1 | // $Id: MultiDimensionalWeighted.cc 1120 2008-02-21 23:18:41Z peter $ |
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2 | |
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3 | /* |
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4 | Copyright (C) 2006, 2007 Jari Häkkinen, Peter Johansson |
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5 | |
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6 | This file is part of the yat library, http://trac.thep.lu.se/yat |
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7 | |
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8 | The yat library is free software; you can redistribute it and/or |
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9 | modify it under the terms of the GNU General Public License as |
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10 | published by the Free Software Foundation; either version 2 of the |
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11 | License, or (at your option) any later version. |
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12 | |
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13 | The yat library is distributed in the hope that it will be useful, |
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14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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16 | General Public License for more details. |
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17 | |
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18 | You should have received a copy of the GNU General Public License |
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19 | along with this program; if not, write to the Free Software |
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20 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA |
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21 | 02111-1307, USA. |
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22 | */ |
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23 | |
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24 | #include "MultiDimensionalWeighted.h" |
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25 | #include "yat/statistics/AveragerWeighted.h" |
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26 | #include "yat/utility/matrix.h" |
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27 | #include "yat/utility/Vector.h" |
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28 | |
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29 | #include <cassert> |
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30 | |
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31 | namespace theplu { |
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32 | namespace yat { |
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33 | namespace regression { |
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34 | |
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35 | MultiDimensionalWeighted::MultiDimensionalWeighted(void) |
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36 | : chisquare_(0), work_(NULL) |
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37 | { |
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38 | } |
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39 | |
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40 | MultiDimensionalWeighted::~MultiDimensionalWeighted(void) |
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41 | { |
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42 | if (work_) |
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43 | gsl_multifit_linear_free(work_); |
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44 | } |
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45 | |
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46 | |
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47 | double MultiDimensionalWeighted::chisq() const |
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48 | { |
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49 | return chisquare_; |
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50 | } |
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51 | |
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52 | |
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53 | void MultiDimensionalWeighted::fit(const utility::matrix& x, |
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54 | const utility::VectorBase& y, |
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55 | const utility::VectorBase& w) |
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56 | { |
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57 | assert(y.size()==w.size()); |
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58 | assert(x.rows()==y.size()); |
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59 | |
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60 | covariance_.resize(x.columns(),x.columns()); |
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61 | fit_parameters_ = utility::Vector(x.columns()); |
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62 | if (work_) |
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63 | gsl_multifit_linear_free(work_); |
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64 | if (!(work_=gsl_multifit_linear_alloc(x.rows(),fit_parameters_.size()))) |
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65 | throw utility::GSL_error("MultiDimensionalWeighted::fit failed to allocate memory"); |
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66 | int status = gsl_multifit_wlinear(x.gsl_matrix_p(), w.gsl_vector_p(), |
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67 | y.gsl_vector_p(), |
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68 | fit_parameters_.gsl_vector_p(), |
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69 | covariance_.gsl_matrix_p(), &chisquare_, |
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70 | work_); |
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71 | if (status) |
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72 | throw utility::GSL_error(std::string("MultiDimensionalWeighted::fit", |
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73 | status)); |
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74 | |
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75 | statistics::AveragerWeighted aw; |
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76 | add(aw, y.begin(), y.end(), w.begin()); |
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77 | s2_ = chisquare_ / (aw.n()-fit_parameters_.size()); |
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78 | covariance_ *= s2_; |
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79 | } |
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80 | |
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81 | |
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82 | const utility::Vector& MultiDimensionalWeighted::fit_parameters(void) const |
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83 | { |
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84 | return fit_parameters_; |
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85 | } |
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86 | |
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87 | |
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88 | double MultiDimensionalWeighted::predict(const utility::VectorBase& x) const |
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89 | { |
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90 | assert(x.size()==fit_parameters_.size()); |
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91 | return fit_parameters_ * x; |
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92 | } |
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93 | |
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94 | |
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95 | double MultiDimensionalWeighted::prediction_error2(const utility::VectorBase& x, |
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96 | const double w) const |
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97 | { |
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98 | return standard_error2(x) + s2(w); |
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99 | } |
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100 | |
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101 | |
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102 | double MultiDimensionalWeighted::s2(const double w) const |
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103 | { |
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104 | return s2_/w; |
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105 | } |
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106 | |
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107 | |
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108 | double |
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109 | MultiDimensionalWeighted::standard_error2(const utility::VectorBase& x) const |
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110 | { |
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111 | double c = 0; |
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112 | for (size_t i=0; i<x.size(); ++i){ |
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113 | c += covariance_(i,i)*x(i)*x(i); |
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114 | for (size_t j=i+1; j<x.size(); ++j) |
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115 | c += 2*covariance_(i,j)*x(i)*x(j); |
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116 | } |
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117 | return c; |
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118 | } |
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119 | |
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120 | }}} // of namespaces regression, yat, and theplu |
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