Low-Dimensional Adaptation of Rectified Flow: A Diffusion and Stochastic Localization Perspective

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Hauptverfasser: Roy, Saptarshi, Rinaldo, Alessandro, Sarkar, Purnamrita
Format: Preprint
Veröffentlicht: 2026
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author Roy, Saptarshi
Rinaldo, Alessandro
Sarkar, Purnamrita
author_facet Roy, Saptarshi
Rinaldo, Alessandro
Sarkar, Purnamrita
contents In recent years, Rectified flow (RF) has gained considerable popularity largely due to its generation efficiency and state-of-the-art performance. In this paper, we investigate the degree to which RF automatically adapts to the intrinsic low dimensionality of the support of the target distribution to accelerate sampling. We show that, using a carefully designed choice of the time-discretization scheme and with sufficiently accurate drift estimates, the RF sampler enjoys an iteration complexity of order $O(k/\varepsilon)$ (up to log factors), where $\varepsilon$ is the precision in total variation distance and $k$ is the intrinsic dimension of the target distribution. In addition, we show that the denoising diffusion probabilistic model (DDPM) procedure is equivalent to a stochastic version of RF by establishing a novel connection between these processes and stochastic localization. Building on this connection, we further design a stochastic RF sampler that also adapts to the low-dimensionality of the target distribution under milder requirements on the accuracy of the drift estimates, and also with a specific time schedule. We illustrate with simulations on the synthetic data and text-to-image data experiments the improved performance of the proposed samplers implementing the newly designed time-discretization schedules.
format Preprint
id arxiv_https___arxiv_org_abs_2601_15500
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Low-Dimensional Adaptation of Rectified Flow: A Diffusion and Stochastic Localization Perspective
Roy, Saptarshi
Rinaldo, Alessandro
Sarkar, Purnamrita
Machine Learning
Artificial Intelligence
Statistics Theory
In recent years, Rectified flow (RF) has gained considerable popularity largely due to its generation efficiency and state-of-the-art performance. In this paper, we investigate the degree to which RF automatically adapts to the intrinsic low dimensionality of the support of the target distribution to accelerate sampling. We show that, using a carefully designed choice of the time-discretization scheme and with sufficiently accurate drift estimates, the RF sampler enjoys an iteration complexity of order $O(k/\varepsilon)$ (up to log factors), where $\varepsilon$ is the precision in total variation distance and $k$ is the intrinsic dimension of the target distribution. In addition, we show that the denoising diffusion probabilistic model (DDPM) procedure is equivalent to a stochastic version of RF by establishing a novel connection between these processes and stochastic localization. Building on this connection, we further design a stochastic RF sampler that also adapts to the low-dimensionality of the target distribution under milder requirements on the accuracy of the drift estimates, and also with a specific time schedule. We illustrate with simulations on the synthetic data and text-to-image data experiments the improved performance of the proposed samplers implementing the newly designed time-discretization schedules.
title Low-Dimensional Adaptation of Rectified Flow: A Diffusion and Stochastic Localization Perspective
topic Machine Learning
Artificial Intelligence
Statistics Theory
url https://arxiv.org/abs/2601.15500