Reliable computation of the eigenvalues of the discrete KdV spectrum

Journal Article (2022)
Author(s)

Peter J. Prins (TU Delft - Team Gabriel Gleizer)

Sander Wahls (TU Delft - Team Gabriel Gleizer)

Research Group
Team Gabriel Gleizer
DOI related publication
https://doi.org/10.1016/j.amc.2022.127361
More Info
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Publication Year
2022
Language
English
Related content
Research Group
Team Gabriel Gleizer
Volume number
433
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Abstract

We propose a numerical algorithm that computes the eigenvalues of the Korteweg–de Vries equation (KdV) from sampled input data with vanishing boundary conditions. It can be used as part of the Non-linear Fourier Transform (NFT) for the KdV equation. The algorithm that we propose makes use of Sturm-Liouville (SL) oscillation theory to guaranty that all eigenvalues are found. In comparison to similar available algorithms, we show that our algorithm is more robust to numerical errors and thus more reliable. Furthermore we show that our root finding algorithm, which is based on the Newton–Raphson (NR) algorithm, typically saves computation time compared to the conventional approaches that rely heavily on bisection.