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We present a geometric formulation of the Multiple Kernel Learning (MKL) problem. To do so, we reinterpret the problem of learning kernel weights as searching for a kernel that maximizes the minimum (kernel) distance between two convex…

Machine Learning · Computer Science 2014-03-18 John Moeller , Parasaran Raman , Avishek Saha , Suresh Venkatasubramanian

In this paper, we propose a domain decomposition dynamical low-rank method to solve high-dimensional radiative transfer problems and similar kinetic equations. The algorithm uses a separate low-rank approximation on each spatial subdomain,…

Numerical Analysis · Mathematics 2026-02-17 Stefan Brunner , Lukas Einkemmer , Terry Haut

The fast multipole method (FMM) has had great success in reducing the computational complexity of solving the boundary integral form of the Helmholtz equation. We present a formulation of the Helmholtz FMM that uses Fourier basis functions…

Numerical Analysis · Mathematics 2014-03-20 Cris Cecka , Eric Darve

In this paper, we investigate wave scattering by a pair of closely spaced inclusions embedded in a homogeneous medium, characterized by a high contrast physical parameters. The system is modeled by the two-dimensional Helmholtz equation. We…

Analysis of PDEs · Mathematics 2025-11-21 Hongjie Dong , Hongjie Li , Longjuan Xu

In this paper, we present a numerical algorithm for the accurate and efficient computation of the convolution of the frequency domain layered media Green's function with a given density function. Instead of compressing the convolution…

Numerical Analysis · Mathematics 2020-06-16 Min Hyung Cho , Jingfang Huang

The Helmholtz equation in one dimension, which describes the propagation of electromagnetic waves in effectively one-dimensional systems, is equivalent to the time-independent Schr\"odinger equation. The fact that the potential term…

Classical Physics · Physics 2021-09-15 Farhang Loran , Ali Mostafazadeh

Numerical simulations of seismic wave propagation in heterogeneous 3D media are central to investigating subsurface structures and understanding earthquake processes, yet are computationally expensive for large problems. This is…

Geophysics · Physics 2025-03-27 Caifeng Zou , Kamyar Azizzadenesheli , Zachary E. Ross , Robert W. Clayton

We introduce a novel diffusion-based spectral algorithm to tackle regression analysis on high-dimensional data, particularly data embedded within lower-dimensional manifolds. Traditional spectral algorithms often fall short in such…

Machine Learning · Statistics 2024-10-21 Weichun Xia , Jiaxin Jiang , Lei Shi

This paper studies quantum three-body scattering within a modern microlocal framework. We show that the three-body Helmholtz operator at positive energy gives rise to a pair of Fredholm maps between suitable anisotropic Hilbert spaces.…

Analysis of PDEs · Mathematics 2026-04-30 Yilin Ma

We present a fast iterative solver for scattering problems in 2D, where a penetrable object with compact support is considered. By representing the scattered field as a volume potential in terms of the Green's function, we arrive at the…

Numerical Analysis · Mathematics 2023-03-28 Vaishnavi Gujjula , Sivaram Ambikasaran

A covariant scattering kernel is a core component in any self-consistent general relativistic radiative transfer formulation in scattering media. An explicit closed-form expression for a covariant Compton scattering kernel with a good…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Ziri Younsi , Kinwah Wu

A collection of codes (in MATLAB & Fortran 77), and examples, for solving reaction-diffusion equations in one and two space dimensions is presented. In areas of the mathematical community spectral methods are used to remove the stiffness…

Numerical Analysis · Mathematics 2018-10-18 Richard V. Craster , Roberto Sassi

This paper generalizes recent advances on quadratic manifold (QM) dimensionality reduction by developing kernel methods-based nonlinear-augmentation dimensionality reduction. QMs, and more generally feature map-based nonlinear corrections,…

Computational Engineering, Finance, and Science · Computer Science 2025-09-03 Alejandro N. Diaz , Jacob T. Needels , Irina K. Tezaur , Patrick J. Blonigan

A method for detecting and approximating fault lines or surfaces, respectively, or decision curves in two and three dimensions with guaranteed accuracy is presented. Reformulated as a classification problem, our method starts from a set of…

Numerical Analysis · Mathematics 2023-02-17 Matthias Grajewski , Andreas Kleefeld

In this paper, we will introduce a new heterogeneous fast multipole method (H-FMM) for 2-D Helmholtz equation in layered media. To illustrate the main algorithm ideas, we focus on the case of two and three layers in this work. The key…

Numerical Analysis · Mathematics 2018-07-04 Min Hyung Cho , Jingfang Huang , Dangxing Chen , Wei Cai

This paper introduces a novel time-frequency distribution, referred to as the Two-Dimensional Non-Separable Quadratic Phase Wigner Distribution (2D-NSQPWD), formulated within the framework of the Two-Dimensional Non-Separable Quadratic…

Signal Processing · Electrical Eng. & Systems 2025-09-25 Mukul Chauhan , Waseem Z. Lone , Amit K. Verma

We investigate high-order Convolution Quadratures methods for the solution of the wave equation in unbounded domains in two dimensions that rely on Nystr\"om discretizations for the solution of the ensemble of associated Laplace domain…

Numerical Analysis · Mathematics 2023-10-24 Peter P. Petropoulos , Catalin Turc , Erli Wind-andersen

Aims. The main goal of this paper is to present an accurate and efficient numerical strategy for solving the radiative transfer problem for polarised radiation in strong resonance lines forming out of local thermodynamic equilibrium, taking…

Solving the wave equation is one of the most (if not the most) fundamental problems we face as we try to illuminate the Earth using recorded seismic data. The Helmholtz equation provides wavefield solutions that are dimensionally reduced,…

Geophysics · Physics 2021-06-04 Tariq Alkhalifah , Chao Song , Umair bin Waheed , Qi Hao

In this paper a mathematical model is given for the scattering of an incident wave from a surface covered with microscopic small Helmholtz resonators, which are cavities with small openings. More precisely, the surface is built upon a…

Numerical Analysis · Mathematics 2020-02-03 Habib Ammari , Kthim Imeri