Unable to solve the XOR problem with just two hidden neurons in Python

Question

I have a small, 3 layer, neural network with two input neurons, two hidden neurons and one output neuron. I am trying to stick to the below format of using only 2 hidden neurons

Answer 1

This is due to the fact that you have not considered any bias for the neurons. You have only used weights to try and fit the XOR model.

Incase of 2 neurons in the hidden layer, the network under-fits as it can't compensate for the bias.

When you use 3 neurons in the hidden layer, the extra neuron counters the effect caused due to the lack of bias.

This is an example of a network for XOR gate. You'll notice theta (bias) added to the hidden layers. This gives the network an additional parameter to tweak.

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