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<?php
declare(strict_types=1);
namespace Phpml\Math\Distance;
use Phpml\Exception\InvalidArgumentException;
use Phpml\Math\Distance as DistanceInterface;
/**
* Class Distance
*/
abstract class Distance implements DistanceInterface
{
* @var float|int
public $norm;
* Distance constructor.
public function __construct(float $norm = 3.0)
$this->norm = $norm;
}
* @throws InvalidArgumentException
public function distance(array $a, array $b): float
$distance = 0;
foreach ($this->deltas($a, $b) as $delta) {
$distance += $delta ** $this->norm;
return $distance ** (1 / $this->norm);
protected function deltas(array $a, array $b): array
$count = count($a);
if ($count !== count($b)) {
throw new InvalidArgumentException('Size of given arrays does not match');
$deltas = [];
for ($i = 0; $i < $count; $i++) {
$deltas[] = abs($a[$i] - $b[$i]);
return $deltas;