source: branches/0.4-stable/yat/statistics/AveragerPairWeighted.cc @ 1743

// $Id: AveragerPairWeighted.cc 1743 2009-01-23 14:20:30Z peter $

/*
  Copyright (C) 2005 Peter Johansson, Markus Ringnér
  Copyright (C) 2006 Jari Häkkinen, Peter Johansson
  Copyright (C) 2007 Jari Häkkinen, Peter Johansson, Markus Ringnér
  Copyright (C) 2008 Peter Johansson

  This file is part of the yat library, http://dev.thep.lu.se/yat

  The yat library is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 2 of the
  License, or (at your option) any later version.

  The yat library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  02111-1307, USA.
*/

#include "AveragerPairWeighted.h"
#include "AveragerPair.h"
#include "Averager.h"

#include <cassert>

namespace theplu {
namespace yat {
namespace statistics {


  AveragerPairWeighted::AveragerPairWeighted(void)
    : wxy_(0), w_(0)
  {
  }


  void  AveragerPairWeighted::add(const double x, const double y, 
                                  const double wx, const double wy)
  { 
    if(wx==0.0 || wy==0.0) {
      return;
    }
    assert(!std::isnan(x) && "x is nan");
    assert(!std::isnan(y) && "y is nan");
    assert(!std::isnan(wx) && "wx is nan");
    assert(!std::isnan(wy) && "wy is nan");
    double w=wx*wy;
    x_.add(x,w);
    y_.add(y,w); 
    wxy_ += w*x*y;    
    w_ +=w;
  }


  double AveragerPairWeighted::correlation(void) const
  {
    return covariance() / sqrt(x_.variance()*y_.variance());
  }


  double AveragerPairWeighted::covariance(void) const
  {
    return sum_xy_centered()/sum_w();
  }


  double AveragerPairWeighted::msd(void) const
  {
    return (x_.sum_wxx()+y_.sum_wxx()-2*wxy_)/w_;
  }


  double AveragerPairWeighted::n(void) const
  {
    return x_.n();
  }


  void AveragerPairWeighted::reset(void)
  {
    x_.reset(); y_.reset(); wxy_=0; w_=0;
  }


  double AveragerPairWeighted::sum_w(void) const
  {
    return w_;
  }


  double AveragerPairWeighted::sum_xy(void) const
  {
    return wxy_;
  }


  double AveragerPairWeighted::sum_xy_centered(void) const
  {
    return sum_xy() - x_.sum_wx()*y_.mean();
  }


  const AveragerWeighted& AveragerPairWeighted::x_averager(void) const
  {
    return x_;
  }


  const AveragerWeighted& AveragerPairWeighted::y_averager(void) const
  {
    return y_;
  }

}}} // of namespace statistics, yat, and theplu