source: trunk/yat/classifier/GaussianKernelFunction.h @ 747

Last change on this file since 747 was 747, checked in by Peter, 15 years ago

replaced includes in header files with forward declarations when possible. Added some includes in cc files.

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date ID
File size: 2.2 KB
Line 
1#ifndef _theplu_yat_classifier_gaussian_kernel_function_
2#define _theplu_yat_classifier_gaussian_kernel_function_
3
4// $Id$
5
6/*
7  Copyright (C) The authors contributing to this file.
8
9  This file is part of the yat library, http://lev.thep.lu.se/trac/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 2 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 this program; if not, write to the Free Software
23  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
24  02111-1307, USA.
25*/
26
27#include "KernelFunction.h"
28
29#include <cmath>
30
31namespace theplu {
32namespace yat {
33namespace classifier {
34
35  class DataLookup1D;
36
37  ///
38  /// Class for Gaussian kernel calculations.
39  ///
40 
41  class GaussianKernelFunction : public KernelFunction
42  {
43   
44  public:
45    ///
46    /// Constructor taking the sigma_ , i.e. the width of the Gaussian,as
47    /// input. Default is sigma_ = 1.
48    ///
49    GaussianKernelFunction(double = 1);
50   
51    ///
52    ///Destructor
53    ///
54       virtual ~GaussianKernelFunction(void) {};
55   
56    ///
57    /// returning the scalar product of two vectors in feature space using the
58    /// Gaussian kernel. @return \f$ exp(-(x - y)^{2}/\sigma^2) \f$ \n
59    ///
60    double operator()(const DataLookup1D& x,
61                      const DataLookup1D& y) const; 
62
63    /**
64       \f$ \exp(-d^2/\sigma^2) \f$ where \f$ d^2 = \sum w_y(x_i-y_i)^2
65       / \sum w_y * N \f$
66     **/
67    double operator()(const DataLookup1D& x,
68                      const DataLookupWeighted1D& y) const; 
69
70    /**
71       \f$ \exp(-d^2/\sigma^2) \f$ where \f$ d^2 = \sum w_xw_y(x_i-y_i)^2
72       / \sum w_xw_y * N \f$
73     **/
74    double operator()(const DataLookupWeighted1D& x,
75                      const DataLookupWeighted1D& y) const; 
76
77  private:
78    double sigma2_;
79
80  }; // class GaussianKernelFunction
81
82}}} // of namespace classifier, yat, and theplu
83
84#endif
Note: See TracBrowser for help on using the repository browser.