Coding a Neural Network in Python

The goal of this project is to code a single-hidden-layer neural network (NN) in Python with only the NumPy library (and matplotlib and tqdm). My motivation is to gain a better grasp of the fundamentals of neural networks, as well as develop intuition about hyperparameters, neuron counts, and activation functions.

The specific problem that this neural network will attempt to solve is approximating the function $f(x) = x^2$. This will be done by an NN with 1 input neuron, 1 output neuron, and some number of hidden neurons.

I wrote all of the code in this Jupyter notebook myself (without generative AI), with the exception of some matplotlib functions used for visualizing results.

© 2025 Simon Wong.