DenoisingAutoEncoder/activation.py at main · Ishwor-git/DenoisingAutoEncoder · GitHub

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import numpy as np


class Activation:

    def __init__(self):
        raise NotImplementedError

    def forward(self, input_data):
        raise NotImplementedError

    def backward(self, gradient):
        raise NotImplementedError


class ReLU(Activation):
    def __init__(self):
        self.input = None

    def forward(self, input_data):
        self.input = input_data
        return np.maximum(0, input_data)

    def backward(self, gradient):
        grad = self.input > 0
        return gradient * grad


class Sigmoid(Activation):
    def __init__(self):
        self.output = None

    def forward(self, input_data):
        self.output = 1 / (1 + np.exp(-input_data))
        return self.output

    def backward(self, gradient):
        return gradient * (self.output * (1 - self.output))