LoRA-DA: Data-Aware Initialization for Low-Rank Adaptation via Asymptotic Analysis

Fuente: arXiv
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Hauptverfasser: Zhang, Qingyue, Chu, Chang, Peng, Tianren, Li, Qi, Luo, Xiangyang, Jiang, Zhihao, Huang, Shao-Lun
Format: Preprint
Veröffentlicht: 2025
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author Zhang, Qingyue
Chu, Chang
Peng, Tianren
Li, Qi
Luo, Xiangyang
Jiang, Zhihao
Huang, Shao-Lun
author_facet Zhang, Qingyue
Chu, Chang
Peng, Tianren
Li, Qi
Luo, Xiangyang
Jiang, Zhihao
Huang, Shao-Lun
contents LoRA has become a widely adopted method for PEFT, and its initialization methods have attracted increasing attention. However, existing methods have notable limitations: many methods do not incorporate target-domain data, while gradient-based methods exploit data only at a shallow level by relying on one-step gradient decomposition. In this paper, we establish a theoretical framework for data-aware LoRA initialization. Starting from minimizing the expectation of the parameter discrepancy between the fine-tuned and target models, we derive an optimization problem with two components: a bias term, which is related to the parameter distance between the fine-tuned and target models, and is approximated using a Fisher-gradient formulation to preserve anisotropy; and a variance term, which accounts for the uncertainty introduced by sampling stochasticity through the Fisher information. Solving this problem yields an optimal initialization strategy for LoRA, based on which we develop an efficient algorithm, LoRA-DA. Empirical results across multiple benchmarks demonstrate that LoRA-DA consistently improves final accuracy over existing initialization methods. Additional studies show faster, more stable convergence, robustness across ranks, and only a small initialization overhead for LoRA-DA. The source code will be released upon publication.
format Preprint
id arxiv_https___arxiv_org_abs_2510_24561
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle LoRA-DA: Data-Aware Initialization for Low-Rank Adaptation via Asymptotic Analysis
Zhang, Qingyue
Chu, Chang
Peng, Tianren
Li, Qi
Luo, Xiangyang
Jiang, Zhihao
Huang, Shao-Lun
Machine Learning
Artificial Intelligence
LoRA has become a widely adopted method for PEFT, and its initialization methods have attracted increasing attention. However, existing methods have notable limitations: many methods do not incorporate target-domain data, while gradient-based methods exploit data only at a shallow level by relying on one-step gradient decomposition. In this paper, we establish a theoretical framework for data-aware LoRA initialization. Starting from minimizing the expectation of the parameter discrepancy between the fine-tuned and target models, we derive an optimization problem with two components: a bias term, which is related to the parameter distance between the fine-tuned and target models, and is approximated using a Fisher-gradient formulation to preserve anisotropy; and a variance term, which accounts for the uncertainty introduced by sampling stochasticity through the Fisher information. Solving this problem yields an optimal initialization strategy for LoRA, based on which we develop an efficient algorithm, LoRA-DA. Empirical results across multiple benchmarks demonstrate that LoRA-DA consistently improves final accuracy over existing initialization methods. Additional studies show faster, more stable convergence, robustness across ranks, and only a small initialization overhead for LoRA-DA. The source code will be released upon publication.
title LoRA-DA: Data-Aware Initialization for Low-Rank Adaptation via Asymptotic Analysis
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2510.24561