SRFT:一种融合监督与强化微调的单阶段推理方法
SRFT: A Single-Stage Method with Supervised and Reinforcement Fine-Tuning for Reasoning
June 24, 2025
作者: Yuqian Fu, Tinghong Chen, Jiajun Chai, Xihuai Wang, Songjun Tu, Guojun Yin, Wei Lin, Qichao Zhang, Yuanheng Zhu, Dongbin Zhao
cs.AI
摘要
大型语言模型(LLMs)在推理任务中取得了显著进展,然而如何最优地整合监督微调(SFT)与强化学习(RL)仍是一个根本性挑战。通过从基于熵的视角对标记分布、学习动态及整合机制进行全面分析,我们揭示了这两种范式之间的关键差异:SFT引发LLM策略分布的粗粒度全局变化,而RL则执行细粒度的选择性优化,其中熵作为训练效果的关键指标。基于这些观察,我们提出了监督强化微调(SRFT),这是一种通过熵感知加权机制统一两种微调范式的单阶段方法。我们的方法同时应用SFT和RL,直接利用演示和自我探索的轨迹来优化LLM,而非采用两阶段顺序方法。大量实验表明,SRFT在五个数学推理基准测试中平均准确率达到59.1%,较无RL方法高出9.0%,在三个分布外基准测试中则高出10.9%。
English
Large language models (LLMs) have achieved remarkable progress in reasoning
tasks, yet the optimal integration of Supervised Fine-Tuning (SFT) and
Reinforcement Learning (RL) remains a fundamental challenge. Through
comprehensive analysis of token distributions, learning dynamics, and
integration mechanisms from entropy-based perspectives, we reveal key
differences between these paradigms: SFT induces coarse-grained global changes
to LLM policy distributions, while RL performs fine-grained selective
optimizations, with entropy serving as a critical indicator of training
effectiveness. Building on these observations, we propose Supervised
Reinforcement Fine-Tuning (SRFT), a single-stage method that unifies both
fine-tuning paradigms through entropy-aware weighting mechanisms. Our approach
simultaneously applies SFT and RL to directly optimize the LLM using
demonstrations and self-exploration rollouts rather than through two-stage
sequential methods. Extensive experiments show that SRFT achieves 59.1% average
accuracy, outperforming zero-RL methods by 9.0% on five mathematical reasoning
benchmarks and 10.9% on three out-of-distribution benchmarks.