NGRPO: Negative-enhanced Group Relative Policy Optimization

Fuente: arXiv
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Autores principales: Nan, Gongrui, Chen, Siye, Huang, Jing, Lu, Mengyu, Wang, Dexun, Xie, Chunmei, Xiong, Weiqi, Zeng, Xianzhou, Zhou, Qixuan, Li, Yadong, Xu, Xingzhong
Formato: Preprint
Publicado: 2025
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author Nan, Gongrui
Chen, Siye
Huang, Jing
Lu, Mengyu
Wang, Dexun
Xie, Chunmei
Xiong, Weiqi
Zeng, Xianzhou
Zhou, Qixuan
Li, Yadong
Xu, Xingzhong
author_facet Nan, Gongrui
Chen, Siye
Huang, Jing
Lu, Mengyu
Wang, Dexun
Xie, Chunmei
Xiong, Weiqi
Zeng, Xianzhou
Zhou, Qixuan
Li, Yadong
Xu, Xingzhong
contents RLVR has enhanced the reasoning capabilities of Large Language Models (LLMs) across various tasks. However, GRPO, a representative RLVR algorithm, suffers from a critical limitation: when all responses within a group are either entirely correct or entirely incorrect, the model fails to learn from these homogeneous responses. This is particularly problematic for homogeneously incorrect groups, where GRPO's advantage function yields a value of zero, leading to null gradients and the loss of valuable learning signals. To overcome this issue, we propose NGRPO (Negative-enhanced Group Relative Policy Optimization), an algorithm designed to convert homogeneous errors into robust learning signals. First, NGRPO introduces Advantage Calibration. This mechanism hypothesizes the existence of a virtual maximum-reward sample during advantage calculation, thereby altering the mean and variance of rewards within a group and ensuring that the advantages for homogeneously incorrect samples are no longer zero. Second, NGRPO employs Asymmetric Clipping, which relaxes the update magnitude for positive samples while imposing stricter constraints on that of negative samples. This serves to stabilize the exploration pressure introduced by the advantage calibration. Our experiments on Qwen2.5-Math-7B demonstrate that NGRPO significantly outperforms baselines such as PPO, GRPO, DAPO, and PSR-NSR on mathematical benchmarks including MATH500, AMC23, and AIME2025. These results validate NGRPO's ability to learn from homogeneous errors, leading to stable and substantial improvements in mathematical reasoning. Our code is available at https://github.com/nangongrui-ngr/NGRPO.
format Preprint
id arxiv_https___arxiv_org_abs_2509_18851
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle NGRPO: Negative-enhanced Group Relative Policy Optimization
Nan, Gongrui
Chen, Siye
Huang, Jing
Lu, Mengyu
Wang, Dexun
Xie, Chunmei
Xiong, Weiqi
Zeng, Xianzhou
Zhou, Qixuan
Li, Yadong
Xu, Xingzhong
Machine Learning
Artificial Intelligence
RLVR has enhanced the reasoning capabilities of Large Language Models (LLMs) across various tasks. However, GRPO, a representative RLVR algorithm, suffers from a critical limitation: when all responses within a group are either entirely correct or entirely incorrect, the model fails to learn from these homogeneous responses. This is particularly problematic for homogeneously incorrect groups, where GRPO's advantage function yields a value of zero, leading to null gradients and the loss of valuable learning signals. To overcome this issue, we propose NGRPO (Negative-enhanced Group Relative Policy Optimization), an algorithm designed to convert homogeneous errors into robust learning signals. First, NGRPO introduces Advantage Calibration. This mechanism hypothesizes the existence of a virtual maximum-reward sample during advantage calculation, thereby altering the mean and variance of rewards within a group and ensuring that the advantages for homogeneously incorrect samples are no longer zero. Second, NGRPO employs Asymmetric Clipping, which relaxes the update magnitude for positive samples while imposing stricter constraints on that of negative samples. This serves to stabilize the exploration pressure introduced by the advantage calibration. Our experiments on Qwen2.5-Math-7B demonstrate that NGRPO significantly outperforms baselines such as PPO, GRPO, DAPO, and PSR-NSR on mathematical benchmarks including MATH500, AMC23, and AIME2025. These results validate NGRPO's ability to learn from homogeneous errors, leading to stable and substantial improvements in mathematical reasoning. Our code is available at https://github.com/nangongrui-ngr/NGRPO.
title NGRPO: Negative-enhanced Group Relative Policy Optimization
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2509.18851