Swift-SVD: Theoretical Optimality Meets Practical Efficiency in Low-Rank LLM Compression

Fuente: arXiv
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Auteurs principaux: Qi, Ruoling, Liu, Yirui, Wu, Xuaner, Wang, Xiangyu, Li, Ming, Chen, Chen, Chen, Jian, Chen, Yin, Weng, Qizhen
Format: Preprint
Publié: 2026
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author Qi, Ruoling
Liu, Yirui
Wu, Xuaner
Wang, Xiangyu
Li, Ming
Chen, Chen
Chen, Jian
Chen, Yin
Weng, Qizhen
author_facet Qi, Ruoling
Liu, Yirui
Wu, Xuaner
Wang, Xiangyu
Li, Ming
Chen, Chen
Chen, Jian
Chen, Yin
Weng, Qizhen
contents The deployment of Large Language Models is constrained by the memory and bandwidth demands of static weights and dynamic Key-Value cache. SVD-based compression provides a hardware-friendly solution to reduce these costs. However, existing methods suffer from two key limitations: some are suboptimal in reconstruction error, while others are theoretically optimal but practically inefficient. In this paper, we propose Swift-SVD, an activation-aware, closed-form compression framework that simultaneously guarantees theoretical optimum, practical efficiency and numerical stability. Swift-SVD incrementally aggregates covariance of output activations given a batch of inputs and performs a single eigenvalue decomposition after aggregation, enabling training-free, fast, and optimal layer-wise low-rank approximation. We employ effective rank to analyze local layer-wise compressibility and design a dynamic rank allocation strategy that jointly accounts for local reconstruction loss and end-to-end layer importance. Extensive experiments across six LLMs and eight datasets demonstrate that Swift-SVD outperforms state-of-the-art baselines, achieving optimal compression accuracy while delivering 3-70X speedups in end-to-end compression time. Our code will be released upon acceptance.
format Preprint
id arxiv_https___arxiv_org_abs_2604_01609
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Swift-SVD: Theoretical Optimality Meets Practical Efficiency in Low-Rank LLM Compression
Qi, Ruoling
Liu, Yirui
Wu, Xuaner
Wang, Xiangyu
Li, Ming
Chen, Chen
Chen, Jian
Chen, Yin
Weng, Qizhen
Computation and Language
The deployment of Large Language Models is constrained by the memory and bandwidth demands of static weights and dynamic Key-Value cache. SVD-based compression provides a hardware-friendly solution to reduce these costs. However, existing methods suffer from two key limitations: some are suboptimal in reconstruction error, while others are theoretically optimal but practically inefficient. In this paper, we propose Swift-SVD, an activation-aware, closed-form compression framework that simultaneously guarantees theoretical optimum, practical efficiency and numerical stability. Swift-SVD incrementally aggregates covariance of output activations given a batch of inputs and performs a single eigenvalue decomposition after aggregation, enabling training-free, fast, and optimal layer-wise low-rank approximation. We employ effective rank to analyze local layer-wise compressibility and design a dynamic rank allocation strategy that jointly accounts for local reconstruction loss and end-to-end layer importance. Extensive experiments across six LLMs and eight datasets demonstrate that Swift-SVD outperforms state-of-the-art baselines, achieving optimal compression accuracy while delivering 3-70X speedups in end-to-end compression time. Our code will be released upon acceptance.
title Swift-SVD: Theoretical Optimality Meets Practical Efficiency in Low-Rank LLM Compression
topic Computation and Language
url https://arxiv.org/abs/2604.01609