降低组合半贝叶斯优化的查询次数,提升大规模场景下的效率。
Oracle-Efficient Combinatorial Semi-Bandits
- 设计高效框架,将每轮查询次数从线性降至对数级
- 在最坏情况下实现√T量级的误差累积,仅需log log T次查询
- 适用于高维、非线性奖励的复杂决策场景
我们研究组合半贝叶斯问题,即智能体选择一组基础臂并获得个体反馈。尽管该问题推广了经典多臂赌博机且应用广泛,但其可扩展性受限于组合优化的高昂成本——每轮都需要进行预言机查询。为此,我们提出了预言机高效的框架,显著减少查询次数的同时保持紧致的后悔上界。在最坏情况线性奖励设置下,算法仅需O(log log T)次预言机查询即可达到˜O(√T)的后悔率。我们还提出了利用噪声结构的自适应协方差算法,进一步优化性能,并将方法拓展至一般(非线性)奖励情形。总体而言,我们的方法将预言机使用量从线性降为(双重)对数级,具备强理论保障。
原文摘要 · Abstract (English)
We study the combinatorial semi-bandit problem where an agent selects a subset of base arms and receives individual feedback. While this generalizes the classical multi-armed bandit and has broad applicability, its scalability is limited by the high cost of combinatorial optimization, requiring oracle queries at every round. To tackle this, we propose oracle-efficient frameworks that significantly reduce oracle calls while maintaining tight regret guarantees. For the worst-case linear reward setting, our algorithms achieve $\tilde{O}(\sqrt{T})$ regret using only $O(\log\log T)$ oracle queries. We also propose covariance-adaptive algorithms that leverage noise structure for improved regret, and extend our approach to general (non-linear) rewards. Overall, our methods reduce oracle usage from linear to (doubly) logarithmic in time, with strong theoretical guarantees.
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