arXiv:2604.18124cs.CLcs.AI2026-04ACL被引 1

TLoRA统一优化LoRA的初始化与参数分配,提升模型适配效率。

TLoRA: Task-aware Low Rank Adaptation of Large Language Models

论文配图:TLoRA: Task-aware Low Rank Adaptation of Large Language Models
图 1 · 摘自论文原文
  • 基于任务相关子空间数据驱动初始化A矩阵,冻结后仅训练B矩阵。
  • 在固定参数预算下,按敏感度自适应分配各层秩与缩放因子。
  • 跨多任务表现优异,显著减少可训练参数量,适合高效微调场景。

低秩适配(LoRA)已成为大语言模型参数高效微调的常用方法,其效果受秩分配、缩放因子及初始化影响显著。现有LoRA变体通常仅优化单一因素,常以增加训练复杂度或降低实用性为代价。本文提出任务感知低秩适配(TLoRA),在训练初期统一优化初始化与资源分配。TLoRA采用数据驱动初始化策略,通过对预训练权重与输入激活协方差乘积进行奇异值分解,使LoRA的A矩阵对齐任务相关子空间;随后冻结A矩阵,仅训练B矩阵。此外,TLoRA基于敏感度重要性度量,在固定参数预算下自适应分配各层的秩与缩放因子。大量实验表明,TLoRA在自然语言理解、常识推理、数学推理、代码生成和对话生成等任务中表现一致优异,同时显著减少可训练参数数量。

原文摘要 · Abstract (English)

Low-Rank Adaptation (LoRA) has become a widely adopted parameter-efficient fine-tuning method for large language models, with its effectiveness largely influenced by the allocation of ranks and scaling factors, as well as initialization. Existing LoRA variants typically address only one of these factors, often at the cost of increased training complexity or reduced practical efficiency. In this work, we present Task-aware Low-Rank Adaptation (TLoRA), a unified framework that jointly optimizes initialization and resource allocation at the outset of training. TLoRA introduces a data-driven initialization strategy that aligns the LoRA $A$ matrix with task-relevant subspaces by performing singular value decomposition on the product of pre-trained weights and input activation covariance. After this, the $A$ matrix is frozen, and only the $B$ matrix is trained. Furthermore, TLoRA employs a sensitivity-based importance metric to adaptively allocate ranks and scaling factors across layers under a fixed parameter budget. We conduct extensive experiments that demonstrate TLoRA consistently performs excellently across various tasks, including natural language understanding, commonsense reasoning, math reasoning, code generation, and chat generation, while significantly reducing the number of trainable parameters.

LoRA参数高效微调大模型

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