Order-Optimal Sample Complexity of Rectified Flows

Fuente: arXiv
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Auteurs principaux: Sahoo, Hari Krishna, Gaur, Mudit, Aggarwal, Vaneet
Format: Preprint
Publié: 2026
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author Sahoo, Hari Krishna
Gaur, Mudit
Aggarwal, Vaneet
author_facet Sahoo, Hari Krishna
Gaur, Mudit
Aggarwal, Vaneet
contents Recently, flow-based generative models have shown superior efficiency compared to diffusion models. In this paper, we study rectified flow models, which constrain transport trajectories to be linear from the base distribution to the data distribution. This structural restriction greatly accelerates sampling, often enabling high-quality generation with a single Euler step. Under standard assumptions on the neural network classes used to parameterize the velocity field and data distribution, we prove that rectified flows achieve sample complexity $\tilde{O}(\varepsilon^{-2})$. This improves on the best known $O(\varepsilon^{-4})$ bounds for flow matching model and matches the optimal rate for mean estimation. Our analysis exploits the particular structure of rectified flows: because the model is trained with a squared loss along linear paths, the associated hypothesis class admits a sharply controlled localized Rademacher complexity. This yields the improved, order-optimal sample complexity and provides a theoretical explanation for the strong empirical performance of rectified flow models.
format Preprint
id arxiv_https___arxiv_org_abs_2601_20250
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Order-Optimal Sample Complexity of Rectified Flows
Sahoo, Hari Krishna
Gaur, Mudit
Aggarwal, Vaneet
Machine Learning
Artificial Intelligence
Information Theory
Recently, flow-based generative models have shown superior efficiency compared to diffusion models. In this paper, we study rectified flow models, which constrain transport trajectories to be linear from the base distribution to the data distribution. This structural restriction greatly accelerates sampling, often enabling high-quality generation with a single Euler step. Under standard assumptions on the neural network classes used to parameterize the velocity field and data distribution, we prove that rectified flows achieve sample complexity $\tilde{O}(\varepsilon^{-2})$. This improves on the best known $O(\varepsilon^{-4})$ bounds for flow matching model and matches the optimal rate for mean estimation. Our analysis exploits the particular structure of rectified flows: because the model is trained with a squared loss along linear paths, the associated hypothesis class admits a sharply controlled localized Rademacher complexity. This yields the improved, order-optimal sample complexity and provides a theoretical explanation for the strong empirical performance of rectified flow models.
title Order-Optimal Sample Complexity of Rectified Flows
topic Machine Learning
Artificial Intelligence
Information Theory
url https://arxiv.org/abs/2601.20250