Results 31 to 40 of about 612 (138)

A Geometric Multigrid Preconditioner for Discontinuous Galerkin Shifted Boundary Method

International Journal for Numerical Methods in Engineering, Volume 127, Issue 21, 15 November 2026.
ABSTRACT I introduce a geometric multigrid preconditioner for the Shifted Boundary Method (SBM) designed to solve PDEs on complex geometries. While the SBM simplifies mesh generation by using a nonconforming background grid, it often results in nonsymmetric linear systems, a complete analysis of which is missing from the literature, especially with ...
Michał Wichrowski
wiley   +1 more source

Extended block Hessenberg method for large-scale Sylvester differential matrix equations [PDF]

Journal of Mahani Mathematical Research
In this paper, we consider large-scale low-rank Sylvester differential matrix equations. We present two iterative methods for the approximate solution of such differential matrix equations. In the first method, exploiting the extended block Krylov method,
Azita Tajaddini
doaj   +1 more source

Subspace Acceleration for Efficient Nonlinear Water Wave Simulation

International Journal for Numerical Methods in Fluids, Volume 98, Issue 10, Page 1165-1180, October 2026.
We introduce an exponentially weighted subspace acceleration technique to reduce GMRES iterations for solving the Poisson equation with time‐dependent coefficients in nonlinear, dispersive free‐surface flows governed by the incompressible Navier‐Stokes equations. The method significantly reduces memory requirements and computational complexity compared
Rasmus Kleist Hørlyck Sørensen, Margherita Guido, Allan Peter Engsig‐Karup, Daniel Kressner   +3 more
wiley   +1 more source

Polynomial Preconditioning for Indefinite Matrices

Numerical Linear Algebra with Applications, Volume 33, Issue 5, October 2026.
ABSTRACT Polynomial preconditioning is an important tool in solving large linear systems and eigenvalue problems. A polynomial from GMRES can be used to precondition restarted GMRES and restarted Arnoldi. Here we give methods for indefinite matrices that make polynomial preconditioning more generally applicable. The new techniques include balancing the
Hayden Henson, Ronald B. Morgan
wiley   +1 more source

Analysis of Eigenvalue Clustering Leads to Optimal Scaling in Numerical Radiative Transfer

Numerical Linear Algebra with Applications, Volume 33, Issue 5, October 2026.
ABSTRACT We consider a multidimensional polychromatic radiative transfer (RT) problem, accounting for scattering processes in a general form, that is, anisotropic (dipole) scattering with partial frequency redistribution. Given a discrete ordinates (SN$$ {S}_N $$) discretization, we report the corresponding matrix structures, depending on the model and
Pietro Benedusi, Simone Riva, Luca Belluzzi, Stefano Serra‐Capizzano   +3 more
wiley   +1 more source

Stochastic estimation of level density in nuclear shell-model calculations

EPJ Web of Conferences, 2016
An estimation method of the nuclear level density stochastically based on nuclear shell-model calculations is introduced. In order to count the number of the eigen-values of the shell-model Hamiltonian matrix, we perform the contour integral of the ...
Shimizu Noritaka, Utsuno Yutaka, Futamura Yasunori, Sakurai Tetsuya, Mizusaki Takahiro, Otsuka Takaharu   +5 more
doaj   +1 more source

Quantum Spectral Clustering Framework via Compact Circuit Structures

Advanced Quantum Technologies, Volume 9, Issue 10, October 2026.
Can a quantum computer cluster data without ever reading the full kernel? This work shows that compact, parameterized circuits estimate the Laplacian quadratic forms directly and perform clustering, without explicitly constructing the full quantum fidelity‐kernel matrix.
Hyeong‐gyu Kim, Siheon Park, June‐Koo Kevin Rhee   +2 more
wiley   +1 more source

Performance of relaxed iterative methods for image deblurring problems

Journal of Algorithms & Computational Technology, 2019
In this paper, we consider performance of relaxation iterative methods for four types of image deblurring problems with different regularization terms.
Jae H Yun
doaj   +1 more source

Seismic Imaging of the Crust From Long‐Offset Ocean‐Bottom Seismometer Data Using Time‐Domain Extended‐Source Full‐Waveform Inversion: Application to the Eastern Nankai Trough, Japan

Journal of Geophysical Research: Solid Earth, Volume 131, Issue 10, October 2026.
Abstract High‐resolution crustal‐scale seismic imaging from long‐offset ocean‐bottom seismometer (OBS) data using full‐waveform inversion (FWI) remains challenging because the large number of propagated wavelengths and waveform complexity make the inversion highly sensitive to time‐shift errors (cycle skipping). To mitigate this nonlinearity, we assess
Gaoshan Guo, Stéphane Operto, Jean‐Xavier Dessa   +2 more
wiley   +1 more source

Nonlinear Dynamic Inverse Solution of the Diffusion Problem Based on Krylov Subspace Methods with Spatiotemporal Constraints

Computer Sciences & Mathematics Forum
In this work, we propose a nonlinear dynamic inverse solution to the diffusion problem based on Krylov Subspace Methods with spatiotemporal constraints. The proposed approach is applied by considering, as a forward problem, a 1D diffusion problem with a ...
Luis Fernando Alvarez-Velasquez, Eduardo Giraldo   +1 more
doaj   +1 more source