Complexity of High-Dimensional Identity Testing with Coordinate Conditional Sampling

Fuente: arXiv
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Auteurs principaux: Blanca, Antonio, Chen, Zongchen, Štefankovič, Daniel, Vigoda, Eric
Format: Preprint
Publié: 2022
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author Blanca, Antonio
Chen, Zongchen
Štefankovič, Daniel
Vigoda, Eric
author_facet Blanca, Antonio
Chen, Zongchen
Štefankovič, Daniel
Vigoda, Eric
contents We study the identity testing problem for high-dimensional distributions. Given as input an explicit distribution $μ$, an $\varepsilon>0$, and access to sampling oracle(s) for a hidden distribution $π$, the goal in identity testing is to distinguish whether the two distributions $μ$ and $π$ are identical or are at least $\varepsilon$-far apart. When there is only access to full samples from the hidden distribution $π$, it is known that exponentially many samples (in the dimension) may be needed for identity testing, and hence previous works have studied identity testing with additional access to various "conditional" sampling oracles. We consider a significantly weaker conditional sampling oracle, which we call the $\mathsf{Coordinate\ Oracle}$, and provide a computational and statistical characterization of the identity testing problem in this new model. We prove that if an analytic property known as approximate tensorization of entropy holds for an $n$-dimensional visible distribution $μ$, then there is an efficient identity testing algorithm for any hidden distribution $π$ using $\tilde{O}(n/\varepsilon)$ queries to the $\mathsf{Coordinate\ Oracle}$. Approximate tensorization of entropy is a pertinent condition as recent works have established it for a large class of high-dimensional distributions. We also prove a computational phase transition: for a well-studied class of $n$-dimensional distributions, specifically sparse antiferromagnetic Ising models over $\{+1,-1\}^n$, we show that in the regime where approximate tensorization of entropy fails, there is no efficient identity testing algorithm unless $\mathsf{RP}=\mathsf{NP}$. We complement our results with a matching $Ω(n/\varepsilon)$ statistical lower bound for the sample complexity of identity testing in the $\mathsf{Coordinate\ Oracle}$ model.
format Preprint
id arxiv_https___arxiv_org_abs_2207_09102
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Complexity of High-Dimensional Identity Testing with Coordinate Conditional Sampling
Blanca, Antonio
Chen, Zongchen
Štefankovič, Daniel
Vigoda, Eric
Data Structures and Algorithms
Machine Learning
Probability
Statistics Theory
We study the identity testing problem for high-dimensional distributions. Given as input an explicit distribution $μ$, an $\varepsilon>0$, and access to sampling oracle(s) for a hidden distribution $π$, the goal in identity testing is to distinguish whether the two distributions $μ$ and $π$ are identical or are at least $\varepsilon$-far apart. When there is only access to full samples from the hidden distribution $π$, it is known that exponentially many samples (in the dimension) may be needed for identity testing, and hence previous works have studied identity testing with additional access to various "conditional" sampling oracles. We consider a significantly weaker conditional sampling oracle, which we call the $\mathsf{Coordinate\ Oracle}$, and provide a computational and statistical characterization of the identity testing problem in this new model. We prove that if an analytic property known as approximate tensorization of entropy holds for an $n$-dimensional visible distribution $μ$, then there is an efficient identity testing algorithm for any hidden distribution $π$ using $\tilde{O}(n/\varepsilon)$ queries to the $\mathsf{Coordinate\ Oracle}$. Approximate tensorization of entropy is a pertinent condition as recent works have established it for a large class of high-dimensional distributions. We also prove a computational phase transition: for a well-studied class of $n$-dimensional distributions, specifically sparse antiferromagnetic Ising models over $\{+1,-1\}^n$, we show that in the regime where approximate tensorization of entropy fails, there is no efficient identity testing algorithm unless $\mathsf{RP}=\mathsf{NP}$. We complement our results with a matching $Ω(n/\varepsilon)$ statistical lower bound for the sample complexity of identity testing in the $\mathsf{Coordinate\ Oracle}$ model.
title Complexity of High-Dimensional Identity Testing with Coordinate Conditional Sampling
topic Data Structures and Algorithms
Machine Learning
Probability
Statistics Theory
url https://arxiv.org/abs/2207.09102