"""
relu
~~~~

Plots a graph of the squashing function used by a rectified linear
unit."""

import numpy as np
import matplotlib.pyplot as plt

z = np.arange(-2, 2, .1)
zero = np.zeros(len(z))
y = np.max([zero, z], axis=0)

fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(z, y)
ax.set_ylim([-2.0, 2.0])
ax.set_xlim([-2.0, 2.0])
ax.grid(True)
ax.set_xlabel('z')
ax.set_title('Rectified linear unit')

plt.show()