1 | #ifndef _theplu_yat_classifier_polynomial_kernel_function_ |
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2 | #define _theplu_yat_classifier_polynomial_kernel_function_ |
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3 | |
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4 | // $Id$ |
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5 | |
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6 | /* |
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7 | Copyright (C) 2003 Peter Johansson |
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8 | Copyright (C) 2004, 2005, 2006 Jari Häkkinen, Peter Johansson |
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9 | Copyright (C) 2007 Peter Johansson |
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10 | |
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11 | This file is part of the yat library, http://trac.thep.lu.se/yat |
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12 | |
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13 | The yat library is free software; you can redistribute it and/or |
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14 | modify it under the terms of the GNU General Public License as |
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15 | published by the Free Software Foundation; either version 2 of the |
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16 | License, or (at your option) any later version. |
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17 | |
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18 | The yat library is distributed in the hope that it will be useful, |
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19 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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20 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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21 | General Public License for more details. |
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22 | |
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23 | You should have received a copy of the GNU General Public License |
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24 | along with this program; if not, write to the Free Software |
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25 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA |
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26 | 02111-1307, USA. |
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27 | */ |
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28 | |
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29 | #include "KernelFunction.h" |
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30 | |
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31 | #include <cmath> |
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32 | |
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33 | namespace theplu { |
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34 | namespace yat { |
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35 | namespace classifier { |
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36 | |
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37 | class DataLookup1D; |
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38 | |
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39 | /// |
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40 | /// @brief Class for polynomial kernel calculations |
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41 | /// |
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42 | |
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43 | |
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44 | class PolynomialKernelFunction : public KernelFunction |
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45 | { |
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46 | |
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47 | public: |
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48 | /// |
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49 | ///Constructor taking the order of the polynomial as input. Default is |
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50 | ///order=1 yielding the linear kernel function. |
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51 | /// |
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52 | PolynomialKernelFunction(int = 1); |
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53 | |
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54 | /// |
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55 | ///Destructor |
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56 | /// |
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57 | virtual ~PolynomialKernelFunction(void) {}; |
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58 | |
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59 | /// |
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60 | /// returning the scalar product of two vectors in feature space using the |
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61 | /// polynomial kernel. @return If order is larger than one: \f$ (1+x \cdot |
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62 | /// y)^{order} \f$ \n If order is one (linear): \f$ x \cdot y \f$ |
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63 | /// |
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64 | double operator()(const DataLookup1D& a1, const DataLookup1D& a2) const; |
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65 | |
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66 | /// |
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67 | /// @return If order is larger than one: \f$ (1+x \cdot y)^{order} |
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68 | /// \f$ \n If order is one (linear): \f$ \sum w_yxy \f$ |
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69 | /// |
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70 | /// |
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71 | double operator()(const DataLookup1D& x, |
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72 | const DataLookupWeighted1D& y) const; |
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73 | /// |
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74 | /// returning the scalar product of two vectors in feature space |
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75 | /// using the polynomial kernel with weights. Having all weights |
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76 | /// equal to unity yields the same as non-weighted version. |
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77 | /// |
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78 | /// @return If order is larger than one: \f$ (1+x \cdot y)^{order} |
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79 | /// \f$ \n If order is one (linear): \f$ \sum w_xw_yxy \f$ |
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80 | /// |
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81 | double operator()(const DataLookupWeighted1D& x, |
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82 | const DataLookupWeighted1D& y) const; |
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83 | |
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84 | |
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85 | private: |
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86 | int order_; |
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87 | |
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88 | }; // class PolynomialKernelFunction |
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89 | |
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90 | }}} // of namespace classifier, yat, and theplu |
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91 | |
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92 | #endif |
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