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Main Authors: Wilson, Andrew Gordon, Hu, Zhiting, Salakhutdinov, Ruslan, Xing, Eric P.
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2509.21228
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author Wilson, Andrew Gordon
Hu, Zhiting
Salakhutdinov, Ruslan
Xing, Eric P.
author_facet Wilson, Andrew Gordon
Hu, Zhiting
Salakhutdinov, Ruslan
Xing, Eric P.
contents This note responds to "Promises and Pitfalls of Deep Kernel Learning" (Ober et al., 2021). The marginal likelihood of a Gaussian process can be compartmentalized into a data fit term and a complexity penalty. Ober et al. (2021) shows that if a kernel can be multiplied by a signal variance coefficient, then reparametrizing and substituting in the maximized value of this parameter sets a reparametrized data fit term to a fixed value. They use this finding to argue that the complexity penalty, a log determinant of the kernel matrix, then dominates in determining the other values of kernel hyperparameters, which can lead to data overcorrelation. By contrast, we show that the reparametrization in fact introduces another data-fit term which influences all other kernel hyperparameters. Thus, a balance between data fit and complexity still plays a significant role in determining kernel hyperparameters.
format Preprint
id arxiv_https___arxiv_org_abs_2509_21228
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Response to Promises and Pitfalls of Deep Kernel Learning
Wilson, Andrew Gordon
Hu, Zhiting
Salakhutdinov, Ruslan
Xing, Eric P.
Machine Learning
This note responds to "Promises and Pitfalls of Deep Kernel Learning" (Ober et al., 2021). The marginal likelihood of a Gaussian process can be compartmentalized into a data fit term and a complexity penalty. Ober et al. (2021) shows that if a kernel can be multiplied by a signal variance coefficient, then reparametrizing and substituting in the maximized value of this parameter sets a reparametrized data fit term to a fixed value. They use this finding to argue that the complexity penalty, a log determinant of the kernel matrix, then dominates in determining the other values of kernel hyperparameters, which can lead to data overcorrelation. By contrast, we show that the reparametrization in fact introduces another data-fit term which influences all other kernel hyperparameters. Thus, a balance between data fit and complexity still plays a significant role in determining kernel hyperparameters.
title Response to Promises and Pitfalls of Deep Kernel Learning
topic Machine Learning
url https://arxiv.org/abs/2509.21228