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We review the numerical analysis' understanding of Krylov subspace methods for solving (non-hermitian) systems of equations and discuss its implications for lattice gauge theory computations using the example of the Wilson fermion matrix.…

High Energy Physics - Lattice · Physics 2009-10-28 Andreas Frommer

The purpose of this work is to introduce a new idea of how to avoid the factorization of large matrices during the solution of stiff systems of ODEs. Starting from the general form of an explicit linear multistep method we suggest to…

Numerical Analysis · Mathematics 2019-08-22 Boris Faleichik

Deflation techniques are typically used to shift isolated clusters of small eigenvalues in order to obtain a tighter distribution and a smaller condition number. Such changes induce a positive effect in the convergence behavior of Krylov…

Numerical Analysis · Mathematics 2024-05-15 Andrei Dumitrasc , Carola Kruse , Ulrich Ruede

We implement an algorithm which is aimed to reduce the dimensions of the Hilbert space of quantum many-body systems by means of a renormalization procedure. We test the role and importance of different representations on the reduction…

Quantum Physics · Physics 2015-05-27 Tarek Khalil , Jean Richert

In the last decade, tensors have shown their potential as valuable tools for various tasks in numerical linear algebra. While most of the research has been focusing on how to compress a given tensor in order to maintain information as well…

Numerical Analysis · Mathematics 2024-09-17 Alberto Bucci , Davide Palitta , Leonardo Robol

We propose a block Krylov subspace version of the GCRO-DR method proposed in [Parks et al.; SISC 2005], which is an iterative method allowing for the efficient minimization of the the residual over an augmented Krylov subspace. We offer a…

Numerical Analysis · Mathematics 2026-05-14 Michael L. Parks , Kirk M. Soodhalter , Daniel B. Szyld

A cascadic multigrid method is proposed for eigenvalue problems based on the multilevel correction scheme. With this new scheme, an eigenvalue problem on the finest space can be solved by smoothing steps on a series of multilevel finite…

Numerical Analysis · Mathematics 2014-09-11 XIaole Han , Hehu Xie

One of the limitations of recycled GCRO methods is the large amount of computation required to orthogonalize the basis vectors of the newly generated Krylov subspace for the approximate solution when combined with those of the recycle…

Numerical Analysis · Mathematics 2023-06-12 Stephen Thomas , Alison Baker , Stephane Gaudreault

This paper proposes a rational filtering domain decomposition technique for the solution of large and sparse symmetric generalized eigenvalue problems. The proposed technique is purely algebraic and decomposes the eigenvalue problem…

Numerical Analysis · Mathematics 2017-11-28 Vassilis Kalantzis , Yuanzhe Xi , Yousef Saad

Polynomial filtering can provide a highly effective means of computing all eigenvalues of a real symmetric (or complex Hermitian) matrix that are located in a given interval, anywhere in the spectrum. This paper describes a technique for…

Numerical Analysis · Mathematics 2015-12-29 Ruipeng Li , Yuanzhe Xi , Eugene Vecharynski , Chao Yang , Yousef Saad

Robust and efficient solvers for coupled-adjoint linear systems are crucial to successful aerostructural optimization. Monolithic and partitioned strategies can be applied. The monolithic approach is expected to offer better robustness and…

Numerical Analysis · Mathematics 2023-09-25 Christophe Blondeau , Mehdi Jadoui

A thick-restart Lanczos type algorithm is proposed for Hermitian $J$-symmetric matrices. Since Hermitian $J$-symmetric matrices possess doubly degenerate spectra or doubly multiple eigenvalues with a simple relation between the degenerate…

Numerical Analysis · Mathematics 2020-09-14 Ken-Ichi Ishikawa , Tomohiro Sogabe

Restarted GMRES is a robust and widely used iterative solver for linear systems. The control of the restart parameter is a key task to accelerate convergence and to prevent the well-known stagnation phenomenon. We focus on the…

Numerical Analysis · Mathematics 2026-02-19 Lennart Duvenbeck , Cedric Riethmüller , Christian Rohde

We combine the multigrid (MG) method with state-of-the-art concepts from the variational formulation of the numerical renormalization group. The resulting MG renormalization (MGR) method is a natural generalization of the MG method for…

Computational Physics · Physics 2018-07-17 Michael Lubasch , Pierre Moinier , Dieter Jaksch

Quantum Krylov subspace diagonalization (QKSD) algorithms provide a low-cost alternative to the conventional quantum phase estimation algorithm for estimating the ground and excited-state energies of a quantum many-body system. While QKSD…

Quantum Physics · Physics 2022-02-23 Cristian L. Cortes , Stephen K. Gray

Block Krylov subspace methods (KSMs) comprise building blocks in many state-of-the-art solvers for large-scale matrix equations as they arise, e.g., from the discretization of partial differential equations. While extended and rational…

Numerical Analysis · Mathematics 2020-02-06 Daniel Kressner , Kathryn Lund , Stefano Massei , Davide Palitta

We consider deflation and augmentation techniques for accelerating the convergence of Krylov subspace methods for the solution of nonsingular linear algebraic systems. Despite some formal similarity, the two techniques are conceptually…

Numerical Analysis · Mathematics 2015-10-20 André Gaul , Martin H. Gutknecht , Jörg Liesen , Reinhard Nabben

Performing Bayesian inference on large spatio-temporal models requires extracting inverse elements of large sparse precision matrices for marginal variances, as well as estimating model hyperparameters. Although direct matrix factorizations…

Computation · Statistics 2026-03-17 Abylay Zhumekenov , Elias T. Krainski , Håvard Rue

Solving the generalized eigenvalue problem is a useful method for finding energy eigenstates of large quantum systems. It uses projection onto a set of basis states which are typically not orthogonal. One needs to invert a matrix whose…

Nuclear Theory · Physics 2023-04-05 Caleb Hicks , Dean Lee

This paper proposes Inverse Gram Matrix (IGM) methods to prioritize the Pairwise Reciprocal Matrix (PRM) in the Analytic Hierarchy Process. The IGM methods include Pseudo-IGM, Normalized-IGM, and Lagrange-IGM. Interestingly, the proposed…

Optimization and Control · Mathematics 2024-01-03 Kevin Kam Fung Yuen