# source:trunk/yat/classifier/PolynomialKernelFunction.h@1486

Last change on this file since 1486 was 1486, checked in by Jari Häkkinen, 14 years ago

• 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) 2003 Peter Johansson
8  Copyright (C) 2004, 2005, 2006, 2007 Jari Häkkinen, Peter Johansson
9
10  This file is part of the yat library, http://dev.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 3 of the
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 "KernelFunction.h"
29
30#include <cmath>
31
32namespace theplu {
33namespace yat {
34namespace classifier {
35
36  class DataLookup1D;
37
38  ///
39  /// @brief Class for polynomial kernel calculations
40  ///
41
42
43  class PolynomialKernelFunction : public KernelFunction
44  {
45
46  public:
47    ///
48    ///Constructor taking the order of the polynomial as input. Default is
49    ///order=1 yielding the linear kernel function.
50    ///
51    PolynomialKernelFunction(int = 1);
52
53    ///
54    ///Destructor
55    ///
56    virtual ~PolynomialKernelFunction(void) {};
57
58    ///
59    /// returning the scalar product of two vectors in feature space using the
60    /// polynomial kernel. @return If order is larger than one: \f$(1+x \cdot 61 /// y)^{order} \f$ \n If order is one (linear): \f$x \cdot y \f$
62    ///
63    double operator()(const DataLookup1D& a1, const DataLookup1D& a2) const;
64
65    ///
66    /// @return If order is larger than one: \f$(1+x \cdot y)^{order} 67 /// \f$ \n If order is one (linear): \f$\sum w_yxy \f$
68    ///
69    ///
70    double operator()(const DataLookup1D& x,
71                      const DataLookupWeighted1D& y) const;
72    ///
73    /// returning the scalar product of two vectors in feature space
74    /// using the polynomial kernel with weights. Having all weights
75    /// equal to unity yields the same as non-weighted version.
76    ///
77    /// @return If order is larger than one: \f$(1+x \cdot y)^{order} 78 /// \f$ \n If order is one (linear): \f$\sum w_xw_yxy \f$
79    ///
80    double operator()(const DataLookupWeighted1D& x,
81                      const DataLookupWeighted1D& y) const;
82
83
84  private:
85    int order_;
86
87  }; // class PolynomialKernelFunction
88
89}}} // of namespace classifier, yat, and theplu
90
91#endif
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