gecode中的meritbase

这个类只是个基类，并没有实现什么，主要作用是给子类提供统一的接口

  /**
   * \defgroup TaskBranchMerit Generic merit for branchers based on view and value selection
   *
   * \ingroup TaskBranchViewVal
   */
  //@{
  /**
   * \brief Base-class for merit class
   */
  template<class _View, class _Val>
  class MeritBase {
  public:
    /// View type
    typedef _View View;
    /// Type of merit
    typedef _Val Val;
    /// Constructor for initialization
    MeritBase(Space& home, const VarBranch& vb);
    /// Constructor for cloning
    MeritBase(Space& home, bool share, MeritBase& mb);
    /// Whether dispose must always be called (that is, notice is needed)
    bool notice(void) const;
    /// Delete view merit class
    void dispose(Space& home);
  };

  // Merit base class
  template<class View, class Val>
  forceinline
  MeritBase<View,Val>::MeritBase(Space&, const VarBranch&) {}
  template<class View, class Val>
  forceinline
  MeritBase<View,Val>::MeritBase(Space&, bool, MeritBase&) {}
  template<class View, class Val>
  forceinline bool
  MeritBase<View,Val>::notice(void) const {
    return false;
  }
  template<class View, class Val>
  forceinline void
  MeritBase<View,Val>::dispose(Space&) {}