php-ai / php-ml

use Phpml\Exception\InvalidArgumentException;

use Phpml\Metric\Distance;

class Chebyshev implements Distance

{

    /**

     * @param array $a

     * @param array $b

     *

     * @return float

     *

     * @throws InvalidArgumentException

     */

    public function distance(array $a, array $b): float

    {

        if (count($a) !== count($b)) {

            throw InvalidArgumentException::sizeNotMatch();

        }

        $differences = [];

        $count = count($a);

        for ($i = 0; $i < $count; ++$i) {

            $differences[] = abs($a[$i] - $b[$i]);

        }

        return max($differences);

    }

}

use Phpml\Exception\InvalidArgumentException;

use Phpml\Metric\Distance;

class Euclidean implements Distance

{

    /**

     * @param array $a

     * @param array $b

     *

     * @return float

     *

     * @throws InvalidArgumentException

     */

    public function distance(array $a, array $b): float

    {

        if (count($a) !== count($b)) {

            throw InvalidArgumentException::sizeNotMatch();

        }

        $distance = 0;

        $count = count($a);

        for ($i = 0; $i < $count; ++$i) {

            $distance += pow($a[$i] - $b[$i], 2);

        }

        return sqrt($distance);

    }

}