neural-network - 如何使用 tanh 激活函数而不是 sigmoid，我应该在哪里进行更改

Question

我已经用 Sigmoid 激活函数测试了我的神经网络。现在我想用双曲 tanh 激活函数测试我的 ANN。我不知道我应该在哪里进行更改。我应该在哪里进行更改？

import numpy
# scipy.special for the sigmoid function expit()
import scipy.special

# class definition for the core structure
class neuralNetwork:
    
    # initialise the neural network
    def __init__(self, inputnodes, hiddennodes, outputnodes, learningrate):
        # set number of nodes in each input, hidden, output layer
        self.inodes = inputnodes
        self.hnodes = hiddennodes
        self.onodes = outputnodes
        
        # link weight matrices, wih and who
        # weights inside the arrays are w_i_j, where link is from node i to node j in the next layer
        # w11 w21
        # w12 w22 etc 
        self.wih = numpy.random.normal(0.0, pow(self.inodes, -0.5), (self.hnodes, self.inodes))
        self.who = numpy.random.normal(0.0, pow(self.hnodes, -0.5), (self.onodes, self.hnodes))

        # learning rate
        self.lr = learningrate
        
        # activation function is the sigmoid function
        self.activation_function = lambda x: scipy.special.expit(x)
        
        pass