UP-MOPD: Update Projection in Multi-Teacher On-Policy Distillation
Read the original on arXiv Computer Vision →The Flow has not summarised this story yet — read it at arXiv Computer Vision.
The Flow has not summarised this story yet — read it at arXiv Computer Vision.
The paper introduces D$^3$-MOPD, a dynamic domain scheduling method for multi-teacher on‑policy distillation. It adapts the domain mixture during training by monitoring each domain’s reverse‑KL trajectory, thereby allocating more compute to slower‑converging domains and less to those that plateau early. Experiments on a Qwen3.6‑35B‑A3B student show that D$^3$-MOPD closes 97% of the student‑to‑teacher performance gap, matches peak performance with roughly three times fewer rollout steps, and outperforms specialist teachers on most benchmarks.
The paper introduces D$^3$-MOPD, a zero‑overhead scheduler that dynamically adjusts domain sampling ratios during multi‑teacher on‑policy distillation by monitoring per‑domain reverse‑KL signals. Unlike static mixtures, D$^3$-MOPD reallocates compute toward slower‑converging domains, improving efficiency and performance. In experiments with a Qwen3.6‑35B‑A3B student distilled from four domain‑expert teachers, the method closes 97% of the student‑to‑teacher gap, matches peak performance with roughly three times fewer rollout steps, and outperforms specialist teachers on most benchmarks.
The paper investigates how teacher signals influence parameter updates in Multi‑Teacher On‑Policy Distillation (MOPD) by analyzing Qwen3‑1.7B and SmolLM3‑3B. It shows that loss averaging, Adam’s first‑moment bias, BF16 rounding, and the choice of averaging rule all shape the gradients and ultimately affect task performance. The study quantifies these effects, revealing, for example, that token‑averaging favors longer responses and that BF16 rounding masks most weight changes.
Latent-MOPD is a new on‑policy distillation method that allows a single large language model student to learn from multiple specialist teachers by using both the teachers’ output distributions and their hidden state representations. The approach selects late‑layer targets based on teacher‑student relationships, bridges hidden width differences with a shared projection, and groups updates by domain, enabling gradual shift from representation to token supervision. Experiments show that Latent‑MOPD outperforms token‑only, representation‑only, and uniform‑averaging baselines across nine benchmarks in math, code, and logic, and even surpasses the best individual teacher on most tasks.
arXiv:2512.22802v2 Announce Type: replace-cross Abstract: Step distillation accelerates diffusion sampling by training a few-step student to imitate a many-step teacher, but distillation itself remai...
MOPD‑Router rethinks teacher routing in multi‑teacher on‑policy distillation by routing supervision over the full teacher pool at each token, eliminating the need for prompt‑level domain labels or a separate routing model. The framework offers a plug‑in interface for various metrics, and introduces ExpertAlign, which scores teachers based on how well their corrections reflect their specialized post‑training knowledge. Experiments on both unlabeled and domain‑labeled mixtures show that ExpertAlign outperforms existing methods, improving overall scores by up to 12.3% on unlabeled data and 7.8% on domain‑labeled data. whyItMatters":"Token‑level routing enables the use of complementary supervision across domains without relying on domain labels, leading to significant performance gains in multi‑teacher distillation settings."