Module 02: Hands-On Fine-Tuning of Transformers

Hands-on fine-tuning of the three Transformer families — implement attention conceptually and adapt encoder, decoder, and encoder-decoder models.

May 28, 20261 min readFollow

Topics You Will Master

How the attention mechanism is constructed from first principles
Fine-tuning workflows for encoder-only models (DistilBERT)
Fine-tuning workflows for decoder-only models (DistilGPT)
Fine-tuning workflows for encoder–decoder models (T5)

Module Overview

This module bridges theory and practice. It revisits the attention mechanism at an implementation level (conceptually, not as production code) and then walks through the fine-tuning workflow for each of the three Transformer families on custom datasets, highlighting where each architecture excels.

Learning Objectives

  • Describe how attention is assembled from its component operations.
  • Outline the fine-tuning workflow for an encoder-only classifier.
  • Outline the fine-tuning workflow for a decoder-only generative model.
  • Outline the fine-tuning workflow for an encoder–decoder sequence-to-sequence model.
  • Map task types (classification, generation, summarisation/translation) to the most suitable architecture.

Topics Covered

Attention Implementation

  • Coding attention mechanisms — the operations behind self and multi-head attention (conceptual walkthrough)

Fine-Tuning Workflows

  • Fine-tuning DistilBERT (encoder-only) with custom data — classification and token-level tasks
  • Fine-tuning DistilGPT (decoder-only) with custom data — text generation and completion
  • Fine-tuning T5 (encoder–decoder) with custom data — summarisation, translation, and text-to-text tasks

Key Concepts & Terminology

Encoder-only vs decoder-only vs encoder–decoder task fit, transfer learning, dataset formatting, train/validation split, evaluation against a held-out set, catastrophic forgetting.

Tools & Frameworks Referenced

Hugging Face Transformers (Trainer), Datasets, DistilBERT, DistilGPT-2, T5.

Prerequisites

Module 01 (Transformer Architecture & Tokenization Foundations).

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