ResearchResearch paperLarge Language Models1 source · Oct 14, 2026

PA1-OPD: One-Step Prefix-Augmented On-Policy Distillation for Language Model Pretraining

Knowledge distillation (KD) improves language-model pretraining by matching teacher distributions at corpus prefixes, but provides no direct supervision at contexts induced by student predictions.

Key points

  • We introduce PA1-OPD, which augments corpus-path distillation with teacher feedback after one student-sampled transition per selected prefix.
  • This expands the supervised states while retaining next-token prediction and corpus-path KD.
  • Data-anchored roots support parallel sampling, and differentiable tree attention shares prefix computation without changing inference.
  • These findings support local student-induced supervision as a complement to pretraining distillation.

Sources (1)

  • [1]PA1-OPD: One-Step Prefix-Augmented On-Policy Distillation for Language Model Pretraining
    arXiv (AI, ML, NLP, CV, robotics, multi-agent) · Oct 14, 05:23 AM
    Knowledge distillation (KD) improves language-model pretraining by matching teacher distributions at corpus prefixes, but provides no direct supervision at contexts induced by student predictions.
    We introduce PA1-OPD, which augments corpus-path distillation with teacher feedback after one student-sampled transition per selected prefix.

Extractive summary: sentences quoted from the sources.

Before this

  1. Oct 14, 2026ActionOPD: Distilling Decisions, Not Tokens
  2. Oct 13, 2026Outcome-Routed Distillation and Reinforcement Learning for Diffusion Language Models
  3. Oct 13, 2026Demystifying On-Policy Distillation: Where Does the Teacher's Advantage Live?
  4. Oct 13, 2026Run fast, private agents on-device with LFM2.5-24B-A2B
  5. Oct 13, 2026Simplifying and Improving On-Policy Distillation for Few-Step Diffusion
  6. Oct 12, 2026JustOPD: On-Policy Distillation from Autoregressive to Diffusion Language Models

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