diff --git a/neural_network/activation_functions/leaky_rectified_linear_unit.py b/neural_network/activation_functions/leaky_rectified_linear_unit.py new file mode 100644 index 000000000..1e99fed4e --- /dev/null +++ b/neural_network/activation_functions/leaky_rectified_linear_unit.py @@ -0,0 +1,45 @@ +""" +Leaky Rectified Linear Unit (LeakyReLU) + +Input: vector (type: np.ndarray) , alpha (type: float) +Output: vector (type: np.ndarray) + +UseCase: LeakyReLU solves the issue of dead neurons or vanishing gradient problem. +Refer the below link for more information: +https://en.wikipedia.org/wiki/Rectifier_(neural_networks)#Leaky_ReLU + +Applications: +Generative Adversarial Networks (GANs) +Object Detection and Image Segmentation +""" + +import numpy as np + + +def leaky_rectified_linear_unit(vector: np.ndarray, alpha: float) -> np.ndarray: + """ + Implements the LeakyReLU activation function. + Parameters: + vector: the array containing input of elu activation + alpha: hyperparameter + return: + leaky_relu (np.array): The input numpy array after applying leaky-relu. + + Formula : f(x) = x if x > 0 else f(x) = alpha * x + + Examples: + >>> leaky_rectified_linear_unit(vector=np.array([2.3,0.6,-2,-3.8]), alpha=0.3) + array([ 2.3 , 0.6 , -0.6 , -1.14]) + + >>> leaky_rectified_linear_unit(vector=np.array([-9.2,-0.3,0.45,-4.56]), \ + alpha=0.067) + array([-0.6164 , -0.0201 , 0.45 , -0.30552]) + + """ + return np.where(vector > 0, vector, alpha * vector) + + +if __name__ == "__main__": + import doctest + + doctest.testmod()