NNで使うactivation functionのサンプル

rectified_linear_unit.py

import numpy as np

# ReLu activation function, which computes the ReLu of a scalar.
def rectified_linear_unit(x):
    """ Returns the ReLU of x, or the maximum between 0 and x. """
    return np.maximum(0, x)

rectified_linear_unit_derivative.py

# ReLUの微分を返す関数。Backpropagationで使う
def rectified_linear_unit_derivative(x):
    """ Returns the derivative of ReLU."""
    return 1 if x > 0 else 0