EuclideanDistance.h

#ifndef theplu_yat_statistics_euclidean_distance_h
#define theplu_yat_statistics_euclidean_distance_h

// $Id: EuclideanDistance.h 2202 2010-02-21 18:39:13Z peter $

/*
  Copyright (C) 2007, 2008 Jari Häkkinen, Peter Johansson, Markus Ringnér
  Copyright (C) 2010 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 3 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 yat. If not, see <http://www.gnu.org/licenses/>.
*/

#include "AveragerPair.h"
#include "AveragerPairWeighted.h"
#include "yat/utility/iterator_traits.h"

#include <cmath>

namespace theplu {
namespace yat {
namespace statistics {
  
  struct EuclideanDistance
  {   
    template <typename ForwardIterator1, typename ForwardIterator2>
    double operator()(ForwardIterator1 beg1, ForwardIterator1 end1, 
                      ForwardIterator2 beg2) const
    {
      using utility::weighted_if_any2;
      typename weighted_if_any2<ForwardIterator1,ForwardIterator2>::type tag; 
      return this->distance(beg1, end1, beg2, tag); 
    }

  private:
    template <typename Iter1, typename Iter2>
    double distance (Iter1 beg1,Iter1 end1, Iter2 beg2, 
                     utility::unweighted_iterator_tag) const
    {
      AveragerPair ap;
      add(ap,beg1,end1,beg2);
      return sqrt(ap.sum_squared_deviation());
    }

    template <typename Iter1, typename Iter2>
    double distance (Iter1 beg1,Iter1 end1, Iter2 beg2, 
                     utility::weighted_iterator_tag) const
    {
      AveragerPairWeighted ap;
      add(ap,beg1,end1,beg2);
      return sqrt(std::distance(beg1,end1)*ap.msd());
    }
    
  };

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