seq-u.cpp

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/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Guido Tack <tack@gecode.org>
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Contributing authors:
 *     Gabor Szokoli <szokoli@gecode.org>
 *
 *  Copyright:
 *     Guido Tack, 2004
 *     Christian Schulte, 2004
 *     Gabor Szokoli, 2004
 *
 *  Last modified:
 *     $Date: 2011-05-23 16:48:31 +0200 (Mon, 23 May 2011) $ by $Author: tack $
 *     $Revision: 12018 $
 *
 *  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
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 */

#include <gecode/set/sequence.hh>

namespace Gecode { namespace Set { namespace Sequence {

  /*
   * "Sequenced union" propagator
   *
   */

  Actor*
  SeqU::copy(Space& home, bool share) {
    return new (home) SeqU(home,share,*this);
  }

  ExecStatus
  SeqU::propagateSeqUnion(Space& home,
                          bool& modified, ViewArray<SetView>& x,
                          SetView& y) {
    Region r(home);
    GlbRanges<SetView>* XLBs = r.alloc<GlbRanges<SetView> >(x.size());
    for (int i=x.size(); i--; ){
      GlbRanges<SetView> lb(x[i]);
      XLBs[i]=lb;
    }
    Iter::Ranges::NaryAppend<GlbRanges<SetView> > u(XLBs,x.size());
    GECODE_ME_CHECK_MODIFIED(modified, y.includeI(home,u));

    GLBndSet before(home);
    for (int i=0; i<x.size(); i++) {
      LubRanges<SetView> xiub(x[i]);
      before.includeI(home, xiub);
      BndSetRanges beforeR(before);
      GlbRanges<SetView> ylb(y);
      Iter::Ranges::Diff<GlbRanges<SetView>, BndSetRanges> diff(ylb, beforeR);
      if (diff()) {
        GECODE_ME_CHECK_MODIFIED(modified, x[i].exclude(home, diff.min(),
                                                        Limits::max));
      }
    }
    before.dispose(home);

    GLBndSet after(home);
    for (int i=x.size(); i--; ) {
      LubRanges<SetView> xiub(x[i]);
      after.includeI(home, xiub);
      BndSetRanges afterR(after);
      GlbRanges<SetView> ylb(y);
      Iter::Ranges::Diff<GlbRanges<SetView>, BndSetRanges> diff(ylb, afterR);
      if (diff()) {
        int max = diff.max();
        for (; diff(); ++diff)
          max = diff.max();
        GECODE_ME_CHECK_MODIFIED(modified, x[i].exclude(home,
                                                        Limits::min,
                                                        max));
      }
    }
    after.dispose(home);

    return ES_FIX;
  }

  //Enforces sequentiality and ensures y contains union of Xi lower bounds.
  ExecStatus
  SeqU::propagate(Space& home, const ModEventDelta& med) {
    ModEvent me0 = SetView::me(med);
    bool ubevent = Rel::testSetEventUB(me0);
    bool anybevent = Rel::testSetEventAnyB(me0);
    bool cardevent = Rel::testSetEventCard(me0);

    bool modified = false;
    bool assigned=false;
    bool oldModified = false;

    do {
      oldModified = modified;
      modified = false;

      if (oldModified || modified || anybevent || cardevent)
        GECODE_ES_CHECK(propagateSeq(home,modified,assigned,x));
      if (oldModified || modified || anybevent)
        GECODE_ES_CHECK(propagateSeqUnion(home,modified,x,y));
      if (oldModified || modified || ubevent)
        GECODE_ES_CHECK(RelOp::unionNXiUB(home,modified,x,y,unionOfDets));
      if (oldModified || modified || ubevent)
        GECODE_ES_CHECK(RelOp::partitionNYUB(home,modified,x,y,unionOfDets));
      if (oldModified || modified || anybevent)
        GECODE_ES_CHECK(RelOp::partitionNXiLB(home,modified,x,y,unionOfDets));
      if (oldModified || modified || cardevent || ubevent)
        GECODE_ES_CHECK(RelOp::partitionNCard(home,modified,x,y,unionOfDets));

    } while (modified);

    for (int i=x.size(); i--;)
      if (!x[i].assigned())
        return ES_FIX;
    return home.ES_SUBSUMED(*this);
  }

}}}

// STATISTICS: set-prop