arXiv:2506.18267cs.LGcs.AI2025-06被引 6

动态分配模型各层适配秩,用更少参数实现更高性能微调。

ARD-LoRA: Dynamic Rank Allocation for Parameter-Efficient Fine-Tuning of Foundation Models with Heterogeneous Adaptation Needs

  • 通过可学习缩放因子自动分配每头的适配秩,实现精细化控制。
  • 仅用0.32%参数达到全量微调99.3%性能,多模态适配内存降41%。
  • 适合需要高效微调大模型且资源受限的研究者与开发者。

传统低秩适配(LoRA)方法采用固定秩,对Transformer各层和注意力头施加统一适配,忽视其异质学习动态。本文提出自适应秩动态LoRA(ARD-LoRA),通过可学习缩放因子自动分配秩,优化目标兼顾任务性能与参数效率,引入ℓ₁稀疏性以最小化秩,及总变差正则化以保证秩变化稳定。该框架支持逐注意力头的连续、可微分秩调整。在LLAMA-3.1-70B和PaliGemma-2上的实验表明,ARD-LoRA仅需0.32%可训练参数即可达到全量微调99.3%的性能,优于DoRA和AdaLoRA等强基线,且多模态适配内存减少41%。结果确立了动态细粒度秩分配作为高效基础模型适配的关键范式。

原文摘要 · Abstract (English)

Conventional Low-Rank Adaptation (LoRA) methods employ a fixed rank, imposing uniform adaptation across transformer layers and attention heads despite their heterogeneous learning dynamics. This paper introduces Adaptive Rank Dynamic LoRA (ARD-LoRA), a novel framework that automates rank allocation through learnable scaling factors. These factors are optimized via a meta-objective balancing task performance and parameter efficiency, incorporating $\ell_1$ sparsity for minimal rank and Total Variation regularization for stable rank transitions. ARD-LoRA enables continuous, differentiable, per-head rank adaptation. Experiments on LLAMA-3.1-70B and PaliGemma-2 demonstrate ARD-LoRA's efficacy, achieving up to 99.3% of full fine-tuning performance with only 0.32% trainable parameters, outperforming strong baselines like DoRA and AdaLoRA. Furthermore, it reduces multimodal adaptation memory by 41%. These results establish dynamic, fine-grained rank allocation as a critical paradigm for efficient foundation model adaptation.

LoRA微调参数效率动态秩

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