Optimal Multi-Distribution Learning

Fuente: arXiv
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Hauptverfasser: Zhang, Zihan, Zhan, Wenhao, Chen, Yuxin, Du, Simon S., Lee, Jason D.
Format: Preprint
Veröffentlicht: 2023
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author Zhang, Zihan
Zhan, Wenhao
Chen, Yuxin
Du, Simon S.
Lee, Jason D.
author_facet Zhang, Zihan
Zhan, Wenhao
Chen, Yuxin
Du, Simon S.
Lee, Jason D.
contents Multi-distribution learning (MDL), which seeks to learn a shared model that minimizes the worst-case risk across $k$ distinct data distributions, has emerged as a unified framework in response to the evolving demand for robustness, fairness, multi-group collaboration, etc. Achieving data-efficient MDL necessitates adaptive sampling, also called on-demand sampling, throughout the learning process. However, there exist substantial gaps between the state-of-the-art upper and lower bounds on the optimal sample complexity. Focusing on a hypothesis class of Vapnik-Chervonenkis (VC) dimension d, we propose a novel algorithm that yields an varepsilon-optimal randomized hypothesis with a sample complexity on the order of (d+k)/varepsilon^2 (modulo some logarithmic factor), matching the best-known lower bound. Our algorithmic ideas and theory are further extended to accommodate Rademacher classes. The proposed algorithms are oracle-efficient, which access the hypothesis class solely through an empirical risk minimization oracle. Additionally, we establish the necessity of randomization, revealing a large sample size barrier when only deterministic hypotheses are permitted. These findings resolve three open problems presented in COLT 2023 (i.e., citet[Problems 1, 3 and 4]{awasthi2023sample}).
format Preprint
id arxiv_https___arxiv_org_abs_2312_05134
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Optimal Multi-Distribution Learning
Zhang, Zihan
Zhan, Wenhao
Chen, Yuxin
Du, Simon S.
Lee, Jason D.
Machine Learning
Multi-distribution learning (MDL), which seeks to learn a shared model that minimizes the worst-case risk across $k$ distinct data distributions, has emerged as a unified framework in response to the evolving demand for robustness, fairness, multi-group collaboration, etc. Achieving data-efficient MDL necessitates adaptive sampling, also called on-demand sampling, throughout the learning process. However, there exist substantial gaps between the state-of-the-art upper and lower bounds on the optimal sample complexity. Focusing on a hypothesis class of Vapnik-Chervonenkis (VC) dimension d, we propose a novel algorithm that yields an varepsilon-optimal randomized hypothesis with a sample complexity on the order of (d+k)/varepsilon^2 (modulo some logarithmic factor), matching the best-known lower bound. Our algorithmic ideas and theory are further extended to accommodate Rademacher classes. The proposed algorithms are oracle-efficient, which access the hypothesis class solely through an empirical risk minimization oracle. Additionally, we establish the necessity of randomization, revealing a large sample size barrier when only deterministic hypotheses are permitted. These findings resolve three open problems presented in COLT 2023 (i.e., citet[Problems 1, 3 and 4]{awasthi2023sample}).
title Optimal Multi-Distribution Learning
topic Machine Learning
url https://arxiv.org/abs/2312.05134