Do you precondition on the left or on the right?
Numerical Analysis
2026-01-23 v2 Numerical Analysis
Abstract
This work is a follow-up to a poster that was presented at the DD29 conference. Participants were asked the question: ``Do you precondition on the left or on the right?''. Here we report on the results of this social experiment. We also provide context on left, right and split preconditioning, share our literature review on the topic, and analyze some of the finer points. Two examples illustrate that convergence bounds can sometimes lead to misleading conclusions.
Cite
@article{arxiv.2512.05160,
title = {Do you precondition on the left or on the right?},
author = {Nicole Spillane and Pierre Matalon and Daniel B Szyld},
journal= {arXiv preprint arXiv:2512.05160},
year = {2026}
}