Abstract
Based on Cauchy’s integral formula and conformal maps, this paper presents a new method for constructing barycentric rational interpolation formulae for complex functions, which may contain singularities such as poles, branch cuts, or essential singularities. The resulting interpolations are pole-free, exponentially convergent, and numerically stable, requiring only \({\mathcal {O}}(N)\) operations. Inspired by the logarithm equilibrium potential, we introduce a Möbius transform to concentrate nodes to the vicinity of singularity to get a spectacular improvement on approximation quality. A thorough convergence analysis is provided, alongside numerous numerical examples that illustrate the theoretical results and demonstrate the accuracy and efficiency of the methodology. Meanwhile, the paper also discusses some applications of the method including the numerical solutions of boundary value problems and the zero locations of holomorphic functions.
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Acknowledgements
The authors would like to thank Guidong Liu, Yanghao Wu and Desong Kong for their useful suggestions. The authors are grateful to the anonymous referees for their valuable comments and suggestions for improvement of this paper.
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This work was supported by the National Natural Science Foundation of China (No. 12271528). The first author is supported by the Fundamental Research Funds for the Central Universities of Central South University (No.2020zzts030).
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Yang, S., Xiang, S. Fast barycentric rational interpolations for complex functions with some singularities. Calcolo 60, 55 (2023). https://doi.org/10.1007/s10092-023-00550-4
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DOI: https://doi.org/10.1007/s10092-023-00550-4
Keywords
- Barycentric rational interpolation
- Conformal map
- Cauchy’s integral formula
- Exponential convergence
- Holomorphic function
- Singularity