arXiv Machine Learning By Yuxuan Wang, Guangxiang Zhao, Xinyu Tan, Yahui Han, Xinxiang Yin, Zhonghai Wu, Xiangzheng Zhang, Lin Sun, Tong Yang

Beyond Distribution Matching: Selective Margin Preservation for Supervised Fine-Tuning

Read the original on arXiv Machine Learning →

The paper introduces Selective Rank-Preserving Supervised Fine‑Tuning (SRP‑SFT), a method that applies a hinge‑based soft margin target to preserve selected local non‑target logit margins during teacher‑forced fine‑tuning. SRP‑SFT uses reference‑scaled lower bounds for pairs from the reference’s top‑K non‑target tokens, stopping once the bound is met. Experiments on Qwen3‑4B‑Base and UltraFeedback show that SRP‑SFT improves MATH‑500 and code‑generation scores compared to cross‑entropy and LP‑SFT baselines.

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