Allocation of Parameters in Transformers

Fuente: arXiv
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Autores principales: Yu, Ruoxi, Jiang, Haotian, Cheng, Jingpu, Yu, Penghao, Li, Qianxiao, Li, Zhong
Formato: Preprint
Publicado: 2025
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author Yu, Ruoxi
Jiang, Haotian
Cheng, Jingpu
Yu, Penghao
Li, Qianxiao
Li, Zhong
author_facet Yu, Ruoxi
Jiang, Haotian
Cheng, Jingpu
Yu, Penghao
Li, Qianxiao
Li, Zhong
contents Transformers have achieved remarkable successes across a wide range of applications, yet the theoretical foundation of their model efficiency remains underexplored. In this work, we investigate how the model parameters -- mainly attention heads and head dimensions -- should be allocated across layers to balance expressivity and efficiency. We first provide mathematical analysis on the role of early layers in information extraction from an approximation perspective, with a theoretical characterization on the trade-off between the number of heads and head dimension under a fixed parameter budget. In addition, we uncover and prove the \emph{saturation} behavior of softmax activations: Continuously increasing head dimensions can lead to diminishing returns in learning errors, particularly for long sequences. Supported by both theory and experiments, this saturation pattern suggests that later layers can operate more efficiently with reduced parameters. Combining these insights, we propose principled strategies for allocating attention heads and dimensions across Transformers' layers, shedding light on theoretically-grounded model efficiency of Transformer-based architectures.
format Preprint
id arxiv_https___arxiv_org_abs_2510_03784
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Allocation of Parameters in Transformers
Yu, Ruoxi
Jiang, Haotian
Cheng, Jingpu
Yu, Penghao
Li, Qianxiao
Li, Zhong
Machine Learning
Transformers have achieved remarkable successes across a wide range of applications, yet the theoretical foundation of their model efficiency remains underexplored. In this work, we investigate how the model parameters -- mainly attention heads and head dimensions -- should be allocated across layers to balance expressivity and efficiency. We first provide mathematical analysis on the role of early layers in information extraction from an approximation perspective, with a theoretical characterization on the trade-off between the number of heads and head dimension under a fixed parameter budget. In addition, we uncover and prove the \emph{saturation} behavior of softmax activations: Continuously increasing head dimensions can lead to diminishing returns in learning errors, particularly for long sequences. Supported by both theory and experiments, this saturation pattern suggests that later layers can operate more efficiently with reduced parameters. Combining these insights, we propose principled strategies for allocating attention heads and dimensions across Transformers' layers, shedding light on theoretically-grounded model efficiency of Transformer-based architectures.
title Allocation of Parameters in Transformers
topic Machine Learning
url https://arxiv.org/abs/2510.03784