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The problem of diagonalizing a class of complicated matrices, to be called ultrametric matrices, is investigated. These matrices appear at various stages in the description of disordered systems with many equilibrium phases by the technique…

Condensed Matter · Physics 2009-10-22 T. Temesvari , C De Dominicis , I. Kondor

A randomized algorithm for computing a data sparse representation of a given rank structured matrix $A$ (a.k.a. an $H$-matrix) is presented. The algorithm draws on the randomized singular value decomposition (RSVD), and operates under the…

Numerical Analysis · Mathematics 2024-06-25 James Levitt , Per-Gunnar Martinsson

The Schur decomposition of a square matrix $A$ is an important intermediate step of state-of-the-art numerical algorithms for addressing eigenvalue problems, matrix functions, and matrix equations. This work is concerned with the following…

Numerical Analysis · Mathematics 2022-03-22 Zvonimir Bujanović , Daniel Kressner , Christian Schröder

Multiresolution analysis and matrix factorization are foundational tools in computer vision. In this work, we study the interface between these two distinct topics and obtain techniques to uncover hierarchical block structure in symmetric…

Computer Vision and Pattern Recognition · Computer Science 2017-05-17 Vamsi K. Ithapu , Risi Kondor , Sterling C. Johnson , Vikas Singh

We introduce Unitaria, a Python library that brings the simplicity of classical linear algebra toolkits such as NumPy and SciPy to the implementation of quantum algorithms based on block encodings, a general-purpose abstraction in which a…

Quantum Physics · Physics 2026-05-12 Matthias Deiml , Oliver Hüttenhofer , Ram Mosco , Jakob S. Kottmann , Daniel Peterseim

We propose efficient parallel algorithms and implementations on shared memory architectures of LU factorization over a finite field. Compared to the corresponding numerical routines, we have identified three main difficulties specific to…

Symbolic Computation · Computer Science 2014-02-17 Jean-Guillaume Dumas , Thierry Gautier , Clément Pernet , Ziad Sultan

Many problems in physics, chemistry and other fields are perturbative in nature, i.e. differ only slightly from related problems with known solutions. Prominent among these is the eigenvalue perturbation problem, wherein one seeks the…

Mathematical Physics · Physics 2020-03-12 Maseim Kenmoe , Matteo Smerlak , Anton Zadorin

Traditional numerical methods for calculating matrix eigenvalues are prohibitively expensive for high-dimensional problems. Iterative random sparsification methods allow for the estimation of a single dominant eigenvalue at reduced cost by…

Numerical Analysis · Mathematics 2023-10-03 Samuel M. Greene , Robert J. Webber , Timothy C. Berkelbach , Jonathan Weare

In this work, we consider rank-one adaptations $X_{new} = X+ab^T$ of a given matrix $X\in \mathbb{R}^{n\times p}$ with known matrix factorization $X = UW$, where $U\in\mathbb{R}^{n\times p}$ is column-orthogonal, i.e. $U^TU=I$. Arguably the…

Numerical Analysis · Mathematics 2019-03-06 Ralf Zimmermann

Vector set orthogonal normalization and matrix QR decomposition are fundamental problems in matrix analysis with important applications in many fields. We know that Gram-Schmidt process is a widely used method to solve these two problems.…

Quantum Physics · Physics 2025-01-03 Zi-Ming Li , Yu-xi Liu

We consider the computation of roots of polynomials expressed in the Chebyshev basis. We extend the QR iteration presented in [Eidelman, Y., Gemignani, L., and Gohberg, I., Numer. Algorithms, 47.3 (2008): pp. 253-273] introducing an…

Numerical Analysis · Mathematics 2021-04-30 Angelo Casulli , Leonardo Robol

Quantum computing and modern tensor-based computing have a strong connection, which is especially demonstrated by simulating quantum computations with tensor networks. The other direction is less studied: quantum computing is not often…

Quantum Physics · Physics 2025-09-03 Valter Uotila

Convergence analysis of block iterative solvers for Hermitian eigenvalue problems and the closely related research on properties of matrix-based signal filters are challenging, and attract increasing attention due to their recent…

Numerical Analysis · Mathematics 2022-01-13 M. Zhou , M. E. Argentati , A. V. Knyazev , K. Neymeyr

The proposed article aims at offering a comprehensive tutorial for the computational aspects of structured matrix and tensor factorization. Unlike existing tutorials that mainly focus on {\it algorithmic procedures} for a small set of…

Signal Processing · Electrical Eng. & Systems 2023-07-19 Xiao Fu , Nico Vervliet , Lieven De Lathauwer , Kejun Huang , Nicolas Gillis

Quadratic Unconstrained Binary Optimization (QUBO) is a standard NP-hard optimization problem. Recently, it has gained renewed interest through quantum computing, as QUBOs directly reduce to the Ising model, on which quantum annealing…

Quantum Physics · Physics 2026-03-16 Katalin Friedl , Levente Gegő , László Kabódi , Viktória Nemkin

In this paper, we study and implement the structural iterative eigensolvers for the large-scale eigenvalue problem in the Bethe-Salpeter equation (BSE) based on the reduced basis approach via low-rank factorizations in generating matrices,…

Numerical Analysis · Mathematics 2017-03-08 Peter Benner , Sergey Dolgov , Venera Khoromskaia , Boris N. Khoromskij

We developed fast direct solver for 3D Helmholtz and Maxwell equations in layered medium. The algorithm is based on the ideas of cyclic reduction for separable matrices. For the grids with major uniform part (within the survey domain in the…

Numerical Analysis · Mathematics 2019-09-04 Vladimir Druskin , Mikhail Zaslavsky

We present two new algorithms for Householder QR factorization of Block Low-Rank (BLR) matrices: one that performs block-column-wise QR, and another that is based on tiled QR. We show how the block-column-wise algorithm exploits BLR…

Numerical Analysis · Mathematics 2022-08-15 M. Ridwan Apriansyah , Rio Yokota

This paper is an algorithmic study of quantum phase estimation with multiple eigenvalues. We present robust multiple-phase estimation (RMPE) algorithms with Heisenberg-limited scaling. The proposed algorithms improve significantly from the…

Quantum Physics · Physics 2023-10-26 Haoya Li , Hongkang Ni , Lexing Ying

Quantum-inspired algorithms can deliver substantial speedups over classical state-of-the-art methods by executing quantum algorithms with tensor networks on conventional hardware. Unlike circuit models restricted to unitary gates, tensor…