A lattice algorithm with multiple shifts for function approximation in Korobov spaces

Fuente: arXiv
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Main Authors: Cai, Mou, Dick, Josef, Goda, Takashi
Format: Preprint
Published: 2025
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author Cai, Mou
Dick, Josef
Goda, Takashi
author_facet Cai, Mou
Dick, Josef
Goda, Takashi
contents In this paper, we propose a novel algorithm for function approximation in a weighted Korobov space based on shifted rank-1 lattice rules. To mitigate aliasing errors inherent in lattice-based Fourier coefficient estimation, we employ $\mathcal{O}((\log N)^{d} )$ good shifts and recover each Fourier coefficient via a least-squares procedure. We show that the resulting approximation achieves the optimal convergence rate for the $L_{\infty}$-approximation error in the worst-case setting, namely $\mathcal{O}(N^{-α+1/2+\varepsilon})$ for arbitrarily small $\varepsilon>0$. Moreover, by incorporating random shifts, the algorithm attains the optimal rate for the $L_{2}$-approximation error in the randomized setting, which is $\mathcal{O}(N^{-α+\varepsilon})$. Numerical experiments are presented to support the theoretical results.
format Preprint
id arxiv_https___arxiv_org_abs_2511_09071
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A lattice algorithm with multiple shifts for function approximation in Korobov spaces
Cai, Mou
Dick, Josef
Goda, Takashi
Numerical Analysis
41A25, 41A63, 65D15, 65D30, 65Y20
In this paper, we propose a novel algorithm for function approximation in a weighted Korobov space based on shifted rank-1 lattice rules. To mitigate aliasing errors inherent in lattice-based Fourier coefficient estimation, we employ $\mathcal{O}((\log N)^{d} )$ good shifts and recover each Fourier coefficient via a least-squares procedure. We show that the resulting approximation achieves the optimal convergence rate for the $L_{\infty}$-approximation error in the worst-case setting, namely $\mathcal{O}(N^{-α+1/2+\varepsilon})$ for arbitrarily small $\varepsilon>0$. Moreover, by incorporating random shifts, the algorithm attains the optimal rate for the $L_{2}$-approximation error in the randomized setting, which is $\mathcal{O}(N^{-α+\varepsilon})$. Numerical experiments are presented to support the theoretical results.
title A lattice algorithm with multiple shifts for function approximation in Korobov spaces
topic Numerical Analysis
41A25, 41A63, 65D15, 65D30, 65Y20
url https://arxiv.org/abs/2511.09071