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<?php |
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declare (strict_types = 1); |
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namespace Phpml\CrossValidation; |
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use Phpml\Dataset\ArrayDataset; |
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use Phpml\Dataset\Dataset; |
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class StratifiedRandomSplit extends RandomSplit |
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{ |
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/** |
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* @param Dataset $dataset |
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* @param float $testSize |
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*/ |
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protected function splitDataset(Dataset $dataset, float $testSize) |
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{ |
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$datasets = $this->splitByTarget($dataset); |
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foreach ($datasets as $targetSet) { |
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parent::splitDataset($targetSet, $testSize); |
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} |
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} |
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/** |
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* @param Dataset $dataset |
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* |
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* @return Dataset[]|array |
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*/ |
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private function splitByTarget(Dataset $dataset): array |
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{ |
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$targets = $dataset->getTargets(); |
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$samples = $dataset->getSamples(); |
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$uniqueTargets = array_unique($targets); |
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$split = array_combine($uniqueTargets, array_fill(0, count($uniqueTargets), [])); |
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foreach ($samples as $key => $sample) { |
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$split[$targets[$key]][] = $sample; |
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} |
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$datasets = $this->createDatasets($uniqueTargets, $split); |
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return $datasets; |
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} |
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/** |
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* @param array $uniqueTargets |
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* @param array $split |
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* |
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* @return array |
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*/ |
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private function createDatasets(array $uniqueTargets, array $split): array |
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{ |
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$datasets = []; |
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foreach ($uniqueTargets as $target) { |
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$datasets[$target] = new ArrayDataset($split[$target], array_fill(0, count($split[$target]), $target)); |
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} |
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return $datasets; |
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} |
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} |
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php-ai /
php-ml
