Minimax Optimal Goodness-of-Fit Testing with Kernel Stein Discrepancy

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Autori principali: Hagrass, Omar, Sriperumbudur, Bharath, Balasubramanian, Krishnakumar
Natura: Preprint
Pubblicazione: 2024
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author Hagrass, Omar
Sriperumbudur, Bharath
Balasubramanian, Krishnakumar
author_facet Hagrass, Omar
Sriperumbudur, Bharath
Balasubramanian, Krishnakumar
contents We explore the minimax optimality of goodness-of-fit tests on general domains using the kernelized Stein discrepancy (KSD). The KSD framework offers a flexible approach for goodness-of-fit testing, avoiding strong distributional assumptions, accommodating diverse data structures beyond Euclidean spaces, and relying only on partial knowledge of the reference distribution, while maintaining computational efficiency. Although KSD is a powerful framework for goodness-of-fit testing, only the consistency of the corresponding tests has been established so far, and their statistical optimality remains largely unexplored. In this paper, we develop a general framework and an operator-theoretic representation of the KSD, encompassing many existing KSD tests in the literature, which vary depending on the domain. Building on this representation, we propose a modified discrepancy by applying the concept of spectral regularization to the KSD framework. We establish the minimax optimality of the proposed regularized test for a wide range of the smoothness parameter $θ$ under a specific alternative space, defined over general domains, using the $χ^2$-divergence as the separation metric. In contrast, we demonstrate that the unregularized KSD test fails to achieve the minimax separation rate for the considered alternative space. Additionally, we introduce an adaptive test capable of achieving minimax optimality up to a logarithmic factor by adapting to unknown parameters. Through numerical experiments, we illustrate the superior performance of our proposed tests across various domains compared to their unregularized counterparts.
format Preprint
id arxiv_https___arxiv_org_abs_2404_08278
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Minimax Optimal Goodness-of-Fit Testing with Kernel Stein Discrepancy
Hagrass, Omar
Sriperumbudur, Bharath
Balasubramanian, Krishnakumar
Statistics Theory
Machine Learning
Primary: 62G10, Secondary: 65J20, 65J22, 46E22, 47A52
We explore the minimax optimality of goodness-of-fit tests on general domains using the kernelized Stein discrepancy (KSD). The KSD framework offers a flexible approach for goodness-of-fit testing, avoiding strong distributional assumptions, accommodating diverse data structures beyond Euclidean spaces, and relying only on partial knowledge of the reference distribution, while maintaining computational efficiency. Although KSD is a powerful framework for goodness-of-fit testing, only the consistency of the corresponding tests has been established so far, and their statistical optimality remains largely unexplored. In this paper, we develop a general framework and an operator-theoretic representation of the KSD, encompassing many existing KSD tests in the literature, which vary depending on the domain. Building on this representation, we propose a modified discrepancy by applying the concept of spectral regularization to the KSD framework. We establish the minimax optimality of the proposed regularized test for a wide range of the smoothness parameter $θ$ under a specific alternative space, defined over general domains, using the $χ^2$-divergence as the separation metric. In contrast, we demonstrate that the unregularized KSD test fails to achieve the minimax separation rate for the considered alternative space. Additionally, we introduce an adaptive test capable of achieving minimax optimality up to a logarithmic factor by adapting to unknown parameters. Through numerical experiments, we illustrate the superior performance of our proposed tests across various domains compared to their unregularized counterparts.
title Minimax Optimal Goodness-of-Fit Testing with Kernel Stein Discrepancy
topic Statistics Theory
Machine Learning
Primary: 62G10, Secondary: 65J20, 65J22, 46E22, 47A52
url https://arxiv.org/abs/2404.08278