Releasing LightKrylov v0.1.1 (Jan. 2026)

[loiseaujc]

Hej everyone!

I’m happy to announce that we’ve just officially released LightKrylov v0.1.1! The code can be found here. It is a joint effort with Simon Kern (postdoctoral researcher in the lab) and Ricardo Frantz (former PhD student here and now at EPFL) and is funded by the Agence Nationale de la Recherche (French equivalent of NSF).

I’ve already discussed about LightKrylov here and here but basically

@loiseaujc

LightKrylov is a lightweight implementation of standard Krylov-based techniques relying on modern Fortran features, in particular its abstract type capabilities. Having no dependencies other than stdlib, it exposes abstract vector and abstract linop types which you can easily extend and adapt to the particular data structure and/or parallelization paradigm you use. Having extending these two types to accomodate your particular applications, LightKrylov lets you solve linear systems, compute leading eigenvalues or singular values of your linear operator fairly easily using standard Krylov techniques such gmres, arnoldi or lanczos.

The repo has a couple of examples and you can find more here. We have just received the green light from all the referees for the associated Journal of Open Source Software publication. You can find the paper here for now. I’ll make sure to update the link once it has officially been published by JOSS.

@jorgeg : Even if the paper won’t probably be published in January (I guess it’ll be very early February), would that count for inclusion in the newsletter?

[fxm]

This is great, @loiseaujc. I have been keping an eye on this for a while now. Congratulations. It may be worth adding it also to the Fortran Wiki list of linear algebra libraries, too.

[jorgeg]

I’ll list it as “submitted”!

[fxm]

@loiseaujc

Even if the paper won’t probably be published in January

That happens quickly after acceptance in JOSS. It looks like it’s all published and online already (see here) and ready to list/cite.

@article{Kern2026, 
doi = {10.21105/joss.09623}, 
url = {https://doi.org/10.21105/joss.09623}, 
year = {2026}, 
publisher = {The Open Journal}, 
volume = {11}, 
number = {117}, 
pages = {9623}, 
author = {Kern, J. Simon and Frantz, Ricardo S. and Loiseau, Jean-Christophe}, 
title = {LightKrylov: Lightweight implementation of Krylov subspace techniques in modern Fortran}, 
journal = {Journal of Open Source Software} } 

[loiseaujc]

I’ve just seen it. It’s been even faster than I anticipated.