plot_rotate_logcosh

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(-20, 20, 200)
y = np.abs(x)
alpha = 0.2
y_Q = np.where(x > 0, alpha * x, (alpha - 1) * x)
y_logcosh = np.where(x > 0, alpha * np.log(np.cosh(x)), (1 - alpha) * np.log(np.cosh(x)))
plt.plot(x, y_Q, label=f'Q = 0.2')
plt.plot(x, y_logcosh, label=f'Smooth Q=0.2 regression using log_cosh')
plt.legend(loc='upper left')
plt.show()