branch.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: 2010-09-03 10:30:37 +0200 (Fri, 03 Sep 2010) $ by $Author: schulte $
 *     $Revision: 11386 $
 *
 *  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
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 *  permit persons to whom the Software is furnished to do so, subject to
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 *
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 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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 */

#include <ctime>

namespace Gecode {

  typedef bool (*BranchFilter)(const Space& home, int i, const Var& x);

  class VarBranchOptions {
  public:
    BranchFilter bf;
    unsigned int seed;
    GECODE_KERNEL_EXPORT static const VarBranchOptions def;
    VarBranchOptions(BranchFilter bf0=NULL);
    static VarBranchOptions time(BranchFilter bf=NULL);
  };

  class ValBranchOptions {
  public:
    unsigned int seed;
    GECODE_KERNEL_EXPORT static const ValBranchOptions def;
    ValBranchOptions(void);
    static ValBranchOptions time(void);
  };


  template<class VarBranch>
  class TieBreakVarBranch {
  public:
    VarBranch a, b, c, d;
    TieBreakVarBranch(VarBranch a0 = static_cast<VarBranch>(0),
                      VarBranch b0 = static_cast<VarBranch>(0),
                      VarBranch c0 = static_cast<VarBranch>(0),
                      VarBranch d0 = static_cast<VarBranch>(0));
  };

  class TieBreakVarBranchOptions {
  public:
    VarBranchOptions a, b, c, d;
    GECODE_KERNEL_EXPORT static const TieBreakVarBranchOptions def;
    TieBreakVarBranchOptions(const VarBranchOptions& a0
                             = VarBranchOptions::def,
                             const VarBranchOptions& b0
                             = VarBranchOptions::def,
                             const VarBranchOptions& c0
                             = VarBranchOptions::def,
                             const VarBranchOptions& d0
                             = VarBranchOptions::def);
  };


  template<class VarBranch>
  TieBreakVarBranch<VarBranch>
  tiebreak(VarBranch a, VarBranch b);
  template<class VarBranch>
  TieBreakVarBranch<VarBranch>
  tiebreak(VarBranch a, VarBranch b, VarBranch c);
  template<class VarBranch>
  TieBreakVarBranch<VarBranch>
  tiebreak(VarBranch a, VarBranch b, VarBranch c, VarBranch d);
  TieBreakVarBranchOptions
  tiebreak(VarBranchOptions a, VarBranchOptions b);
  TieBreakVarBranchOptions
  tiebreak(VarBranchOptions a, VarBranchOptions b, VarBranchOptions c);
  TieBreakVarBranchOptions
  tiebreak(VarBranchOptions a, VarBranchOptions b, VarBranchOptions c,
           VarBranchOptions d);


  GECODE_KERNEL_EXPORT void
  branch(Home home, void (*f)(Space& home));


  // Variable branch options
  forceinline
  VarBranchOptions::VarBranchOptions(BranchFilter bf0) 
    : bf(bf0), seed(0) {}

  forceinline VarBranchOptions
  VarBranchOptions::time(BranchFilter bf) {
    VarBranchOptions o(bf); 
    o.seed=static_cast<unsigned int>(::time(NULL));
    return o;
  }

  // Value branch options
  forceinline
  ValBranchOptions::ValBranchOptions(void) : seed(0) {}

  forceinline ValBranchOptions
  ValBranchOptions::time(void) {
    ValBranchOptions o; o.seed=static_cast<unsigned int>(::time(NULL));
    return o;
  }


  /*
   * Combine variable selection criteria for tie-breaking
   */
  template<class VarBranch>
  forceinline
  TieBreakVarBranch<VarBranch>::TieBreakVarBranch(VarBranch a0,
                                                  VarBranch b0,
                                                  VarBranch c0,
                                                  VarBranch d0)
    : a(a0), b(b0), c(c0), d(d0) {}

  template<class VarBranch>
  forceinline TieBreakVarBranch<VarBranch>
  tiebreak(VarBranch a, VarBranch b) {
    TieBreakVarBranch<VarBranch> ab(a,b);
    return ab;
  }

  template<class VarBranch>
  forceinline TieBreakVarBranch<VarBranch>
  tiebreak(VarBranch a, VarBranch b, VarBranch c) {
    TieBreakVarBranch<VarBranch> abc(a,b,c);
    return abc;
  }

  template<class VarBranch>
  forceinline TieBreakVarBranch<VarBranch>
  tiebreak(VarBranch a, VarBranch b, VarBranch c, VarBranch d) {
    TieBreakVarBranch<VarBranch> abcd(a,b,c,d);
    return abcd;
  }

  /*
   * Combine branch options for tie-breaking
   */
  forceinline
  TieBreakVarBranchOptions::
  TieBreakVarBranchOptions(const VarBranchOptions& a0,
                           const VarBranchOptions& b0,
                           const VarBranchOptions& c0,
                           const VarBranchOptions& d0)
    : a(a0), b(b0), c(c0), d(d0) {}

  forceinline TieBreakVarBranchOptions
  tiebreak(VarBranchOptions a, VarBranchOptions b) {
    TieBreakVarBranchOptions ab(a,b);
    return ab;
  }

  forceinline TieBreakVarBranchOptions
  tiebreak(VarBranchOptions a, VarBranchOptions b, VarBranchOptions c) {
    TieBreakVarBranchOptions abc(a,b,c);
    return abc;
  }

  forceinline TieBreakVarBranchOptions
  tiebreak(VarBranchOptions a, VarBranchOptions b, VarBranchOptions c,
           VarBranchOptions d) {
    TieBreakVarBranchOptions abcd(a,b,c,d);
    return abcd;
  }

}

// STATISTICS: kernel-branch