline void
169 SupportSet::support(unsigned int i) {
170 bs.set(i);
171 }
172 forceinline bool
173 SupportSet::supported(unsigned int i) const {
174 return bs.get(i);
175 }
176
178 SupportSet::ResultIter::ResultIter(const SupportSet& s0, const IntView& x)
179 : ViewValues<IntView>(x), s(s0), p(0) {
180 while (ViewValues<IntView>::operator ()() && s.supported(p)) {
181 ViewValues<IntView>::operator ++(); ++p;
182 }
183 }
184 forceinline void
186 do {
188 } while (ViewValues<IntView>::operator ()() && s.supported(p));
189 }
190
191
194 switch (bs.status()) {
196 return ME_INT_FAILED;
197 case Support::BSS_ALL:
198 return ME_INT_NONE;
200 {
201 ResultIter i(*this,x);
202 return x.minus_v(home,i);
203 }
204 default:
206 }
207 return ME_INT_NONE;
208 }
209
210
211 /*
212 * Base-class for support-based iterator
213 *
214 */
215 template<class Val>
216 forceinline void
218 int a0, const IntView& x0, Val l0, Val u0) {
219 a=a0; x=x0; l=l0; u=u0;
220 s.init(r,x.size());
221 }
222 template<class Val>
223 forceinline void
225 s.support(p);
226 }
227 template<class Val>
230 return s.tell(home,x);
231 }
232
233
234 /*
235 * Support-based iterator for positive view
236 *
237 */
238 template<class Val>
239 forceinline bool
241 // Way too small, no value can make it big enough
242 if (d + static_cast<Val>(a)*x.max() < u)
243 return false;
244 // Restart iterator and position of values
245 i.init(x.varimp()); p = 0;
246 // Skip all ranges which are too small
247 while (d + static_cast<Val>(a)*i.max() < u) {
248 p += i.width(); ++i;
249 }
250 // There is at least one range left (check of max)
251 assert(i());
252 // Initialize current range and adjust value
253 c = i.min();
254 // Skip all values which are too small
255 while (d + static_cast<Val>(a)*c < u) {
256 p++; c++;
257 }
258 // Adjust to new value
259 d += static_cast<Val>(a) * c;
260 return true;
261 }
262 template<class Val>
263 forceinline bool
265 // Current value
266 Val v = static_cast<Val>(a) * c;
267 // Subtract current value from d
268 d -= v;
269 // Move to next position (number of value)
270 p++;
271 // Still in the same range
272 if (c < i.max()) {
273 // Decrement current values
274 c += 1; v += a;
275 } else {
276 // Go to next range
277 ++i;
278 if (!i())
279 return false;
280 c = i.min(); v = static_cast<Val>(a) * c;
281 }
282 // Is d with the current value too large?
283 if (d + v > l)
284 return false;
285 // Update d
286 d += v;
287 return true;
288 }
289
290
291 /*
292 * Support-based iterator for negative view
293 *
294 */
295 template<class Val>
296 forceinline bool
298 // Way too small, no value can make it big enough
299 if (d + static_cast<Val>(a)*x.min() < u)
300 return false;
301 // Restart iterator and position of values
302 i.init(x.varimp()); p = x.size()-1;
303 // Skip all ranges which are too small
304 while (d + static_cast<Val>(a)*i.min() < u) {
305 p -= i.width(); ++i;
306 }
307 // There is at least one range left (check of max)
308 assert(i());
309 // Initialize current range
310 c = i.max();
311 // Skip all values which are too small
312 while (d + static_cast<Val>(a)*c < u) {
313 p--; c--;
314 }
315 // Adjust to new value
316 d += static_cast<Val>(a) * c;
317 return true;
318 }
319 template<class Val>
320 forceinline bool
322 // Current value
323 Val v = static_cast<Val>(a) * c;
324 // Subtract current value from d
325 d -= v;
326 // Move to next position (number of value)
327 p--;
328 // Still in the same range
329 if (c > i.min()) {
330 // Decrement current values
331 c -= 1; v -= a;
332 } else {
333 // Go to next range
334 ++i;
335 if (!i())
336 return false;
337 c = i.max(); v = static_cast<Val>(a) * c;
338 }
339 // Is d with the current value too large?
340 if (d + v > l)
341 return false;
342 // Update d
343 d += v;
344 return true;
345 }
346
347
348
349 /*
350 * The domain consisten equality propagator
351 *
352 */
353 template<class Val, class View>
359
360 template<class Val, class View>
364 Val c) {
365 (void) new (home) DomEq<Val,View>(home,x,y,c);
366 return ES_OK;
367 }
368
369 template<class Val, class View>
372 : Lin<Val,View,View,PC_INT_DOM>(home,p) {}
373
374 template<class Val, class View>
375 Actor*
377 return new (home) DomEq<Val,View>(home,*this);
378 }
379
380 template<class Val, class View>
383 if (View::me(med) != ME_INT_DOM)
384 return PropCost::linear(PropCost::LO, x.size()+y.size());
385 else
386 return PropCost::crazy(PropCost::HI, x.size()+y.size());
387 }
388
389 template<class Val, class View>
392 if (View::me(med) != ME_INT_DOM) {
393 ExecStatus es = prop_bnd<Val,View,View>(home,med,*this,x,y,c);
394 GECODE_ES_CHECK(es);
395 return home.ES_FIX_PARTIAL(*this,View::med(ME_INT_DOM));
396 }
397
398 // Value of equation for partial assignment
399 Val d = -c;
400
401 int n = x.size();
402 int m = y.size();
403
404 Region r;
405 // Create support-base iterators
408
409 // Initialize views for assignments
410 {
411 Val l = 0;
412 Val u = 0;
413 for (int j=m; j--; ) {
414 yp[j].init(r,-y[j].scale(),y[j].base(),l,u);
415 l += y[j].max(); u += y[j].min();
416 }
417 for (int i=n; i--; ) {
418 xp[i].init(r,x[i].scale(),x[i].base(),l,u);
419 l -= x[i].min(); u -= x[i].max();
420 }
421 }
422
423 // Collect support information by iterating assignments
424 {
425 // Force reset of all iterators in first round
426 int i = 0;
427 int j = 0;
428
429 next_i:
430 // Reset all iterators for positive views and update d
431 while (i<n) {
432 if (!xp[i].reset(d)) goto prev_i;
433 i++;
434 }
435 next_j:
436 // Reset all iterators for negative views and update d
437 while (j<m) {
438 if (!yp[j].reset(d)) goto prev_j;
439 j++;
440 }
441 // Check whether current assignment is solution
442 if (d == 0) {
443 // Record support
444 for (int is=0; is<n; is++) xp[is].support();
445 for (int js=0; js<m; js++) yp[js].support();
446 }
447 prev_j:
448 // Try iterating to next assignment: negative views
449 while (j>0) {
450 if (yp[j-1].adjust(d)) goto next_j;
451 j--;
452 }
453 prev_i:
454 // Try iterating to next assignment: positive views
455 while (i>0) {
456 if (xp[i-1].adjust(d)) goto next_i;
457 i--;
458 }
459 }
460
461 // Tell back new variable domains
462 bool assigned = true;
463 for (int i=0; i<n; i++) {
464 GECODE_ME_CHECK(xp[i].tell(home));
465 if (!x[i].assigned())
466 assigned = false;
467 }
468 for (int j=0; j<m; j++) {
469 GECODE_ME_CHECK(yp[j].tell(home));
470 if (!y[j].assigned())
471 assigned = false;
472 }
473 if (assigned)
474 return home.ES_SUBSUMED(*this);
475 return ES_FIX;
476 }
477
478}}}
479
480// STATISTICS: int-prop
Base-class for both propagators and branchers.
Definition core.hpp:628
Home class for posting propagators
Definition core.hpp:856
Backward iterator for ranges of integer variable implementations.
Definition var-imp.hpp:435
Range iterator for ranges of integer variable implementation.
Definition var-imp.hpp:392
Integer view for integer variables.
Definition view.hpp:129
Propagator for domain consistent n-ary linear equality
Definition linear.hh:609
virtual PropCost cost(const Space &home, const ModEventDelta &med) const
Cost function.
Definition int-dom.hpp:382
virtual Actor * copy(Space &home)
Create copy during cloning.
Definition int-dom.hpp:376
virtual ExecStatus propagate(Space &home, const ModEventDelta &med)
Perform propagation.
Definition int-dom.hpp:391
DomEq(Space &home, DomEq &p)
Constructor for cloning p.
static ExecStatus post(Home home, ViewArray< View > &x, ViewArray< View > &y, Val c)
Post propagator for .
Definition int-dom.hpp:362
Base-class for n-ary linear propagators.
Definition linear.hh:497
Lin(Space &home, Lin< Val, View, View, pc > &p)
Definition int-nary.hpp:69
Support-based iterator for negative view.
Definition int-dom.hpp:138
bool reset(Val &d)
Reset iterator to beginning and adjust.
Definition int-dom.hpp:297
Support-based iterator for positive view.
Definition int-dom.hpp:113
bool reset(Val &d)
Reset iterator to beginning and adjust.
Definition int-dom.hpp:240
Base-class for support-based iterator.
Definition int-dom.hpp:82
IntView x
Integer view.
Definition int-dom.hpp:87
void init(Region &r, int a, const IntView &x, Val l, Val u)
Initialize view.
Definition int-dom.hpp:217
int a
Integer coefficient for view.
Definition int-dom.hpp:85
Val u
Upper bound information for value.
Definition int-dom.hpp:97
Val l
Lower bound information for value.
Definition int-dom.hpp:95
void support(void)
Record value at current position as supported.
Definition int-dom.hpp:224
unsigned int p
Position of current value.
Definition int-dom.hpp:93
SupportSet s
Set of support for values in x.
Definition int-dom.hpp:89
ModEvent tell(Space &home)
Tell back new variable domain according to support found.
Definition int-dom.hpp:229
Set for support information
Definition int-dom.hpp:43
bool supported(unsigned int i) const
Check whether position.
Definition int-dom.hpp:173
ModEvent tell(Space &home, IntView &x) const
Perform tell according to recorded support information on.
Definition int-dom.hpp:193
SupportSet(void)
Default constructor.
Definition int-dom.hpp:163
void support(unsigned int i)
Record that there is support at position i.
Definition int-dom.hpp:169
void init(Region &r, unsigned int n)
Initialize support set with cardinality n.
Definition int-dom.hpp:165
Value iterator for integer views.
Definition view.hpp:94
Propagation cost.
Definition core.hpp:486
static PropCost crazy(PropCost::Mod m, unsigned int n)
Exponential complexity for modifier m and size measure n.
Definition core.hpp:4776
static PropCost linear(PropCost::Mod m, unsigned int n)
Linear complexity for modifier pcm and size measure n.
Definition core.hpp:4803
@ HI
Expensive.
Definition core.hpp:514
friend class Space
Definition core.hpp:1068
ModEventDelta med
A set of modification events (used during propagation)
Definition core.hpp:1077
Handle to region.
Definition region.hpp:55
Computation spaces.
Definition core.hpp:1744
Basic bitset support.
View arrays.
Definition array.hpp:253
ExecStatus ES_FIX_PARTIAL(Propagator &p, const ModEventDelta &med)
Propagator p has computed partial fixpoint
Definition core.hpp:3576
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
#define GECODE_ES_CHECK(es)
Check whether execution status es is failed or subsumed, and forward failure or subsumption.
Definition macros.hpp:91
Linear propagators
ExecStatus prop_bnd(Space &home, ModEventDelta med, Propagator &p, ViewArray< P > &x, ViewArray< N > &y, Val &c)
Definition int-nary.hpp:183
Finite domain integers.
const Gecode::ModEvent ME_INT_FAILED
Domain operation has resulted in failure.
Definition var-type.hpp:52
const Gecode::PropCond PC_INT_DOM
Propagate when domain changes.
Definition var-type.hpp:100
const Gecode::ModEvent ME_INT_DOM
Domain operation has changed the domain.
Definition var-type.hpp:72
const Gecode::ModEvent ME_INT_NONE
Domain operation has not changed domain.
Definition var-type.hpp:54
@ BSS_NONE
No bits set.
@ BSS_ALL
All bits set.
@ BSS_SOME
Some but not all bits set.
Gecode toplevel namespace
Post propagator for SetVar SetOpType SetVar SetRelType r
Definition set.hh:773
ExecStatus
Definition core.hpp:472
@ ES_OK
Execution is okay.
Definition core.hpp:476
@ ES_FIX
Propagation has computed fixpoint.
Definition core.hpp:477
Post propagator for SetVar x
Definition set.hh:773
int ModEvent
Type for modification events.
Definition core.hpp:62
#define forceinline
Definition config.hpp:194
#define GECODE_NEVER
Assert that this command is never executed.
Definition macros.hpp:56