Semester 2 · Core
Neural Networks & Deep Learning
https://epochschool.com/subjects/neural-networks-deep-learning
Take the first neural network you met in Foundations of ML and turn it into modern deep learning.
You derive backpropagation by hand, build your own automatic-differentiation engine, then use PyTorch with full understanding of what it computes. You learn why deep networks fail to train and how initialisation, normalisation, regularisation, convolutions and residual connections fix it, and you finish with embeddings and learned representations. Every idea is derived, implemented from scratch and tested in five CPU labs on real and synthetic data.
- Prerequisites
- Required: Finish this subject before you start. The subject builds directly on it.Recommended: Helpful background. You can start without it if you are willing to fill the gaps.
What you’ll be able to do
- LO1Derive the forward and backward passes of deep fully connected networks in batched matrix form, including softmax cross-entropy, and verify gradients numerically.
- LO2Implement reverse-mode automatic differentiation over a computational graph, including broadcasting and gradient accumulation, and explain how deep-learning frameworks compute gradients.
- LO3Build, train, save and evaluate neural networks in PyTorch with correct use of tensors, autograd, modules, data loaders and train/eval modes, reproducibly.
- LO4Choose activation functions and initialisation schemes from a signal-propagation analysis, and diagnose vanishing, exploding and dead units.
- LO5Control overfitting in deep networks with weight decay, dropout, early stopping and data augmentation, and justify each choice with validation evidence.
- LO6Apply batch, layer and group normalisation, derive the batch-norm backward pass, and explain their behaviour in training and inference.
- LO7Design, implement and analyse convolutional networks: convolution arithmetic and cost, pooling, receptive fields and residual connections.
- LO8Debug and tune a training run systematically with sanity checks, loss curves, internal statistics, gradient checks and controlled multi-seed experiments.
- LO9Use embedding layers and learned representations (entity embeddings, autoencoders, linear probes, frozen-feature transfer) and evaluate their quality.
Chapters
- 01Deep networks as functions: tensors, losses and why depth helps
- 02Backpropagation in matrix form
- 03Reverse-mode automatic differentiation: build a tiny engine
- 04PyTorch fundamentals
- 05Activations, initialisation and signal propagation
- 06Regularisation for deep networks
- 07Normalisation layers
- 08Training practice and debugging
- 09Convolution
- 10Convolutional networks
- 11Residual networks and training very deep models
- 12Embeddings and learned representations
Graded labs
- L1
Backpropagation by hand: a NumPy MLP for digits
After chapter 2 · about 9 hours · Optical recognition of handwritten digits · BSD-3-Clause (scikit-learn) · Runs on a CPU
- L2
Build a reverse-mode autodiff engine
After chapter 3 · about 10 hours · Optical recognition of handwritten digits · BSD-3-Clause (scikit-learn) · Runs on a CPU
- L3
Making deep networks train: initialisation, normalisation, regularisation and a broken loop
After chapter 8 · about 10 hours · Optical recognition of handwritten digits · BSD-3-Clause (scikit-learn) · Runs on a CPU
- L4
Convolutions from scratch and a small residual network
After chapter 11 · about 10 hours · Optical recognition of handwritten digits · BSD-3-Clause (scikit-learn) · Runs on a CPU
- L5
Embeddings and learned representations
After chapter 12 · about 10 hours · Synthetic suburban-rail delays · Own work, CC BY 4.0 · Runs on a CPU
Before you start
Required
Finish this subject before you start. The subject builds directly on it.
Linear Algebra & Calculus for ML
Recommended
Helpful background. You can start without it if you are willing to fill the gaps.
Probability & Statistics for ML
Where it leads
Optimisation & Training at Scale
Sequence Models & Transformers
Responsible AI, Ethics & Governance
NLP & Language Model Foundations
Building and Training LLMs from Scratch
LLM Applications: Retrieval, RAG and Agents
Image Formation and Classical Computer Vision
Deep Visual Recognition
Probabilistic ML & Bayesian Methods
Reinforcement Learning Foundations
Capstone Project
How it’s taught
You read short sections written for the page. Each ends with a check, and in-browser exercises let you practise. Graded labs run on your own cloud lab machine, CPU-friendly.
No videos. No live classes. No AI tutor.