Restoring Exploration after Post-Training: Latent Exploration Decoding for Large Reasoning Models

Fuente: arXiv
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Autores principales: Tan, Wenhui, Parascandolo, Fiorenzo, Sangineto, Enver, Ju, Jianzhong, Luo, Zhenbo, Cao, Qian, Cucchiara, Rita, Song, Ruihua, Luan, Jian
Formato: Preprint
Publicado: 2026
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author Tan, Wenhui
Parascandolo, Fiorenzo
Sangineto, Enver
Ju, Jianzhong
Luo, Zhenbo
Cao, Qian
Cucchiara, Rita
Song, Ruihua
Luan, Jian
author_facet Tan, Wenhui
Parascandolo, Fiorenzo
Sangineto, Enver
Ju, Jianzhong
Luo, Zhenbo
Cao, Qian
Cucchiara, Rita
Song, Ruihua
Luan, Jian
contents Large Reasoning Models (LRMs) have recently achieved strong mathematical and code reasoning performance through Reinforcement Learning (RL) post-training. However, we show that modern reasoning post-training induces an unintended exploration collapse: temperature-based sampling no longer increases pass@$n$ accuracy. Empirically, the final-layer posterior of post-trained LRMs exhibit sharply reduced entropy, while the entropy of intermediate layers remains relatively high. Motivated by this entropy asymmetry, we propose Latent Exploration Decoding (LED), a depth-conditioned decoding strategy. LED aggregates intermediate posteriors via cumulative sum and selects depth configurations with maximal entropy as exploration candidates. Without additional training or parameters, LED consistently improves pass@1 and pass@16 accuracy by 0.61 and 1.03 percentage points across multiple reasoning benchmarks and models. Furthermore, integrating LED into reinforcement learning, e.g., using GRPO as the rollout strategy, yields faster reward improvement and higher final performance, due to the efficient exploration capability of LED. Project page: https://github.com/AlbertTan404/LED.
format Preprint
id arxiv_https___arxiv_org_abs_2602_01698
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Restoring Exploration after Post-Training: Latent Exploration Decoding for Large Reasoning Models
Tan, Wenhui
Parascandolo, Fiorenzo
Sangineto, Enver
Ju, Jianzhong
Luo, Zhenbo
Cao, Qian
Cucchiara, Rita
Song, Ruihua
Luan, Jian
Computation and Language
Machine Learning
Large Reasoning Models (LRMs) have recently achieved strong mathematical and code reasoning performance through Reinforcement Learning (RL) post-training. However, we show that modern reasoning post-training induces an unintended exploration collapse: temperature-based sampling no longer increases pass@$n$ accuracy. Empirically, the final-layer posterior of post-trained LRMs exhibit sharply reduced entropy, while the entropy of intermediate layers remains relatively high. Motivated by this entropy asymmetry, we propose Latent Exploration Decoding (LED), a depth-conditioned decoding strategy. LED aggregates intermediate posteriors via cumulative sum and selects depth configurations with maximal entropy as exploration candidates. Without additional training or parameters, LED consistently improves pass@1 and pass@16 accuracy by 0.61 and 1.03 percentage points across multiple reasoning benchmarks and models. Furthermore, integrating LED into reinforcement learning, e.g., using GRPO as the rollout strategy, yields faster reward improvement and higher final performance, due to the efficient exploration capability of LED. Project page: https://github.com/AlbertTan404/LED.
title Restoring Exploration after Post-Training: Latent Exploration Decoding for Large Reasoning Models
topic Computation and Language
Machine Learning
url https://arxiv.org/abs/2602.01698