Proyectos de Subversion Moodle

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<?php
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declare(strict_types=1);
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namespace Phpml\FeatureSelection;
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use Phpml\Exception\InvalidArgumentException;
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use Phpml\Exception\InvalidOperationException;
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use Phpml\FeatureSelection\ScoringFunction\ANOVAFValue;
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use Phpml\Transformer;
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final class SelectKBest implements Transformer
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{
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    /**
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     * @var ScoringFunction
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     */
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    private $scoringFunction;
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    /**
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     * @var int
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     */
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    private $k;
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    /**
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     * @var array|null
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     */
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    private $scores = null;
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    /**
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     * @var array|null
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     */
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    private $keepColumns = null;
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    public function __construct(int $k = 10, ?ScoringFunction $scoringFunction = null)
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    {
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        if ($scoringFunction === null) {
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            $scoringFunction = new ANOVAFValue();
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        }
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        $this->scoringFunction = $scoringFunction;
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        $this->k = $k;
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    }
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    public function fit(array $samples, ?array $targets = null): void
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    {
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        if ($targets === null || count($targets) === 0) {
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            throw new InvalidArgumentException('The array has zero elements');
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        }
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        $this->scores = $sorted = $this->scoringFunction->score($samples, $targets);
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        if ($this->k >= count($sorted)) {
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            return;
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        }
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        arsort($sorted);
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        $this->keepColumns = array_slice($sorted, 0, $this->k, true);
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    }
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    public function transform(array &$samples, ?array &$targets = null): void
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    {
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        if ($this->keepColumns === null) {
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            return;
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        }
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        foreach ($samples as &$sample) {
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            $sample = array_values(array_intersect_key($sample, $this->keepColumns));
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        }
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    }
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    public function scores(): array
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    {
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        if ($this->scores === null) {
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            throw new InvalidOperationException('SelectKBest require to fit first to get scores');
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        }
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        return $this->scores;
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    }
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}