81 citations · 234 across the 14 of their papers we have counts for
14 papers
On the rational approximation of Markov functions,with applications to the computation of Markovfunctions of Toeplitz matrices
Bernhard Beckermann, Joanna Bisch, Robert Luce
We investigate the problem of approximating the matrix function by , with a Markov function, a rational interpolant of , and a symmetric Toeplitz matrix…
Using incomplete indefinite preconditioning for inexact interior point methods for linear programming
Robert Luce
Most linear algebra kernels in interior point methods for linear programming require the solution of linear systems of equation with the matrix (or ),…
The index of singular zeros of harmonic mappings of anti-analytic degree one
Robert Luce, Olivier Sète
We study harmonic mappings of the form , where is an analytic function. In particular we are interested in the index (a generalized multiplicity) of…
A Fast Gradient Method for Nonnegative Sparse Regression with Self Dictionary
Nicolas Gillis, Robert Luce
A nonnegative matrix factorization (NMF) can be computed efficiently under the separability assumption, which asserts that all the columns of the given input data matrix belong to…
Fast computation of the matrix exponential for a Toeplitz matrix
Daniel Kressner, Robert Luce
The computation of the matrix exponential is a ubiquitous operation in numerical mathematics, and for a general, unstructured matrix it can be computed in $\mathcal{O}(…
Using separable non-negative matrix factorization techniques for the analysis of time-resolved Raman spectra
Robert Luce, Peter Hildebrandt, Uwe Kuhlmann +1
The key challenge of time-resolved Raman spectroscopy is the identification of the constituent species and the analysis of the kinetics of the underlying reaction network. In this…
Finite element formulation of general boundary conditions for incompressible flows
Roland Becker, Daniela Capatina, Robert Luce +1
We study the finite element formulation of general boundary conditions for incompressible flow problems. Distinguishing between the contributions from the inviscid and viscid parts…
Fast Recovery and Approximation of Hidden Cauchy Structure
Jörg Liesen, Robert Luce
We derive an algorithm of optimal complexity which determines whether a given matrix is a Cauchy matrix, and which exactly recovers the Cauchy points defining a Cauchy matrix from…
A Note on the Maximum Number of Zeros of
Robert Luce, Olivier Sète, Jörg Liesen
An important theorem of Khavinson & Neumann (Proc. Amer. Math. Soc. 134(4), 2006) states that the complex harmonic function , where is a rational function of de…
Creating images by adding masses to gravitational point lenses
Olivier Sète, Robert Luce, Jörg Liesen
A well-studied maximal gravitational point lens construction of S. H. Rhie produces images of a light source using deflector masses. The construction arises from a circu…
Perturbing rational harmonic functions by poles
Olivier Sète, Robert Luce, Jörg Liesen
We study how adding certain poles to rational harmonic functions of the form , with rational and of degree , affects the number of zeros of the result…
Sharp parameter bounds for certain maximal point lenses
Robert Luce, Olivier Sète, Jörg Liesen
Starting from an -point circular gravitational lens having images, Rhie (2003) used a perturbation argument to construct an -point lens producing images. In t…
On the minimum FLOPs problem in the sparse Cholesky factorization
Robert Luce, Esmond Ng
Prior to computing the Cholesky factorization of a sparse, symmetric positive definite matrix, a reordering of the rows and columns is computed so as to reduce both the number of f…
Robust Near-Separable Nonnegative Matrix Factorization Using Linear Optimization
Nicolas Gillis, Robert Luce
Nonnegative matrix factorization (NMF) has been shown recently to be tractable under the separability assumption, under which all the columns of the input data matrix belong to the…