Natalie Wellen

collaborators

2 papers

math.NA2023

Optimal Polynomial Approximation to Rational Matrix Functions Using the Arnoldi Algorithm

Tyler Chen, Anne Greenbaum, Natalie Wellen

Given an $n$ by $n$ matrix $A$ and an $n$ -vector $b$ , along with a rational function $R (z) := D (z)^{- 1} N (z)$ , we show how to find the optimal approximation to $R (A) b$ from the K…

math.NA2023

K-Spectral Sets

Anne Greenbaum, Natalie Wellen

We use results in [M. Crouzeix and A. Greenbaum,Spectral sets: numerical range and beyond, SIAM Jour. Matrix Anal. Appl., 40 (2019), pp. 1087-1101] to derive a variety of K-spectra…