“ if”语句不适用于np.abs(np.max(f_5.all()))

for ii in range (0,70):
    for jj in range (0,70):
        f_max = 0
        for k in range (0,50):
            if np.abs(np.max(f_5.all())) > f_max:
                f_max = f_5 #(+/-)

Here f_5 shape is (70,70,50) and it has maximum values around 360 and minimum values around 230. I want to save the max value and that points index in k. But the f_max is not updating.