view-values.hpp

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/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Copyright:
 *     Christian Schulte, 2008
 *
 *  Last modified:
 *     $Date: 2013-07-04 17:03:13 +0200 (Thu, 04 Jul 2013) $ by $Author: schulte $
 *     $Revision: 13801 $
 *
 *  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
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 *  permit persons to whom the Software is furnished to do so, subject to
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namespace Gecode { namespace Int { namespace Branch {

  class GECODE_VTABLE_EXPORT PosValuesChoice : public PosChoice {
  private:
    class PosMin {
    public:
      unsigned int pos;
      int min;
    };
    unsigned int n;
    PosMin* pm;
  public:
    GECODE_INT_EXPORT
    PosValuesChoice(const Brancher& b, const Pos& p, IntView x);
    GECODE_INT_EXPORT
    PosValuesChoice(const Brancher& b, unsigned int alt, Pos p, Archive& e);
    int val(unsigned int a) const;
    GECODE_INT_EXPORT
    virtual size_t size(void) const;
    GECODE_INT_EXPORT
    virtual ~PosValuesChoice(void);
    GECODE_INT_EXPORT
    virtual void archive(Archive& e) const;
  };

  forceinline int
  PosValuesChoice::val(unsigned int a) const {
    PosMin* l = &pm[0];
    PosMin* r = &pm[n-1];
    while (true) {
      PosMin* m = l + (r-l)/2;
      if (a < m->pos) {
        r=m-1;
      } else if (a >= (m+1)->pos) {
        l=m+1;
      } else {
        return m->min + static_cast<int>(a - m->pos);
      }
    }
    GECODE_NEVER;
    return 0;
  }


  template<int n, bool min>
  forceinline
  ViewValuesBrancher<n,min>::
  ViewValuesBrancher(Home home, ViewArray<IntView>& x,
                     ViewSel<IntView>* vs[n], 
                     BranchFilter bf, IntVarValPrint vvp0)
    : ViewBrancher<IntView,n>(home,x,vs,bf), vvp(vvp0) {}

  template<int n, bool min>
  BrancherHandle
  ViewValuesBrancher<n,min>::post(Home home, ViewArray<IntView>& x, 
                                  ViewSel<IntView>* vs[n],
                                  BranchFilter bf, IntVarValPrint vvp) {
    return *new (home) ViewValuesBrancher<n,min>(home,x,vs,bf,vvp);
  }

  template<int n, bool min>
  forceinline
  ViewValuesBrancher<n,min>::
  ViewValuesBrancher(Space& home, bool shared, ViewValuesBrancher& b)
    : ViewBrancher<IntView,n>(home,shared,b), vvp(b.vvp) {}

  template<int n, bool min>
  Actor*
  ViewValuesBrancher<n,min>::copy(Space& home, bool shared) {
    return new (home) ViewValuesBrancher<n,min>(home,shared,*this);
  }

  template<int n, bool min>
  const Choice*
  ViewValuesBrancher<n,min>::choice(Space& home) {
    Pos p = ViewBrancher<IntView,n>::pos(home);
    return new PosValuesChoice(*this,p,
                               ViewBrancher<IntView,n>::view(p));
  }

  template<int n, bool min>
  const Choice*
  ViewValuesBrancher<n,min>::choice(const Space& home, Archive& e) {
    (void) home;
    int p;
    unsigned int a;
    e >> p >> a;
    return new PosValuesChoice(*this,a,p,e);
  }

  template<int n, bool min>
  ExecStatus
  ViewValuesBrancher<n,min>::commit(Space& home, const Choice& c, 
                                    unsigned int a) {
    const PosValuesChoice& pvc
      = static_cast<const PosValuesChoice&>(c);
    IntView x(ViewBrancher<IntView,n>::view(pvc.pos()));
    unsigned int b = min ? a : (pvc.alternatives() - 1 - a);
    return me_failed(x.eq(home,pvc.val(b))) ? ES_FAILED : ES_OK;
  }

  template<int n, bool min>
  NGL*
  ViewValuesBrancher<n,min>::ngl(Space& home, const Choice& c, 
                                 unsigned int a) const {
    const PosValuesChoice& pvc
      = static_cast<const PosValuesChoice&>(c);
    IntView x(ViewBrancher<IntView,n>::view(pvc.pos()));
    unsigned int b = min ? a : (pvc.alternatives() - 1 - a);
    return new (home) EqNGL<IntView>(home,x,pvc.val(b));
  }

  template<int n, bool min>
  void
  ViewValuesBrancher<n,min>::print(const Space& home, const Choice& c, 
                                   unsigned int a, std::ostream& o) const {
    const PosValuesChoice& pvc
      = static_cast<const PosValuesChoice&>(c);
    IntVar x(ViewBrancher<IntView,n>::view(pvc.pos()).varimp());
    unsigned int b = min ? a : (pvc.alternatives() - 1 - a);
    int nn = pvc.val(b);
    if (vvp != NULL)
      vvp(home,*this,a,x,pvc.pos().pos,nn,o);
    else
      o << "var[" << pvc.pos().pos << "] = " << nn;
  }

}}}

// STATISTICS: int-branch