Python sigmoid()

$$ f(x) = \frac{1}{ (1 + e^{-x}) } $$ $$ f'(x) = f*(1-f) $$ pip install numpy matplotlib sympy import numpy as np import matplotlib.pyplot as plt import sympy as sp x = sp.Symbol('x') f1 = 1 / (1 + sp.exp(-1*x)) df1 = sp.diff(f1, x) f1 = sp.lambdify(x, f1, 'numpy') df1 = sp.lambdify(x, df1, 'numpy') x = np.linspace(-10, 10, 400) y = f1(x) y_df = df1(x) plt.figure(figsize=(8, 5)) # 1行2列 plt1 = plt.subplot(1,2,1) plt2 = plt.subplot(1,2,2) plt1.plot(x, y, label='f(x)', color='blue') plt2.plot(x, y_df, label='df(x)', color='red') plt1.grid() plt2.grid() plt1.legend() plt2.legend() plt.show()