论文标题

通过自避免步道从重尾噪声中估算一号尖峰

Estimating Rank-One Spikes from Heavy-Tailed Noise via Self-Avoiding Walks

论文作者

Ding, Jingqiu, Hopkins, Samuel B., Steurer, David

论文摘要

我们研究了相对于一般噪声分布的对称尖峰矩阵模型。考虑到随机噪声矩阵的等级-1变形,其条目以零均值和单位方差为零分布,目标是估计秩-1部分。对于高斯噪声的情况,给定基质的最高特征向量是已知的广泛估计量,可以实现最佳的统计保证,例如,从著名的BBP相变的意义上讲。但是,对于重尾噪声,该估计器可能会完全失败。在这项工作中,我们展示了一个估计器,该估计器可用于重尾噪声,直至BBP阈值,即使对于高斯噪声也是最佳的。我们对我们的估计器进行了非反应分析,该分析仅依赖于随着矩阵的大小的增长,每个条目的方差保持恒定:较高的矩可能会任意快速增长甚至不存在。以前,只有知道噪声的高阶力矩的恒定与矩阵的大小无关,才知道如何实现这些保证。可以通过颜色编码技术来计算自我避免步行,可以在多项式时间内评估我们的估计器。此外,我们将估计量扩展到尖峰张量模型并建立类似的结果。

We study symmetric spiked matrix models with respect to a general class of noise distributions. Given a rank-1 deformation of a random noise matrix, whose entries are independently distributed with zero mean and unit variance, the goal is to estimate the rank-1 part. For the case of Gaussian noise, the top eigenvector of the given matrix is a widely-studied estimator known to achieve optimal statistical guarantees, e.g., in the sense of the celebrated BBP phase transition. However, this estimator can fail completely for heavy-tailed noise. In this work, we exhibit an estimator that works for heavy-tailed noise up to the BBP threshold that is optimal even for Gaussian noise. We give a non-asymptotic analysis of our estimator which relies only on the variance of each entry remaining constant as the size of the matrix grows: higher moments may grow arbitrarily fast or even fail to exist. Previously, it was only known how to achieve these guarantees if higher-order moments of the noises are bounded by a constant independent of the size of the matrix. Our estimator can be evaluated in polynomial time by counting self-avoiding walks via a color -coding technique. Moreover, we extend our estimator to spiked tensor models and establish analogous results.

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