The Nineteenth Byte

Lyxal

00:02

@Adám I know, but I figured this was the most effective way to reach you

Adám

@Lyxal Why would you think so?

Lyxal

@Adám because I know my way around these parts more than other communities

Adám

@Lyxal But I'd get a notification if you answered or commented.

Lyxal

@Adám I know, but I feel most comfortable on CGCC than creating a new account for that network

And any mods, feel free to delete this conversation if it isn't the right place.

Adám

@Lyxal If you have something to say on that site, then join the site and say it. I can assure you that joining an additional SE site does not hurt in any way.

@Lyxal Not "if" — "since". Also, mods and room owners are always free to do so, so you don't have to tell them that.

New Main Posts

04:50

-1

Q: Narcissistic Quine

Write a program/method that becomes a quine if and only if the input matches the source code. If the input doesn't match the source code, the program is in don't care situation except it cannot be a quine. (Hint: Falling into an infinite loop makes the program a non-quine.)

Anush

06:24

CMC If we sample N binary strings of 50 each, we can compute the smallest Hamming distance between any pair. Write code to give the expected value for this minimum for each N = 1, ..., 10.

of length 50 each.

ngn

@Anush you specialize in binary-string-distance challenges? :)

Anush

06:40

@ngn this month, yes :)

binary-string-distance-challenguary

but then isn't everything a binary string?

@ngn I think this gets hard to do for larger N. I was thinking of posing a challenge around it

ngn

@Anush here are my results for the first few starting from N=2

Anush

@ngn That's pretty cool. Are these exact, in principle?

ngn

@Anush no, just random sampling

Anush

@ngn ah sorry.. I was hoping for exact which I think makes it interesting/difficult

although I think we can infer the correct exact answers from your approximate ones.

ngn

@Anush but that requires thinking :)

Anush

06:47

@ngn :)

@ngn some of those answers seem surprising. [Fraction(499, 20), Fraction(542, 25), Fraction(2073, 100), Fraction(1961, 100), Fraction(941, 50), Fraction(464, 25), Fraction(181, 10), Fraction(1757, 100), Fraction(17, 1), Fraction(1703, 100), Fraction(416, 25), Fraction(823, 50), Fraction(409, 25), Fraction(1599, 100), Fraction(397, 25), Fraction(399, 25), Fraction(313, 20), Fraction(769, 50), Fraction(1551, 100), Fraction(1543, 100)]

how can we increase the number of samples?

Fraction(499, 20) is not right

ngn

@Anush replace 100 with a larger number - it may take longer

Anush

[Fraction(25, 1), Fraction(22, 1), Fraction(103, 5), Fraction(176, 9), Fraction(151, 8), Fraction(55, 3), Fraction(179, 10), Fraction(141, 8), Fraction(69, 4), Fraction(169, 10), Fraction(117, 7), Fraction(33, 2), Fraction(163, 10), Fraction(129, 8), Fraction(16, 1), Fraction(95, 6), Fraction(47, 3), Fraction(125, 8), Fraction(139, 9), Fraction(46, 3)]

maybe that is the correct answer?

ngn

rationals are hard to compare visually

Anush

what do you mean by visually?

ngn

only with my eyes, without involving my brain

Anush

06:59

your code might be slightly buggy in fact. Replace 100 by 10000 and you get 25.03490000000000037 for the first value for N = 2

now replace it with 1000 and you get a better approximation

either that or the random number generator is broken

ngn

@Anush buggy - quite possible

Anush

let's see if we can compute the answer exactly

naively, it seems we need to try every possible way of sampling N strings from 2^50 ... argh

that's ok for N = 2 :)

do you know how to iterate over all possible ways of choosing N strings from 2^50 strings?

ngn

@Anush yes but it would be too slow

@Anush i forgot to negate the result from =

Anush

@ngn maybe we can't do it even for N = 2

ngn

does this look better (10000 samples)?

Anush

07:06

@ngn no. Compare 10000 to 1000 to 100 samples

it should be getting better the more samples you do

I may have to reduce 50 to 30, say

for the exact question

or even less....??

@ngn which random number generator is it using?

ngn

@Anush bitbucket.org/ngn/k/src/…

Anush

@ngn that is impossible to interpret :)

xorshift it seems

ngn

just read the comment: xoshiro256+ seeded with the central column of rule30

Anush

ok well something is broken

just test the N = 2 case

ngn

@Anush close to 25, shouldn't it be so?

Anush

07:14

@ngn yes but it should get closer as the number of samples increases and it doesn't

25.. the exact answer is 25

could you try the same code but in python for example and see the difference?

ngn

it is getting closer. this is N=2 for 10 100 1000 etc samples: 25.39999999999999853 25.14999999999999857 24.97800000000000150 24.94620000000000101 24.98882000000000045

Anush

I get 24.96509999999999960 for 10,000 samples and 24.99800000000000108 for 1000

using tio.run/##y9bNS8/7/79aw0DPQFtbv0hTVbnIqlpNX1tfXUe/…

24.97800000000000150 24.94620000000000101 <- that is getting further away too

it seems that 10,000 samples is always worse than 1000

ngn

here's up to 10 million

Anush

24.97800000000000150 24.94620000000000101 <-- same problem

do you have a random seed?

ngn

it's a prng with a fixed seed. if you keep running the same program, you'll keep getting the same results.

Anush

07:22

that makes it hard to test

it could just be a bad seed

I wonder how to pose this as a challenge

do you think it's just impossible for any string length over 100, say?

I mean to do exactly

ngn

@Anush the central column of rule30 is as nothing-up-my-sleeve as it gets - mathematica uses it. the xoroshiro family of prngs has been tested well afaict. so, the only possibilities left are: my implementation is buggy or we were unlucky with the sampling

Anush

I would try a random seed myself but maybe that's not possible?

ngn

@Anush you can prepend 1234?0; - that would generate and discard 1234 random numbers

Kritixi Lithos

08:13

@Anush not yet, as for the challenge type, I think it would be nice to have it be a code-golf, to ban brute-force solutions, you can place a maximum time limit on certain inputs, but I'm not sure either

or like quintec suggests, something like returning the nfa, not necessarily optimised to be the minimum, could work

RGS

10:06

Hello guys, where should I go to get help for learning Jelly?

Adám

@RGS chat.stackexchange.com/transcript/57815

RGS

@Adám ty Adám, but "the room is frozen" and I cannot add a new message

Adám

@RGS In any case, it is by invite only. You can ping any one of the room owners and ask them to train you. They ask a mod to unfreeze the room whenever it is needed.

RGS

Thanks!

@Adám they talk about a "request access" button that is nowhere to be found :P

Adám

10:21

@RGS The room needs to be unfrozen to have that. @Doorknob Can you unfreeze chat.stackexchange.com/transcript/57815 ?

RGS

oh thanks. I also messaged mr xcode directly in a room.

thanks for your help!

Adám

@RGS No problem. Also, whether the Jelly training works out or not, I'll be happy to teach you APL, which is a very mathematically oriented language which manages to simultaneously be a real world language while not being too shabby at golfing.

RGS

I like maths :P But I don't have that much time so I might start with some Jelly just to get the feel for it. If I keep coming here and I really stick to golfing, I'll ping you for some apl lessons ;)

(also I just posted a sandbox challenge, so feel free to give feedback on that codegolf.meta.stackexchange.com/a/18489/75323 )

wizzwizz4

10:42

Anyone interested in committing to the Drones and Model Aircraft Area 51 proposal? It needs 30 more existing SE users to get off the ground, and is possibly our last hope of saving Area 51.

New Sandboxed Posts

0

A: Sandbox for Proposed Challenges

Generator functions to solve combinatorics problems This is a code-golf and math challenge that came to life after some input on my sandboxed challenge for symbolic differentiation of polynomials. Generator functions are a very interesting object in mathematics (see Wikipedia or Wolfram's MathW...

Lyxal

I have a question for y'all

And I don't know if it's been asked on meta at all

Okay. In python, functions are defined like so:

Pavel

is this about needing f= on lambdas

Lyxal

def name(params): code

Because I know with lambdas you can

Now, can I hide the def part in the header?

Pavel

no

Lyxal

10:53

ah

So I can't do this?

Pavel

no

dzaima

11:10

@Lyxal definitely not as that requires me writing the l and r specifically. a better question would be if def f(): can be excluded, but the answer still is no. with lambdas you still have to include the lambda:

wizzwizz4

@dzaima So, you couldn't write an expression to be compiled with mode='single' (Python IDLE) that takes no input / input from STDIN and returns to the _ variable?

Pavel

@wizzwizz4 Sure, your language is now python repl

wizzwizz4

Oh, yeah, good point.

Anush

11:29

@KritixiLithos these sounds like good ideas. I hope you can get it to work soon so we can test it out too

here is a simpler version of my CMC. Sample 3 binary strings uniformly of length 30. What is the exact expected minimum distance between the closest pair?

Kritixi Lithos

11:54

@Anush i haven't started on a solution yet though

Anush

@KritixiLithos ah ok. I have a vague idea how to do it but haven't fully worked it out yet

a'_'

12:31

I'd be glad to know whether this is a duplicate. (I hope so.)

Oh right, this is a duplicate.

Adám

@a'_' Really? Of what?

a'_'

44

Q: Output integers in negative order, increase the maximum integer everytime

Main task Your task is to print out integers in descending order, starting from 1, and increasing as you keep hitting 1 again, up until the given input is reached, then, print out the rest until you hit 1 again. Example with input 6: 1 21 321 4321 54321 654321 Without newlines (valid output): 12...

code-golf sequence integer

New Sandboxed Posts

12:50

0

A: Sandbox for Proposed Challenges

Indexes of indexes reversed code-golf Sorry for the confusing name. I didn't invent this challenge, but I find it very interesting to solve. (I hope this isn't a duplicate.) For every input number, e.g.: 4 Generate a range from 1 to that number: [1 2 3 4] And then, for every item in that ...

caird coinheringaahing

13:27

Man it seems that something bad has happened every time I log into PPCG at this point :/

Anush

@ngn are you still here?

@cairdcoinheringaahing what happened?

a'_'

13:51

@Anush No reply means nothing. The comment is an eyeball catcher.

point[this] = PPCG.logs().each(happened("bad"[sth.]))

Adám

@cairdcoinheringaahing Cause and effect?

John Dvorak

14:13

@Adám Definitely. Why bother logging in when there's nothing going on with the site?

caird coinheringaahing

@Anush DJ stepping down as mod

@a'_' Or maybe it means that I was busy doing something else, and just now was able to reply?

a'_'

14:44

After reading this answer I now don't really care about the moderators resigning.

I wrote 427 answers. Just 7,371 rep. (I'm not complaining because all of my answers did not require any effort to write.)

ngn

15:36

@Anush now i'm here

Luis Mendo

16:39

Question to all: is there an established procedure if we run out of moderators? The community made it clear that there's not much enthusiasm of its members in becoming moderators. This is not for lack of interest in the community, but for the same reasons that the former mods stepped down. So what happens if there are no mods, or if one mod alone cannot handle all the work?

It seems like writing.stackexchange.com has no active mods now. How are they doing?

Adám

@LuisMendo They do have moderators — they're over here.

Luis Mendo

@Adám What do you mean? That's another community. I mean within StackExchange

Adám

@LuisMendo If there are no mods, then there's no clean-up on the site. I think that's about it.

Post Rock Garf Hunter

@LuisMendo The community made it clear we didn't want an election when we had two moderators, but the situation has changed from then, I don't think it is obvious that the community opionion has remained the same.

Luis Mendo

@Adám So no danger that we are somehow shut down by SE? Do you think it would be a good idea to ask on Meta.SE? Or would that call unnecessary attenation on us?

@PostRockGarfHunter That's a very good point

dzaima

16:46

-37

Q: January 2020 Moderator Election — Community Interest Check

This community last had an election last year, and has recently seen their moderator team reduced by two. As such, by request of the remaining two moderators on the team, and to find replacements for Mego and Dennis, we're looking at scheduling an election to start somewhere in January 2020. To...

discussion moderators election

Adám

@LuisMendo At least we have one mod. Writing has none, and has been getting a lot of exposure as Monica's home turf. I don't think any site will get shut down.

Post Rock Garf Hunter

@dzaima Yes? that is the post we were discussing.

dzaima

@PostRockGarfHunter ah, you mean after even that. i don't think active moderator amount would influence the community's thoughts about becoming moderators, definitely not positively

Luis Mendo

2 days ago, by Doorknob

@Pavel unclear

Post Rock Garf Hunter

Why not? It seems like the number of moderators is the general single largest influencing factor on desire for more moderators.

Adám

16:50

@LuisMendo unclear>absent

Luis Mendo

@dzaima I think it can influence it. Many of us dislike recent events with SE and therefore do not want to become mods. But if he community's future is at stake that could change

John Dvorak

In the worst case - we still have a Discord or two

dzaima

@LuisMendo I don't think SE would kill communities, and community activity isn't influenced much by how many moderators there are. Many moderators leaving doesn't make it seem like being a mod is fun either.

Luis Mendo

Mods have left mostly out of disagreement with SE's decisions, rather than lack of fun

dzaima

@LuisMendo maybe "fun" wasn't the best word, but most of what mods do is be janitors, it doesn't seem like they can change SE/site future much more than regular users.

(as for me, i've settled on not answering/asking questions for the foreseeable future, but i have nothing against staying in chat because afaik SE has no gain from me using chat)

New Main Posts

17:23

-1

Q: Largest subsequence with the given pattern

We have to find the Largest subsequence with the given pattern. X1X2X3X4XnXnX4X3X2X1 No adjacent characters should be same except Xn. example: string is : acdbdea Then the output is adda. Can somebody please help me in this. How to solve it.

c++

Luis Mendo

17:37

@dzaima Yes, I understood what you meant. But before the unfortunate events of recent months more people were willing to become mods. The janitor stuff has always been there

My fear was that a community without mods could be seen as a problem by SE, and I don't want to see this community shut down or negatively impacted

Adám

@LuisMendo or negatively impacted? Dennis, Mego, TIO…

dzaima

@LuisMendo afaict SE wouldn't dare to do anything bad that they can't attempt to hide, and shutting down a community is a pretty visible thing.

John Dvorak

Is it visible, though? Besides they could claim "they couldn't moderate themselves" as the reason. It would upset everyone, yes, but that's no stopping for them, is it?

dzaima

@JohnDvorak it would upset everyone on CGCC, whereas most of their current actions only upset the people who find out about the action, the changes aren't visible in the site (outside of featured/hot questions which can very easily be ignored, as opposed to, y'know, the whole site not being there)

New Main Posts

18:04

-1

Q: Tetris Game in C challange(Strictly in C)

The challenge is to show your game written in Mother of all programming language ie C. Criteria: A reasonable scoring system must be in place, which rewards multi-line clears more than single-line clears. The current score must be visible at all times. The next piece that will appear must be indi...

code-challenge game c tetris

Luis Mendo

18:25

@Adám Yes, it's sad that they ceased being mods. I meant on top of that. As for TIO and why Dennis is no longer active, I don't know what happened, so I can't make any assumptions

Anush

20:29

hi all

a'_'

22:54

hi all

a'_'

23:13

6

A: Narcissistic Quine

GolfScript, 23 bytes A Jelly submission means that I can port it to GolfScript. "`\".~\"+{.2$=}do\\;".~ Try it online! Explanation " ".~ # Evaluate the following string as GolfScript code, using the string itself as argument: ` # - Uneval (effectively...

It seems that they are really fond of GolfScript ..

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