Transformers without Tears: Improving the Normalization of Self-AttentionThanks: Work done during an internship at Amazon AWS AI.
Toan Q. Nguyen Thanks: Equal contribution. Affiliation: University of Notre Dame Email: Julian Salazar Affiliation: Amazon AWS AI Email:
Abstract
We evaluate three simple, normalization-centric changes to improve Transformer training. First, we show that pre-norm residual connections (PreNorm) and smaller initializations enable warmup-free, validation-based training with large learning rates. Second, we propose $\ell_{2}$ normalization with a single scale parameter (ScaleNorm) for faster training and better performance. Finally, we reaffirm the effectiveness of normalizing word embeddings to a fixed length (FixNorm). On five low-resource translation pairs from TED Talks-based corpora, these changes always converge, giving an average +1.1 BLEU over state-of-the-art bilingual baselines and a new 32.8 BLEU on IWSLT '15 English-Vietnamese. We observe sharper performance curves, more consistent gradient norms, and a linear relationship between activation scaling and decoder depth. Surprisingly, in the high-resource setting (WMT '14 English-German), ScaleNorm and FixNorm remain competitive but PreNorm degrades performance. Preprocessing scripts and code are released at https://github.com/tnq177/transformers_without_tears.
原文 arXiv:1910.05895;中英对照 + 大白话阅读 https://aha.fim.ai/paper/1910.05895v2