Warm Start Marginal Likelihood Optimisation for Iterative Gaussian Processes

Fuente: arXiv
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Autori principali: Lin, Jihao Andreas, Padhy, Shreyas, Mlodozeniec, Bruno, Hernández-Lobato, José Miguel
Natura: Preprint
Pubblicazione: 2024
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author Lin, Jihao Andreas
Padhy, Shreyas
Mlodozeniec, Bruno
Hernández-Lobato, José Miguel
author_facet Lin, Jihao Andreas
Padhy, Shreyas
Mlodozeniec, Bruno
Hernández-Lobato, José Miguel
contents Gaussian processes are a versatile probabilistic machine learning model whose effectiveness often depends on good hyperparameters, which are typically learned by maximising the marginal likelihood. In this work, we consider iterative methods, which use iterative linear system solvers to approximate marginal likelihood gradients up to a specified numerical precision, allowing a trade-off between compute time and accuracy of a solution. We introduce a three-level hierarchy of marginal likelihood optimisation for iterative Gaussian processes, and identify that the computational costs are dominated by solving sequential batches of large positive-definite systems of linear equations. We then propose to amortise computations by reusing solutions of linear system solvers as initialisations in the next step, providing a $\textit{warm start}$. Finally, we discuss the necessary conditions and quantify the consequences of warm starts and demonstrate their effectiveness on regression tasks, where warm starts achieve the same results as the conventional procedure while providing up to a $16 \times$ average speed-up among datasets.
format Preprint
id arxiv_https___arxiv_org_abs_2405_18328
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Warm Start Marginal Likelihood Optimisation for Iterative Gaussian Processes
Lin, Jihao Andreas
Padhy, Shreyas
Mlodozeniec, Bruno
Hernández-Lobato, José Miguel
Machine Learning
Gaussian processes are a versatile probabilistic machine learning model whose effectiveness often depends on good hyperparameters, which are typically learned by maximising the marginal likelihood. In this work, we consider iterative methods, which use iterative linear system solvers to approximate marginal likelihood gradients up to a specified numerical precision, allowing a trade-off between compute time and accuracy of a solution. We introduce a three-level hierarchy of marginal likelihood optimisation for iterative Gaussian processes, and identify that the computational costs are dominated by solving sequential batches of large positive-definite systems of linear equations. We then propose to amortise computations by reusing solutions of linear system solvers as initialisations in the next step, providing a $\textit{warm start}$. Finally, we discuss the necessary conditions and quantify the consequences of warm starts and demonstrate their effectiveness on regression tasks, where warm starts achieve the same results as the conventional procedure while providing up to a $16 \times$ average speed-up among datasets.
title Warm Start Marginal Likelihood Optimisation for Iterative Gaussian Processes
topic Machine Learning
url https://arxiv.org/abs/2405.18328