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Full-stack recurrence

ScaleRLT

ScaleRLT: Exact Log-Probabilities and Fast Deferred Rollouts for Reinforcement Learning on Looped Transformers

Dezhen Lu, Zixiang Ni, Runguo Li

Makes on-policy RL practical for looped language models such as Ouro. Rollouts defer and batch the deeper loops, and the learner uses a hybrid log-probability whose value replays the rollout schedule exactly while its gradient comes from a dense pass, removing the floating-point mismatch between sampler and learner.

Inside the method

Rollout: deferred deep loops → Learner: dense gradient + exact scheduled replay

Simplified conceptual schematic. Consult the paper for the complete architecture.

Recurrence family
Full-stack recurrence
Depth control
Ouro-style fixed loops; mixed-depth or native readout
KV / state strategy
One-wave KV admission with CUDA graphs

Reading note

Replay is bit-exact in all reported FP32 and bf16 cells. Deferral raises single-GPU rollout throughput 1.47–1.56× and a two-node GRPO update is 2.71× faster. The GSM8K gains come from 100-update runs in the authors' setup.

Sources checked 2026-10-28. This catalog does not imply independent reproduction.

Related works

Cite this work

@misc{scalerlt2026,
  title = {ScaleRLT: Exact Log-Probabilities and Fast Deferred Rollouts for Reinforcement Learning on Looped Transformers},
  author = {Dezhen Lu and Zixiang Ni and Runguo Li},
  year = {2026},
  eprint = {2610.34427},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.34427}
}

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