source: trunk/yat/statistics/EuclideanDistance.h @ 1093

Last change on this file since 1093 was 1093, checked in by Peter, 14 years ago

some doc for EuclideanDistance? refs #254

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File size: 2.4 KB
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1#ifndef theplu_yat_statistics_euclidean_distance_h
2#define theplu_yat_statistics_euclidean_distance_h
3
4// $Id: EuclideanDistance.h 1093 2008-02-14 22:08:10Z peter $
5
6/*
7  Copyright (C) 2007 Peter Johansson, Markus Ringnér
8  Copyright (C) 2008 Peter Johansson
9
10  This file is part of the yat library, http://trac.thep.lu.se/yat
11
12  The yat library is free software; you can redistribute it and/or
13  modify it under the terms of the GNU General Public License as
14  published by the Free Software Foundation; either version 2 of the
15  License, or (at your option) any later version.
16
17  The yat library is distributed in the hope that it will be useful,
18  but WITHOUT ANY WARRANTY; without even the implied warranty of
19  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20  General Public License for more details.
21
22  You should have received a copy of the GNU General Public License
23  along with this program; if not, write to the Free Software
24  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
25  02111-1307, USA.
26*/
27
28#include "AveragerPair.h"
29#include "AveragerPairWeighted.h"
30#include "yat/utility/iterator_traits.h"
31
32#include <cmath>
33
34namespace theplu {
35namespace yat {
36namespace statistics {
37 
38  ///
39  /// @brief Calculates the Euclidean distance between two points
40  /// stored in 1-dimensional containers. Implements the concept \ref
41  /// concept_distance.
42  ///
43  ///
44  struct EuclideanDistance
45  {   
46    /**
47       \brief Calculates the Euclidean distance between two ranges.
48   
49       If both ranges are unweighted the distance is calculated as \f$
50       \sqrt{\sum (x_i-y_i)^2 } \f$
51
52       Else distance is calculated as \f$ N \frac{\sum
53       w_xw_y(x-y)^2}{\sum w_xw_y} \f$
54    */
55    template <typename Iter1, typename Iter2>
56    double operator()
57    (Iter1 beg1,Iter1 end1, Iter2 beg2) const
58    {
59      return this->distance(beg1, end1, beg2, 
60                      typename utility::weighted_if_any2<Iter1,Iter2>::type());
61    }
62
63  private:
64    template <typename Iter1, typename Iter2>
65    double distance (Iter1 beg1,Iter1 end1, Iter2 beg2, 
66                     utility::unweighted_iterator_tag) const
67    {
68      AveragerPair ap;
69      add(ap,beg1,end1,beg2);
70      return sqrt(ap.sum_squared_deviation());
71    }
72
73    template <typename Iter1, typename Iter2>
74    double distance (Iter1 beg1,Iter1 end1, Iter2 beg2, 
75                     utility::weighted_iterator_tag) const
76    {
77      AveragerPairWeighted ap;
78      add(ap,beg1,end1,beg2);
79      return sqrt(std::distance(beg1,end1)*ap.msd());
80    }
81   
82  };
83
84}}} // of namespace statistics, yat, and theplu
85   
86#endif
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