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arXiv 2402.15432math.STcs.LGstat.MLstat.TH
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次指数混合模型中的通用下界与最优速率:实现极小极大聚类误差

Universal Lower Bounds and Optimal Rates: Achieving Minimax Clustering Error in Sub-Exponential Mixture Models

École Polytechnique Fédérale de Lausanne (EPFL)(洛桑联邦理工学院);Bilkent University(比尔肯特大学)

Maximilien Dreveton, Alperen Gözeten, Matthias Grossglauser, Patrick Thiran

AI总结:

本文针对次指数混合模型,提出基于Chernoff散度的通用聚类误差下界,证明迭代算法可达最优速率,并验证Bregman硬聚类在指数族混合模型中的速率最优性。

摘要:

聚类是无监督机器学习中的一个关键挑战,通常通过混合模型的视角进行研究。在高斯和次高斯混合模型中,恢复聚类标签的最优误差率涉及特定的信噪比。简单的迭代算法,如Lloyd算法,能够达到这一最优误差率。在本文中,我们首先为任意混合模型的聚类误差率建立了一个通用下界,该下界通过Chernoff散度表达,这是一种比信噪比更通用的模型信息度量。然后,我们证明在具有次指数尾部的混合模型中,迭代算法能够达到这一下界,特别强调了具有拉普拉斯分布误差的位置-尺度混合模型。此外,对于更适合用泊松或负二项混合建模的数据集,我们研究了其分布属于指数族的混合模型。在此类混合模型中,我们证明了Bregman硬聚类(一种采用Bregman散度的Lloyd算法变体)是速率最优的。

英文摘要:

Clustering is a pivotal challenge in unsupervised machine learning and is often investigated through the lens of mixture models. The optimal error rate for recovering cluster labels in Gaussian and sub-Gaussian mixture models involves ad hoc signal-to-noise ratios. Simple iterative algorithms, such as Lloyd's algorithm, attain this optimal error rate. In this paper, we first establish a universal lower bound for the error rate in clustering any mixture model, expressed through a Chernoff divergence, a more versatile measure of model information than signal-to-noise ratios. We then demonstrate that iterative algorithms attain this lower bound in mixture models with sub-exponential tails, notably emphasizing location-scale mixtures featuring Laplace-distributed errors. Additionally, for datasets better modelled by Poisson or Negative Binomial mixtures, we study mixture models whose distributions belong to an exponential family. In such mixtures, we establish that Bregman hard clustering, a variant of Lloyd's algorithm employing a Bregman divergence, is rate optimal.

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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