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Author Topic: Accuracy/length of time  (Read 4710 times)

digitalbeachbum

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Accuracy/length of time
« on: May 23, 2011, 02:37:22 AM »
I'm curious if there is a problem with the game when you speed things up to pass time quicker?
For example. If you take the stock solar system which is given, then speed it up so that every second is 1,000 years, by the year 4000 all the planets have flung out of the solar system.

I find this highly inaccurate for the result of only trying to speed up time in order to see a quicker end result. None of the planets from our sun will be flung out of orbit in 4000 years. So what is going on?

Bla

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Re: Accuracy/length of time
« Reply #1 on: May 23, 2011, 07:24:42 AM »
It's not a bug, it is bound to be more inaccurate when the simulation is faster.

Every time step, the position of everything in the simulation is calculated. If you have a planet orbiting a star, and the planet takes 8 days to orbit the star, the simulation will be fine if the time step is 1 minute or even 1 hour (if the time step is 1 hour and the orbit is 8 days = 192 hours, the orbit will appear as a circle with 192 edges). But if you speed up the simulation to 1 day, you will get an octogonal orbit, and it will be extremely unstable. If you increase it more than that, the planet will probably be flung into space.

Maxpm

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Re: Accuracy/length of time
« Reply #2 on: May 23, 2011, 01:33:17 PM »
If you have a powerful computer you can crank up the "1 real second = ..." option.

digitalbeachbum

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Re: Accuracy/length of time
« Reply #3 on: May 24, 2011, 03:21:58 AM »
After I posted my message I thought that maybe my computer was not powerful enough to provide accurate results at the extremely fast time step (1 sec = 1000 years). So I let it run at the default speed and after several thousand years all the planets were thrown off the star and in to outer space.

I am now running a simulation where (1 sec = 1 day) and will let it run.


Bla

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Re: Accuracy/length of time
« Reply #4 on: May 24, 2011, 09:26:35 AM »
Because the time step is the time between each calculation, every computer is equally accurate at the same time step. But with a faster computer, the simulation will appear faster on lower time steps, because it can make more of those calculations in the same amount of time.

Using the "1 sec = x amount of time" is pretty much opposite, where every computer is running the sim equally fast, but not equally accurate.

Triplanetary

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Re: Accuracy/length of time
« Reply #5 on: May 26, 2011, 04:29:41 AM »
Using the "1 sec = x amount of time" is pretty much opposite, where every computer is running the sim equally fast, but not equally accurate.

Ah, I didn't know this. In that case, I can't wait to get my quad-core gaming PC repaired. :D