Compress Then Test: Powerful Kernel Testing in Near-linear Time

Fuente: arXiv
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Autores principales: Domingo-Enrich, Carles, Dwivedi, Raaz, Mackey, Lester
Formato: Preprint
Publicado: 2023
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author Domingo-Enrich, Carles
Dwivedi, Raaz
Mackey, Lester
author_facet Domingo-Enrich, Carles
Dwivedi, Raaz
Mackey, Lester
contents Kernel two-sample testing provides a powerful framework for distinguishing any pair of distributions based on $n$ sample points. However, existing kernel tests either run in $n^2$ time or sacrifice undue power to improve runtime. To address these shortcomings, we introduce Compress Then Test (CTT), a new framework for high-powered kernel testing based on sample compression. CTT cheaply approximates an expensive test by compressing each $n$ point sample into a small but provably high-fidelity coreset. For standard kernels and subexponential distributions, CTT inherits the statistical behavior of a quadratic-time test -- recovering the same optimal detection boundary -- while running in near-linear time. We couple these advances with cheaper permutation testing, justified by new power analyses; improved time-vs.-quality guarantees for low-rank approximation; and a fast aggregation procedure for identifying especially discriminating kernels. In our experiments with real and simulated data, CTT and its extensions provide 20--200x speed-ups over state-of-the-art approximate MMD tests with no loss of power.
format Preprint
id arxiv_https___arxiv_org_abs_2301_05974
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Compress Then Test: Powerful Kernel Testing in Near-linear Time
Domingo-Enrich, Carles
Dwivedi, Raaz
Mackey, Lester
Machine Learning
Statistics Theory
Methodology
Kernel two-sample testing provides a powerful framework for distinguishing any pair of distributions based on $n$ sample points. However, existing kernel tests either run in $n^2$ time or sacrifice undue power to improve runtime. To address these shortcomings, we introduce Compress Then Test (CTT), a new framework for high-powered kernel testing based on sample compression. CTT cheaply approximates an expensive test by compressing each $n$ point sample into a small but provably high-fidelity coreset. For standard kernels and subexponential distributions, CTT inherits the statistical behavior of a quadratic-time test -- recovering the same optimal detection boundary -- while running in near-linear time. We couple these advances with cheaper permutation testing, justified by new power analyses; improved time-vs.-quality guarantees for low-rank approximation; and a fast aggregation procedure for identifying especially discriminating kernels. In our experiments with real and simulated data, CTT and its extensions provide 20--200x speed-ups over state-of-the-art approximate MMD tests with no loss of power.
title Compress Then Test: Powerful Kernel Testing in Near-linear Time
topic Machine Learning
Statistics Theory
Methodology
url https://arxiv.org/abs/2301.05974