Proof that Factorio is deterministic

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Tertius
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Proof that Factorio is deterministic

Post by Tertius »

This is the proof why Factorio is indeed deterministic: there is no interference pattern at the screen.



(the screen are the lamps at the left, not the belt area in front. Those have a pattern due to the moire effect with image resizing)
This setup in general can also prove some fish are faster than other fish and actually be faster than the speed of light speed of the belt.
And it's proof I have too much time on my hands. But my internet was down yesterday evening.

Unfortunately, a blueprint isn't available - these kind of quantum physics blueprints are just too large.
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mmmPI
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Re: Proof that Factorio is deterministic

Post by mmmPI »

Tertius wrote: Sat Jan 04, 2025 9:59 pm This is the proof why Factorio is indeed deterministic: there is no interference pattern at the screen.
Uh ? I wish i understand what is the proof there x) Maybe a bit more explanation is required ?

I had made this setup some time ago : 112735 , lightning lamps based on "random" number. And i could "see" when/if there was pattern in the lamps, which gives an indication on wether or not the random generator is properly random.

I don't understand how one could proove something "deterministic" by a similar "absence of pattern".

Am i confusing things or missing something ?

Edit : you can use this website maybe to host the blueprint : https://factorioprints.com/
or just attach a .txt with it in it if it's more than 60K character for forum posts ?
I'd be curious to see the same with better definition :D, couldn't even tell the item on belt was fish :(
jdrexler75
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Re: Proof that Factorio is deterministic

Post by jdrexler75 »

In any case the proof of determinism is the ability of multiplayer games. If it wasn't deterministic, multiplayer games would desync. And in fact whenever a desync bug is fixed, it's because something was accidentally not deterministic.
Tertius
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Re: Proof that Factorio is deterministic

Post by Tertius »

The whole thing is a joke, of course. It's a Factorio version of the double-slit experiment. The double slit is on the right, the detector is on the left.

By the way, it cannot work in the first place, because it's always known which slit some fish will take. Previous builds had the double slit in the middle, so it wasn't that clear, but fish accumulated in front of the slits. I guess I sent too many fish, so there are no "fish waves", so there is no coherence.
mmmPI
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Re: Proof that Factorio is deterministic

Post by mmmPI »

Tertius wrote: Sun Jan 05, 2025 1:24 pm It's a Factorio version of the double-slit experiment.
A quick wikipedia search made me realize i knew this, but didn't recognized it :roll:

Now i can only admit the proof that fish aren't waves is quite compelling :D
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Re: Proof that Factorio is deterministic

Post by waterBear »

OK, I'll bite. (No pun intended, since fish seem to be involved).

I took 2 semesters of quantum as an undergrad, but I don't get how you're simulating a solution to the Schrodinger equation here. If you feel like explaining, I'm curious.
Tertius
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Re: Proof that Factorio is deterministic

Post by Tertius »

Well, it's not really an experiment that follows some theoretical equations you do before the experiment. From a physics point of view, it's totally nonsense (not just from a physics point of view).

It started by making a huge field of interconnected splitters out of boredom. If you feed items on all of the entries, you get surprising patterns on the output. Some items are even a bit faster than the speed of the belt, probably due to how the engine handles items within a splitter in a congestion situation. The pattern reminded me of interference, but actually it isn't interference of course, because the game engine doesn't have an idea about that. It's perhaps more the result of a Moiré effect.
But that doesn't kept me from trying to find out what happens with the patterns if I send items just on 2 specific inputs. Could produce this maxima and minima in the distribution? Water waves can interfere as well after all, so I gave it a try.

Other ideas of mine, usually connected with the circuit network, usually result in more productive results. This one was just fun.
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Re: Proof that Factorio is deterministic

Post by waterBear »

Tertius wrote: Mon Jan 20, 2025 4:21 pm Well, it's not really an experiment that follows some theoretical equations you do before the experiment. From a physics point of view, it's totally nonsense (not just from a physics point of view).

It started by making a huge field of interconnected splitters out of boredom. If you feed items on all of the entries, you get surprising patterns on the output. Some items are even a bit faster than the speed of the belt, probably due to how the engine handles items within a splitter in a congestion situation. The pattern reminded me of interference, but actually it isn't interference of course, because the game engine doesn't have an idea about that. It's perhaps more the result of a Moiré effect.
But that doesn't kept me from trying to find out what happens with the patterns if I send items just on 2 specific inputs. Could produce this maxima and minima in the distribution? Water waves can interfere as well after all, so I gave it a try.

Other ideas of mine, usually connected with the circuit network, usually result in more productive results. This one was just fun.
My naive guess would be that it depends on the initial state of the splitters, which is probably more-or-less random. Splitters remember the last item of a given type that passed through them and switch its output. If you lay a million splitters, I can believe their oscillations would appear pseudo-random. It's like that peg board when you drop a ball on the top. If I recall right, you get a Gaussian distribution on the outputs. That's what I'd naively guess here, just washing everything out and saying that each splitter "randomly" shuffles with 50/50 odds, where the randomness comes from the initial state of a million splitters.
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