{"title":"Variable-time-step weighted IMEX FEMs for nonlinear evolution equations","authors":"Meng Li , Dan Wang , Junjun Wang , Xiaolong Zhao","doi":"10.1016/j.apnum.2025.01.005","DOIUrl":null,"url":null,"abstract":"<div><div>In this paper, the variable-time-step weighted implicit-explicit (IMEX) finite element methods (FEMs) are developed for some types of nonlinear real- or complex-valued evolution equations. Extensive research is conducted on the discrete orthogonal convolution (DOC) kernels and the discrete complementary convolution (DCC) kernels of the variable-time-step weighted IMEX scheme, elucidating their crucial properties in both real- and complex-valued scenarios. We prove that the scheme exhibits optimal convergence without any restrictions on the time-space step ratio. At last, several numerical examples are provided to demonstrate our theoretical results. With the weighted parameter <span><math><mi>θ</mi><mo>=</mo><mn>1</mn></math></span>, the scheme in this work can degenerate into a special case: variable-time-step two-step backward differentiation formula (BDF2) scheme, and the convergence analysis in this special case was introduced in Liao et al. (2020) <span><span>[15]</span></span> and Liao et al. (2021) <span><span>[29]</span></span>.</div></div>","PeriodicalId":8199,"journal":{"name":"Applied Numerical Mathematics","volume":"211 ","pages":"Pages 123-143"},"PeriodicalIF":2.4000,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Numerical Mathematics","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0168927425000054","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2025/1/15 0:00:00","PubModel":"Epub","JCR":"Q1","JCRName":"MATHEMATICS, APPLIED","Score":null,"Total":0}
引用次数: 0
Abstract
In this paper, the variable-time-step weighted implicit-explicit (IMEX) finite element methods (FEMs) are developed for some types of nonlinear real- or complex-valued evolution equations. Extensive research is conducted on the discrete orthogonal convolution (DOC) kernels and the discrete complementary convolution (DCC) kernels of the variable-time-step weighted IMEX scheme, elucidating their crucial properties in both real- and complex-valued scenarios. We prove that the scheme exhibits optimal convergence without any restrictions on the time-space step ratio. At last, several numerical examples are provided to demonstrate our theoretical results. With the weighted parameter , the scheme in this work can degenerate into a special case: variable-time-step two-step backward differentiation formula (BDF2) scheme, and the convergence analysis in this special case was introduced in Liao et al. (2020) [15] and Liao et al. (2021) [29].
本文针对一类非线性实值或复值演化方程,建立了变时间步长加权隐显有限元方法。对变时间步长加权IMEX格式的离散正交卷积(DOC)核和离散互补卷积(DCC)核进行了广泛的研究,阐明了它们在实值和复值情况下的关键性质。证明了该方案在不受时空步长比限制的情况下具有最优收敛性。最后,通过数值算例对理论结果进行了验证。在加权参数θ=1的情况下,本文方案可以退化为一种特殊情况:变时间步两步后向微分公式(BDF2)方案,并在Liao et al.(2020)[15]和Liao et al.(2021)[29]中介绍了这种特殊情况下的收敛性分析。
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