Clustering in pure-attention hardmax transformers and its role in sentiment analysis

Fuente: arXiv
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Hauptverfasser: Alcalde, Albert, Fantuzzi, Giovanni, Zuazua, Enrique
Format: Preprint
Veröffentlicht: 2024
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author Alcalde, Albert
Fantuzzi, Giovanni
Zuazua, Enrique
author_facet Alcalde, Albert
Fantuzzi, Giovanni
Zuazua, Enrique
contents Transformers are extremely successful machine learning models whose mathematical properties remain poorly understood. Here, we rigorously characterize the behavior of transformers with hardmax self-attention and normalization sublayers as the number of layers tends to infinity. By viewing such transformers as discrete-time dynamical systems describing the evolution of points in a Euclidean space, and thanks to a geometric interpretation of the self-attention mechanism based on hyperplane separation, we show that the transformer inputs asymptotically converge to a clustered equilibrium determined by special points called \textit{leaders}. We then leverage this theoretical understanding to solve sentiment analysis problems from language processing using a fully interpretable transformer model, which effectively captures `context' by clustering meaningless words around leader words carrying the most meaning. Finally, we outline remaining challenges to bridge the gap between the mathematical analysis of transformers and their real-life implementation.
format Preprint
id arxiv_https___arxiv_org_abs_2407_01602
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Clustering in pure-attention hardmax transformers and its role in sentiment analysis
Alcalde, Albert
Fantuzzi, Giovanni
Zuazua, Enrique
Computation and Language
Machine Learning
Dynamical Systems
68T07, 68T50
Transformers are extremely successful machine learning models whose mathematical properties remain poorly understood. Here, we rigorously characterize the behavior of transformers with hardmax self-attention and normalization sublayers as the number of layers tends to infinity. By viewing such transformers as discrete-time dynamical systems describing the evolution of points in a Euclidean space, and thanks to a geometric interpretation of the self-attention mechanism based on hyperplane separation, we show that the transformer inputs asymptotically converge to a clustered equilibrium determined by special points called \textit{leaders}. We then leverage this theoretical understanding to solve sentiment analysis problems from language processing using a fully interpretable transformer model, which effectively captures `context' by clustering meaningless words around leader words carrying the most meaning. Finally, we outline remaining challenges to bridge the gap between the mathematical analysis of transformers and their real-life implementation.
title Clustering in pure-attention hardmax transformers and its role in sentiment analysis
topic Computation and Language
Machine Learning
Dynamical Systems
68T07, 68T50
url https://arxiv.org/abs/2407.01602