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Thinking Machines又发高质量博客:力推LoRA,不输全量微调
机器之心·2025-09-30 10:38

Core Insights - The article emphasizes the advantages of LoRA (Low-Rank Adaptation) over Full Fine-tuning (FullFT) in terms of cost-effectiveness and performance in various training scenarios [2][7][18]. Group 1: Importance of LoRA - LoRA is a popular parameter-efficient fine-tuning method that updates a low-dimensional adapter instead of the entire model weights, leading to lower memory requirements and faster loading [11][13]. - The research indicates that LoRA can achieve performance comparable to FullFT in small to medium-sized datasets, while it may struggle in large datasets due to capacity limitations [14][22]. Group 2: Key Findings - The study found that LoRA's performance is closely tied to the training conditions, including the size of the training dataset and the rank of the LoRA parameters [16][25]. - In reinforcement learning tasks, even with a very low rank (rank=1), LoRA can perform similarly to FullFT, indicating that reinforcement learning has lower capacity demands [29]. Group 3: Experimental Methodology - The research utilized models like LLaMA 3 and Qwen3, adjusting LoRA ranks from 1 to 512 and scanning learning rates to find optimal training conditions [20][21]. - Results showed that high-rank LoRA performed almost identically to FullFT in certain datasets, but performance varied across different tasks due to training dynamics [22][24]. Group 4: Practical Implications - LoRA's optimal learning rate is typically about 10 times that of FullFT, allowing it to accept higher learning rates under the same conditions [35]. - The study suggests that applying LoRA across all layers, especially MLP and MoE layers, is crucial for achieving performance close to FullFT [37].