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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- *//* * Main authors: * Christian Schulte <schulte@gecode.org> * * Contributing authors: * Mikael Lagerkvist <lagerkvist@gecode.org> * * Copyright: * Christian Schulte, 2006 * Mikael Lagerkvist, 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 Channel {
/** * \brief Combine view with information for value propagation * */ template<class View> class ValInfo { public: /// The view View view; /// Whether it has been propagated that view is assigned bool a; /// Initialize void init(View x, int n); /// Update during cloning void update(Space& home, ValInfo<View>& vi); /// Check whether propagation for assignment is to be done bool doval(void) const; /// Check whether propagation for domain is to be done bool dodom(void) const; /// Record that view got assigned void assigned(void); /// Record that one value got removed void removed(int i); /// Update the cardinality and bounds information after pruning void done(void); };
template<class View> forceinline void ValInfo<View>::init(View x, int) { view = x; a = false; }
template<class View> forceinline void ValInfo<View>::update(Space& home, ValInfo<View>& vi) { view.update(home,vi.view); a = vi.a; }
template<class View> forceinline bool ValInfo<View>::doval(void) const { return !a && view.assigned(); }
template<class View> forceinline bool ValInfo<View>::dodom(void) const { return false; }
template<class View> forceinline void ValInfo<View>::assigned(void) { a = true; }
template<class View> forceinline void ValInfo<View>::removed(int) {}
template<class View> forceinline void ValInfo<View>::done(void) {}
// Propagate assigned views for x template<class View, class Offset, class Info> ExecStatus doprop_val(Space& home, int n, Info* x, Offset& ox, Info* y, Offset& oy, int& n_na, ProcessStack& xa, ProcessStack& ya) { do { int i = xa.pop(); int j = ox(x[i].view).val(); // Assign the y variable to i (or test if already assigned!) { ModEvent me = oy(y[j].view).eq(home,i); if (me_failed(me)) { return ES_FAILED; } // Record that y[j] has been assigned and must be propagated if (me_modified(me)) ya.push(j); } // Prune the value j from all x variables for (int k=0; k<i; k++) { ModEvent me = ox(x[k].view).nq(home,j); if (me_failed(me)) { return ES_FAILED; } if (me_modified(me)) { if (me == ME_INT_VAL) { // Record that x[k] has been assigned and must be propagated xa.push(k); } else { // One value has been removed and this removal does not need // to be propagated again: after all y[j] = i, so it holds // that y[j] != k. x[k].removed(j); } } } // The same for the other views for (int k=i+1; k<n; k++) { ModEvent me = ox(x[k].view).nq(home,j); if (me_failed(me)) { return ES_FAILED; } if (me_modified(me)) { if (me == ME_INT_VAL) { // Record that x[k] has been assigned and must be propagated xa.push(k); } else { // One value has been removed and this removal does not need // to be propagated again: after all y[j] = i, so it holds // that y[j] != k. x[k].removed(j); } } } x[i].assigned(); n_na--; } while (!xa.empty()); return ES_OK; }
// Just do a test whether a call to the routine is necessary template<class View, class Offset, class Info> forceinline ExecStatus prop_val(Space& home, int n, Info* x, Offset& ox, Info* y, Offset& oy, int& n_na, ProcessStack& xa, ProcessStack& ya) { if (xa.empty()) return ES_OK; return doprop_val<View,Offset,Info>(home,n,x,ox,y,oy,n_na,xa,ya); }
/* * The actual propagator * */ template<class View, class Offset, bool shared> forceinline Val<View,Offset,shared>::Val(Home home, int n, ValInfo<View>* xy, Offset& ox, Offset& oy) : Base<ValInfo<View>,Offset,PC_INT_VAL>(home,n,xy,ox,oy) {}
template<class View, class Offset, bool shared> forceinline Val<View,Offset,shared>::Val(Space& home, Val<View,Offset,shared>& p) : Base<ValInfo<View>,Offset,PC_INT_VAL>(home,p) {}
template<class View, class Offset, bool shared> Actor* Val<View,Offset,shared>::copy(Space& home) { return new (home) Val<View,Offset,shared>(home,*this); }
template<class View, class Offset, bool shared> ExecStatus Val<View,Offset,shared>::propagate(Space& home, const ModEventDelta&) { Region r; ProcessStack xa(r,n); ProcessStack ya(r,n);
ValInfo<View>* x = xy; ValInfo<View>* y = xy+n;
// Scan x and y for assigned but not yet propagated views for (int i=0; i<n; i++) { if (x[i].doval()) xa.push(i); if (y[i].doval()) ya.push(i); }
do { // Propagate assigned views for x GECODE_ES_CHECK((prop_val<View,Offset,ValInfo<View> > (home,n,x,ox,y,oy,n_na,xa,ya))); // Propagate assigned views for y GECODE_ES_CHECK((prop_val<View,Offset,ValInfo<View> > (home,n,y,oy,x,ox,n_na,ya,xa))); assert(ya.empty()); } while (!xa.empty());
if (n_na == 0) return home.ES_SUBSUMED(*this); return shared ? ES_NOFIX : ES_FIX; }
template<class View, class Offset, bool shared> ExecStatus Val<View,Offset,shared>::post(Home home, int n, ValInfo<View>* xy, Offset& ox, Offset& oy) { assert(n > 0); if (n == 1) { GECODE_ME_CHECK(ox(xy[0].view).eq(home,0)); GECODE_ME_CHECK(oy(xy[1].view).eq(home,0)); return ES_OK; } for (int i=0; i<n; i++) { GECODE_ME_CHECK(ox(xy[i ].view).gq(home,0)); GECODE_ME_CHECK(ox(xy[i ].view).le(home,n)); GECODE_ME_CHECK(oy(xy[i+n].view).gq(home,0)); GECODE_ME_CHECK(oy(xy[i+n].view).le(home,n)); } (void) new (home) Val<View,Offset,shared>(home,n,xy,ox,oy); return ES_OK; }
}}}
// STATISTICS: int-prop