The Nineteenth Byte

flawr

22:08

@Riker Yep it's awesome, I think we have a feed into Primes&Squares.

Riley

@LliwTelracs It doesn't seem all that hard. For every pair of stations generate a list of all paths between them (depth first search would work). Then for every order of station visits (e.g. A->B->C, A->C->B, B->C->A...) test every combination of paths until you find one that doesn't overlap.

Destructible Watermelon

Idea for a challenge: given a dictionary of string keys and string values, where the values are links, and one string, output whether, by following the link of a string key, by moving onto the string value, if it is a key in the dictionary, all the values eventually reach the one string

like how "every" article on wikipedia eventually leads to philosophy

Jan Dvorak

@Riley yeah, that would take ages

LliwTelracs

@JanDvorak At least I have already reduced the map to the valid rails only

Riley

@JanDvorak It would get the job done eventually

Sami Liedes

22:22

About the evolution of powers of two. I extracted the codes. Edit distance of #18 is 12 and that of #44, #47, #52, #56, #60 and #66 is 11.

LliwTelracs

Only took me about 5k characters of conditional statements

Sami Liedes

Proves, I guess, that editing and calculating edit distance by hand is too error prone :P

Jan Dvorak

/me Beats Sami with a wooden sign that says the single word "grandfathered"

Sami Liedes

s/56/57/

(Copying numbers by hand is hard too)

LliwTelracs

@Riley The adjacency matrix for the rails is something like a 70*n by 70*n table

orlp

22:38

wow this illusion is way better than the checkerboard

the spot in the middle is the exact same colour

Jan Dvorak

the same pixel value, or the same texture color?

Comparing the pixel values in face of wildly different lighting conditions would be a fatal mistake - an yet that's what everyone keeps doing when they call it an illusion

ATaco

@SamiLiedes I checked #18, And the two unaccounted for differences are two homoglyphs that don't actually effect the challenge. Seems like the mistake of a text editor more than anything.

orlp

@JanDvorak the lighting conditions are the same

those are the conditions of whatever room you happen to be in

Maltysen

@orlp which spot?

the middle of the x's?

orlp

@Maltysen yes

Jan Dvorak

22:45

Yeah, but those yellow and blue rectangles are either stained glass, or stained glass with very specific cutout in the middle, tuned to the camera position

Destructible Watermelon

oooooh

orlp

@JanDvorak what are you talking about

I could print this image out on paper

then you could take scissors

and cut out the middle x parts

Jan Dvorak

Then maybe. But I care about what the image represents, not what images are used to represent the images.

orlp

bring them together, and see that they are indeed the same color

Jan Dvorak

Your argumentation might pass here because you're vague enough, but it falls apart in the cylinder-on-checkerboard image

orlp

22:47

@JanDvorak that's an unreasonable position, would this optical illusion only become real for you as soon as someone stitches it in real life? or paints it on a painting

the fact is that your brain interprets a color wrongly based on surrounding information

that's the illusion

Destructible Watermelon

yeah ok stop whining. the entire point is that you can't imagine them being the same shade in the checkerboard cylinder illusion

regardless of whether its because of the lighting

Jan Dvorak

Then why does everyone keep calling the areas A and B in the checkerboard image "squares"? They clearly aren't. They're parallelopipeds.

Destructible Watermelon

what?

ATaco

Perhaps they are and the image was simply stretched?

orlp

@JanDvorak I'm not interested in arguing against your strawman.

ATaco

22:49

I'm not interested in argueing.

I'm interested in code golf.

Sami Liedes

@ATaco: Also, in #66 one extra change is merely a change in whitespace at the end of lines, which I don't think probably matters.

Jan Dvorak

I'm just saying your claim is being vague - and the less useful interpretation in real life.

And, the claims about the checkerboard image are blatantly false

Pavel

CMC: The exponential factorial: Given an integer n, output (((...(1^2)^3)^4)...^N)

Jan Dvorak

I take it you disagree with those other claims about "the squares being the same colors"?

I want you to delete that image

Destructible Watermelon

why?

Jan Dvorak

22:53

It offends me mildly - and your refusal to remove it offends me non-mildly

Kaz Wolfe

I don't think he can delete it anymore.

Rainbolt

It's not an offensive image, any more than your saying someone's claim is vague and not useful in real life is offensive

Kaz Wolfe

Needs a mod or a bunch of flags.

Jan Dvorak

Then trash please

Somebody cleared the "bunch of flags", unfortunately

Kaz Wolfe

more than one person.

Jan Dvorak

22:54

@Rainbolt I'm trying to be objective. Did I come up as ad hominem?

Rainbolt

Martin's avatar moved to the front. Is that an unintended giveaway that he took mod actions?

Riley

@Pavel Isn't that always 1?

Pavel

Yes, pretend it starts at 2

Kaz Wolfe

@Rainbolt basically, yes.

Jan Dvorak

I accept suggestions how to reword what I said

orlp

22:55

@Pavel that grows way too fast

Pavel

Is point

orlp

make it more interesting by doing it modulo a second input :)

Pavel

Sure, do that. It's a CMC after all.

orlp

oh actually it's fine

lambda n:1

that's my answer :)

1^2^3 = 1

Destructible Watermelon

@orlp yeah, I saw one like that before, with yellow and brown, but this one is better

Riley

22:56

@Pavel (((..(2^1)^2)^3)..^N)?

orlp

1^2^3^4^5 = 1

1 <- Pyth implementation

Pavel

I meant to say ((2^3)^4)^n

Sorry

Destructible Watermelon

that reminds me of when someone made a CMC that given input n output if n squared was prime

Mistah Figgins

(((((A^1)^2)^3)^4)...^B)?

Jan Dvorak

Let's just promise to not talk about optical illusions (air-quoted or not) here.

orlp

23:00

@JanDvorak how about no?

Martin Ender

@Pavel surprisingly fun to Golf in Mathematica: ##2^1&@@Range@#&

orlp

I've never had issues posting them before

a lot of people find them (mildly) interesting and discuss them

Pavel

@MartinEnder Which version is that?

There's like 4 now

Martin Ender

?

oh

your latest one

Pavel

Ok

Martin Ender

23:01

actually no

Pavel

I was about to merge the suggestions into:

Martin Ender

it's 2^3^...^N

Pavel

Revised CMC: Given integers A, B, and C, output ((...((((A^1)^2)^3)^4)^...)^B)%C

Martin Ender

so wrong associativity

Pavel

@MartinEnder I'm somewhat surprised to realize that I know how that works mostly, but what is ##?

Martin Ender

23:03

## is a sequence (like a splat) of all arguments. ##2 is the same thing but starting from the second argument. ##2^1 is syntactic sugar for Power[##2,1] then ##2 gets expanded so we get Power[2,3,...,N,1]

but like I said, unfortunately that's 2^(3^(...^N...))

Riley

@Pavel 05AB1E: ¹²GNm}³%

orlp

btw the challenge is equivalent to a^(b!)%c

Pavel

Not familiar with what a splat is... is it just a set?

@orlp oh, really? huh

Bah, math is hard

orlp

@Pavel assuming positive numbers, (a^b)^c = a^(bc)

Jan Dvorak

The fifth panel also applies to postmodernists.

Martin Ender

23:06

@Pavel no, it's just what the same thing is called in some other languages... it basically means that you insert a list without any "wrapper". {1,##,3}&[1,2] is {1,1,2,3} as opposed to {1,{1,2},3}, say.

orlp

@JanDvorak why are you so hostile? have I done something to upset you?

Pavel

@MartinEnder So, it's a list that flattens into it's parent list?

orlp

@Pavel it's quite intuitive

let's say you have (a^3)^5

Martin Ender

@Pavel basically

orlp

you can see that like this:

Pavel

23:08

@orlp No I know

orlp

a*a*a * a*a*a * a*a*a * a*a*a * a*a*a

Pavel

I just forgot

orlp

3 groups of 5

but that's the same as 5 groups of 3

Pavel

It's been like a year since I've done this whole Algebra 2 thing

Jan Dvorak

@orlp Not you specifically, but I don't like that people keep saying "ha! the brain is so stupid for thinking this image represents a 3d scene, and confuses the 3d scene with the image that represents it", while they themselves make the same mistakes.

orlp

23:08

or 1 group of 15

@JanDvorak again with the strawmen, I (nor did anyone else here) never mentioned that the brain was stupid for doing so, just interesting how the brain makes these kinds of mistakes

that's the whole point of optical illusions

Jan Dvorak

I keep saying it's not a mistake

Mistah Figgins

It's more like an assumption

orlp

and regardless of that, that's not the hostility I refer to

Pavel

Can some mod trash this entire optical illusion discussion? Pretty please?

Jan Dvorak

Well, I started with a question, to which you replied "what lighting condition are you talking about" as if the image was disconnected from any meaning

orlp

23:11

the part that's hostile is using comics that, when used as a reply to me, would refer to me as being 'smug', asking other users to self-censor mild jokes, abusing flags for that, constantly putting up strawmen and then attempting to argue against those straw men, and just in general being very argumentative and hostile

Destructible Watermelon

I got a pack of optical illusion cards once. its pretty cool

orlp

I just really don't appreciate it

Jan Dvorak

A targetted joke is never percieved as mild

and I, particularly, have trouble distinguishing mild/non-mild jokes. I can apologise for that.

I didn't mean to call you smug, what I meant to say that a big part of these illusions is that the claims are poorly defined.

Destructible Watermelon

basically its just that even after being told its essentially impossible to see the colours as being the same

without isolating them

Mistah Figgins

I have a KOTH idea:
Players submit a program in a 2d, self-modifying language (possibly the same one for all contestants, haven't decided) That fits in a certain size bounding box
The programs are put onto the same toroidal grid at different spots, and they compete to see how long their programs can run.
The key is that they interact with eachother, so if a program puts a "terminate" program" command somewhere, and another runs into it, the program that ran into it ends.

Destructible Watermelon

23:16

@MistahFiggins soooo 2d core war?

Jan Dvorak

Now that's an interesting note - and one worth making - that the brain does not provide the low-level information. I suspect it's because this data isn't even present because the eye only detects changes, not constant values.

Mistah Figgins

Essentially

Destructible Watermelon

impossible colours are also fun

Jan Dvorak

I had a 500-character reply prepared, but then I decided that a comic reference would be better percieved than anything I could say

orlp

@JanDvorak no, the low level information is definitely there

TuxCopter

23:19

Esolang idea: The program flow follows an Hilbert curve

Jan Dvorak

@orlp reference?

orlp

5

Q: How does the eye perform the equivalent of white balance?

Possible Duplicate: How can knowledge of human perception of color be used in photography? How does the eye perform the equivalent of white balance? Why is the camera not able to replicate it?

Jan Dvorak

That answer essentially says that color processing is intrinsically local, doesn't it?

> uses separate white balance on different areas

pretty much what the retinex filter emulates

- and has the same benefits as the retinex filter - it boosts contrast in favor of absolute brightness. It's a feature.

Destructible Watermelon

also, ever heard of eigengrau?

Eigengrau

Eigengrau (German: "intrinsic gray", lit. "own gray"; pronounced [ˈʔaɪ̯gn̩ˌgʁaʊ̯]), also called Eigenlicht ("own light"), dark light, or brain gray, is the uniform dark gray background that many people report seeing in the absence of light. The term Eigenlicht dates back to the nineteenth century, but has rarely been used in recent scientific publications. Nowadays, the phenomenon is more commonly referred to as "visual noise" or "background adaptation". Eigengrau is perceived as lighter than a black object in normal lighting conditions, because contrast is more important to the visual system than...

Jan Dvorak

The information that's lost is exactly the kind of information that you only really care about while trying to find the deficiencies of human vision

orlp

23:26

@JanDvorak it says it happens in the visual cortex, which means the low level information is there at the eye nerves

Jan Dvorak

The eye nerves carry differences, not (or only weakly) absolute values

at least in the peripheal vision

orlp

@JanDvorak you have to be more precise here

differences between what?

Jan Dvorak

The change of brightness over time. The eye wiggles a bit to convert spatial edges into temporal edges.

orlp

@JanDvorak ah but that's the crux, that happens only per sensor in the eye

and each of the tristimulus sensors are doing that on their own

no 'white balance' happens

Jan Dvorak

Except that the sensors seeing the flat areas stay completely silent. Only those that can see edges report any signal.

orlp

23:29

you can not have white balance until you combine tristimulus values not only cross-channel, but also non-local

Jan Dvorak

I'm not entirely sure about the details, unfortunately

orlp

@JanDvorak your theory also doesn't work for slow changing gradients, your eyes would not be able to perceive a very slight gradient in a direction orthogonal to your eyes wiggle

Jan Dvorak

Try fixating your eyes on a very slight gradient and you will notice it starts to disappear

` en.wikipedia.org/wiki/Filling-in

Downgoat

@JanDvorak can confirm. Does dissapesr

orlp

@JanDvorak alright, but here's the crux

you claim the whitebalance correction occurs due to this effect, but we also see that this effect works slowly on a gradient, then why does it work instantly on the optical illusion? even if the optical illusion is only flashed for a fraction of a second?

it's a different mechanic

Jan Dvorak

23:36

I expect most of it is given by the brain reconstructing a 3d scene from the image

if you see strawberries under strong blue light, you don't want your brain to think they're mold-grey and should be thrown out.

orlp

the brain is reconstructing a lighting scenario, and interpreting the image under that assumed lighting scenario, but that is not something that happens at the low level

that only happens in the visual cortex

the (objectively correct) low level information is there, and does make it to the brain

however we cannot access it, even if we are told of what is happening

Jan Dvorak

What happens if you flash the checkerboard image while focusing on trying to get the raw data?

orlp

@JanDvorak I don't know, or even how to test that

but I do have another testable idea

you can make many different versions of the optical illusion I showed

Jan Dvorak

On one hand, the raw stimulus should be more accurate, on the other you have trouble focusing the right pixels in the visual field

orlp

with different discolorations etc

and show people the image for 0.5 sec

and then ask them 'are the two centre colors the same, or not'

and then see if people do better than random chance

(assuming you told them the optical illusion beforehand, and that they must try to ignore that)

Jan Dvorak

23:41

Yeah, be sure to communicate clearly

orlp

my hypothesis is that people will not be able to do better than random chance

ASCII-only

@ConorO'Brien Not that I'm aware of

Jan Dvorak

What color difference do you want them to discern as different?

ASCII-only

Also yay i got an answer with >10 votes

Jan Dvorak

some colors are difficult to tell apart even when presented with the exact same surroundings

The same kind of difference as is between the "white squares" (lit) and the "dark squares" (lit) on the checkerboard picture?

Do let me know the results

orlp

23:44

I'm not planning on executing the experiment, sorry

Jan Dvorak

d'awww :-(

Wheat Wizard

@0 ' Congrats for doing 3 meta-reviews today.

0 '

@WheatWizard I nearly doubled my total number of meta close vote reviews today

Jan Dvorak

One nice effect I like is the color afterimage effect. It doesn't work for me very well, though.

DJMcMayhem

I'm about to post this soon. Does anyone have thoughts on it?

2

A: Sandbox for Proposed Challenges

Happy birthday V! code-golf ascii-art string V is a programming language that I wrote so that I could use and extend vim for code-golf challenges. The very first commit was on March 3rd, 2016, meaning that today V turns one year old! Woo-hoo Over V's first year of existence, there have been ...

ATaco

23:58

Looks good to me.

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