The paper titled "Attention Is All You Need" introduces the Transformer, a novel architecture for sequence transduction models that relies entirely on self-attention mechanisms, dispensing with traditional recurrence and convolutions. Key aspects of the model include:
- Architecture: The Transformer consists of an encoder-decoder structure, with both components utilizing stacked layers of multi-head self-attention mechanisms and feed-forward networks. It avoids recurrence and convolutions, allowing for greater parallelism and faster training.
- Attention Mechanism: The model uses scaled dot-product attention for computing attention scores, which scales down the dot products to prevent softmax from saturating.
- Multi-head attention is employed to allow the model to attend to information from different representation subspaces at different positions.
- Training and Regularization: The authors use the Adam optimizer with a particular learning rate schedule that initially increases the rate and then decreases it based on the number of training steps. They also employ techniques like dropout and label smoothing to regularize the model during training.
- Performance: The Transformer achieves state-of-the-art results on machine translation benchmarks (WMT 2014 English-to-German and English-to-French), outperforming previous models with significantly less training time and computational resources.
- Generalization: The model demonstrates strong performance on tasks other than machine translation, such as English constituency parsing, indicating its versatility and ability to learn complex dependencies and structures.
The paper emphasizes the efficiency and scalability of the Transformer, highlighting its potential for various sequence transduction tasks, and provides a foundation for subsequent advancements in natural language processing and beyond.
This article is part of a series titled ‘LLMs from Scratch’, a complete guide to understanding and building Large Language Models (LLMs). In this article, we discuss the self-attention mechanism and how it is used by transformers to create rich and context-aware transformer embeddings.
The Self-Attention mechanism is used to add context to learned embeddings, which are vectors representing each word in the input sequence. The process involves the following steps:
Learned Embeddings: These are the initial vector representations of words, learned during the training phase. The weights matrix, storing the learned embeddings, is stored in the first linear layer of the Transformer architecture.
Positional Encoding: This step adds positional information to the learned embeddings. Positional information helps the model understand the order of the words in the input sequence, as transformers process all words in parallel, and without this information, they would lose the order of the words.
Self-Attention: The core of the Self-Attention mechanism is to update the learned embeddings with context from the surrounding words in the input sequence. This mechanism determines which words provide context to other words, and this contextual information is used to produce the final contextualized embeddings.
