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In this paper, we present a finite element method (FEM) framework enhanced by an operator-adapted wavelet decomposition algorithm designed for the efficient analysis of multiscale electromagnetic problems. Usual adaptive FEM approaches,…

Computational Physics · Physics 2026-02-18 F. Şık , F. L. Teixeira , B. Shanker

Detecting maximal square submatrices of ones in binary matrices is a fundamental problem with applications in computer vision and pattern recognition. While the standard dynamic programming (DP) solution achieves optimal asymptotic…

Data Structures and Algorithms · Computer Science 2025-07-22 Swastik Bhandari

An overlapped continuous model framework, for the Helmholtz wave propagation problem in unbounded regions comprising bounded heterogeneous media, was recently introduced and analyzed by the authors ({\tt J. Comput. Phys., {\bf 403}, 109052,…

Numerical Analysis · Mathematics 2021-06-30 V. Domínguez , M. Ganesh

The structure and function of biological molecules are strongly influenced by the water and dissolved ions that surround them. This aqueous solution (solvent) exerts significant electrostatic forces in response to the biomolecule's…

Numerical Analysis · Mathematics 2015-12-29 Matthew G. Knepley , Jaydeep P. Bardhan

The quality of numerically simulated spectra using real-time evolution methods for strongly correlated systems is affected by both the length of simulation time and the system size, limiting resolution in both frequency and momentum. In…

Strongly Correlated Electrons · Physics 2025-09-22 Ta Tang , Chunjing Jia , Brian Moritz , Thomas P. Devereaux

We develop a sparse multiscale operator-adapted wavelet decomposition-based finite element method (FEM) on unstructured polygonal mesh hierarchies obtained via a coarsening procedure. Our approach decouples different resolution levels,…

Computational Physics · Physics 2025-12-19 Furkan Şık , F. L. Teixeira , B. Shanker

The real-space density-functional perturbation theory (DFPT) for the computations of the response properties with respect to the atomic displacement and homogeneous electric field perturbation has been recently developed and implemented…

Computational Physics · Physics 2020-10-28 Honghui Shang , Wanzhen Liang , Yunquan Zhang , Jinlong Yang

A novel boundary element method (BEM) removes the classical dependence on explicit fundamental solutions and extends quasi-optimal BEM discretisations to strongly elliptic operators with variable coefficients. The approach constructs a…

Numerical Analysis · Mathematics 2026-05-22 Benedikt Gräßle , Stefan A. Sauter

This paper proposes a new Helmholtz decomposition based windowed Green function (HD-WGF) method for solving the time-harmonic elastic scattering problems on a half-space with Dirichlet boundary conditions in both 2D and 3D. The Helmholtz…

Computational Physics · Physics 2023-12-27 Tao Yin , Lu Zhang , Weiying Zheng , Xiaopeng Zhu

In this paper, we propose a fast multipole method (FMM) for 3-D linearized Poisson-Boltzmann (PB) equation in layered media. The main framework of the algorithm is analogous to the FMM for Helmholtz and Laplace equation in layered media…

Numerical Analysis · Mathematics 2020-12-02 Bo Wang , Wen Zhong Zhang , Wei Cai

We present a fast and memory-efficient algorithm for transient, space-time-domain, and elastodynamic boundary-integral analysis. Associated data-sparse approximations and operations are named fast domain partitioning hierarchical matrices…

Computational Physics · Physics 2026-03-20 Dye SK Sato , Ryosuke Ando

The Hilbert-Huang transform (HHT) consists of empirical mode decomposition (EMD), which is a template-free method that represents the combination of different intrinsic modes on a time-frequency map (i.e., the Hilbert spectrum). The…

Instrumentation and Methods for Astrophysics · Physics 2025-06-05 Lupin Chun-Che Lin , Chin-Ping Hu , Chien-Chang Yen , Kuo-Chuan Pan , C. Y. Hui , Kwan-Lok Li , Yu-Chiung Lin , Yi-Sheng Huang , Albert K. H. Kong

Multiple scale homogenization problems are reduced to single scale problems in higher dimension. It is shown that sparse tensor product Finite Element Methods (FEM) allow the numerical solution in complexity independent of the dimension and…

Numerical Analysis · Mathematics 2025-10-20 Christoph Schwab

We consider GMRES applied to discretisations of the high-frequency Helmholtz equation with strong trapping; recall that in this situation the problem is exponentially ill-conditioned through an increasing sequence of frequencies. Under…

Numerical Analysis · Mathematics 2021-11-15 Pierre Marchand , Jeffrey Galkowski , Alastair Spence , Euan A. Spence

Hidden Markov Models (HMMs) can be accurately approximated using co-occurrence frequencies of pairs and triples of observations by using a fast spectral method in contrast to the usual slow methods like EM or Gibbs sampling. We provide a…

Machine Learning · Statistics 2012-03-29 Dean P. Foster , Jordan Rodu , Lyle H. Ungar

Simulation of 3D low-frequency electromagnetic fields propagating in the Earth is computationally expensive. We present a fictitious wave domain high-order finite-difference time-domain (FDTD) modelling method on nonuniform grids to compute…

Numerical Analysis · Mathematics 2023-02-13 Pengliang Yang , Rune Mittet

A nonlinear Helmholtz equation (NLH) with high wave number and Sommerfeld radiation condition is approximated by the perfectly matched layer (PML) technique and then discretized by the linear finite element method (FEM).…

Numerical Analysis · Mathematics 2022-07-12 Run Jiang , Yonglin Li , Haijun Wu , Jun Zou

Many-body calculations at the two-particle level require a compact representation of two-particle Green's functions. In this paper, we introduce a sparse sampling scheme in the Matsubara frequency domain as well as a tensor network…

Strongly Correlated Electrons · Physics 2020-01-29 Hiroshi Shinaoka , Dominique Geffroy , Markus Wallerberger , Junya Otsuki , Kazuyoshi Yoshimi , Emanuel Gull , Jan Kuneš

The use of boundary integral equations in modeling boundary value problems-such as elastic, acoustic, or electromagnetic ones-is well established in the literature and widespread in practical applications. These equations are typically…

Computational Engineering, Finance, and Science · Computer Science 2025-05-28 Viviana Giunzioni , Adrien Merlini , Francesco P. Andriulli

We present a new discretization method for homogeneous convection-diffusion-reaction boundary value problems in 3D that is a non-standard finite element method with PDE-harmonic shape functions on polyhedral elements. The element stiffness…

Numerical Analysis · Mathematics 2017-08-29 Clemens Hofreither , Ulrich Langer , Steffen Weißer