Understanding Tokens in AI

A Deep Dive into OpenAI’s Model Tokenization

One of the questions I most get asked about is “Just what are tokens ?” In today’s blog I try and answer the question. A crucial aspect of AI models is the concept of tokens, which play a vital role in how these models understand and process language. In this blog, we will explore what tokens are, how they function within OpenAI’s model, as this is the one I have spent the most time working with and most people have interactive with themselves.

In the context of AI and natural language processing, tokens are the fundamental units of text that a model processes. Tokens can represent words, subwords, or even individual characters, depending on the language and the tokenization method used. By breaking down text into tokens, AI models can better understand the structure and meaning of sentences, allowing them to generate coherent and contextually relevant responses.

In OpenAI’s Model OpenAI’s models, like GPT-3, use a technique called Byte Pair Encoding (BPE) to tokenize text. BPE is a data compression algorithm that tokenizes text based on the most frequently occurring character combinations. This helps the model efficiently represent and process a wide range of languages and writing systems. Let’s consider the following example using OpenAI’s model:

Prompt: “What is the capital of France?”

Response: “The capital of France is Paris.”

In this case, the number of tokens in the prompt and response are as follows: — Prompt: 7 tokens (“What”, “ is”, “ the”, “ capital”, “ of”, “ France”, “?”) — Response: 7 tokens (“The”, “ capital”, “ of”, “ France”, “ is”, “ Paris”, “.”) Each token contributes to the total token count, which affects the complexity and computational cost of processing and ultimately in some models the financial cost.

Tokenization is an essential step in preparing text data for AI models, and the mathematics behind it involves a combination of statistical and linguistic techniques. In the case of BPE, the algorithm starts by representing each character as a distinct token. It then iteratively merges the most frequently occurring token pairs until a predefined number of tokens (the vocabulary size) is reached. The process of tokenization can be represented mathematically as a function that maps a given input text to a sequence of tokens: T: Text → (t1, t2, t3, …, tn) Where T is the tokenization function, Text is the input text, and (t1, t2, t3, …, tn) is the resulting sequence of tokens.

Tokens play a vital role in AI models like OpenAI’s GPT-3, enabling them to process and understand text efficiently. By breaking down text into tokens using techniques like Byte Pair Encoding, these models can generate coherent and contextually relevant responses. Understanding the concept of tokens and the mathematics behind tokenization is essential for anyone working with AI and natural language processing.

Hopefully that cleared things up a bit. If you have some other questions or areas you would like me to explain just post it in the comments.