php-ml/src/Phpml/Metric/Distance/Manhattan.php

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<?php
declare (strict_types = 1);
namespace Phpml\Metric\Distance;
use Phpml\Exception\InvalidArgumentException;
use Phpml\Metric\Distance;
class Manhattan 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::arraySizeNotMatch();
}
$distance = 0;
$count = count($a);
for ($i = 0; $i < $count; ++$i) {
$distance += abs($a[$i] - $b[$i]);
}
return $distance;
}
}