summary_manager.py 文件源码

def add(self, x):
        x = float(x)
        n1 = self.count

        self.count += 1

        if x < self.min or self.min is None:
            self.min = x

        if x > self.max or self.max is None:
            self.max = x

        delta = x - self.M1
        delta_n = delta / self.count
        delta_n2 = delta_n * delta_n
        term = delta * delta_n * n1
        self.M1 += delta_n
        self.M4 += term * delta_n2 * \
                ( self.count * self.count - 3*self.count + 3 ) + \
                6 * delta_n2 * self.M2 - 4 * delta_n * self.M3
        self.M3 += term * delta_n * (self.count - 2) - 3 * delta_n * self.M2
        self.M2 += term

        return