arXiv:2605.12058cs.LGcs.AI2026-05

通过动态调节聚合方式提升大模型策略优化的稳定性和效果。

Holder Policy Optimisation

论文配图:Holder Policy Optimisation
图 1 · 摘自论文原文
  • 用霍尔德均值统一建模概率聚合,可调参数控制梯度集中与方差平衡。
  • 在数学推理和ALFWorld任务上分别达到54.9%和93.8%的顶尖性能。
  • 动态调度参数使训练更稳定,适合追求高效策略优化的研究者。

组相对策略优化(GRPO)通过估计一组采样轨迹的优劣来增强大语言模型。然而,将轨迹级优势映射到策略更新需对每条序列内的词元级概率进行聚合。依赖固定聚合机制会严重限制算法的适应性。实验发现:某些固定聚合常导致训练崩溃,而另一些则表现不佳。为此,我们提出 extbf{HölderPO},一种基于霍尔德均值的通用策略优化框架,统一了词元级概率的聚合方式。通过显式调节参数 $p$,该框架可连续控制梯度集中度与方差上限之间的权衡。理论上证明:较大 $p$ 能集中梯度以放大稀疏学习信号,较小 $p$ 则严格约束梯度方差。由于静态配置无法兼顾此权衡,我们引入动态退火算法,随训练进程逐步调度 $p$。大量实验表明,本方法在稳定性与收敛性上优于现有基线。具体而言,在多个数学基准上平均准确率达 $54.9\$,较标准GRPO提升 $7.2\\$相对收益,并在ALFWorld上取得 $93.8\\$的成功率。

原文摘要 · Abstract (English)

Group Relative Policy Optimisation (GRPO) enhances large language models by estimating advantages across a group of sampled trajectories. However, mapping these trajectory-level advantages to policy updates requires aggregating token-level probabilities within each sequence. Relying on a fixed aggregation mechanism for this step fundamentally limits the algorithm's adaptability. Empirically, we observe a critical trade-off: certain fixed aggregations frequently suffer from training collapse, while others fail to yield satisfactory performance. To resolve this, we propose \textbf{HölderPO}, a generalised policy optimisation framework unifying token-level probability aggregation via the Hölder mean. By explicitly modulating the parameter $p$, our framework provides continuous control over the trade-off between gradient concentration and variance bounds. Theoretically, we prove that a larger $p$ concentrates the gradient to amplify sparse learning signals, whereas a smaller $p$ strictly bounds gradient variance. Because no static configuration can universally resolve this concentration-stability trade-off, we instantiate the framework with a dynamic annealing algorithm that progressively schedules $p$ across the training lifecycle. Extensive evaluations demonstrate superior stability and convergence over existing baselines. Specifically, our approach achieves a state-of-the-art average accuracy of $54.9\%$ across multiple mathematical benchmarks, yielding a substantial $7.2\%$ relative gain over standard GRPO and secures an exceptional $93.8\%$ success rate on ALFWorld.

策略优化大模型强化学习动态调度

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