MathPHP\Statistics\Average::simpleMovingAverage PHP Method

    public static function simpleMovingAverage(array $numbers, int $n) : array
    {
        $m = count($numbers);
        $SMA = [];
        // Counters
        $new = $n;
        // New value comes into the sum
        $drop = 0;
        // Old value drops out
        $yesterday = 0;
        // Yesterday's SMA
        // Base case: initial average
        $SMA[] = array_sum(array_slice($numbers, 0, $n)) / $n;
        // Calculating successive values: New value comes in; old value drops out
        while ($new < $m) {
            $SMA[] = $SMA[$yesterday] + $numbers[$new] / $n - $numbers[$drop] / $n;
            $drop++;
            $yesterday++;
            $new++;
        }
        return $SMA;
    }