source: trunk/src/WeightedAverager.h @ 94

// $Id: WeightedAverager.h 94 2004-06-09 10:24:53Z peter $

#ifndef _theplu_cpptools_weighted_averager_
#define _theplu_cpptools_weighted_averager_

//#include <cmath>
#include "Averager.h"

namespace theplu{
namespace cpptools{
  ///
  /// Averager class for weights.
  ///
  class WeightedAverager
  {
  public:

    ///
    /// Default constructor
    ///
    WeightedAverager(void);
    
    ///
    /// adding a data point d, with weight w (default is 1)
    ///
    inline void add(const double d,const double w=1)
    {w_.add(w); wx_.add(w*d); wwx_.add(w*w*d);}

    ///
    /// @return average
    ///
    inline double average(void) const {return mean();}

    ///
    /// @return average
    ///
    inline double mean(void) const { return w_.sum_x() ? 
                                       wx_.sum_x()/w_.sum_x() : 0; }
  
    ///
    /// @return squarred error
    ///
    inline double squarred_error(void)  const 
    { return (wx_.sum_xsqr()-2*mean()*wwx_.sum_x()+
              mean()*mean()*w_.sum_xsqr()) / (w_.sum_x()*w_.sum_x()); }

  private:
    Averager w_;
    Averager wx_;
    Averager wwx_;
    

  };


}} // of namespace cpptools and namespace theplu

#endif