source: trunk/yat/classifier/PolynomialKernelFunction.h @ 680

Last change on this file since 680 was 680, checked in by Jari Häkkinen, 15 years ago

Addresses #153. Introduced yat namespace. Removed alignment namespace. Clean up of code.

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