The article provides insights on implementing attention blocks in pure Python + Numpy with a focus on the exact code implementation and explanation of shapes throughout the process.
It starts with a basic scaled dot product self-attention for a single sequence of tokens without masking, utilizing weight matrices Wk, Wq, and Wv.
The article introduces a Numpy implementation of self-attention and explains the 'scaled' part by dividing by the square root of the head size to manage dot product values.
Batched self-attention is discussed for processing batches of input sequences efficiently, leveraging parallelism and Numpy matrix operations.
Multi-head attention, a common technique in modern models, is covered, where multiple heads handle attention separately and results are concatenated and linearly projected.
The article delves into masked (causal) self-attention, essential in decoder blocks to prevent tokens from attending to future tokens, ensuring proper generative model training.
Cross-attention is explained as a variant where elements of one sequence attend to elements in another sequence, commonly seen in decoder blocks of models like the AIAYN paper.
A vectorized implementation of multi-head attention is provided to optimize the code for accelerators like GPUs and TPUs, concatenating weight matrices for efficiency.
The article concludes by offering detailed code samples, including tests, available in a repository for further exploration and understanding of attention mechanism implementations.
The article emphasizes the importance of attention in neural network architectures and presents clear examples for better comprehension and implementation.
Attention mechanisms like self-attention, multi-head attention, and masked attention play a crucial role in enhancing model performance and training for various NLP tasks.
Different variants of attention blocks, including cross-attention, cater to diverse requirements in neural network design and enable advanced functionalities in model learning and inference.