Bruno Levy

Researcher in Computational Physics,
Scientific Director of Program Inria Quadrant,
2018-2022 director of Inria Nancy G-Est,
ERC GOODSHAPE-VORPALINE,
#riscv ambassador

Last Notes

2026-07-17 16:53:29 UTC

An effect of the heat wave in France ?
No, getting ready with Cyprien Plateau-Holleville for our course at ACM SIGGRAPH, don't miss it !
Sunday, 9am to 12:15pm, room 408 B
https://cdn.fosstodon.org/media_attachments/files/116/936/355/262/477/200/original/cd04db24c62b9e65.mp4

2026-06-03 04:03:26 UTC

Still working on hashtag#geogram / geogram+ / Tessael boolean operations for meshes,
Making them faster without sacrifying robustness and generality.
More to come ...
(this test suggested by Cyprien Plateau Holleville)
https://cdn.fosstodon.org/media_attachments/files/116/684/185/394/637/295/original/192626a2944ef118.mp4

2026-03-04 21:03:55 UTC

My brand new computer !
- does not fit in my backpack (bad !)
- runs Unix (good !)
- OS does not have AI extension that I don't want (good !)
- 32 Kb of main memory, I'll need to optimize hashtag#geogram a bit (good !)
https://cdn.fosstodon.org/media_attachments/files/116/172/929/162/641/990/original/9d7af45e3aa5459e.png

2025-12-31 12:15:25 UTC

What does this new trend
of writing posts on
social media
formatted into multiple tiny
paragaphs
that contain a few
words
only ?
Does it means that generative AI systems
are degenerating ?
and will
then produce content
token
by token ?
Then character by
c
h
a
r
a
c
t
e
r
?
01000100110010001111
01010
0
0
00000000000000000000000000
Aahhh, finally, the end of all this non-sense !!!

2025-12-28 15:47:59 UTC

Geogram 1.9.8 is out !
https://github.com/BrunoLevy/geogram
Geogram is a programming library with geometric algorithm.
it has mesh repair, mesh simplification, mesh intersection, Delaunay triangulation, exact predicates and much more !
https://cdn.fosstodon.org/media_attachments/files/115/797/967/920/009/170/original/1d970c918c95c92f.png

2025-12-27 22:45:03 UTC

Found under the christmass tree, very nice lego set for a computer graphic programmer 😉. Customized it a bit with a powerful LED.
https://cdn.fosstodon.org/media_attachments/files/115/793/946/430/262/855/original/ee618466cf342010.jpg

2025-12-15 08:34:10 UTC

[Leaving X] .... DONE
Goodby to my 10000 followers, so long X, and thanks for the fish !
My stream of computational physics news / hardware engineering / geek stuff will continue here:
- https://www.linkedin.com/in/blevy/
- https://fosstodon.org/@BrunoLevy01
- https://bsky.app/profile/brunolevy01.bsky.social
https://cdn.fosstodon.org/media_attachments/files/115/722/645/798/987/697/original/1734e716d3d0732e.png

2025-12-15 07:46:53 UTC

This chip is special,
(https://tinytapeout.com/chips/ttsky25b/)
- it has designs made by hobbyists
- and, more importantly, it has two #FemtoRV designs in it !!
- these two FemtoRV designs were authored by others
What is FemtoRV ? It is a super simple RiscV processor that we designed with @nprofile…2pa7 because we were boring during COVID...),
More information here:
https://github.com/BrunoLevy/learn-fpga/
I am super excited, can't wait to see whether these 200 lines of VERILOG can be turned into a real Risc-V CPU on a chip !
https://cdn.fosstodon.org/media_attachments/files/115/722/457/209/326/108/original/e7b023b08b241bb2.png

2025-11-16 19:46:34 UTC

learn-fpga works (almost completely, SPI flash is on its way) on tang-nano-9k !
Thank you for your help @nprofile…shwv !
What is it ? Learn to design your own processor with a FPGA in 18 simple steps
What's new ? Now works with tangnano9k FPGA board and opensource toolsuite
Why does it matter ? Because tangnano is cheap
Tutorial up to date here:
https://github.com/BrunoLevy/learn-fpga/blob/master/FemtoRV/TUTORIALS/FROM_BLINKER_TO_RISCV/README.md
https://cdn.fosstodon.org/media_attachments/files/115/561/077/759/574/278/original/0255fe1a8448e563.mp4

2025-11-10 21:00:12 UTC

AI, AI, AI everywhere, but I prefer...
... a more elegant weapon of a civilized age !
https://cdn.fosstodon.org/media_attachments/files/115/527/408/607/404/063/original/2229c2cb497e1b3c.jpeg

2025-11-10 18:13:12 UTC

- reply

@nprofile…00p2 yes, my motivations were:
- faster for my use case (and it is not negligible, in multithreaded code, avoiding dynamic allocation can be good...)
- easy to compile for folks running Windows (gmp takes 10 min to compile when installed through vcpkg)
- possibilities to try several optimizations and easily do non-regression tests

2025-11-10 15:34:01 UTC

You are doing geometry processing, you need precision, performance, and easy compilation on Linux/Mac/Windows ?
My fork of the mini-gmp lib is available here:
https://github.com/BrunoLevy/mini-gmp-plus
Use it wisely ! (with great power comes great responsibilities...)
Image credit: Ed Sheeran
https://cdn.fosstodon.org/media_attachments/files/115/526/126/563/868/495/original/d30f5910e5a5da0f.png

2025-10-31 15:54:45 UTC

https://github.com/BrunoLevy/learn-fpga has just reached 3000 stars on github.
What is it ? a hand-on tutorial to learn processor design with FPGAs.
In a couple of evenings, you will create a full-fledged Risc-V.
Why would I want to do that ? Why not !!
https://cdn.fosstodon.org/media_attachments/files/115/469/585/989/648/193/original/b1acd09960340e91.mp4

2025-10-30 16:15:21 UTC

Oops, once again I spilled some aperiodic coffee !
https://cdn.fosstodon.org/media_attachments/files/115/464/004/486/477/055/original/0dac8cb128565ff0.png

2025-10-09 08:00:17 UTC

#geogram 1.9.7 is out !
Geogram is a software library of geometric algorithms, it has mesh intersection, remeshing, CSG, Delaunay and Voronoi in 2D and 3D, constrained Delaunay triangulation in 2D ... and much more !
New in this version: improved compatibility with OpenSCAD.
https://github.com/BrunoLevy/geogram
https://cdn.fosstodon.org/media_attachments/files/115/343/149/477/496/085/original/347a61fcbe7d3c8a.png

2025-04-30 16:30:15 UTC

Let's try to do smthg by hand
Generating this starter pack used considerable resources
- at least 10 ml of ink
- a sheet of paper
- 5 min of my time (one can guess it is not more, but at least it looks like no other one)
https://cdn.fosstodon.org/media_attachments/files/114/427/861/165/401/981/original/d2c90bdc48bc64e5.png

2025-03-20 13:27:41 UTC

Fun with Gallouet-Merigot scheme:
Semi-discrete fluid sim with cubes.
https://cdn.fosstodon.org/media_attachments/files/114/194/987/262/126/185/original/a6d3aff24b2e5ad1.mp4

2025-01-16 08:15:50 UTC

Rendering donuts with just shifts and adds, down the rabbit hole (amazing blog post by aik0n:
https://www.a1k0n.net/2025/01/10/tiny-tapeout-donut.html
https://cdn.fosstodon.org/media_attachments/files/113/837/033/395/154/166/original/cc87d0ef6dea7a3c.png