Mitten in der Stadt bei vollem Licht, trot dem nit bloßem Auge zu sehen. #Nordlicht

Accompanying the talk at the last JuliaCon and the LieGroups.jl package, we now have a JuliaCon Proceedings paper giving a short introduction to Lie groups and how to work with them in Julia doi.org/10.21105/jco...

Mateusz Baran gave a nice overview at #JuliaCon2025 about the JuliaManifolds ecosystem in #julialang: Manifolds in numerical computations with JuliaManifolds youtu.be/ybbhy8nnlEA?...

At #JuliaCOn2025 @ronnybergmann.net gave a talk about LieGroups.jl. That is now available online #julialang #manifolds #LieGroups youtu.be/_L9u8r42oSQ?...

Hajg Jasa, Ronny Bergmann, Christian K\"ummerle, Avanti Athreya, Zachary Lubberts: Procrustes Problems on Random Matrices https://arxiv.org/abs/2510.05182 https://arxiv.org/pdf/2510.05182 https://arxiv.org/html/2510.05182

na sowas... 🥴

Ronny Bergmann, Hajg Jasa, Paula John, Max Pfeffer: The Intrinsic Riemannian Proximal Gradient Method for Convex Optimization https://arxiv.org/abs/2507.16055 https://arxiv.org/pdf/2507.16055 https://arxiv.org/html/2507.16055

Laura Weigl, Ronny Bergmann, Anton Schiela: Newton's method for nonlinear mappings into vector bundles Part II: Application to variational problems https://arxiv.org/abs/2507.13836 https://arxiv.org/pdf/2507.13836 https://arxiv.org/html/2507.13836

Lukas Baumg\"artner, Ronny Bergmann, Roland Herzog, Stephan Schmidt, Manuel Wei{\ss}: Total Generalized Variation of the Normal Vector Field and Applications to Mesh Denoising https://arxiv.org/abs/2507.13530 https://arxiv.org/pdf/2507.13530 https://arxiv.org/html/2507.13530

Jo Andersson Stokke, Ronny Bergmann, Martin Hanik, Christoph von Tycowicz: p-Laplacians for Manifold-valued Hypergraphs https://arxiv.org/abs/2507.10335 https://arxiv.org/pdf/2507.10335 https://arxiv.org/html/2507.10335

On Manifolds, the gradient depends on the Riemannian metric, the differential does not. For a costly metric, using the gradient for the differential might be costly. Manopt.jl 0.5.19 now offers first order objectives with dedicated implementations of differentials: manoptjl.org/stable/plans...

Es ist 23:08, eine halbe Stunde vor Sonnenuntergang an St. Hans. Allen einen schönen Mittsommerabend!

As dem Leben von #IchwarHanna - ja, ich bin heute um 3:30 aufgestanden, um zur nächsten Botschaft zu fliegen (1h) für Passangelegenheiten, ja, die Sonne war da schon wach (siehe Bild), und nun geht es mit dem Zug 7h zurück…

Abendbrotblick. Korsvika.

Proximal methods have become popular on manifolds as well the last few years, among them also the proximal gradient method. In our new preprint we derive a new proximal gradient method that for the first time does not need the embedding and/or solving problems in tangent spaces.

Mateusz Baran, Ronny Bergmann: A geometric perspective of state estimation using Kalman filters https://arxiv.org/abs/2506.01086 https://arxiv.org/pdf/2506.01086 https://arxiv.org/html/2506.01086

My lab, at Karolinska, in Stockholm, is looking for a PhD student with a computational/quantitative background to work on probabilistic/generative models of proteins (structure and sequence). The research will involve methods development, and applications in vaccine design.

Oh, this post from earlier today is missing the #julialang tag (because I forgot it). So if you work with Lie groups somewhere, maybe consider checking out our new package LieGroups.jl!

We have a new package! LieGroups.jl juliamanifolds.github.io/LieGroups.jl... provides Lie groups based in Manifolds.jl. See the full announcement at discourse.julialang.org/t/ann-liegro...

The newest version of Manopt.jl – 0.5.12 introduces a new algorithm: The gradient projection method. See manoptjl.org/stable/solve... as well as the arXiv preprint arxiv.org/abs/2504.11815 #Manifolds #julialang #Manopt

Ronny Bergmann, Orizon P. Ferreira, Sandor N\'emeth, Jinzhen Zhu: On projection mappings and the gradient projection method on hyperbolic space forms https://arxiv.org/abs/2504.11815 https://arxiv.org/pdf/2504.11815 https://arxiv.org/html/2504.11815

Tariffs xkcd.com/3073

This fall I'm organizing a conference about open-source software. Thing is, I'm tired of plenaries given by straight white dudes. Does the hive mind have *diverse* recommendations for speakers located in Europe who have interesting things to say about programming? Got some names but would love more!

We are giving an introduction to Julia! Next Tuesday, March 20, 16.00 at Seminarroom S5, Sentralbygg 2, NTNU (Trondheim). You can also see that on our homepage julia-users-trondheim.github.io and have a sneak preview at the slides already at github.com/Julia-Users-...

In the new version Manopt.jl v0.5.7 we introduce the Mesh Adaptive Direct Reach (MADS) algorithm(s) manoptjl.org/stable/solve... mainly providing the LTMADS which @oddsen.bsky.social worked on in his masters thesis. Thanks Sander! #Manifolds #julialang #Manopt

We started a monthly community call recently! The next one is coming Tuesday, 16.00 (4pm) CET. You can find the zoom link on discourse discourse.julialang.org/t/juliamanif...

Welcome to 2025 – a square year! After 44^2 = 1936 this is 45^2, and the next one will only be 46^2 = 2116. The prime factor decomposition reads quite nice this year: (3^2*5)^2 = 3^4 * 5^2

🌨️🥰

#DieHellenDinge sind heute am kürzesten (4:30 mit Sonne), da heute aber wenig Wolken und -3 Grad sind, haben wir herrliches Licht, hier 5 Minuten nach Sonnenaufgang.

9:50, Trondheim. Es sieht nicht ganz danach aus, aber: Sonnenaufgang! 😎 (Untergang 14:33) Und leider ein paar Grad zu warm für Schnee.

It's #ManifoldMonday! It is also exam week, so I was a bit busy. We will continue the story about how Riemann defined manifolds in general next week. For this week: If you want to do optimisation on manifolds I recommend the book www.nicolasboumal.net/book/index.h..., where you can get the free PDF

It's #ManifoldMonday! After talking about angles in triangles on the sphere last time, there is another very interesting concept to discuss: the construction of parallel lines. 1/10

I am in Lausanne and besides at the workshop, I will give another talk in the MathICSE on Friday about “Nonlinear Fenchel Conjugates” (cf memento.epfl.ch/event/nonlin...), see also the preprint at arxiv.org/abs/2409.04492. You can find the slides already online ronnybergmann.net/talks/2024-L...

Hey folks! I got a bit swamped with all the new #julialang BlueSky people and made my own mega Julia #programmer starter pack! go.bsky.app/Hv4RKzM What other starter packs would you want to see? I'm in health research, mathematics, and open source/science. 🧪🛟🩺 📊

It's #ManifoldMonday! Today we talk about angles in a triangle. If you take a sheet of paper and draw a triangle, then the sum of the inner angles always sums up to 180 degrees. This observation goes back to the greek mathematician Euclid and is hence part of Euclidean geometry. 1/8

I will be in Lausanne next week and give a talk at the workshop “Julia for numerical problems in quantum and solid-state physics” (cf. www.cecam.org/workshop-det...) #julialang about #Manopt on Wednesday. The slides are already online at ronnybergmann.net/talks/2024-L...

Sometimes in the early morning I do interesting typos triggering autocorrect: The travelling salmon problem. 🍣🧳

"Dem Problem der Toleranz dürften Sie kaum gewachsen sein, Ingenieur. Prägen Sie sich immerhin ein, daß Toleranz zum Verbrechen wird, wenn sie dem Bösen gilt." Heute vor 100 Jahren erschienen: Der Zauberberg von Thomas Mann.

I made a #starterpack for computational math 💻🧮 so please 1. share 2. let me know if you want to be on the list! (I have many new followers which I do not know well yet, so I'm sorry if you follow me and are not on here, but want to - drop me a note and I'll add you!) go.bsky.app/DXdZkzV

Word of this morning is ‘procaffeinate’: to put everything on hold until you’ve had sufficient amounts of coffee.

I want to restart my #ManifoldMondays with random facts about Riemannian manifolds including applications like optimization. The goal is, to present a bit of information about them every Monday: what they are, what they are useful for, properties I find cool, specific examples,… 1/4

Trenger du julekort i år? Jeg har! 60 kr. stykket for kvadratiske, ca. 15x15 cm 50 kr. stykket for A6 Har også A5-kort med skøytenisser til 100 kr. Porto kommer i tillegg hvis de skal sendes, men kan også møtes i Trondheim! Repost gjerne🎀

After the first bit of snow the weather today was really nice for a short hike up to Vãttakammen and Theissendammen.

An awesome sky this Morning on the way to work. #Nidelva

Short reintroduction for all my new followers: Hi! 👋 I work on numerical methods and optimization involving Riemannian manifolds #mathsky. I am a fan of #julialang, so I also implement these methods in Julia. Sometimes I take detours into documentation, e.g. with Quarto, for reproducible research.

I just learned that one can use their own domain as a handle here – in case you can verify its yours with an DNS entry, see bsky.social/about/blog/4... – so: I now have a new handle! @ronnybergmann.net

Wer ein wenig Ablenkung von der Politik möchte: Die Vendée Globe hat heute begonnen, mit Boris Hermann ndr.de/segeln/ #TeamMalizia

The News.

Ein schöner Start in den Trag mit einer uniweiten Mitteilung in der statt von Gitternetzen von Glitzernetzen in einem Forschungsbereich gesprochen wird 🥰

Wir haben #DieHellenDinge jetzt auch wieder Abends ❄️🌨️