1 | /*! |
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2 | \file |
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3 | \brief Probability distributions for Mixtures of pdfs |
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4 | \author Vaclav Smidl. |
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5 | |
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6 | ----------------------------------- |
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7 | BDM++ - C++ library for Bayesian Decision Making under Uncertainty |
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8 | |
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9 | Using IT++ for numerical operations |
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10 | ----------------------------------- |
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11 | */ |
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12 | |
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13 | #ifndef EMIX_H |
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14 | #define EMIX_H |
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15 | |
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16 | #define LOG2 0.69314718055995 |
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17 | |
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18 | #include "../shared_ptr.h" |
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19 | #include "exp_family.h" |
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20 | |
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21 | namespace bdm { |
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22 | |
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23 | //this comes first because it is used inside emix! |
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24 | |
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25 | /*! \brief Class representing ratio of two densities |
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26 | which arise e.g. by applying the Bayes rule. |
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27 | It represents density in the form: |
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28 | \f[ |
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29 | f(rv|rvc) = \frac{f(rv,rvc)}{f(rvc)} |
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30 | \f] |
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31 | where \f$ f(rvc) = \int f(rv,rvc) d\ rv \f$. |
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32 | |
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33 | In particular this type of arise by conditioning of a mixture model. |
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34 | |
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35 | At present the only supported operation is evallogcond(). |
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36 | */ |
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37 | class mratio: public pdf { |
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38 | protected: |
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39 | //! Nominator in the form of pdf |
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40 | const epdf* nom; |
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41 | |
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42 | //!Denominator in the form of epdf |
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43 | shared_ptr<epdf> den; |
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44 | |
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45 | //!flag for destructor |
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46 | bool destroynom; |
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47 | //!datalink between conditional and nom |
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48 | datalink_m2e dl; |
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49 | public: |
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50 | //!Default constructor. By default, the given epdf is not copied! |
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51 | //! It is assumed that this function will be used only temporarily. |
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52 | mratio ( const epdf* nom0, const RV &rv, bool copy = false ) : pdf ( ), dl ( ) { |
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53 | // adjust rv and rvc |
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54 | |
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55 | set_rv ( rv ); |
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56 | dim = rv._dsize(); |
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57 | |
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58 | rvc = nom0->_rv().subt ( rv ); |
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59 | dimc = rvc._dsize(); |
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60 | |
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61 | //prepare data structures |
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62 | if ( copy ) { |
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63 | bdm_error ( "todo" ); |
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64 | // destroynom = true; |
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65 | } else { |
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66 | nom = nom0; |
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67 | destroynom = false; |
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68 | } |
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69 | bdm_assert_debug ( rvc.length() > 0, "Makes no sense to use this object!" ); |
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70 | |
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71 | // build denominator |
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72 | den = nom->marginal ( rvc ); |
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73 | dl.set_connection ( rv, rvc, nom0->_rv() ); |
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74 | }; |
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75 | |
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76 | double evallogcond ( const vec &val, const vec &cond ) { |
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77 | double tmp; |
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78 | vec nom_val ( dimension() + dimc ); |
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79 | dl.pushup_cond ( nom_val, val, cond ); |
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80 | tmp = exp ( nom->evallog ( nom_val ) - den->evallog ( cond ) ); |
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81 | return tmp; |
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82 | } |
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83 | |
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84 | //! Returns a sample from the density conditioned on \c cond, \f$x \sim epdf(rv|cond)\f$. \param cond is numeric value of \c rv |
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85 | virtual vec samplecond ( const vec &cond ) NOT_IMPLEMENTED(0); |
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86 | |
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87 | //! Object takes ownership of nom and will destroy it |
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88 | void ownnom() { |
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89 | destroynom = true; |
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90 | } |
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91 | //! Default destructor |
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92 | ~mratio() { |
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93 | if ( destroynom ) { |
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94 | delete nom; |
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95 | } |
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96 | } |
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97 | |
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98 | |
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99 | |
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100 | |
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101 | private: |
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102 | // not implemented |
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103 | mratio ( const mratio & ); |
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104 | mratio &operator= ( const mratio & ); |
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105 | }; |
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106 | |
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107 | /*! |
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108 | * \brief Mixture of epdfs |
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109 | |
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110 | Density function: |
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111 | \f[ |
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112 | f(x) = \sum_{i=1}^{n} w_{i} f_i(x), \quad \sum_{i=1}^n w_i = 1. |
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113 | \f] |
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114 | where \f$f_i(x)\f$ is any density on random variable \f$x\f$, called \a component, |
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115 | |
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116 | */ |
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117 | class emix : public epdf { |
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118 | protected: |
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119 | //! weights of the components |
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120 | vec w; |
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121 | |
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122 | //! Component (epdfs) |
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123 | Array<shared_ptr<epdf> > Coms; |
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124 | |
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125 | public: |
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126 | //! Default constructor |
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127 | emix ( ) : epdf ( ) { } |
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128 | |
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129 | virtual void validate (); |
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130 | |
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131 | vec sample() const; |
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132 | |
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133 | vec mean() const; |
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134 | |
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135 | vec variance() const; |
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136 | |
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137 | double evallog ( const vec &val ) const; |
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138 | |
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139 | vec evallog_mat ( const mat &Val ) const; |
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140 | |
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141 | //! Auxiliary function that returns pdflog for each component |
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142 | mat evallog_coms ( const mat &Val ) const; |
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143 | |
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144 | shared_ptr<epdf> marginal ( const RV &rv ) const; |
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145 | //! Update already existing marginal density \c target |
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146 | void marginal ( const RV &rv, emix &target ) const; |
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147 | shared_ptr<pdf> condition ( const RV &rv ) const; |
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148 | |
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149 | //Access methods |
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150 | //! returns a reference to the internal weights. Use with Care! |
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151 | vec& _w() { |
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152 | return w; |
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153 | } |
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154 | |
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155 | /*! |
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156 | \brief returns a reference to the internal array of components. Use with Care! Set components \c Coms |
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157 | |
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158 | Shared pointers in Coms are kept inside this instance and |
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159 | shouldn't be modified after being passed to this method. |
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160 | */ |
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161 | Array<shared_ptr<epdf> >& _Coms ( ) { |
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162 | return Coms; |
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163 | } |
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164 | |
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165 | //! returns a reference to the internal components specified by index i. Use with Care! |
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166 | shared_ptr<epdf> _Coms ( int i ) { |
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167 | return Coms ( i ); |
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168 | } |
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169 | |
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170 | void set_rv ( const RV &rv ) { |
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171 | epdf::set_rv ( rv ); |
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172 | for ( int i = 0; i < Coms.length(); i++ ) { |
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173 | Coms ( i )->set_rv ( rv ); |
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174 | } |
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175 | } |
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176 | |
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177 | //! Load from structure with elements: |
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178 | //! \code |
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179 | //! { class='emix'; |
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180 | //! pdfs = (..., ...); // list of pdfs in the mixture |
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181 | //! weights = ( 0.5, 0.5 ); // weights of pdfs in the mixture |
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182 | //! } |
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183 | //! \endcode |
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184 | //!@} |
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185 | void from_setting ( const Setting &set ); |
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186 | }; |
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187 | SHAREDPTR ( emix ); |
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188 | UIREGISTER ( emix ); |
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189 | |
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190 | /*! |
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191 | * \brief Mixture of egiws |
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192 | |
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193 | */ |
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194 | class egiwmix : public egiw { |
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195 | protected: |
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196 | //! weights of the components |
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197 | vec w; |
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198 | //! Component (epdfs) |
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199 | Array<egiw*> Coms; |
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200 | //!Flag if owning Coms |
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201 | bool destroyComs; |
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202 | public: |
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203 | //!Default constructor |
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204 | egiwmix ( ) : egiw ( ) {}; |
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205 | |
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206 | //! Set weights \c w and components \c Coms |
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207 | //!By default Coms are copied inside. Parameter \c copy can be set to false if Coms live externally. Use method ownComs() if Coms should be destroyed by the destructor. |
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208 | void set_parameters ( const vec &w, const Array<egiw*> &Coms, bool copy = false ); |
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209 | |
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210 | //!return expected value |
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211 | vec mean() const; |
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212 | |
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213 | //!return a sample from the density |
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214 | vec sample() const; |
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215 | |
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216 | //!return the expected variance |
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217 | vec variance() const; |
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218 | |
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219 | // TODO!!! Defined to follow ANSI and/or for future development |
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220 | void mean_mat ( mat &M, mat&R ) const {}; |
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221 | double evallog_nn ( const vec &val ) const { |
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222 | return 0; |
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223 | }; |
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224 | double lognc () const { |
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225 | return 0; |
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226 | } |
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227 | |
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228 | shared_ptr<epdf> marginal ( const RV &rv ) const; |
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229 | //! marginal density update |
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230 | void marginal ( const RV &rv, emix &target ) const; |
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231 | |
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232 | //Access methods |
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233 | //! returns a pointer to the internal mean value. Use with Care! |
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234 | vec& _w() { |
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235 | return w; |
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236 | } |
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237 | virtual ~egiwmix() { |
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238 | if ( destroyComs ) { |
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239 | for ( int i = 0; i < Coms.length(); i++ ) { |
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240 | delete Coms ( i ); |
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241 | } |
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242 | } |
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243 | } |
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244 | //! Auxiliary function for taking ownership of the Coms() |
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245 | void ownComs() { |
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246 | destroyComs = true; |
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247 | } |
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248 | |
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249 | //!access function |
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250 | egiw* _Coms ( int i ) { |
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251 | return Coms ( i ); |
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252 | } |
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253 | |
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254 | void set_rv ( const RV &rv ) { |
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255 | egiw::set_rv ( rv ); |
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256 | for ( int i = 0; i < Coms.length(); i++ ) { |
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257 | Coms ( i )->set_rv ( rv ); |
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258 | } |
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259 | } |
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260 | |
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261 | //! Approximation of a GiW mix by a single GiW pdf |
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262 | egiw* approx(); |
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263 | }; |
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264 | |
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265 | /*! \brief Chain rule decomposition of epdf |
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266 | |
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267 | Probability density in the form of Chain-rule decomposition: |
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268 | \[ |
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269 | f(x_1,x_2,x_3) = f(x_1|x_2,x_3)f(x_2,x_3)f(x_3) |
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270 | \] |
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271 | Note that |
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272 | */ |
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273 | class mprod: public pdf { |
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274 | private: |
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275 | Array<shared_ptr<pdf> > pdfs; |
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276 | |
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277 | //! Data link for each pdfs |
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278 | Array<shared_ptr<datalink_m2m> > dls; |
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279 | |
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280 | public: |
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281 | //! \brief Default constructor |
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282 | mprod() { } |
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283 | |
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284 | /*!\brief Constructor from list of mFacs |
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285 | */ |
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286 | mprod ( const Array<shared_ptr<pdf> > &mFacs ) { |
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287 | set_elements ( mFacs ); |
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288 | } |
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289 | //! Set internal \c pdfs from given values |
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290 | void set_elements ( const Array<shared_ptr<pdf> > &mFacs ); |
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291 | |
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292 | double evallogcond ( const vec &val, const vec &cond ); |
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293 | |
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294 | vec evallogcond_mat ( const mat &Dt, const vec &cond ); |
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295 | |
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296 | vec evallogcond_mat ( const Array<vec> &Dt, const vec &cond ); |
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297 | |
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298 | //TODO smarter... |
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299 | vec samplecond ( const vec &cond ) { |
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300 | //! Ugly hack to help to discover if mpfs are not in proper order. Correct solution = check that explicitely. |
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301 | vec smp = std::numeric_limits<double>::infinity() * ones ( dimension() ); |
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302 | vec smpi; |
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303 | // Hard assumption here!!! We are going backwards, to assure that samples that are needed from smp are already generated! |
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304 | for ( int i = ( pdfs.length() - 1 ); i >= 0; i-- ) { |
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305 | // generate contribution of this pdf |
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306 | smpi = pdfs ( i )->samplecond ( dls ( i )->get_cond ( smp , cond ) ); |
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307 | // copy contribution of this pdf into smp |
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308 | dls ( i )->pushup ( smp, smpi ); |
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309 | } |
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310 | return smp; |
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311 | } |
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312 | |
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313 | //! Load from structure with elements: |
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314 | //! \code |
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315 | //! { class='mprod'; |
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316 | //! pdfs = (..., ...); // list of pdfs in the order of chain rule |
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317 | //! } |
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318 | //! \endcode |
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319 | //!@} |
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320 | void from_setting ( const Setting &set ) { |
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321 | Array<shared_ptr<pdf> > temp_array; |
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322 | UI::get ( temp_array, set, "pdfs", UI::compulsory ); |
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323 | set_elements ( temp_array ); |
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324 | } |
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325 | }; |
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326 | UIREGISTER ( mprod ); |
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327 | SHAREDPTR ( mprod ); |
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328 | |
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329 | //! Product of independent epdfs. For dependent pdfs, use mprod. |
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330 | class eprod: public epdf { |
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331 | protected: |
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332 | //! Components (epdfs) |
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333 | Array<const epdf*> epdfs; |
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334 | //! Array of indeces |
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335 | Array<datalink*> dls; |
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336 | public: |
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337 | //! Default constructor |
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338 | eprod () : epdfs ( 0 ), dls ( 0 ) {}; |
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339 | //! Set internal |
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340 | void set_parameters ( const Array<const epdf*> &epdfs0, bool named = true ) { |
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341 | epdfs = epdfs0;//.set_length ( epdfs0.length() ); |
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342 | dls.set_length ( epdfs.length() ); |
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343 | |
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344 | bool independent = true; |
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345 | if ( named ) { |
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346 | for ( int i = 0; i < epdfs.length(); i++ ) { |
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347 | independent = rv.add ( epdfs ( i )->_rv() ); |
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348 | bdm_assert_debug ( independent, "eprod:: given components are not independent." ); |
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349 | } |
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350 | dim = rv._dsize(); |
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351 | } else { |
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352 | dim = 0; |
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353 | for ( int i = 0; i < epdfs.length(); i++ ) { |
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354 | dim += epdfs ( i )->dimension(); |
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355 | } |
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356 | } |
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357 | // |
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358 | int cumdim = 0; |
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359 | int dimi = 0; |
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360 | int i; |
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361 | for ( i = 0; i < epdfs.length(); i++ ) { |
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362 | dls ( i ) = new datalink; |
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363 | if ( named ) { |
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364 | dls ( i )->set_connection ( epdfs ( i )->_rv() , rv ); |
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365 | } else { |
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366 | dimi = epdfs ( i )->dimension(); |
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367 | dls ( i )->set_connection ( dimi, dim, linspace ( cumdim, cumdim + dimi - 1 ) ); |
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368 | cumdim += dimi; |
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369 | } |
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370 | } |
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371 | } |
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372 | |
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373 | vec mean() const; |
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374 | |
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375 | vec variance() const; |
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376 | |
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377 | vec sample() const; |
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378 | |
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379 | double evallog ( const vec &val ) const; |
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380 | |
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381 | //!access function |
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382 | const epdf* operator () ( int i ) const { |
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383 | bdm_assert_debug ( i < epdfs.length(), "wrong index" ); |
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384 | return epdfs ( i ); |
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385 | } |
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386 | |
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387 | //!Destructor |
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388 | ~eprod() { |
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389 | for ( int i = 0; i < epdfs.length(); i++ ) { |
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390 | delete dls ( i ); |
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391 | } |
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392 | } |
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393 | }; |
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394 | |
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395 | |
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396 | /*! \brief Mixture of pdfs with constant weights, all pdfs are of equal RV and RVC |
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397 | |
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398 | */ |
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399 | class mmix : public pdf { |
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400 | protected: |
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401 | //! Component (pdfs) |
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402 | Array<shared_ptr<pdf> > Coms; |
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403 | //!weights of the components |
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404 | vec w; |
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405 | public: |
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406 | //!Default constructor |
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407 | mmix() : Coms ( 0 ) { } |
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408 | |
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409 | double evallogcond ( const vec &dt, const vec &cond ) { |
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410 | double ll = 0.0; |
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411 | for ( int i = 0; i < Coms.length(); i++ ) { |
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412 | ll += Coms ( i )->evallogcond ( dt, cond ); |
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413 | } |
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414 | return ll; |
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415 | } |
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416 | |
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417 | vec samplecond ( const vec &cond ); |
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418 | |
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419 | //! Load from structure with elements: |
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420 | //! \code |
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421 | //! { class='mmix'; |
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422 | //! pdfs = (..., ...); // list of pdfs in the mixture |
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423 | //! weights = ( 0.5, 0.5 ); // weights of pdfs in the mixture |
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424 | //! } |
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425 | //! \endcode |
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426 | //!@} |
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427 | void from_setting ( const Setting &set ); |
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428 | |
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429 | virtual void validate(); |
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430 | }; |
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431 | SHAREDPTR ( mmix ); |
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432 | UIREGISTER ( mmix ); |
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433 | |
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434 | } |
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435 | #endif //MX_H |
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