Proyectos de Subversion Moodle

<?php

declare(strict_types=1);

namespace Phpml\CrossValidation;

use Phpml\Dataset\ArrayDataset;

use Phpml\Dataset\Dataset;

class StratifiedRandomSplit extends RandomSplit

{

    protected function splitDataset(Dataset $dataset, float $testSize): void

    {

        $datasets = $this->splitByTarget($dataset);

        foreach ($datasets as $targetSet) {

            parent::splitDataset($targetSet, $testSize);

        }

    }

    /**

     * @return Dataset[]

     */

    private function splitByTarget(Dataset $dataset): array

    {

        $targets = $dataset->getTargets();

        $samples = $dataset->getSamples();

        $uniqueTargets = array_unique($targets);

        /** @var array $split */

        $split = array_combine($uniqueTargets, array_fill(0, count($uniqueTargets), []));

        foreach ($samples as $key => $sample) {

            $split[$targets[$key]][] = $sample;

        }

        return $this->createDatasets($uniqueTargets, $split);

    }

    private function createDatasets(array $uniqueTargets, array $split): array

    {

        $datasets = [];

        foreach ($uniqueTargets as $target) {

            $datasets[$target] = new ArrayDataset($split[$target], array_fill(0, count($split[$target]), $target));

        }

        return $datasets;

    }

}