Numerical Method for Space-Time Fractional Diffusion: A Stochastic Approach

Fuente: arXiv
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Autores principales: Cui, Tengteng, Sheng, Chengtao, Su, Bihao, Zhou, Zhi
Formato: Preprint
Publicado: 2025
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author Cui, Tengteng
Sheng, Chengtao
Su, Bihao
Zhou, Zhi
author_facet Cui, Tengteng
Sheng, Chengtao
Su, Bihao
Zhou, Zhi
contents In this paper, we develop and analyze a stochastic algorithm for solving space-time fractional diffusion models, which are widely used to describe anomalous diffusion dynamics. These models pose substantial numerical challenges due to the memory effect of the time-fractional derivative and the nonlocal nature of the spatial fractional Laplacian and the, leading to significant computational costs and storage demands, particularly in high-dimensional settings. To overcome these difficulties, we propose a Monte Carlo method based on the Feynman--Kac formula for space-time fractional models. The novel algorithm combines the simulation of the monotone path of a stable subordinator in time with the ``walk-on-spheres'' method that efficiently simulates the stable Levy jumping process in space. We rigorously derive error bounds for the proposed scheme, explicitly expressed in terms of the number of simulation paths and the time step size. Numerical experiments confirm the theoretical error bounds and demonstrate the computational efficiency of the method, particularly in domains with complex geometries or high-dimensional spaces. Furthermore, both theoretical and numerical results emphasize the robustness of the proposed approach across a range of fractional orders, particularly for small fractional values, a capability often absent in traditional numerical methods.
format Preprint
id arxiv_https___arxiv_org_abs_2508_20361
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Numerical Method for Space-Time Fractional Diffusion: A Stochastic Approach
Cui, Tengteng
Sheng, Chengtao
Su, Bihao
Zhou, Zhi
Numerical Analysis
In this paper, we develop and analyze a stochastic algorithm for solving space-time fractional diffusion models, which are widely used to describe anomalous diffusion dynamics. These models pose substantial numerical challenges due to the memory effect of the time-fractional derivative and the nonlocal nature of the spatial fractional Laplacian and the, leading to significant computational costs and storage demands, particularly in high-dimensional settings. To overcome these difficulties, we propose a Monte Carlo method based on the Feynman--Kac formula for space-time fractional models. The novel algorithm combines the simulation of the monotone path of a stable subordinator in time with the ``walk-on-spheres'' method that efficiently simulates the stable Levy jumping process in space. We rigorously derive error bounds for the proposed scheme, explicitly expressed in terms of the number of simulation paths and the time step size. Numerical experiments confirm the theoretical error bounds and demonstrate the computational efficiency of the method, particularly in domains with complex geometries or high-dimensional spaces. Furthermore, both theoretical and numerical results emphasize the robustness of the proposed approach across a range of fractional orders, particularly for small fractional values, a capability often absent in traditional numerical methods.
title Numerical Method for Space-Time Fractional Diffusion: A Stochastic Approach
topic Numerical Analysis
url https://arxiv.org/abs/2508.20361