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<?php |
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declare(strict_types=1); |
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namespace Phpml\Metric; |
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use Phpml\Exception\InvalidArgumentException; |
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use Phpml\Math\Statistic\Correlation; |
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use Phpml\Math\Statistic\Mean; |
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final class Regression |
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{ |
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public static function meanSquaredError(array $targets, array $predictions): float |
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{ |
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self::assertCountEquals($targets, $predictions); |
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$errors = []; |
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foreach ($targets as $index => $target) { |
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$errors[] = (($target - $predictions[$index]) ** 2); |
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} |
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return Mean::arithmetic($errors); |
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} |
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public static function meanSquaredLogarithmicError(array $targets, array $predictions): float |
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{ |
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self::assertCountEquals($targets, $predictions); |
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$errors = []; |
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foreach ($targets as $index => $target) { |
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$errors[] = log((1 + $target) / (1 + $predictions[$index])) ** 2; |
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} |
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return Mean::arithmetic($errors); |
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} |
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public static function meanAbsoluteError(array $targets, array $predictions): float |
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{ |
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self::assertCountEquals($targets, $predictions); |
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$errors = []; |
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foreach ($targets as $index => $target) { |
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$errors[] = abs($target - $predictions[$index]); |
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} |
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return Mean::arithmetic($errors); |
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} |
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public static function medianAbsoluteError(array $targets, array $predictions): float |
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{ |
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self::assertCountEquals($targets, $predictions); |
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$errors = []; |
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foreach ($targets as $index => $target) { |
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$errors[] = abs($target - $predictions[$index]); |
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} |
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return (float) Mean::median($errors); |
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} |
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public static function r2Score(array $targets, array $predictions): float |
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{ |
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self::assertCountEquals($targets, $predictions); |
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return Correlation::pearson($targets, $predictions) ** 2; |
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} |
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public static function maxError(array $targets, array $predictions): float |
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{ |
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self::assertCountEquals($targets, $predictions); |
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$errors = []; |
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foreach ($targets as $index => $target) { |
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$errors[] = abs($target - $predictions[$index]); |
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} |
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return (float) max($errors); |
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} |
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private static function assertCountEquals(array &$targets, array &$predictions): void |
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{ |
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if (count($targets) !== count($predictions)) { |
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throw new InvalidArgumentException('Targets count must be equal with predictions count'); |
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} |
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} |
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} |
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php-ai /
php-ml
