Fast and backward stable computation of roots of polynomials

JL Aurentz, T Mach, R Vandebril, DS Watkins - SIAM Journal on Matrix …, 2015 - SIAM
A stable algorithm to compute the roots of polynomials is presented. The roots are found by
computing the eigenvalues of the associated companion matrix by Francis's implicitly shifted …

[图书][B] Core-chasing algorithms for the eigenvalue problem

Core-Chasing Algorithms for the Eigenvalue Problem : Back Matter Page 1 Bibliography [1] GS
Ammar, WB Gragg, and L. Reichel. On the eigenproblem for orthogonal matrices. In Proceedings …

Fast and backward stable computation of roots of polynomials, Part II: Backward error analysis; companion matrix and companion pencil

JL Aurentz, T Mach, L Robol, R Vandebril… - SIAM Journal on Matrix …, 2018 - SIAM
This work is a continuation of work by JL Aurentz, T. Mach, R. Vandebril, and DS Watkins, J.
Matrix Anal. Appl., 36 (2015), pp. 942--973. In that paper we introduced a companion QR …

Fast and backward stable computation of eigenvalues and eigenvectors of matrix polynomials

J Aurentz, T Mach, L Robol, R Vandebril… - Mathematics of …, 2019 - ams.org
In the last decade matrix polynomials have been investigated with the primary focus on
adequate linearizations and good scaling techniques for computing their eigenvalues and …

[PDF][PDF] Computing approximate (block) rational Krylov subspaces without explicit inversion with extensions to symmetric matrices

T Mach, MS Pranic, R Vandebril - Electron. Trans. Numer. Anal, 2014 - kurims.kyoto-u.ac.jp
It has been shown that approximate extended Krylov subspaces can be computed, under
certain assumptions, without any explicit inversion or system solves. Instead, the vectors …

[PDF][PDF] Fast and stable unitary QR algorithm

JL Aurentz, T Mach, R Vandebril, DS Watkins - Electron. Trans. Numer …, 2015 - emis.de
A fast Fortran implementation of a variant of Gragg's unitary Hessenberg QR algorithm is
presented. It is proved, moreover, that all QR-and QZ-like algorithms for the unitary …

Fast QR iterations for unitary plus low rank matrices

R Bevilacqua, GM Del Corso, L Gemignani - Numerische Mathematik, 2020 - Springer
Some fast algorithms for computing the eigenvalues of a (block) companion matrix have
recently appeared in the literature. In this paper we generalize the approach to encompass …

[HTML][HTML] An implicit filter for rational Krylov using core transformations

D Camps, K Meerbergen, R Vandebril - Linear Algebra and its Applications, 2019 - Elsevier
The rational Krylov method is a powerful tool for computing a selected subset of eigenvalues
in large-scale eigenvalue problems. In this paper we study a method to implicitly apply a …

[PDF][PDF] Roots of polynomials: on twisted QR methods for companion matrices and pencils

JL Aurentz, T Mach, L Robol, R Vandebril… - arXiv preprint arXiv …, 2016 - researchgate.net
Two generalizations of the companion QR algorithm by JL Aurentz, T. Mach, R. Vandebril,
and DS Watkins, SIAM Journal on Matrix Analysis and Applications, 36 (3): 942–973, 2015 …

An extended Hamiltonian QR algorithm

M Ferranti, B Iannazzo, T Mach, R Vandebril - Calcolo, 2017 - Springer
An extended QR algorithm specifically tailored for Hamiltonian matrices is presented. The
algorithm generalizes the customary Hamiltonian QR algorithm with additional freedom in …