Open-Reasoner-Zero: An Open Source Approach to Scaling Up Reinforcement Learning on the Base Model

Fuente: arXiv
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Main Authors: Hu, Jingcheng, Zhang, Yinmin, Han, Qi, Jiang, Daxin, Zhang, Xiangyu, Shum, Heung-Yeung
Format: Preprint
Published: 2025
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author Hu, Jingcheng
Zhang, Yinmin
Han, Qi
Jiang, Daxin
Zhang, Xiangyu
Shum, Heung-Yeung
author_facet Hu, Jingcheng
Zhang, Yinmin
Han, Qi
Jiang, Daxin
Zhang, Xiangyu
Shum, Heung-Yeung
contents We introduce Open-Reasoner-Zero, the first open source implementation of large-scale reasoning-oriented RL training on the base model focusing on scalability, simplicity and accessibility. Through extensive experiments, we demonstrate that a minimalist approach, vanilla PPO with GAE ($λ=1$, $γ=1$) and straightforward rule-based rewards, without any KL regularization, is sufficient to scale up both benchmark performance and response length, replicating the scaling phenomenon observed in DeepSeek-R1-Zero. Using the same base model, Qwen2.5-32B base, as DeepSeek-R1-Zero-Qwen-32B, our implementation achieves superior performance across AIME2024, MATH500, and GPQA Diamond, while demonstrating remarkable efficiency, requiring only 1/10 of the training steps compared to the DeepSeek-R1-Zero pipeline. Moreover, our analysis not only covers training dynamics and ablation for critical design choices, but also quantitatively shows how the learned critic in Reasoner-Zero training effectively identifies and devalues repetitive response patterns, yielding more robust advantage estimations and enhancing training stability. Embracing the principles of open-source, we release our source code, training data, and various model weights, fostering reproducibility and encouraging further exploration of the properties of related models.
format Preprint
id arxiv_https___arxiv_org_abs_2503_24290
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Open-Reasoner-Zero: An Open Source Approach to Scaling Up Reinforcement Learning on the Base Model
Hu, Jingcheng
Zhang, Yinmin
Han, Qi
Jiang, Daxin
Zhang, Xiangyu
Shum, Heung-Yeung
Machine Learning
Computation and Language
We introduce Open-Reasoner-Zero, the first open source implementation of large-scale reasoning-oriented RL training on the base model focusing on scalability, simplicity and accessibility. Through extensive experiments, we demonstrate that a minimalist approach, vanilla PPO with GAE ($λ=1$, $γ=1$) and straightforward rule-based rewards, without any KL regularization, is sufficient to scale up both benchmark performance and response length, replicating the scaling phenomenon observed in DeepSeek-R1-Zero. Using the same base model, Qwen2.5-32B base, as DeepSeek-R1-Zero-Qwen-32B, our implementation achieves superior performance across AIME2024, MATH500, and GPQA Diamond, while demonstrating remarkable efficiency, requiring only 1/10 of the training steps compared to the DeepSeek-R1-Zero pipeline. Moreover, our analysis not only covers training dynamics and ablation for critical design choices, but also quantitatively shows how the learned critic in Reasoner-Zero training effectively identifies and devalues repetitive response patterns, yielding more robust advantage estimations and enhancing training stability. Embracing the principles of open-source, we release our source code, training data, and various model weights, fostering reproducibility and encouraging further exploration of the properties of related models.
title Open-Reasoner-Zero: An Open Source Approach to Scaling Up Reinforcement Learning on the Base Model
topic Machine Learning
Computation and Language
url https://arxiv.org/abs/2503.24290