Communications on Applied Mathematics and Computation ›› 2026, Vol. 8 ›› Issue (3): 1207-1225.doi: 10.1007/s42967-025-00493-3

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A Fast Averaged L1 Finite Difference Method for Time Fractional Mobile/Immobile Diffusion Equation with Weakly Singular Solution

Haili Qiao1, Aijie Cheng2   

  1. 1. School of Mathematical Sciences, Liaocheng University, Liaocheng, 252059, Shandong, China;
    2. School of Mathematics, Shandong University, Jinan, 250100, Shandong, China
  • 收稿日期:2024-10-27 修回日期:2025-01-29 出版日期:2026-06-20 发布日期:2026-05-29
  • 通讯作者: Aijie Cheng, Email: aijie@sdu.edu.cn E-mail:aijie@sdu.edu.cn
  • 作者简介:Haili Qiao, Email: QHLmath@163.com
  • 基金资助:
    This work was supported in part by the Shandong Provincial Natural Science Foundation of China under Grant No. ZR2022QA038 and the Doctoral Research Foundation of Liaocheng University of China under Grant No.318052155.

A Fast Averaged L1 Finite Difference Method for Time Fractional Mobile/Immobile Diffusion Equation with Weakly Singular Solution

Haili Qiao1, Aijie Cheng2   

  1. 1. School of Mathematical Sciences, Liaocheng University, Liaocheng, 252059, Shandong, China;
    2. School of Mathematics, Shandong University, Jinan, 250100, Shandong, China
  • Received:2024-10-27 Revised:2025-01-29 Online:2026-06-20 Published:2026-05-29
  • Contact: Aijie Cheng, Email: aijie@sdu.edu.cn E-mail:aijie@sdu.edu.cn
  • Supported by:
    The research is supported partly by the National Natural Science Foundation of China (Grant No. 12071392).

摘要: In this paper, the time fractional mobile/immobile diffusion equation with the weak singular solution at the initial time is studied. The averaged L1 finite difference scheme is established for the equation. The stability of the numerical scheme is analyzed by the Fourier analysis method. The convergence order of the scheme is method. The convergence order of the scheme is $O\left(\tau^2|\ln \tau|+h^2\right)$, where $\tau$ and $h$ are the sizes of the time and space steps, respectively. In addition, due to the historical dependence of the time fractional derivative, we establish a fast method based on the exponential-sum-approximation, effectively reducing computation and storage. Furthermore, we provide an error estimate of the fast algorithm. Finally, a numerical experiment verifies the effectiveness of the algorithm.

关键词: Time fractional mobile/immobile diffusion equation, Averaged L1 scheme, Exponential-sum-approximation, Weak singularity

Abstract: In this paper, the time fractional mobile/immobile diffusion equation with the weak singular solution at the initial time is studied. The averaged L1 finite difference scheme is established for the equation. The stability of the numerical scheme is analyzed by the Fourier analysis method. The convergence order of the scheme is method. The convergence order of the scheme is $O\left(\tau^2|\ln \tau|+h^2\right)$, where $\tau$ and $h$ are the sizes of the time and space steps, respectively. In addition, due to the historical dependence of the time fractional derivative, we establish a fast method based on the exponential-sum-approximation, effectively reducing computation and storage. Furthermore, we provide an error estimate of the fast algorithm. Finally, a numerical experiment verifies the effectiveness of the algorithm.

Key words: Time fractional mobile/immobile diffusion equation, Averaged L1 scheme, Exponential-sum-approximation, Weak singularity

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