解决大模型多奖励冲突问题,让不同目标训练更高效。
GD$^2$PO: Mitigating Multi-Reward Conflicts via Group-Dynamic reward-Decoupled Policy Optimization

- 通过动态过滤冲突样本,避免奖励信号互相抵消。
- 在工具调用和偏好对齐任务中显著提升训练效率。
- 适合需要平衡多个目标的复杂大模型微调场景。
随着大模型发展,后训练强化学习越来越依赖多维度奖励来培养综合能力。这要求新算法能同时优化多种可能相互冲突的目标。现有方法如组奖励解耦策略(GDPO)将总分拆分为独立奖励组,在每组内分别计算强化学习损失。然而,该策略仍面临多奖励冲突:单次采样可能在某些奖励维度上有正优势,但在其他维度上为负,导致信号在聚合时相互抵消,进一步降低强化学习训练效率。受动态采样策略(DAPO)启发,该文提出组动态奖励解耦策略(GD²PO),采用冲突感知过滤机制,屏蔽存在严重奖励分歧的采样结果。通过阻止冲突信号互相抵消,该掩码策略有效保留并增强有效强化学习优势,显著提升学习效率。此外,引入查询级重加权机制,根据每个查询的奖励一致性动态调整更新强度。在工具调用、人类偏好对齐等多种多奖励场景下的实验表明,GD²PO持续且显著优于现有基线方法。代码已开源:https://github.com/Qwen-Applications/GD2PO。
原文摘要 · Abstract (English)
As LLMs advance, post-training reinforcement learning (RL) increasingly relies on multi-dimensional rewards to cultivate comprehensive capabilities. This shift demands new algorithms capable of optimizing diverse and potentially competing objectives simultaneously. To address this, existing methods such as Group reward-Decoupled Policy Optimization (GDPO) decompose the overall score into independent reward groups, then compute the RL loss separately within each group. However, this strategy still encounters multi-reward conflicts: a single rollout can yield positive advantages on certain reward dimensions but negative ones on others, causing opposing signals to cancel each other out during aggregation, further hindering RL training efficiency. Inspired by Dynamic sAmpling Policy Optimization (DAPO), which improves RL training efficiency by filtering out ineffective rollouts with near-zero advantages, we propose Group-Dynamic reward-Decoupled Policy Optimization (GD$^2$PO). Specifically, GD$^2$PO employs a conflict-aware filtering mechanism to mask out rollouts suffering from severe reward-wise disagreement. By preventing conflicting signals from canceling each other out, this masking strategy preserves and enhances the magnitude of effective RL advantages, thereby significantly accelerating learning efficiency. Furthermore, we introduce query-level reweighting to dynamically adjust the update intensity of each query based on its overall reward consensus. Experiments on various multi-reward scenarios, including tool calling and human preference alignment, demonstrate that GD$^2$PO consistently and significantly outperforms existing baselines. The code is available at https://github.com/Qwen-Applications/GD2PO.
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