Python使用matplotlib绘制Logistic曲线操作示例

f(x) = 1 / ( 1 + exp(-x) )

f'(x) = f(x) * ( 1 - f(x) )

# -*- coding:utf-8 -*-
#!python3
import numpy as np
import matplotlib.pyplot as plt
a = np.linspace(-10, 10, 1000)
b = 1.0 / (1.0 + np.exp(-a))
c = b * (1 - b)
plt.subplot(2, 1, 1)
plt.title('f(x) = 1 / ( 1 + exp(-x) )')
plt.plot(a, b)
plt.subplot(2, 1, 2)
plt.title('f\'(x) = f(x) * ( 1 - f(x) )')
plt.plot(a, c)
plt.show()