source: trunk/yat/classifier/GaussianKernelFunction.h

Last change on this file was 2119, checked in by Peter, 12 years ago

converted files to utf-8. fixes #577

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date ID
File size: 2.1 KB
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1#ifndef _theplu_yat_classifier_gaussian_kernel_function_
2#define _theplu_yat_classifier_gaussian_kernel_function_
3
4// $Id$
5
6/*
7  Copyright (C) 2004, 2005, 2006, 2007, 2008 Jari Häkkinen, Peter Johansson
8
9  This file is part of the yat library, http://dev.thep.lu.se/yat
10
11  The yat library is free software; you can redistribute it and/or
12  modify it under the terms of the GNU General Public License as
13  published by the Free Software Foundation; either version 3 of the
14  License, or (at your option) any later version.
15
16  The yat library is distributed in the hope that it will be useful,
17  but WITHOUT ANY WARRANTY; without even the implied warranty of
18  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19  General Public License for more details.
20
21  You should have received a copy of the GNU General Public License
22  along with yat. If not, see <http://www.gnu.org/licenses/>.
23*/
24
25#include "KernelFunction.h"
26
27#include <cmath>
28
29namespace theplu {
30namespace yat {
31namespace classifier {
32
33  class DataLookup1D;
34
35  ///
36  /// @brief Class for Gaussian kernel calculations.
37  ///
38 
39  class GaussianKernelFunction : public KernelFunction
40  {
41   
42  public:
43    ///
44    /// Constructor taking the sigma_ , i.e. the width of the Gaussian,as
45    /// input. Default is sigma_ = 1.
46    ///
47    GaussianKernelFunction(double = 1);
48   
49    ///
50    ///Destructor
51    ///
52       virtual ~GaussianKernelFunction(void) {};
53   
54    ///
55    /// returning the scalar product of two vectors in feature space using the
56    /// Gaussian kernel. @return \f$ exp(-(x - y)^{2}/\sigma^2) \f$ \n
57    ///
58    double operator()(const DataLookup1D& x,
59                      const DataLookup1D& y) const; 
60
61    /**
62       \f$ \exp(-d^2/\sigma^2) \f$ where \f$ d^2 = \sum w_y(x_i-y_i)^2
63       / \sum w_y * N \f$
64     **/
65    double operator()(const DataLookup1D& x,
66                      const DataLookupWeighted1D& y) const; 
67
68    /**
69       \f$ \exp(-d^2/\sigma^2) \f$ where \f$ d^2 = \sum w_xw_y(x_i-y_i)^2
70       / \sum w_xw_y * N \f$
71     **/
72    double operator()(const DataLookupWeighted1D& x,
73                      const DataLookupWeighted1D& y) const; 
74
75  private:
76    double sigma2_;
77
78  }; // class GaussianKernelFunction
79
80}}} // of namespace classifier, yat, and theplu
81
82#endif
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