DVAO introduces dynamic variance-adaptive weighting for multi-reward GRPO in LLMs, addressing magnitude explosion and objective isolation. It bounds advantages while enabling cross-objective regularization, achieving superior accuracy-compliance trade-offs across tasks and scales.
论文原始摘要
Reinforcement Learning has become a standard paradigm for aligning Large Language Models with human intent and task requirements. While Group Relative Policy Optimization offers an efficient, value-model-free alternative to Proximal Policy Optimization, adapting it to real-world multi-reward settings remains challenging. Standard scalarization practices, such as Reward Combination and Advantage Combination, suffer from significant drawbacks: Reward Combination frequently generates advantages with excessively large squared magnitudes that lead to training instability, while Advantage Combination relies on static hyperparameters and ignores cross-objective correlations. To address these limitations, we propose Dynamic Variance-adaptive Advantage Optimization (DVAO), which dynamically adjusts combination weights based on the empirical reward variance of each objective within a rollout group, effectively up-weighting objectives with a stronger learning signal while suppressing noisy ones. We mathematically prove that DVAO maintains bounded advantage magnitudes for stable training and introduces a self-adaptive cross-objective regularization mechanism. Extensive experiments on mathematical reasoning and tool-use benchmarks using Qwen3 and Qwen2.5 models demonstrate that DVAO significantly outperforms baseline methods, achieving a superior multi-objective Pareto frontier and robust training stability.
Paper Collector 中文速览
方差自适应的多奖励优势优化方法
方法概述
DVAO根据rollout组内各目标的经验奖励方差动态调整组合权重,增强强学习信号目标权重并抑制噪声目标,通过数学证明保持有界优势幅度,引入自适应跨目标正则化机制
核心贡献
提出基于奖励方差动态调整权重的DVAO算法,解决多奖励RL中的训练不稳定性问题
原始来源与核验范围
核验仅覆盖论文正文中的主张、证据片段和参考文献关系。NGJOO 未独立运行作者代码、重做实验或验证真实部署效果;页面中的可复现性分数是文档完整度评估,不是复现实验结果。
核心问题
How can Group Relative Policy Optimization (GRPO) be effectively adapted to multi-reward settings for Large Language Models while avoiding the magnitude explosion of Reward Combination and the objective isolation of Advantage Combination?
核心方法
DVAO replaces fixed combination weights with variance-adaptive weights that up-weight high-variance objectives and down-weight low-variance ones within rollout groups. The authors provide theoretical proofs (Propositions 1-3) establishing bounded advantage magnitudes and cross-objective regularization properties, then evaluate on mathematical reasoning (AIME, MATH500, OlympiadBench, AMC23) and tool-use (BFCL-v4) benchmarks using Qwen models.
方法组件
- The section serves as an introduction to the detailed methodology discussion.
- The authors will analyze shortcomings of existing methods before presenting DVAO.
论点验证
The paper provides a complete specification of DVAO in paragraphs 31-33, including the mathematical formulation for dynamic variance-adaptive weights. The method is fully defined and empirically evaluated across multiple benchmarks.
Proposition 1 (paragraphs 24-26, proof in paragraphs 57-62) mathematically demonstrates magnitude explosion in reward combination. Paragraphs 27-29 analyze objective isolation in advantage combination. DVAO is proposed as the solution.
The weighting scheme is defined in paragraphs 31-33 as fully data-driven (computed from empirical variance). Proposition 2 proves bounded magnitudes, and Proposition 3 proves the cross-objective regularization mechanism.
This is a formal mathematical proposition with a complete proof provided in paragraphs 57-62. The proof derives the expected squared advantage for both methods and establishes the inequality through correlation analysis.
This is a formal mathematical proposition with a complete proof provided in paragraphs 63-73. The proof uses Cauchy-Schwarz inequality to establish the pointwise bound on advantage magnitudes.
This is a formal mathematical proposition with a complete proof provided in paragraphs 74-86. The proof derives the partial derivatives for both methods using standard calculus and the quotient rule.
This is the interpretation of Proposition 3's mathematical result. The sensitivity formula for DVAO (∂A_DVAO/∂r_k = A_DVAO/σ_sum) shows dependency on the combined advantage, while advantage combination's sensitivity depends only on isolated w_k/σ_k.
This claim follows from Proposition 3's sensitivity analysis. The mathematical result shows that DVAO's gradient contribution for objective k is scaled by the overall multi-objective advantage A_DVAO, creating implicit cross-objective regularization.
This is a clearly stated design choice in paragraph 46. The paper evaluates on mathematical reasoning (AIME, MATH500, OlympiadBench, AMC23) and tool-use (BFCL-v4) tasks.
The benchmarks are explicitly listed in paragraph 46: AIME-2024, AIME-2025, MATH500, OlympiadBench, and AMC23 for mathematical reasoning.
The objectives are clearly stated in paragraph 46: accuracy and length constraint for mathematical reasoning; tool-use correctness and format compliance for tool-use.
The model choices are explicitly stated in paragraph 47: Qwen3-4B-Base and Qwen3-8B-Base for math reasoning; Qwen2.5-3B-Instruct and Qwen2.5-7B-Instruct for tool-use.
The training dataset is specified in paragraph 87: DAPO-MATH-17K with 17k prompts, each paired with an integer answer.
The reward functions are explicitly stated in paragraph 87: accuracy reward and length reward for math; accuracy reward and format reward for tool-use.
The length reward definition and target length are explicitly stated in paragraph 87: r_length ∈ {0, 1} checking output within target length of 4,000 tokens.
The optimizer and learning rate are explicitly stated in paragraph 87: AdamW optimizer with constant learning rate of 1 × 10^-6.
The batch size and rollout sampling are explicitly stated in paragraph 87: prompt batch size 128, G = 16 responses per prompt.
The training duration is explicitly stated in paragraph 87: 500 steps to ensure convergence.
... 共 40 个论点
可复现性评估
较低可复现性 (0%)
缺失的复现细节
- Code is not available - no repository link provided
- Data is not available - no dataset links provided
- Appendix D containing 'complete implementation details' is not provided in the paper
- Random seeds are not specified
- DVAO-specific algorithm parameters (variance-adaptive mechanism details) are missing
- Complete AdamW optimizer settings (weight decay, beta parameters) not provided
- Exact reward combination weights - only stated as 'equal' without specific values
- Number of experimental runs and statistical significance measures not reported
- KL penalty coefficient (typically used in GRPO-based methods) not mentioned
- Gradient clipping settings not specified
局限与证据边界
- the accuracy of DVAO's dynamic weighting relies on the empirical variance estimation within a rollout group (G). In our experiments, a standard group size of G = 16 provided highly robust signals. However, for extremely large models where hardware memory constraints force very small group sizes (e.g., G ≤ 4), the intra-group variance estimation might become noisy.
- our empirical evaluations primarily focus on dual-objective scenarios (e.g., accuracy and length/format). Although our theoretical proofs mathematically hold for an arbitrary number of n rewards, the empirical optimization dynamics in hyper-dimensional reward spaces-such as simultaneously aligning helpfulness, harmlessness, style, length, and tool-use-remain an open question for future exploration.
- because DVAO inherently amplifies learning signals based on variance, its efficacy is tied to the quality of the underlying reward functions. If a poorly designed auxiliary reward exhibits artificially high variance due to noise rather than meaningful learning signals, DVAO may inadvertently up-weight it.
- Future work will explore scaling the DVAO framework to environments with a larger number of conflicting reward functions and extending the varianceadaptive mechanism to broader alignment paradigms.
- Future work could explore incorporating historical momentum or cross-batch moving averages to stabilize variance estimation under extreme memory constraints.
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分析时间:2026-05-27T01:27:10+00:00 · 数据来源:Paper Collector