1 | #include <vector> |
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2 | #include "mixtures.h" |
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3 | |
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4 | namespace bdm { |
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5 | |
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6 | |
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7 | void MixEF::init ( BMEF* Com0, const mat &Data, int c ) { |
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8 | //prepare sizes |
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9 | Coms.set_size ( c ); |
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10 | n = c; |
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11 | weights.set_parameters ( ones ( c ) ); //assume at least one observation in each comp. |
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12 | //est will be done at the end |
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13 | // |
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14 | int i; |
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15 | int ndat = Data.cols(); |
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16 | //Estimate Com0 from all data |
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17 | Coms ( 0 ) = Com0->_copy_(); |
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18 | // Coms(0)->set_evalll(false); |
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19 | Coms ( 0 )->bayesB ( Data ); |
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20 | // Flatten it to its original shape |
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21 | Coms ( 0 )->flatten ( Com0 ); |
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22 | |
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23 | //Copy it to the rest |
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24 | for ( i = 1; i < n; i++ ) { |
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25 | //copy Com0 and create new rvs for them |
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26 | Coms ( i ) = Coms ( 0 )->_copy_ ( ); |
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27 | } |
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28 | //Pick some data for each component and update it |
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29 | for ( i = 0; i < n; i++ ) { |
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30 | //pick one datum |
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31 | int ind = floor ( ndat * UniRNG.sample() ); |
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32 | Coms ( i )->bayes ( Data.get_col ( ind ), 1.0 ); |
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33 | //flatten back to oringinal |
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34 | Coms ( i )->flatten ( Com0 ); |
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35 | } |
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36 | |
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37 | //est already exists - must be deleted before build_est() can be used |
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38 | delete est; |
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39 | build_est(); |
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40 | |
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41 | } |
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42 | |
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43 | void MixEF::bayesB ( const mat &data , const vec &wData ) { |
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44 | int ndat = data.cols(); |
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45 | int t, i, niter; |
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46 | bool converged = false; |
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47 | |
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48 | multiBM weights0 ( weights ); |
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49 | |
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50 | Array<BMEF*> Coms0 ( n ); |
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51 | for ( i = 0; i < n; i++ ) { |
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52 | Coms0 ( i ) = ( BMEF* ) Coms ( i )->_copy_(); |
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53 | } |
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54 | |
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55 | niter = 0; |
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56 | mat W = ones ( n, ndat ) / n; |
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57 | mat Wlast = ones ( n, ndat ) / n; |
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58 | vec w ( n ); |
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59 | vec ll ( n ); |
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60 | // tmp for weights |
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61 | vec wtmp = zeros ( n ); |
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62 | int maxi; |
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63 | double maxll; |
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64 | //Estim |
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65 | while ( !converged ) { |
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66 | // Copy components back to their initial values |
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67 | // All necessary information is now in w and Coms0. |
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68 | Wlast = W; |
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69 | // |
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70 | //#pragma omp parallel for |
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71 | for ( t = 0; t < ndat; t++ ) { |
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72 | //#pragma omp parallel for |
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73 | for ( i = 0; i < n; i++ ) { |
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74 | ll ( i ) = Coms ( i )->logpred ( data.get_col ( t ) ); |
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75 | wtmp = 0.0; |
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76 | wtmp ( i ) = 1.0; |
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77 | ll ( i ) += weights.logpred ( wtmp ); |
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78 | } |
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79 | |
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80 | maxll = max ( ll, maxi ); |
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81 | switch ( method ) { |
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82 | case QB: |
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83 | w = exp ( ll - maxll ); |
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84 | w /= sum ( w ); |
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85 | break; |
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86 | case EM: |
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87 | w = 0.0; |
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88 | w ( maxi ) = 1.0; |
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89 | break; |
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90 | } |
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91 | |
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92 | W.set_col ( t, w ); |
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93 | } |
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94 | |
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95 | // copy initial statistics |
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96 | //#pragma omp parallel for |
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97 | for ( i = 0; i < n; i++ ) { |
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98 | Coms ( i )-> set_statistics ( Coms0 ( i ) ); |
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99 | } |
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100 | weights.set_statistics ( &weights0 ); |
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101 | |
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102 | // Update statistics |
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103 | // !!!! note wData ==> this is extra weight of the data record |
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104 | // !!!! For typical cases wData=1. |
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105 | for ( t = 0; t < ndat; t++ ) { |
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106 | //#pragma omp parallel for |
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107 | for ( i = 0; i < n; i++ ) { |
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108 | Coms ( i )-> bayes ( data.get_col ( t ), W ( i, t ) * wData ( t ) ); |
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109 | } |
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110 | weights.bayes ( W.get_col ( t ) * wData ( t ) ); |
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111 | } |
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112 | |
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113 | niter++; |
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114 | //TODO better convergence rule. |
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115 | converged = ( niter > 10 );//( sumsum ( abs ( W-Wlast ) ) /n<0.1 ); |
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116 | } |
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117 | |
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118 | //Clean Coms0 |
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119 | for ( i = 0; i < n; i++ ) { |
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120 | delete Coms0 ( i ); |
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121 | } |
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122 | } |
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123 | |
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124 | void MixEF::bayes ( const vec &data ) { |
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125 | |
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126 | }; |
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127 | |
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128 | void MixEF::bayes ( const mat &data ) { |
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129 | this->bayesB ( data, ones ( data.cols() ) ); |
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130 | }; |
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131 | |
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132 | |
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133 | double MixEF::logpred ( const vec &dt ) const { |
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134 | |
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135 | vec w = weights.posterior().mean(); |
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136 | double exLL = 0.0; |
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137 | for ( int i = 0; i < n; i++ ) { |
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138 | exLL += w ( i ) * exp ( Coms ( i )->logpred ( dt ) ); |
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139 | } |
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140 | return log ( exLL ); |
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141 | } |
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142 | |
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143 | emix* MixEF::epredictor ( ) const { |
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144 | Array<shared_ptr<epdf> > pC ( n ); |
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145 | for ( int i = 0; i < n; i++ ) { |
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146 | pC ( i ) = Coms ( i )->epredictor ( ); |
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147 | } |
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148 | emix* tmp; |
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149 | tmp = new emix( ); |
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150 | tmp->set_parameters ( weights.posterior().mean(), pC ); |
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151 | return tmp; |
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152 | } |
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153 | |
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154 | void MixEF::flatten ( const BMEF* M2 ) { |
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155 | const MixEF* Mix2 = dynamic_cast<const MixEF*> ( M2 ); |
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156 | it_assert_debug ( Mix2->n == n, "Different no of coms" ); |
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157 | //Flatten each component |
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158 | for ( int i = 0; i < n; i++ ) { |
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159 | Coms ( i )->flatten ( Mix2->Coms ( i ) ); |
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160 | } |
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161 | //Flatten weights = make them equal!! |
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162 | weights.set_statistics ( & ( Mix2->weights ) ); |
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163 | } |
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164 | } |
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