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re-eq.hpp

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00001 /* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
00002 /*
00003  *  Main authors:
00004  *     Guido Tack <tack@gecode.org>
00005  *     Christian Schulte <schulte@gecode.org>
00006  *
00007  *  Bugfixes provided by:
00008  *     Grégoire Dooms <dooms@info.ucl.ac.be>
00009  *
00010  *  Copyright:
00011  *     Guido Tack, 2004
00012  *     Christian Schulte, 2004
00013  *
00014  *  Last modified:
00015  *     $Date: 2010-03-03 17:32:21 +0100 (Wed, 03 Mar 2010) $ by $Author: schulte $
00016  *     $Revision: 10364 $
00017  *
00018  *  This file is part of Gecode, the generic constraint
00019  *  development environment:
00020  *     http://www.gecode.org
00021  *
00022  *  Permission is hereby granted, free of charge, to any person obtaining
00023  *  a copy of this software and associated documentation files (the
00024  *  "Software"), to deal in the Software without restriction, including
00025  *  without limitation the rights to use, copy, modify, merge, publish,
00026  *  distribute, sublicense, and/or sell copies of the Software, and to
00027  *  permit persons to whom the Software is furnished to do so, subject to
00028  *  the following conditions:
00029  *
00030  *  The above copyright notice and this permission notice shall be
00031  *  included in all copies or substantial portions of the Software.
00032  *
00033  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
00034  *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
00035  *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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00038  *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
00039  *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00040  *
00041  */
00042 
00043 namespace Gecode { namespace Set { namespace Rel {
00044 
00045   template<class View0, class View1>
00046   forceinline
00047   ReEq<View0,View1>::ReEq(Home home, View0 y0, View1 y1,
00048                           Gecode::Int::BoolView y2)
00049     : Propagator(home), x0(y0), x1(y1), b(y2) {
00050     b.subscribe(home,*this, Gecode::Int::PC_INT_VAL);
00051     x0.subscribe(home,*this, PC_SET_ANY);
00052     x1.subscribe(home,*this, PC_SET_ANY);
00053   }
00054 
00055   template<class View0, class View1>
00056   forceinline
00057   ReEq<View0,View1>::ReEq(Space& home, bool share, ReEq& p)
00058     : Propagator(home,share,p) {
00059     x0.update(home,share,p.x0);
00060     x1.update(home,share,p.x1);
00061     b.update(home,share,p.b);
00062   }
00063 
00064   template<class View0, class View1>
00065   PropCost
00066   ReEq<View0,View1>::cost(const Space&, const ModEventDelta&) const {
00067     return PropCost::ternary(PropCost::LO);
00068   }
00069 
00070   template<class View0, class View1>
00071   forceinline size_t
00072   ReEq<View0,View1>::dispose(Space& home) {
00073     b.cancel(home,*this, Gecode::Int::PC_INT_VAL);
00074     x0.cancel(home,*this, PC_SET_ANY);
00075     x1.cancel(home,*this, PC_SET_ANY);
00076     (void) Propagator::dispose(home);
00077     return sizeof(*this);
00078   }
00079 
00080   template<class View0, class View1>
00081   ExecStatus
00082   ReEq<View0,View1>::post(Home home, View0 x0, View1 x1,
00083                             Gecode::Int::BoolView b) {
00084     (void) new (home) ReEq<View0,View1>(home,x0,x1,b);
00085     return ES_OK;
00086   }
00087 
00088   template<class View0, class View1>
00089   Actor*
00090   ReEq<View0,View1>::copy(Space& home, bool share) {
00091     return new (home) ReEq<View0,View1>(home,share,*this);
00092   }
00093 
00094   template<class View0, class View1>
00095   ExecStatus
00096   ReEq<View0,View1>::propagate(Space& home, const ModEventDelta&) {
00097     if (b.one())
00098       GECODE_REWRITE(*this,(Eq<View0,View1>::post(home(*this),x0,x1)));
00099     if (b.zero())
00100       GECODE_REWRITE(*this,(Distinct<View0,View1>::post(home(*this),x0,x1)));
00101 
00102     if (x0.assigned() && x1.assigned()) {
00103       // directly test x0==x1
00104       GlbRanges<View0> x0lb(x0);
00105       GlbRanges<View1> x1lb(x1);
00106       for (; x0lb() && x1lb(); ++x0lb, ++x1lb) {
00107         if (x0lb.min() != x1lb.min() ||
00108             x0lb.max() != x1lb.max()) {
00109           GECODE_ME_CHECK(b.zero_none(home));
00110           return home.ES_SUBSUMED(*this);
00111         }
00112       }
00113       if (!x0lb() && !x1lb()) {
00114         GECODE_ME_CHECK(b.one_none(home));
00115         return home.ES_SUBSUMED(*this);
00116       } else {
00117         GECODE_ME_CHECK(b.zero_none(home));
00118         return home.ES_SUBSUMED(*this);
00119       }
00120     }
00121 
00122     // check whether cardinalities still allow equality
00123     if (x0.cardMin() > x1.cardMax() ||
00124         x1.cardMin() > x0.cardMax()) {
00125       GECODE_ME_CHECK(b.zero_none(home));
00126       return home.ES_SUBSUMED(*this);
00127     }
00128 
00129     // check glb(x0) subset lub(x1)
00130     GlbRanges<View0> x0lb(x0);
00131     LubRanges<View1> x1ub(x1);
00132     Iter::Ranges::Diff<GlbRanges<View0>, LubRanges<View1> > diff1(x0lb, x1ub);
00133     if ( diff1() ) {
00134       GECODE_ME_CHECK(b.zero_none(home));
00135       return home.ES_SUBSUMED(*this);
00136     }
00137 
00138     // check glb(x1) subset lub(x0)
00139     GlbRanges<View1> x1lb(x1);
00140     LubRanges<View0> x0ub(x0);
00141     Iter::Ranges::Diff<GlbRanges<View1>, LubRanges<View0> > diff2(x1lb, x0ub);
00142     if ( diff2() ) {
00143       GECODE_ME_CHECK(b.zero_none(home));
00144       return home.ES_SUBSUMED(*this);
00145     }
00146 
00147     return ES_FIX;
00148   }
00149 
00150 }}}
00151 
00152 // STATISTICS: set-prop