Złożoność obliczeniowa algorytmu

$dane = Array
(
    [0] => 130
    [1] => 4
    [2] => 12
    [3] => 32
    [4] => 40
    [5] => 3
    [6] => 14
    [7] => 19
    [8] => 27
    [9] => 25
    [10] => 31
    [11] => 49
    [12] => 51
    [13] => 55
    [14] => 50
    [15] => 100
)

function shell_sort($arr) {
  $x = round(count($arr)/2);
  while($x > 0) {
    for($i = $x; $i < count($arr);$i++){
      $temp = $arr[$i];
      $j = $i;
      while($j >= $x && $arr[$j-$x] > $temp)       {
        $arr[$j] = $arr[$j - $x];
        $j -= $x;
      }
      $arr[$j] = $temp;
    }
    $x = round($x/2.2);
  }
  return $arr;
}
$dane = shell_sort($dane);
echo "Posortowana tablica:";
echo "<pre>\$dane = ";
print_r($dane);
echo "</pre><hr>";
Posortowana tablica:
$dane = Array
(
    [0] => 3
    [1] => 4
    [2] => 12
    [3] => 14
    [4] => 19
    [5] => 25
    [6] => 27
    [7] => 31
    [8] => 32
    [9] => 40
    [10] => 49
    [11] => 50
    [12] => 51
    [13] => 55
    [14] => 100
    [15] => 130
)
Złożoność obliczeniowa algorytmu O(n⋅(log n)²).