SURGE: Approximation and Training Free Particle Filter for Diffusion Surrogate

Fuente: arXiv
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Main Authors: Wei, Lifu, Ren, Yinuo, Shi, Naichen, Lu, Yiping
Format: Preprint
Published: 2026
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author Wei, Lifu
Ren, Yinuo
Shi, Naichen
Lu, Yiping
author_facet Wei, Lifu
Ren, Yinuo
Shi, Naichen
Lu, Yiping
contents Data assimilation (DA) addresses the problem of sequentially estimating the state of a dynamical system from noisy and incomplete observations. In this work, we employ a diffusion model as a world model to simulate and predict the system's dynamics. Recently, score-based diffusion models have learned global diffusion priors that effectively model (stochastic) dynamics, revealing strong potential for data assimilation. In this paper, we investigate how information from noisy observations can be incorporated to enable continuous correction and refinement of the predicted system state when using a diffusion prior. Motivated by particle filtering methods, we represent the posterior distribution using a set of particles. After receiving noisy observations, the diffusion model is guided using the observation likelihood to steer the generation process toward observation-consistent states. Nevertheless, such guidance does not guarantee sampling from the true posterior. We therefore employ a Sequential Monte Carlo approach over the diffusion trajectory, viewed as a path measure, to reweight and resample particles, thereby correcting the generation process and ensuring convergence toward the desired posterior distribution. This leads to an unbiased particle filtering method that rigorously fuses observational data with diffusion model simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2605_18745
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle SURGE: Approximation and Training Free Particle Filter for Diffusion Surrogate
Wei, Lifu
Ren, Yinuo
Shi, Naichen
Lu, Yiping
Machine Learning
Numerical Analysis
Probability
Mathematical Finance
Computation
Data assimilation (DA) addresses the problem of sequentially estimating the state of a dynamical system from noisy and incomplete observations. In this work, we employ a diffusion model as a world model to simulate and predict the system's dynamics. Recently, score-based diffusion models have learned global diffusion priors that effectively model (stochastic) dynamics, revealing strong potential for data assimilation. In this paper, we investigate how information from noisy observations can be incorporated to enable continuous correction and refinement of the predicted system state when using a diffusion prior. Motivated by particle filtering methods, we represent the posterior distribution using a set of particles. After receiving noisy observations, the diffusion model is guided using the observation likelihood to steer the generation process toward observation-consistent states. Nevertheless, such guidance does not guarantee sampling from the true posterior. We therefore employ a Sequential Monte Carlo approach over the diffusion trajectory, viewed as a path measure, to reweight and resample particles, thereby correcting the generation process and ensuring convergence toward the desired posterior distribution. This leads to an unbiased particle filtering method that rigorously fuses observational data with diffusion model simulations.
title SURGE: Approximation and Training Free Particle Filter for Diffusion Surrogate
topic Machine Learning
Numerical Analysis
Probability
Mathematical Finance
Computation
url https://arxiv.org/abs/2605.18745