1 | <?php |
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11 | class RandomForest extends Bagging |
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12 | { |
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13 | /** |
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14 | * @var float|string |
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15 | */ |
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16 | protected $featureSubsetRatio = 'log'; |
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17 | |||
18 | /** |
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19 | * @var array |
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20 | */ |
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21 | protected $columnNames = null; |
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22 | |||
23 | /** |
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24 | * Initializes RandomForest with the given number of trees. More trees |
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25 | * may increase the prediction performance while it will also substantially |
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26 | * increase the processing time and the required memory |
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27 | */ |
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28 | public function __construct(int $numClassifier = 50) |
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29 | { |
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30 | parent::__construct($numClassifier); |
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31 | |||
32 | $this->setSubsetRatio(1.0); |
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33 | } |
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34 | |||
35 | /** |
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36 | * This method is used to determine how many of the original columns (features) |
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37 | * will be used to construct subsets to train base classifiers.<br> |
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38 | * |
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39 | * Allowed values: 'sqrt', 'log' or any float number between 0.1 and 1.0 <br> |
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40 | * |
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41 | * Default value for the ratio is 'log' which results in log(numFeatures, 2) + 1 |
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42 | * features to be taken into consideration while selecting subspace of features |
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43 | * |
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44 | * @param mixed $ratio string or float should be given |
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45 | * |
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46 | * @return $this |
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47 | * |
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48 | * @throws \Exception |
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49 | */ |
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50 | public function setFeatureSubsetRatio($ratio) |
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51 | { |
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52 | if (is_float($ratio) && ($ratio < 0.1 || $ratio > 1.0)) { |
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53 | throw new Exception('When a float given, feature subset ratio should be between 0.1 and 1.0'); |
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54 | } |
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55 | |||
56 | if (is_string($ratio) && $ratio != 'sqrt' && $ratio != 'log') { |
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57 | throw new Exception("When a string given, feature subset ratio can only be 'sqrt' or 'log' "); |
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58 | } |
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59 | |||
60 | $this->featureSubsetRatio = $ratio; |
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61 | |||
62 | return $this; |
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63 | } |
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64 | |||
65 | /** |
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66 | * RandomForest algorithm is usable *only* with DecisionTree |
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67 | * |
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68 | * @return $this |
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69 | * |
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70 | * @throws \Exception |
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71 | */ |
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72 | public function setClassifer(string $classifier, array $classifierOptions = []) |
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73 | { |
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74 | if ($classifier != DecisionTree::class) { |
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75 | throw new Exception('RandomForest can only use DecisionTree as base classifier'); |
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76 | } |
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77 | |||
78 | return parent::setClassifer($classifier, $classifierOptions); |
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79 | } |
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80 | |||
81 | /** |
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82 | * This will return an array including an importance value for |
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83 | * each column in the given dataset. Importance values for a column |
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84 | * is the average importance of that column in all trees in the forest |
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85 | */ |
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86 | public function getFeatureImportances(): array |
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113 | |||
114 | /** |
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115 | * A string array to represent the columns is given. They are useful |
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116 | * when trying to print some information about the trees such as feature importances |
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117 | * |
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118 | * @return $this |
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119 | */ |
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120 | public function setColumnNames(array $names) |
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126 | |||
127 | /** |
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128 | * @param DecisionTree $classifier |
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129 | * |
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130 | * @return DecisionTree |
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131 | */ |
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132 | protected function initSingleClassifier(Classifier $classifier): Classifier |
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154 | } |
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155 |
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different implementation of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the interface: