source: trunk/yat/classifier/PolynomialKernelFunction.h @ 767

Last change on this file since 767 was 767, checked in by Peter, 15 years ago

Fixes #65

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date ID
File size: 2.6 KB
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1#ifndef _theplu_yat_classifier_polynomial_kernel_function_
2#define _theplu_yat_classifier_polynomial_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  /// @brief Class for polynomial kernel calculations
39  ///
40
41 
42  class PolynomialKernelFunction : public KernelFunction
43  {
44   
45  public:
46    ///
47    ///Constructor taking the order of the polynomial as input. Default is
48    ///order=1 yielding the linear kernel function.
49    ///
50    PolynomialKernelFunction(int = 1);
51   
52    ///
53    ///Destructor
54    ///
55    virtual ~PolynomialKernelFunction(void) {};
56   
57    ///
58    /// returning the scalar product of two vectors in feature space using the
59    /// polynomial kernel. @return If order is larger than one: \f$ (1+x \cdot
60    /// y)^{order} \f$ \n If order is one (linear): \f$ x \cdot y \f$
61    ///   
62    double operator()(const DataLookup1D& a1, const DataLookup1D& a2) const;
63
64    ///
65    /// @return If order is larger than one: \f$ (1+x \cdot y)^{order}
66    /// \f$ \n If order is one (linear): \f$ \sum w_yxy \f$
67    ///
68    ///
69    double operator()(const DataLookup1D& x, 
70                      const DataLookupWeighted1D& y) const;
71    ///
72    /// returning the scalar product of two vectors in feature space
73    /// using the polynomial kernel with weights. Having all weights
74    /// equal to unity yields the same as non-weighted version.
75    ///
76    /// @return If order is larger than one: \f$ (1+x \cdot y)^{order}
77    /// \f$ \n If order is one (linear): \f$ \sum w_xw_yxy \f$
78    ///
79    double operator()(const DataLookupWeighted1D& x, 
80                      const DataLookupWeighted1D& y) const;
81
82
83  private:
84    int order_;
85
86  }; // class PolynomialKernelFunction
87
88}}} // of namespace classifier, yat, and theplu
89
90#endif
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