MathPHP\Statistics\Average::arithmeticGeometricMean PHP Метод

    public static function arithmeticGeometricMean($x, $y) : float
    {
        // x or y < 0 = NaN
        if ($x < 0 || $y < 0) {
            return \NAN;
        }
        // x or y zero = 0
        if ($x == 0 || $y == 0) {
            return 0;
        }
        // Standard case x and y > 0
        list($a, $g) = [$x, $y];
        foreach (range(1, 10) as $_) {
            list($a, $g) = [self::mean([$a, $g]), self::geometricMean([$a, $g])];
        }
        return $a;
    }