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arXiv 2410.02403stat.ME
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高维协方差矩阵惩罚似然估计的统一方法

A unified approach to penalized likelihood estimation of covariance matrices in high dimensions

Luca Cibinel, Alberto Roverato, Veronica Vinciotti

AI总结:

本文提出一种统一框架,将稀疏模式最大似然、l_1惩罚对数似然和岭正则化三种协方差矩阵估计方法结合,通过双惩罚项约束优化实现高效稳定的高维稀疏估计,并提供R包gicf。

摘要:

我们考虑高维环境下高斯数据协方差矩阵的估计问题。现有方法包括在预先指定的稀疏模式下的最大似然估计、l_1惩罚对数似然优化以及样本协方差的岭正则化。我们证明,通过考虑一个涉及两个适当定义的惩罚项的目标函数的约束优化,这三种方法可以以统一的方式处理。这一统一程序利用了每种方法的各自优势,同时在三者的结合中带来了新颖性。我们为正则化目标函数的优化提供了一种高效算法,并描述了两个惩罚项之间的关系,从而突出了三种方法联合应用的重要性。一项模拟研究展示了该程序返回的协方差矩阵稀疏估计在低维和高维环境下均稳定且准确,并且其计算在部分已知稀疏模式下比现有方法更高效。文中还给出了一个基于声呐数据的示例,用于识别从某种材料反射的信号之间的协方差结构。该方法已在公开可用的R包gicf中实现。

英文摘要:

We consider the problem of estimation of a covariance matrix for Gaussian data in a high dimensional setting. Existing approaches include maximum likelihood estimation under a pre-specified sparsity pattern, l_1-penalized loglikelihood optimization and ridge regularization of the sample covariance. We show that these three approaches can be addressed in an unified way, by considering the constrained optimization of an objective function that involves two suitably defined penalty terms. This unified procedure exploits the advantages of each individual approach, while bringing novelty in the combination of the three. We provide an efficient algorithm for the optimization of the regularized objective function and describe the relationship between the two penalty terms, thereby highlighting the importance of the joint application of the three methods. A simulation study shows how the sparse estimates of covariance matrices returned by the procedure are stable and accurate, both in low and high dimensional settings, and how their calculation is more efficient than existing approaches under a partially known sparsity pattern. An illustration on sonar data shows is presented for the identification of the covariance structure among signals bounced off a certain material. The method is implemented in the publicly available R package gicf.

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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