Something went wrong. Try again.
This repository has no description
Something went wrong. Try again.
13 kB · 480 lines
C++
at develop
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- *//* * Main authors: * Christian Schulte <schulte@gecode.org> * * Copyright: * Christian Schulte, 2006 * * 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. * */
namespace Gecode { namespace Int { namespace Linear {
/** * \brief %Set for support information * * Records supported positions of values such that with iteration * the supported values can be reconstructed. * */ class SupportSet { private: /// Bitset for storing support information Support::BitSetBase bs; public: /// Default constructor SupportSet(void); /// Initialize support set with cardinality \a n void init(Region& r, unsigned int n); /// Record that there is support at position \a i void support(unsigned int i); /// Check whether position \arg i has support bool supported(unsigned int i) const;
private: /// Support-based iterator: iterates values to be removed class ResultIter : public ViewValues<IntView> { protected: /// The support set used const SupportSet& s; /// The current position of the value unsigned int p; public: /// Initialize iterator ResultIter(const SupportSet& s0, const IntView& x); /// Increment to next supported value void operator ++(void); };
public: /// Perform tell according to recorded support information on \arg x ModEvent tell(Space& home, IntView& x) const; };
/** * \brief Base-class for support-based iterator * */ template<class Val> class SupportIter { protected: /// Integer coefficient for view int a; /// Integer view IntView x; /// Set of support for values in x SupportSet s; /// Current value int c; /// Position of current value unsigned int p; /// Lower bound information for value Val l; /// Upper bound information for value Val u; public: /// Initialize view void init(Region& r, int a, const IntView& x, Val l, Val u); /// Record value at current position as supported void support(void); /// Tell back new variable domain according to support found ModEvent tell(Space& home); };
/** * \brief Support-based iterator for positive view * */ template<class Val> class PosSupportIter : public SupportIter<Val> { private: /// Iterate ranges of integer view in increasing order IntVarImpFwd i; // Using-declarations for dependant names using SupportIter<Val>::a; using SupportIter<Val>::x; using SupportIter<Val>::s; using SupportIter<Val>::c; using SupportIter<Val>::p; using SupportIter<Val>::l; using SupportIter<Val>::u; public: /// Reset iterator to beginning and adjust \arg d accordingly bool reset(Val& d); /// Adjust \arg d and return true if next value still works bool adjust(Val& d); };
/** * \brief Support-based iterator for negative view * */ template<class Val> class NegSupportIter : public SupportIter<Val> { private: /// Iterate ranges of integer view in decreasing order IntVarImpBwd i; // Using-declarations for dependant names using SupportIter<Val>::a; using SupportIter<Val>::x; using SupportIter<Val>::s; using SupportIter<Val>::c; using SupportIter<Val>::p; using SupportIter<Val>::l; using SupportIter<Val>::u; public: /// Reset iterator to beginning and adjust \arg d accordingly bool reset(Val& d); /// Adjust \arg d and return true if next value still works bool adjust(Val& d); };
/* * Support set * */ forceinline SupportSet::SupportSet(void) {} forceinline void SupportSet::init(Region& r, unsigned int n) { bs.init(r,n); } forceinline void SupportSet::support(unsigned int i) { bs.set(i); } forceinline bool SupportSet::supported(unsigned int i) const { return bs.get(i); }
forceinline SupportSet::ResultIter::ResultIter(const SupportSet& s0, const IntView& x) : ViewValues<IntView>(x), s(s0), p(0) { while (ViewValues<IntView>::operator ()() && s.supported(p)) { ViewValues<IntView>::operator ++(); ++p; } } forceinline void SupportSet::ResultIter::operator ++(void) { do { ViewValues<IntView>::operator ++(); ++p; } while (ViewValues<IntView>::operator ()() && s.supported(p)); }
forceinline ModEvent SupportSet::tell(Space& home, IntView& x) const { switch (bs.status()) { case Support::BSS_NONE: return ME_INT_FAILED; case Support::BSS_ALL: return ME_INT_NONE; case Support::BSS_SOME: { ResultIter i(*this,x); return x.minus_v(home,i); } default: GECODE_NEVER; } return ME_INT_NONE; }
/* * Base-class for support-based iterator * */ template<class Val> forceinline void SupportIter<Val>::init(Region& r, int a0, const IntView& x0, Val l0, Val u0) { a=a0; x=x0; l=l0; u=u0; s.init(r,x.size()); } template<class Val> forceinline void SupportIter<Val>::support(void) { s.support(p); } template<class Val> forceinline ModEvent SupportIter<Val>::tell(Space& home) { return s.tell(home,x); }
/* * Support-based iterator for positive view * */ template<class Val> forceinline bool PosSupportIter<Val>::reset(Val& d) { // Way too small, no value can make it big enough if (d + static_cast<Val>(a)*x.max() < u) return false; // Restart iterator and position of values i.init(x.varimp()); p = 0; // Skip all ranges which are too small while (d + static_cast<Val>(a)*i.max() < u) { p += i.width(); ++i; } // There is at least one range left (check of max) assert(i()); // Initialize current range and adjust value c = i.min(); // Skip all values which are too small while (d + static_cast<Val>(a)*c < u) { p++; c++; } // Adjust to new value d += static_cast<Val>(a) * c; return true; } template<class Val> forceinline bool PosSupportIter<Val>::adjust(Val& d) { // Current value Val v = static_cast<Val>(a) * c; // Subtract current value from d d -= v; // Move to next position (number of value) p++; // Still in the same range if (c < i.max()) { // Decrement current values c += 1; v += a; } else { // Go to next range ++i; if (!i()) return false; c = i.min(); v = static_cast<Val>(a) * c; } // Is d with the current value too large? if (d + v > l) return false; // Update d d += v; return true; }
/* * Support-based iterator for negative view * */ template<class Val> forceinline bool NegSupportIter<Val>::reset(Val& d) { // Way too small, no value can make it big enough if (d + static_cast<Val>(a)*x.min() < u) return false; // Restart iterator and position of values i.init(x.varimp()); p = x.size()-1; // Skip all ranges which are too small while (d + static_cast<Val>(a)*i.min() < u) { p -= i.width(); ++i; } // There is at least one range left (check of max) assert(i()); // Initialize current range c = i.max(); // Skip all values which are too small while (d + static_cast<Val>(a)*c < u) { p--; c--; } // Adjust to new value d += static_cast<Val>(a) * c; return true; } template<class Val> forceinline bool NegSupportIter<Val>::adjust(Val& d) { // Current value Val v = static_cast<Val>(a) * c; // Subtract current value from d d -= v; // Move to next position (number of value) p--; // Still in the same range if (c > i.min()) { // Decrement current values c -= 1; v -= a; } else { // Go to next range ++i; if (!i()) return false; c = i.max(); v = static_cast<Val>(a) * c; } // Is d with the current value too large? if (d + v > l) return false; // Update d d += v; return true; }
/* * The domain consisten equality propagator * */ template<class Val, class View> forceinline DomEq<Val,View>::DomEq(Home home, ViewArray<View >& x, ViewArray<View >& y, Val c) : Lin<Val,View,View,PC_INT_DOM>(home,x,y,c) {}
template<class Val, class View> ExecStatus DomEq<Val,View>::post(Home home, ViewArray<View>& x, ViewArray<View>& y, Val c) { (void) new (home) DomEq<Val,View>(home,x,y,c); return ES_OK; }
template<class Val, class View> forceinline DomEq<Val,View>::DomEq(Space& home, DomEq<Val,View>& p) : Lin<Val,View,View,PC_INT_DOM>(home,p) {}
template<class Val, class View> Actor* DomEq<Val,View>::copy(Space& home) { return new (home) DomEq<Val,View>(home,*this); }
template<class Val, class View> PropCost DomEq<Val,View>::cost(const Space&, const ModEventDelta& med) const { if (View::me(med) != ME_INT_DOM) return PropCost::linear(PropCost::LO, x.size()+y.size()); else return PropCost::crazy(PropCost::HI, x.size()+y.size()); }
template<class Val, class View> ExecStatus DomEq<Val,View>::propagate(Space& home, const ModEventDelta& med) { if (View::me(med) != ME_INT_DOM) { ExecStatus es = prop_bnd<Val,View,View>(home,med,*this,x,y,c); GECODE_ES_CHECK(es); return home.ES_FIX_PARTIAL(*this,View::med(ME_INT_DOM)); }
// Value of equation for partial assignment Val d = -c;
int n = x.size(); int m = y.size();
Region r; // Create support-base iterators PosSupportIter<Val>* xp = r.alloc<PosSupportIter<Val> >(n); NegSupportIter<Val>* yp = r.alloc<NegSupportIter<Val> >(m);
// Initialize views for assignments { Val l = 0; Val u = 0; for (int j=m; j--; ) { yp[j].init(r,-y[j].scale(),y[j].base(),l,u); l += y[j].max(); u += y[j].min(); } for (int i=n; i--; ) { xp[i].init(r,x[i].scale(),x[i].base(),l,u); l -= x[i].min(); u -= x[i].max(); } }
// Collect support information by iterating assignments { // Force reset of all iterators in first round int i = 0; int j = 0;
next_i: // Reset all iterators for positive views and update d while (i<n) { if (!xp[i].reset(d)) goto prev_i; i++; } next_j: // Reset all iterators for negative views and update d while (j<m) { if (!yp[j].reset(d)) goto prev_j; j++; } // Check whether current assignment is solution if (d == 0) { // Record support for (int is=0; is<n; is++) xp[is].support(); for (int js=0; js<m; js++) yp[js].support(); } prev_j: // Try iterating to next assignment: negative views while (j>0) { if (yp[j-1].adjust(d)) goto next_j; j--; } prev_i: // Try iterating to next assignment: positive views while (i>0) { if (xp[i-1].adjust(d)) goto next_i; i--; } }
// Tell back new variable domains bool assigned = true; for (int i=0; i<n; i++) { GECODE_ME_CHECK(xp[i].tell(home)); if (!x[i].assigned()) assigned = false; } for (int j=0; j<m; j++) { GECODE_ME_CHECK(yp[j].tell(home)); if (!y[j].assigned()) assigned = false; } if (assigned) return home.ES_SUBSUMED(*this); return ES_FIX; }
}}}
// STATISTICS: int-prop