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arXiv 1602.08448cs.LG
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最佳手臂识别的简单贝叶斯算法

Simple Bayesian Algorithms for Best Arm Identification

Daniel Russo

摘要:

本文考虑了测量工作量的最优自适应分配,以确定有限的选项或设计集合中的最佳选项或设计。实验者依次选择设计来测量并观察其质量的噪声信号,目的是在少量测量后自信地识别最佳设计。本文提出了三个简单而直观的贝叶斯算法自适应分配测量工作,并形式化的意义上说,这些看似天真的规则是最好的可能。一个建议是前两个概率抽样,它计算两个设计的最高后验概率是最佳的,然后随机选择这两个。一种是前两个抽样的变体,它不仅考虑设计是最优的概率,而且考虑其质量超过其他设计的预期量。最后的算法是一个修改版本的汤普森采样,是专为确定最佳的设计。我们证明了这些简单的算法满足尖锐的最优性属性。在设计的真实质量是固定的频率论设置中,人们希望后验确定地识别最优设计,在这个意义上,分配给其他一些设计是最优的事件的后验概率随着测量的收集而收敛到零。我们证明了在所提出的算法下,这种收敛以指数速率发生,并且相应的指数是所有分配中最好的

英文摘要:

This paper considers the optimal adaptive allocation of measurement effort for identifying the best among a finite set of options or designs. An experimenter sequentially chooses designs to measure and observes noisy signals of their quality with the goal of confidently identifying the best design after a small number of measurements. This paper proposes three simple and intuitive Bayesian algorithms for adaptively allocating measurement effort, and formalizes a sense in which these seemingly naive rules are the best possible. One proposal is top-two probability sampling, which computes the two designs with the highest posterior probability of being optimal, and then randomizes to select among these two. One is a variant of top-two sampling which considers not only the probability a design is optimal, but the expected amount by which its quality exceeds that of other designs. The final algorithm is a modified version of Thompson sampling that is tailored for identifying the best design. We prove that these simple algorithms satisfy a sharp optimality property. In a frequentist setting where the true quality of the designs is fixed, one hopes the posterior definitively identifies the optimal design, in the sense that that the posterior probability assigned to the event that some other design is optimal converges to zero as measurements are collected. We show that under the proposed algorithms this convergence occurs at an exponential rate, and the corresponding exponent is the best possible among all allocation

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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