sphw

5 ms·

1.
by sphw 2y ago
I've never seen anyone use Barnes-Hut for an earth gravity model. I'd be curious to see how an implementation like that would work. I think Barnes-Hut is typically used for large N-body simulations where each particle moves indepe
2.
by sphw 2y ago
Fair point. We will fix the language up
3.
by sphw 2y ago
Yup, your understanding is correct. When set to full fidelity, it computes and sums 2,331,720 terms. What we optimized is the way the spherical harmonics are generated, which allows for the generation and summation to happen in less than 25
4.
A better approach to gravity: how we made EGM2008 faster(elodin.systems)
88 points by sphw 2y ago|23 comments
5.
by sphw 3y ago
At the risk of exemplifying the coder turned physicist turned coder again, I think we are really talking about two slightly different fields here. There is the world of computational physics, which we haven't specifically built this to
6.
by sphw 3y ago
Thanks for looking into it more. I was able to reproduce. We will get that fixed ASAP
7.
by sphw 3y ago
Yes you can use Nox separately today. https://github.com/elodin-sys/elodin/tree/main/libs/nox . It just hasn't been released on crates.io yet, and no promises about stability. I mentioned this
8.
by sphw 3y ago
Yeah we are huge fans of Bevy, and heavily inspired by their API. Mutability is tricky in XLA / JAX's computation model. Its optimizations rely on a purely functional style of programming, and so we've tried to map that onto
9.
by sphw 3y ago
We can't seem to reproduce that issue on Firefox. Is it possible you have animations disabled or some other setting?
10.
by sphw 3y ago
For me, it boils down to 3 reasons. One is that the JAX tracing process can get a little slow for more complex programs. By bringing Jaxprs into Rust, we can optimize the compile path more. This doesn't matter for small simple programs
11.
by sphw 3y ago
You can try out the frontend online at https://app.elodin.systems/sandbox/hn/cube-sat or you can install the desktop version using pip: `pip install elodin` and then run `elodin editor cube_sat.py` against this fi
12.
by sphw 3y ago
Yeah we totally will have a free-tier for students / non-commercial. Our long-term plan is to replace Simulink & MatLab as the de-facto student tool
13.
by sphw 3y ago
Re: Gazebo - it's possible, but IMO Gazebo likes to approach things from a slightly different angle. Gazebo uses, mostly, config files to create your simulation whereas we prefer people to use code. Someone could certainly build a phys
14.
by sphw 3y ago
Yeah I recently found out about `nox` in the Python world. That combined with someone squatting the crates.io name might make us change it completely. Our Python library right now installs as `elodin`, and we might just stick with that
15.
by sphw 3y ago
We were curious as well, but after some research when we named the company we discovered that names (even distinctive ones) can't be copyrighted just trademarked. Of course IANAL, so do your own digging :)
16.
by sphw 3y ago
Yeah we totally intend to build out good wind and motor models for drones. We are still building out are component library, and trying to decide exactly what to prioritize
17.
by sphw 3y ago
You are completely correct; right now it is just mechanics that we have built out. But, there isn't any theoretical reason you couldn't use this framework for other types of simulation. In particular, the Monte Carlo runner is sup
18.
by sphw 3y ago
We completely agree. We want to develop a series of prebuilt modules for various components (motors, IMUs, star trackers, etc). The goal would be to let people easily test out new configurations quickly by just changing the code. Ideally, t
19.
by sphw 3y ago
Yes! We are big fans
20.
Show HN: Elodin – A better framework for physics simulation(github.com)
167 points by sphw 3y ago|50 comments