arXiv Machine Learning

Divergence controls entropy in distillation

The paper investigates how the choice of divergence in knowledge distillation affects the entropy of the student model. It shows that forward KL increases student entropy beyond the teacher’s, while reverse KL decreases it, and that interpolating between the two yields a smooth entropy change early in training but a sharp shift at convergence. The study also finds that on‑policy distillation’s lower entropy stems from token‑level reverse KL rather than sampling, positioning divergence as an implicit entropy regularizer, especially evident in self‑distillation scenarios.

arXiv Computation and Language
Sep 2

Knowledge Distillation During Mid-Training Favors Reasoning over Factual Recall

arXiv:2609.01532v1 Announce Type: new Abstract: Logit-based knowledge distillation (KD) is used to train smaller language models (LMs) via supervision from stronger teachers, but whether its benefits...

By Jacqueline He, Howard Yen, Shuyue Stella Li, Margaret Li, Hanqing Zeng, Yinglong Xia, Benyu Zhang, Zhuokai Zhao, Qiang Zhang, Pang Wei Koh, Luke Zettlemoyer, Wen-tau Yih
arXiv Machine Learning
Jun 4

Self-Distilled Policy Gradient

arXiv:2606. 04036v1 Announce Type: new Abstract: On-policy self-distillation, where a language model conditions on privileged context to supervise its own generations, is a promising source of dense supervision for sparse-reward reinforcement learning.

By Yifeng Liu, Shiyuan Zhang, Yifan Zhang, Quanquan Gu
arXiv Statistics ML
5d ago

Unbiased Top-$k$ Estimation for On-Policy Distillation

The paper introduces Tail‑Corrected Top‑k On‑Policy Distillation (TT‑OPD), a method that improves on existing Top‑k OPD by combining the selected top‑k tokens with a sampled token from the student’s rollout. This hybrid approach recovers the probability mass discarded by limiting to top‑k, yielding an unbiased estimator of the reverse KL divergence gradient while maintaining low computational cost. Experiments show TT‑OPD outperforms other OPD variants in accuracy.

By Linjian Meng, Siyuan Gan, YuHan Li, Xiran Wang, Ziyang Ding, Ditang Gou, Yiming Wu, Zhen Zhao
arXiv AI
Jul 3

DemoPSD: Disagreement-Modulated Policy Self-Distillation

arXiv:2607. 02502v1 Announce Type: cross Abstract: On-policy self-distillation (OPSD) has emerged as a practical method for training large language models (LLMs) to reason, where a single model acts as both the teacher and the student with different levels of information access.

By Yunhe Li, Hao Shi, Wenhao Liu, Mengzhe Ruan, Hanxu Hou, Zhongxiang Dai, Shuang Qiu, Linqi Song