Journal of Shanghai University(Natural Science Edition) ›› 2026, Vol. 32 ›› Issue (1): 166-186.doi: 10.12066/j.issn.1007-2861.2658

• Mathematics • Previous Articles    

The non-uniform L1-2 formula for Caputo derivatives and its applications

WANG Junling1, LI Dongxia2   

  1. 1. College of Sciences, Shanghai University, Shanghai 200444, China;
    2. College of Sciences, Inner Mongolia University of Technology, Hohhot 010051, Inner Mongolia, China
  • Received:2024-11-11 Published:2026-03-16

Abstract: This paper constructs a numerical approximation formula for the Caputo derivative of order α∈(0,1). Considering the weak regularity of the Caputo derivative at the initial time, linear interpolation is employed over the first subinterval of the non-uniform mesh, while quadratic interpolation is utilized for each subsequent subinterval, leading to the derivation of a non-uniform L1-2 formula. It is proven that the truncation error can achieve (3-fi)-order accuracy, and the corresponding coefficient properties are discussed. The derived formula is applied to the numerical solution of the time-fractional diffusion equation, and numerical experiments have verified the effectiveness and correctness of the formula.

Key words: L1-2 formula, graded mesh, weak regularity, fractional diffusion equation

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