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5:03 PM
And ... that's how you cause a room to be dead, folks!
 
hooray
 
@Zacharý Me showing up?! 'Cause that's what usually kills the room! :D
 
no old people allowed! (jk bye!)
 
@Riker you have use Julia before right? Are you familiar with how to do more complex distribution of tasks rather than @parallell
 
Isn't it only one l at the end?
@Downgoat It's @parallel I think.
 
No. Autocorrect should've helped you there.
 
but it didn't which is autocorrect's fault
 
export Executable
iota(n)=array[\ZZ32\](n).fill(fn(x)=>x)
run(args) = do
    u = iota(20)
    v:ZZ32 := 0
    for i <- 0#u.size() do
        v := i
    end
    println(v)
end
Yeah. That's pretty much random number generation in Fortress.
(Parallelism in the for loop)
 
@Zacharý What part is the random generation one?
 
5:20 PM
It's not really random generation, it's just Fortress using parallelism.
(There's probably an actual way to do it)
 
@Zacharý Ah, I get it. It isn't random. It is shuffle.
 
Well. It also uses the last value... effectively making it a random int in the range [0,20).
 
@Zacharý Love how you're excited about Fortress instead of APL – only to go ahead and implement APL primitives in Fortress
 
Iota would be something like iota(n)=<| x | x <- 0#n |>. But, with the incomplete implementation I have ... the long iota(n)=array[\ZZ32\](n).fill(fn(x)=>x) will have to do.
 
5:28 PM
@Zacharý Equivalent (I think) APL: v⊣⎕TSYNC {i~←v,←⊃i}&¨i←⍳20⊣v←⍬ However, the timing always results in the original order.
 
@Adám APL emojis make me go ⍨
 
question: what should the command , do in ,,,
 
@totallyhuman Quine of course.
 
eval
 
@Uriel
 
5:30 PM
@Adám it'd be a cheating quine though
@TwiNight ooh good idea
 
, puts',' to the stack with default output, would that be considered a cheatingquine?
 
Link on definition of cheating quine?
 
by definition, 1 byte quine is always cheating
@Zacharý one second
 
I know reading the source code directly is definitely considered cheating.
 
5:32 PM
21
A: What counts as a proper quine?

Martin EnderWe've been discussing this in chat recently, and coming up with a solid definition seems difficult. The best idea I've got is to base a definition for a true quine on the principles given on this page: a true quine will in one way or another consist of data, and code. The data represents the code...

 
@totallyhuman How about return language name?
 
@Adám If he only outputs the top value of the stack ... ,,, would be a quine.
 
huh
> It must be possible to identify a section of the program which encodes a different part of the program. ("Different" meaning that the two parts appear in different positions.)
i mean
it's valid...
i think
and it's not an extremely dirty builtin)
 
@Adám In my opinion, Fortress (specification) > APL > Fortress (implementation).
How is , => ',,,' not an extremely dirty builtin?
 
i mean it stands for something...
 
5:40 PM
Pretty sure there are other (esoteric or not) languages that have built-ins for the language name
 
2
Q: Reverse a Rubik's Cube Algorithm

Julian LachnietWhenever you make a move on a Rubik's Cube, there is a reverse move which undoes the first move. Because of this, every algorithm (set of moves) has a reverse algorithm which undoes the first algorithm. The goal of this challenge is to find the reverse of a given algorithm. Specification: The ...

 
Yeah, , => ',,,' sounds fine.
Do you have commands for concatenation?
 
@Rod I just finished solving this. Has anyone else tried.
 
@WheatWizard doing it
 
I'm attempting it right now.
 
5:53 PM
Looks cool I'll work on it
 
@Zacharý I see. What is it that Fortress Spec has which makes it superior to APL? All the built-in maths?
 
It's just my opinion, (to me) it's more of the fact that it stays closer to mathematics than APL does. That makes the specs better then APL in my opinion.
(Also, you can use ASCII)
Fortress isn't perfect, as I realize, no language can be.
 
Why are they doing \- you don't need to escape if it if it's outside a character class >_>
 
That threw me off as well for a bit
 
same
 
6:05 PM
Can someone explain what [AOB?] means? Is ? the literal ?
 
yeah
finished it
that threw me off for a bit too
 
Could it be the literal ?
 
^ ^^^^
 
It would have to be actual character ?.
Because the ? metacharacter doesn't make sense inside of character classes.
(I'm assuming you're talking about regular expressions)
 
It is the literal ? character
 
6:12 PM
@Zacharý python does.
 
@Uriel No. Why would there be ongoing revisions to the language if it was perfect?
 
To make it perfecter.
 
<look of disappointment here>
 
ಠ_ಠ
 
6:27 PM
@Zacharý I wasn't talking about python 3. I was talking about python float('inf').
 
1.0/0.0.
 
0
Q: n * k = dd0d00d where d = ...?

ArnauldGiven a positive integer n ≤ 500: Find the smallest positive integer k such that all digits in the decimal representation of n*k are either 0 or d, with 1 ≤ d ≤ 9. Print or return d. Easy examples The first 30 values of d are given below: +----+-------+---------+---+ +----+-------+------...

 
0
Q: Remember IP5 challenges? Why not BP10?

ChristopherI would like to propose a set of 10 basic challenges meant to be an intro to code golf. It would cover pop-con, golf, bowling, challenge, koth (iffy), CnR and other types. They would be listed on the FAQ as beginner challenges. All of them allow any language to compete even new ones. What do you ...

 
@betseg Isn't Mercator an infinite projection? I think this is cropped just less so than normal
 
6:32 PM
yeah we cant see quarks anyways, also north pole is cropped too
 
Still cool
 
why have I not implemented sorting in SOGL...
 
You're the creator of SOGL?
(I *almost* made the same mistake of not having it be a 1-byte atom ...)
 
what should sort do on an array with strings, numbers and arrays?
 
Let's see what CJam does
It dies a horrible death
 
6:41 PM
makes sense
 
It doesn't really make sense to sort with multiple types anyway
 
@dzaima You could do it JS style and convert them all to strings if necessary.
 
@dzaima Something, anything is better than nothing
 
@TwiNight obviously
 
And my suggestion is something.
 
6:43 PM
I think 2 important philosophies of golfing language design are minimize error states and reasonable defaults
 
I'm thinking vectorize on arrays, and either numbers convert to strings or sort each type separately and then join them together after
or sort each run of types separately
 
^
@dzaima This one. This one is probably the best option.
 
k then
 
7:00 PM
I finished the regex puzzle.
 
0
Q: A Simple Patttern

DurgaInputs: 1> any two digits (m,n) 2> any two char (a,b) Output: 1> m times char a, 2> m times char b, 3> total char in output will be 'n' Cases: 1> Input: m=2,n=4,char1 = A,char2 = B; Output: AABB 2> Input: m=3,n=8,char1 = A,char2 = B; Output: AAABBBAA 3> Input: m=4,n=3,char1 = A,char2 ...

 
^ seems like it's been copied from somewhere
 
Where though?
These are called the Dennis numbers: oeis.org/A263172 (not related to the above)
 
whoa
hold up he has a sequence of numbers named after him?!
 
> Called Dennis numbers as a tribute to user Dennis for winning the robbers' part of The Programming Language Quiz of the Programming Puzzles & Code Golf Stack Exchange website.
 
7:08 PM
whoa.
 
62
Q: Generate Dennis Numbers

Helka HombaThis challenge is a tribute to PPCG user Dennis for winning the robbers' part of The Programming Language Quiz. Looking at Dennis' PPCG profile page we can see some pretty impressive stuff: He currently has over sixty-eight thousand reputation, making him second in rep overall, surpassing thi...

 
2
A: Generate Dennis Numbers

DennisJelly, 33 bytes (non-competing) ṚḌ= =ċ0^2°;ḌÇ DŒ!Qç@ÐfDL©Ṡ>ѵ#Ṫ,® Try it online! How it works DŒ!Qç@ÐfDL©Ṡ>ѵ#Ṫ,® Main link. No arguments. µ Combine the chain to the left into a link. # Find; execute the chain with arguments k = 0, 1, 2, ... ...

 
Oh. I feel stupid. This was before Jelly was made, wasn't it?
 
Probably.
 
Wait, are mathematica comments (* ... *)?
 
7:12 PM
Hold up what happened to this person
 
Oh let's not get into that again
 
I'm surprised that I've never heard anything about that user before (chat search gives me a general idea of what happened)
 
oh no more parsing java to javascript with regex
 
@dzaima What do you mean?
 
@Zacharý I made SOGL in Processing (aka less verbose java) and I wanted a javascript SOGL online interpreter
and then this happened
 
7:21 PM
Isn't there a Processing => Javascript thing already available?
 
it doesn't do everything
 
What do you mean "it doesn't do everything"?
 
it doesn't contain all the java classes
 
Which classes do you need that it doesn't have?
 
it's bad with functions with the same name but different parameters
 
7:24 PM
@dzaima Oh ... that.
 
Collections.sort() :p
 
I like how one of the foobar challenges I think I've already answered here
 
@dzaima Well ... good luck with that.
 
Probably just making a Collections class that redirects to arr.sort will be good enough
why do I even try to support the java version actually
 
10
Q: Combinatory Conundrum!

Qwerp-DerpIntroduction: Combinatory Logic Combinatory logic (CL) is based off of things called combinators, which are basically functions. There are two basic "built-in" combinators, S and K, which will be explained later. Left-associativity CL is left-associative, which means brackets (containing stuff...

 
7:31 PM
I hate it when I'm trying to insert the character and accidentally click alt+ctrl+left arrow and it rotates my screen
 
For what purpose do you need ?
 
wait, there's a shortcut for an arrow?
what is it?
 
that's SOGLs evaluate as javascript character
I made an AHK script for SOGL characters
 
oh
lame :)
 
I was gonna test my sorting function and gave the input [1,2,3,4] -_-
 
7:37 PM
0
Q: The sum of consecutive odd numbers

musicman523Although related challenges have been asked, this one is different to warrant its own question. Challenge Given a positive integer, return the largest sequence of consecutive odd numbers whose sum is the given integer. If no such sequence exists, you may report an error in whatever way makes ...

 
hi all.. have we had fastest-code questions where there is a max size on the code?
 
Yes. I've limited the code size in one or two to prevent hardcoding.
 
@Dennis that's interesting
I either what to limit the time and have code size as the objective or limit the size and have time as the objective
I quite like the idea of limiting size as it somehow punishes languages such as C which are normally fastest
 
Quick question for clarification: PeterTaylor's post on What is a programming language? says a language needs to support tuples. Does that mean a lang needs to have some way of storing multiple values associated with each other, that it can take multiple inputs, that it can have tuple output, or something else?
 
The definition of a language is pretty much vestigial at this point answers are not required to be in languages.
 
7:47 PM
ok just posted a slightly bonkers challenge to the sandbox :)
I hope at least someone enjoys
 
@Lembik If you're going to use a long random number, you at least have to explain what's so special about it :P
 
@StepHen I am changing it to something more special as we speak :)
 
@Adám from hat I can read from that it looks like sorting runs of same type would be more practical (and SOGL doesn't have imaginary numbers)
 
Does every OEIS entry have a text file like this? https://oeis.org/A263172/b263172.txt
 
7:59 PM
@Zacharý afaik yes
@StepHen It means it needs to be able to store multiple values in memory at once.
This can be a stack, variables, whatever.
 
@Phoenix Oh, that makes more sense. Thanks.
 
@Phoenix That reminds me that I wanted to make a language where the only data that the program can deal with is a single BigDecimal :p
now I have 3 languages that I want to make :/
 
AFAIK that would be possible (but it would take ... a lot of work to get anything)
 
0
A: Sandbox for Proposed Challenges

LembikThe task Your code should take in an integer 0 < x < 15452417011775787851951047309563159388840946309807 and output the smallest integer m such that x^m mod 15452417011775787851951047309563159388840946309807 = 1. You may take the input in any format that is convenient and output in any conveni...

 
Oh god. This again.
 
8:05 PM
17 mins ago, by Lembik
ok just posted a slightly bonkers challenge to the sandbox :)
 
By "This" I mean inversion.
 
aw man
 
Yep. No builtins.
 
out-golfed by 30 bytes ><
 
On what?
 
8:09 PM
You've only got half a code-page (if you're using your language) so you can cut ~15 bytes once you fill your code-page (theoretically)
 
In ,,,?
 
@StepHen 15 bits* pretty sure
 
@dzaima I was saying that theoretically, once you have double the operations, you'll have half as much code (not in practice though)
 
@StepHen I challenge you to fit 30 * 7 bits in 15 * 8 bits :p
 
@dzaima no no no no, if you've only implemented ~128 operations, the other 128 bytes are no-ops, right? So once you make them do something, you (theoretically) can do twice as much
 
8:13 PM
5
Q: The sum of consecutive odd numbers

musicman523Although related challenges have been asked, this one is different to warrant its own question. Challenge Given a positive integer, return the largest sequence of consecutive odd numbers whose sum is the given integer. If no such sequence exists, you may report an error in whatever way makes ...

 
question updated on the sandbox
did it actually appear here??
 
Yeah, it did.
 
oh yes it's above
please let me know what you think of the new version
 
@Lembik Yay, no more arbitrary numbers :)
 
@StepHen :)
unless you think the prime after 2**100 is arbitrary of course :)
 
8:16 PM
@StepHen if the rest of the 128 operations are just 1-byte equivalents of 2-byters, then you'd save a byte every 256*256/128 = 512 bytes
 
please add comments if you see any problems or if you love the question :)
 
8:27 PM
0
Q: Let's code a faster combination generator for R

skanSome days ago I found that R combn function is very slow. That function it's used to generate all combinations of the elements of x taken m at a time. I was specially interested in m = 2. Then I tried different alternative packages and found that combinat, iterpc, and other packages are able ...

 
CMC: Prove that forall n > 0: 2**n will contain a digit other than 1 and 0 in base 5.
 
8:44 PM
@WheatWizard for(i=1;;i++){if(!Math.pow(2,i)%5){console.log(false);break;}} I think (infinite loop is truthy)
 
another question :o
 
@WheatWizard waiting for a scheme-1 answer :p
 
@StepHen Thats not a proof. :p
I don't actually know if its true, I've verified it up to the 200,000th power of 2 but I have not been able to prove it.
 
@WheatWizard OK, I'll hazard a proof. The only numbers only 1s and 0s in base 5 are 1 and any number divisible by 5. 5 is not a prime factor in 2**n, and 2 is not a factor in 1. QED
@WheatWizard ofc you didn't say n is an integer, so the answer is n = log2 5
 
Sorry n is an integer
> The only numbers only 1s and 0s in base 5 are 1 and any number divisible by 5.
Why is this the case
Well to be frank this is false
 
8:50 PM
@WheatWizard oh wait, 11111 et al
My proof is only valid if 11 is not allowed as the end of the number
 
1
Q: Reduce the list to a final number

HenryInputs A list (array) of numbers, or numerical strings if that makes it easier. You can assume there will always be at least two elements in the list and every element will be a natural number (integer larger than zero). Outputs A single number, or again, a numerical string Problem The idea ...

 
It is a proof that it must end in 1 which is probably useful
 
@WheatWizard Now it's a different problem
@WheatWizard Prove that no base-10 number ending in 6 or 1 is a power of 2
 
are there any numbers only made of [0123] above 2^20? From my 1000 I got from SOGL there are none
 
@StepHen Powers of 2 can also end in 01, for example 1048576 is 232023301 in base 5
 
8:55 PM
First shop I've seen that uses an instrument for scale: ohmspeaker.com/speakers
 
@StepHen Ummm... by power I'm assuming you exclude 2^0.
 
0
A: Sandbox for Proposed Challenges

ChristopherMake me some ASCII cities! Your job is to pseudo randomly generate ASCII cities (top down view) with n building per row with x rows. Each house should have a number label starting with 000 and working up. First number is the row (assume x<9) and the other two are places in the row. i.e 000, 001,...

Would you VTC my pop con
 
I don't think that testing numbers wouldn't lead to success as the chance that a 100 digit number would only contain 1s and 0s would be (2/5)^100 :p
 
@dzaima I've checked up to 2^200000 and found none
 
@Zacharý Ignore that line, it's dead wrong, I waited too long to delete it
 
8:57 PM
At 5PM EST if my sandbox gets no more feedback I will be posting
 
@dzaima I'm getting that feeling too. Thats why I was hoping to make a proof.
 
@Zacharý And that was part of the spec, but 2^4 == 16
 
We can prove that they are all powers of 16, because only powers of 16 end in 1 and nothing ends in 0.
 
@Christopher It'll get closed fyi
 
@StepHen Pop con?
 
8:58 PM
@Christopher Pop con where creativity is objective winning condition (aka creativity isn't)
 
question: why is this looping infinitely
 
@StepHen Hmmm. But pop con should be objective :_(
Because popularity is objective
 
@Christopher You need an objective winning condition that is separate from popularity, aka, describe the perfect program, and people vote on how close it is to that
 
Because they are multiples of 16 their digits must sum to 4 as well.
(or a multiple of 4)
 
@WheatWizard I'm gonna guess that it's perfectly possible but just rare
 
9:01 PM
@WheatWizard Dunno if this means the same thing, but it must have an even number of 1s to even be even
 
@StepHen Ahh
 
@StepHen Its a slightly weaker statement but correct.
 
6 mins ago, by totallyhuman
question: why is this looping infinitely
anybody pls ;-;
 
@totallyhuman i and i/10 are always True, the list never changes
and what does i start as?
 
What are we trying to prove?
 
9:06 PM
29 mins ago, by Wheat Wizard
CMC: Prove that forall n > 0: 2**n will contain a digit other than 1 and 0 in base 5.
 
In order for 2^n to contain only 1s and 0s 2^(n-1) must contain no 4s or 1s
 
@WheatWizard in what base?
 
Base 5
because when you multiply by 2, 4 can become either 3 or 4 depending on whether or not there is a carry. And 1s can become either 2 or 3 depending on the carry.
Ok I think I have a proof
 
:O
 
Jim
Someone knows Pyth here?
 
9:21 PM
@WheatWizard Try it online! times out for me, not at home atm. This would find it right? (if it existed)
 
looks like it
 
Okay, say the proof!
 
typing it up
 
Does anyone here have an Amazon Business account?
 
Never mind it doesn't work
 
9:23 PM
@WheatWizard Can you give us the gist of it anyway?
 
Guess we'll just wait for Dennis.
 
I have a promo code for a free Amazon Echo Dot when purchased with a business account
Can anyone with a business account get it shipped to me?
 
The idea was to prove that the first digit must be 3 (a premise which is false) and use that in combo with induction to prove that none exist.
 
We can generalize this, right? Given bases a and b, where a > b, can b ^ n be expressed as a sum of ((a ^ n || 0) ... (1 || 0))?
 
We can't even solve this special case, I would wait a bit before generalizing.
@StepHen Here's my Haskell to check
I've already checked up to 2^1000000
 
9:28 PM
@WheatWizard OK, there's a pattern: Try it online!
on the left side
it's like 32142113213214211... or something
I'm no good at this, but figure out the pattern and you can eliminate a bunch more
 
I'm guessing someone will eventually ask this on Math SE?
 
Hopefully we will prove this by ourselves
 
We have a Dennis if necessary.
 
Yeah I want to get this solved before the real mathematician shows up.
@StepHen What is this pattern?
Oh yes the leading digits
yes we can use this pattern, we can also use the second to last digits because they are periodic
 
@WheatWizard Try it online!
 
9:34 PM
@WheatWizard shouldn't all the digits be periodic (if looking from the end)?
 
@WheatWizard Exponents of 16 that start with 1: Try it online!
 
@dzaima yes and from the front
 
someone make a program that finds each digits cycle
 
@dzaima I have to drive home, but here's a base for you if you know Python
8 mins ago, by Step Hen
@WheatWizard OK, there's a pattern: Try it online!
 
The first and second to last digits line up 5 times every 45 powers of 16.
Here's the order: x x x x x x 1 x x 1 x x x x x x 1 x x 1 x x x x x x 1 x x x x x x x 1
1 means both are 1 or 0 x means one of them is not
 
9:40 PM
I feel like there should be a nice mathematical equation to find the xth digits cycle
 
There is I don't remember what it is. tbh we probably have a ppcg question about it
 
I think I'm going to be inspired to make a bunch of challenges involving prime bases after this discussion :P
 
oh is that the reason this is so hard in base 5. Didn't think of that
 
@dzaima Well kind of, it's because base 5 and base 2 don't share any factors
 
I've done something like the digit cycles with a (failed) hypothesis I had about cellular automata diagonals.
Can anyone find a pattern here?
1243
00013120124443132432
0000012000013200120131243244312013244320124313131244444324444312443243132012001324312001243201313132
000000012431201243243243200132443131320124320012000132013132013120131324443131244320012431320001200131243120000001312443131201201313120013200001313131201320120132000132444320001243244432431201312001201243124431243200001244313244443243244444312012001244444443201324320120120124431200131312432012443244431243131243132431312000131320012443201312444324431320132444444313200131324324313132443124444313131324312432431244431200012444320120001201
 
9:48 PM
that's... big
 
Digit cycles.
 
I'm wondering if the growing leading zero columns have anything to do with it.
 
what are those zeores anyway?
 
Well one hint we get is that the number of 0, 1, 2, 3, and 4 are consistent accross each row (with the exception of the first row, which has no zeroes).
In the first one, there is 1 of each digit. In the second, 4, the third, 20, and the fourth, 100.
4 * 5 => 20, 20 * 5 => 100.
 
Um...can anyone find the pattern for the digit with the value n*5^5?
 
9:54 PM
The run-lengths of the second part are [3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1]
The first part of the second row is 0001312012. If we subtract each of those digits from 4, we get the second part, 4443132432.
The run-lengths of the third row are [5, 1, 1, 4, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 4, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1].
Also a duplicated list.
The first part of that is 00000120000132001201312432443120132443201243131312.
 
Okx
Is this really valid? It stores input in variables but has 12 net votes.
 
Subtracting each digit from 4, we get 44444324444312443243132012001324312001243201313132.
Not surprisingly, that's the second part.
@Okx At least 100% of those votes are because of the language choice.
 

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