Title
You Only Sample (Almost) Once: Linear Cost Self-Attention Via Bernoulli Sampling
Abstract
Transformer-based models are widely used in natural language processing (NLP). Central to the transformer model is the self-attention mechanism, which captures the interactions of token pairs in the input sequences and depends quadratically on the sequence length. Training such models on longer sequences is expensive. In this paper, we show that a Bernoulli sampling attention mechanism based on Locality Sensitive Hashing (LSH), decreases the quadratic complexity of such models to linear. We bypass the quadratic cost by considering self-attention as a sum of individual tokens associated with Bernoulli random variables that can, in principle, be sampled at once by a single hash (although in practice, this number may be a small constant). This leads to an efficient sampling scheme to estimate self-attention which relies on specific modifications of LSH (to enable deployment on GPU architectures). We evaluate our algorithm on the GLUE benchmark with standard 512 sequence length where we see favorable performance relative to a standard pretrained Transformer. On the Long Range Arena (LRA) benchmark, for evaluating performance on long sequences, our method achieves results consistent with softmax self-attention but with sizable speed-ups and memory savings and often outperforms other efficient self-attention methods. Our code is available at https://github.com/m1pen/YOSO.
Year
Venue
DocType
2021
INTERNATIONAL CONFERENCE ON MACHINE LEARNING, VOL 139
Conference
Volume
ISSN
Citations 
139
2640-3498
0
PageRank 
References 
Authors
0.34
0
6
Name
Order
Citations
PageRank
Zhanpeng Zeng100.68
Yunyang Xiong221.36
Sathya Ravi3208.13
Shailesh Acharya400.34
Glenn Fung51531113.49
Vikas Singh656249.01