TailRL works even with poor initial policy coverage, authors show in navigation tasks

YouJiacheng · x · 2026-09-08

stablegradients presents TailRL, addressing the objection that Best-of-k objectives fail when the initial policy is weak: in navigation tasks, the method still works even when the initial policy has poor coverage over good rollouts, by spending more training compute on a weighted Best-of-k objective. YouJiacheng notes even 0.01% coverage is valid. Part 6 of a thread.

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