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Fourier series of smooth, non-periodic functions on $[-1,1]$ are known to exhibit the Gibbs phenomenon, and exhibit overall slow convergence. One way of overcoming these problems is by using a Fourier series on a larger domain, say $[-T,T]$…

Numerical Analysis · Computer Science 2015-09-02 Roel Matthysen , Daan Huybrechs

We analyze the inverse problem to reconstruct the shape of a three dimensional homogeneous dielectric obstacle from the knowledge of noisy far field data. The forward problem is solved by a system of second kind boundary integral equations.…

Numerical Analysis · Mathematics 2020-06-22 Thorsten Hohage , Frédérique Le Louër

An approach is developed for constructing simple analytical formulae accurately approximating solutions to eigenvalue problems of quantum mechanics. This approach is based on self-similar approximation theory. In order to derive…

Condensed Matter · Physics 2009-10-31 V. I. Yukalov , E. P. Yukalova , S. Gluzman

This paper addresses the issue of inversion in cases where (1) the observation system is modeled by a linear transformation and additive noise, (2) the problem is ill-posed and regularization is introduced in a Bayesian framework by an a…

Machine Learning · Statistics 2026-02-12 Jean-François Giovannelli

This paper is to introduce a type of full multigrid method for the nonlinear eigenvalue problem. The main idea is to transform the solution of nonlinear eigenvalue problem into a series of solutions of the corresponding linear boundary…

Numerical Analysis · Mathematics 2016-11-03 Shanghui Jia , Hehu Xie , Manting Xie , Fei Xu

In this paper, we propose Fourier pseudospectral methods to solve the variable-order space fractional wave equation and develop an accelerated matrix-free approach for its effective implementation. In constant-order cases, our methods can…

Numerical Analysis · Mathematics 2024-02-06 Yanzhi Zhang , Xiaofei Zhao , Shiping Zhou

We consider a large class of physical fields $u$ written as double inverse Fourier transforms of some functions $F$ of two complex variables. Such integrals occur very often in practice, especially in diffraction theory. Our aim is to…

Analysis of PDEs · Mathematics 2022-10-18 Raphaël C. Assier , Andrey V. Shanin , Andrey I. Korolkov

Spectral methods, thanks to the high accuracy and the possibility of using fast algorithms, represent an effective way to approximate collisional kinetic equations in kinetic theory. On the other hand, the loss of some local invariants can…

Numerical Analysis · Mathematics 2021-05-28 Lorenzo Pareschi , Thomas Rey

We study Bayesian inference methods for solving linear inverse problems, focusing on hierarchical formulations where the prior or the likelihood function depend on unspecified hyperparameters. In practice, these hyperparameters are often…

Numerical Analysis · Mathematics 2018-08-01 Qingping Zhou , Wenqing Liu , Jinglai Li , Youssef M. Marzouk

The correlation spectrum of fully developed one-dimensional mappings are studied near and at a weakly intermittent situation. Using a suitable infinite matrix representation, the eigenvalue equation of the Frobenius-Perron operator is…

chao-dyn · Physics 2009-10-30 J. Bene , Z. Kaufmann , H. Lustfeld

Laumon introduced the local Fourier transform for $\ell$-adic Galois representations of local fields, of equal characteristic $p$ different from $\ell$, as a powerful tool to study the Fourier-Deligne transform of $\ell$-adic sheaves over…

Algebraic Geometry · Mathematics 2010-12-13 Ahmed Abbes , Takeshi Saito

Iterative multiscale methods for electronic structure calculations offer several advantages for large-scale problems. Here we examine a nonlinear full approximation scheme (FAS) multigrid method for solving fixed potential and…

Materials Science · Physics 2007-05-23 Nimal Wijesekera , Guogang Feng , Thomas L. Beck

We propose a boundary-corrected weak Galerkin mixed finite element method for solving elliptic interface problems in 2D domains with curved interfaces. The method is formulated on body-fitted polygonal meshes, where interface edges are…

Numerical Analysis · Mathematics 2025-02-06 Yongli Hou , Yi Liu , Yanqiu Wang

Denoising diffusion models have driven significant progress in the field of Bayesian inverse problems. Recent approaches use pre-trained diffusion models as priors to solve a wide range of such problems, only leveraging inference-time…

Machine Learning · Statistics 2025-02-06 Yazid Janati , Badr Moufad , Mehdi Abou El Qassime , Alain Durmus , Eric Moulines , Jimmy Olsson

In the mathematical problem of linear hydrodynamic stability for shear flows against Tollmien-Schlichting perturbations, the continuity equation for the perturbation of the velocity is replaced by a Poisson equation for the pressure…

Numerical Analysis · Mathematics 2024-09-17 Cătălin Liviu Bichir , Adelina Georgescu

Graph Transformers (GTs) have shown advantages in numerous graph structure tasks but their self-attention mechanism ignores the generalization bias of graphs, with existing methods mainly compensating for this bias from aspects like…

Machine Learning · Computer Science 2025-04-29 Yonghui Zhai , Yang Zhang , Minghao Shang , Lihua Pang , Yaxin Ren

Based on the interaction between different spatial modes, semiconductor Bragg-reflection waveguides provide a highly functional platform for non-linear optics. Therefore, the control and engineering of the properties of each spatial mode is…

Quantum Physics · Physics 2016-05-03 B. Pressl , T. Günthner , K. Laiho , J. Geßler , M. Kamp , S. Höfling , C. Schneider , G. Weihs

This paper introduces a new accurate model for periodic fractional optimal control problems (PFOCPs) using Riemann-Liouville (RL) and Caputo fractional derivatives (FDs) with sliding fixed memory lengths. The paper also provides a novel…

Optimization and Control · Mathematics 2023-09-26 Kareem T. Elgindy

An improved approach to updating the electric field in simulations of Coulomb gases using the local lattice technique introduced by Maggs and Rossetto, is described and tested. Using the Fast Fourier Transform (FFT) an independent…

Other Condensed Matter · Physics 2009-11-11 A. Duncan , R. D. Sedgewick , R. D. Coalson

Mean-field molecular dynamics based on path integrals is used to approximate canonical quantum observables for particle systems consisting of nuclei and electrons. A computational bottleneck is the sampling from the Gibbs density of the…

Numerical Analysis · Mathematics 2023-11-30 Xin Huang , Petr Plechac , Mattias Sandberg , Anders Szepessy