SA-OPSD distills self-teacher knowledge at beam-search pruning boundaries for generative recommendation

_reachsumit · x · 2026-11-04

The SA-OPSD paper improves on-policy self-distillation (OPSD) for generative recommendation training.

Two problems: visited states in beam search differ in importance, and initially reliable decisions can approach the pruning boundary as training evolves; conventional distribution matching couples target-token confidence with preferences among competing continuations, weakening relational supervision when the self-teacher strongly favors the target.

The method introduces Evolving-Boundary Sampling, which prioritizes search-critical states by weighing pruning-boundary proximity and the decline of initial reference retention margins under a controlled distillation budget, plus Confidence-Decoupled Branch Distillation, which separates target-probability calibration from informative sibling relations to better preserve the teacher's preferences among competing branches.

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