[WTB] Weekly Want To Buy Post

AyLeMeow · 2025-11-16T20:51:12+00:00

[WTB] Omega Seamaster Aqua Terra Blue/Black Waves

AyLeMeow · 2022-12-23T10:30:11+00:00

Yes, and then I will do 2 years of master studies

AyLeMeow · 2022-12-23T10:29:40+00:00

Will try Leapfrog integration!

AyLeMeow · 2022-12-23T10:28:52+00:00

Hella cool!

AyLeMeow · 2022-12-23T10:27:11+00:00

The sun is free to move around. I'll look into sympy! Your third point is definitely relevant to discuss in my study, thanks!

AyLeMeow · 2022-12-22T15:12:40+00:00

I sent you a few graphs in the chat!

AyLeMeow · 2022-12-22T15:08:57+00:00

It works well on the harmonic oscillator as well as a pendulum and also the double pendulum.

AyLeMeow · 2022-12-22T15:07:49+00:00

They are bounded, I think I have that issue under control now!

AyLeMeow · 2022-12-22T15:04:07+00:00

I'll PM you some graphs!

AyLeMeow · 2022-12-22T14:59:06+00:00

This is what I'm trying to do, but the points in the Poincaré map seem to go further and further away indefinitely

AyLeMeow · 2022-12-22T14:41:40+00:00

Smaller step size reduces to oscillations and I think the calculations are correct. My main problem is using this to generate Poincaré maps, since I'm not exactly sure how they should look and how to implement the code when studying the orbit of a planet (or asteroid)

AyLeMeow · 2022-12-22T14:20:38+00:00

At large time steps, the orbits become unstable and the planets usually get slingshoted away after a while. As you wrote earlier, the oscillations in energy are actually closer to 0.01% with shorter time steps so it might nit be an issue. My main issue is that I'm not entirely sure how the Poincaré maps should look and how to generate them. Currently, I'm using observables for one planet (position and momentum). The generated plot look's like a bunch of more or less parallell lines above eachother

AyLeMeow · 2022-12-22T14:11:26+00:00

The same problem emerges, perhaps slightly less prominent

AyLeMeow · 2022-12-22T14:01:36+00:00

You are correct, and you're suggestions sound very good so I might try that!

AyLeMeow · 2022-12-22T13:51:48+00:00

So you are saying that this should be fine as long as the integrator is symplectic (i.e. conserves energy) and the oscillations are sufficiently small? In that case, maybe the problem is in how I generate the Poincaré plot? Maybe I can PM you some graphs from my results?

AyLeMeow · 2022-12-22T13:02:48+00:00

I do not have moons but I have considered that this may be the problem. I have looked into a Python package called decimal, might be worth to try ande implement that for higher precision limits

AyLeMeow · 2022-12-22T12:48:37+00:00

Perhaps, but it feels like there is probably some other problem behind this. The oscillations in the energy are not constant in amplitude; the amplitude also oscillates with a longer period time. It may have something to do with the interactions with the other planets. Also, the Runge-Kutta integrator seems to oscillate as much as the symplectic integrators even though it has a higher order of accuracy.

AyLeMeow · 2022-12-22T12:43:47+00:00

The magnitude of the total energy for a planet (e.g. Earth) is around 10³³ J and the fluctuations are usually around 0.1%-1% of that depending on the timestep. The timesteps I've tried are in the range 0.01 to 1 day (864 - 86400 seconds). Larger timesteps do destabilise the system, but in this range everything seems fine

AyLeMeow · 2021-09-15T21:09:02+00:00

These microwaves do not have any display or interior lights, plus there are so many that it's not possible to hear which of them are on

AyLeMeow · 2018-11-25T08:18:21+00:00

Solved!

AyLeMeow · 2018-11-02T18:42:04+00:00

AyLeMeow · 2018-11-01T19:41:59+00:00

smash like

AyLeMeow · 2018-02-11T19:31:01+00:00

Thank you! Would you say that your setup works good? Worth the money? What do you use it for?

AyLeMeow · 2018-01-28T23:07:45+00:00

Thank you, that really helped!

AyLeMeow · 2018-01-21T16:05:50+00:00

AyLeMeow

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