AI Practitioner

Byte Pair Encoding (BPE) is one of the most important and widely adopted subword tokenization algorithms in modern Natural Language Processing (NLP), especially in training Large Language Models (LLMs) like GPT. This guide provides a deep technical dive into how BPE works, compares it with other tokenizers like WordPiece and SentencePiece, and explains its practical implementation with Python code. This article is optimized for AI engineers building real-world models and systems. 1. What is Byte Pair Encoding? BPE was originally introduced as a data compression algorithm by Gage in 1994. It replaces the most frequent pair of bytes in a sequence with a single, unused byte. In 2015, Sennrich et al. adapted BPE for NLP to address the out-of-vocabulary (OOV) problem in neural machine translation. Instead of working with full words, BPE decomposes them into subword units that can be recombined to represent rare or unseen words. 2. Why Tokenization Matters in LLMs Tokenization is th...

What is a Transformer? The Transformer is a neural network architecture introduced by Vaswani et al. in the 2017 paper "Attention is All You Need." It revolutionized natural language processing by replacing sequential models like RNNs and LSTMs. Transformers process entire sentences in parallel using self-attention , effectively addressing the difficulty of learning from long input sequences and enabling high computational efficiency by overcoming the limitations of sequential processing. 1. Transformer Components and Overcoming RNN/LSTM Limitations The Transformer is composed of an encoder and a decoder, with each block consisting of the following key components: Self-Attention: Learns the relationships between tokens within the input sequence by enabling each token to attend to all others, effectively capturing long-range dependencies and rich contextual information. Multi-Head Attention (MHA): Divides self-attention into multiple parallel heads. Each head focuses o...