Title
Consistency Of Empirical Bayes And Kernel Flow For Hierarchical Parameter Estimation
Abstract
Gaussian process regression has proven very powerful in statistics, machine learning and inverse problems. A crucial aspect of the success of this methodology, in a wide range of applications to complex and real-world problems, is hierarchical modeling and learning of hyperparameters. The purpose of this paper is to study two paradigms of learning hierarchical parameters: one is from the probabilistic Bayesian perspective, in particular, the empirical Bayes approach that has been largely used in Bayesian statistics; the other is from the deterministic and approximation theoretic view, and in particular the kernel flow algorithm that was proposed recently in the machine learning literature. Analysis of their consistency in the large data limit, as well as explicit identification of their implicit bias in parameter learning, are established in this paper for a Matern-like model on the torus. A particular technical challenge we overcome is the learning of the regularity parameter in the Matern-like field, for which consistency results have been very scarce in the spatial statistics literature. Moreover, we conduct extensive numerical experiments beyond the Matern-like model, comparing the two algorithms further. These experiments demonstrate learning of other hierarchical parameters, such as amplitude and lengthscale; they also illustrate the setting of model misspecification in which the kernel flow approach could show superior performance to the more traditional empirical Bayes approach.
Year
DOI
Venue
2021
10.1090/mcom/3649
MATHEMATICS OF COMPUTATION
DocType
Volume
Issue
Journal
90
332
ISSN
Citations 
PageRank 
0025-5718
0
0.34
References 
Authors
0
3
Name
Order
Citations
PageRank
Yifan Chen15819.82
Houman Owhadi224721.02
Andrew M. Stuart332485.31