The Nineteenth Byte

New Posts

02:38

0

Q: Shorten this recursive even fibonacci implementation

I have the following Haskell code to generate the even values of the Fibonacci sequence as an infinite list: z=zipWith(+) g=z((*2)<$>0:0:g)$z(0:g)$(*2)<$>scanl(+)1g This works by starting with 0,2 and then defining every following term to be the sum of: twice all prior terms the previous term t...

Bubbler

03:01

@NewPosts will post an answer after lunch

Aiden Chow

06:45

@Bubbler rip closed

The Empty String Photographer

07:36

@AidenChow self-closing question :p

Neil

CMC: Given an integer n, return the smallest integer k such that all kth Fibonacci numbers are divisible by n.

Bubbler

07:53

What are "all kth Fibonacci numbers"? F0, Fk, F2k, ...?

Simd

@Bubbler. ntt_par was clearly the fastest on my PC

Bubbler

yeah I saw the update

Simd

Is that surprising?

Your code is very cool

I will pose a challenge with larger ints soon

Bubbler

@Simd please don't

Simd

@Bubbler how come?

I think it’s a very interesting area

And maybe even practically useful!

(….maybe…. :) )

Bubbler

08:02

managing high precision in individual cells becomes the bottleneck

not the core algorithm anymore

Simd

@Bubbler right although there are still different approaches possible

That’s what makes it so interesting to me

A good karatsuba implementation would be very interesting to time too

Bubbler

@Simd I mean, the submissions will just be the same FFT and NTT, but way slower because u128 division or some other multi-precision arithmetic

"way slower" being X times slower for pretty much the same X value for every submission

Simd

@Bubbler I don’t know what tradeoff are needed if you want 256 bit outputs

In any case, thank you for your awesome answers

Bubbler

@Simd There is no tradeoff at all.

Simd

I can also time the code more accurately which would be good

I don’t know if we have ever had any code using the new _BitInt

The c23 thing

@Bubbler if you are multiplying x bit numbers, at some point you want to do that not using naive multiplication, no?

Neil

08:19

@Bubbler what was confusing you?

Bubbler

@Simd Incorrect, naive multiplication is the fastest (because simple loops are pretty fast) up to, say, 24 64-bit numbers (which is what dashu uses)

@Neil Not really, I guess it's the only interpretation that makes sense but figured I'd ask

Neil

OK, so then the answer is yes, obviously

as opposed to "yes, obviously"

Bubbler

and it's kinda unnecessarily complex because it is equivalent to "find the first k>0 where Fk is divisible by n" :P

Simd

@Bubbler I guess 24 is "some point" :)

Bubbler

or is it a trick question where the answer is always k=0?

Simd

08:25

Is that when karatsuba is faster?

Bubbler

@Simd seems so

Simd

@Bubbler I think it's hardware department at least to se

@Bubbler I think it's hardware department at least to some degree

The Wikipedia page claims a much lower threshold

Bubbler

@Simd but "24 64-bit numbers" here is pretty large, it is literally a 24*64=1536-bit number

@Simd that's likely outdated. I'd rather trust benchmarks for a currently maintained library

@Simd not implemented in gcc/clang yet

Simd

@Bubbler that is true

@Bubbler I thought it was in clang but that's just from the dev notes so I might have that wrong

Bubbler

08:42

oh ok, I figured out how to use it

so you can do this, but the result seems to be just a fully inlined naive multiplication

The Empty String Photographer

But if it's unsigned, the maximum number it can store is only:

2410312426921032588580116606028314112912093247945688951359675039065257391591803200669085024107346049663448766280888004787862416978794958324969612987890774651455213339381625224770782077917681499676845543137387820057597345857904599109461387122099507964997815641342300677629473355281617428411794163967785870370368969109221591943054232011562758450080579587850900993714892283476646631181515063804873375182260506246992837898705971012525843324401232986857004760339316735

Bubbler

@TheEmptyStringPhotographer yes but the context is the number to store in one cell in the convolution challenge

Neil

09:05

CMC: Given an integer k, output the formula for F(kn+k) in terms of F(kn) and F(kn-k), where F(n) is the Fibonacci sequence

The Empty String Photographer

@RydwolfPrograms I'm implementing it, but in a website instead. It's actually getting some progress, since I managed to hook it up to a database.

mousetail

@TheEmptyStringPhotographer How will you bypass CORS then? There is a reason people do it as a userscript

The Empty String Photographer

@mousetail wdym

mousetail

You will need data from stack overflow right? But you can't fetch data from different websites client side because of the same origin policy

If you have a website you have a different origin, while a user script has the same origin as SE

The Empty String Photographer

1. I'm using the API.
2. I don't know if this makes the issue less of an issue, but I'm using GitHub Pages.

mousetail

09:18

Does the API have CORS?

The Empty String Photographer

@mousetail IDK

mousetail

You wouldn't be able to use it clientside if it didn't have cors headers

It didn't use to, might be a recent change

The Empty String Photographer

well, I haven't tested yet...

i still need to add the fetch code

mousetail

...that might not work then

You may be able to host on vercel then use the serverless functioninality to create a CORS proxy

The Empty String Photographer

@mousetail could I add the CORS header in the fetch function directly?

Simd

09:27

@Bubbler cool!

mousetail

@TheEmptyStringPhotographer No, the server needs to add it

Or you won't be able to access the content of the response client-side

The Empty String Photographer

@mousetail Well, it does seem to send the request, but it results in a 403 error since the access token apparently does not match the key.

but then it also sent a 400

strange

mousetail

For GET requests it doesn't prevent sending the request, just reading the content of the response

For POST requests it CORS will prevent sending the request at all

Bubbler

@Neil Lucas(k), -(-1)^k

The Empty String Photographer

@mousetail It let me see the response, which was a json object with the 403 error.

mousetail

09:32

In the script or in the inspector?

The Empty String Photographer

@mousetail I made the script log the json to the console, so both i guess.

mousetail

Then it may have the required CORS headers

The Empty String Photographer

the end of the fetch code line was .then((json) => console.log(json))

mousetail

Why use .then instead of await?

The Empty String Photographer

@mousetail I can understand it more easily.

I am not the all-knowing god of JavaScript.

The Empty String Photographer

10:08

I managed to query the API using javascript! yes!

on the web!

The Empty String Photographer

10:19

right now time to configure the review buttons

Neil

10:30

@Bubbler wow it's that easy? well, thanks for letting me know

New Posts

11:35

0

Q: Print a meter of numbers to a specified limit

The question may be unclear, but example outputs aren't. Given an input number n, output a number meter formatted like this: 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 1 1 1 1 1 1 1 1 1 1 2 The input number is 20 in this example. All numbers should be printed, and any size of numb...

code-golf string number ascii-art

Codidact Posts

11:47

New Posts - Challenges - Code Golf: Reverse the bits in a Byte

posted on August 18, 2023 by [Object object]‭

Simple challenge: Read a byte, swap bit 7 with 0, 6 with 1, 5 with 2 and 4 with 3 and then output the byte. For example the byte 0b1001'1100 would turn into 0b0011'1001...

Rydwolf Programs

13:16

@mousetail Almost certainly not

Most APIs don't, and it provides a way for users to securely sign in with the API

mousetail

How did they manage to query data then? It seems they may have it enabled on a few routes at least if the photographer isn't lying

Rydwolf Programs

No I mean they don't have CORS protections, sorry

mousetail

Must be a recent addition then, I know I struggled with that before

Maybe most APIs have CORS but the ones I need to work with hardly ever have it

The Empty String Photographer

17:12

@mousetail Maybe because I registered an app on Stack Apps?

mousetail

It's a header

Isn't it required to register?

The Empty String Photographer

@mousetail If you want to use access tokens

RSNBATWPL stands for "Read SE's Nineteenth Byte At The Work Place Lol"

The Empty String Photographer

18:59

Here is how to bypass a RecursionError in Python:

def f():
    try:
        f()
    except RecursionError:
        f()

caird coinheringaahin g

19:10

Is your program raising a RecursionError? Just say no! Python legally cannot RecursionError without your permission

5

Joao-3

@TheEmptyStringPhotographer

if you golf and remove recursion error you will unfortunately not be able to ctrl+c

mousetail

@TheEmptyStringPhotographer This will eventually crash with recursion error but it will take 2^n steps where n is the recusion limit

Joao-3

aka 2^1000

mousetail

Depending on how many stack frames you use before even getting to f, and how big your memory is

def f():
    try:
        f()
    except RecursionError:
        sys.setrecursionlimit(sys.getrecursionlimit() + 1)
        f()

This should go on for longer though

Joao-3

@mousetail import sys

mousetail

19:20

I have implicit imports

Joao-3

okay????

in 3.11 the default reclimit is 1000

also i hate my keyboard

mousetail

It depends on some things, it's usually 1000 yes

Joao-3

人(个一个)

The Empty String Photographer

@mousetail I guess… the script eventually errored and then was printing more than 50,000 lines to STDERR, so this could be a contender for longest error message compared to program size.

mousetail

You could post it as an answer to that question

Or at least see if there is already a longer python answer

The Empty String Photographer

19:34

@mousetail I don’t think there is a question like that.

mousetail

Yes there is

The Empty String Photographer

What’s the link?

Joao-3

why is there a blank space at the end of chat

reloading fixed it nvm

mousetail

4

Q: Largest Error Message in 100 bytes

The goal is to raise the error message with the most bytes! The error message may not be generated by the program itself, such as Python's raise. errors that do not terminate the program are not allowed unless they do not show an error message. Here is an example in python that raises 243041 byte...

code-challenge restricted-source busy-beaver error-message

The Empty String Photographer

@Joao-3 It looks better.

Rydwolf Programs

19:37

> Python 3, ≈
A(A(A(9,9),A(9,9)),A(A(9,9),A(99,99))) where A is the Ackermann function,or limited by RAM

Looks like there is :p

mousetail

It needs to specifically be an error

And while not required it's only really interesting if you don't raise it yourself

Joao-3

does forkbombing on linux count as an error message

New Loophole Proposal

0

A: Loopholes that are forbidden by default

Using a very high base (like base Graham’s number) in a challenge where you need to output a big number In my answer, I just outputted 10, and claimed it was in base number that is bigger than any number printed in the challenge by another submission. And of course, this seems like cheating.

mousetail

20:04

@Joao-3 It won't generate a long error at all, fork bombs typically don't generate any error at all

Rydwolf Programs

20:20

CMP: Do you use the Firefox shortcut Ctrl+M (mute)? Would you be okay with a userscript overriding that in chat?

Unrelated String

never even heard of it

but also never heard of any other way to mute tabs when the little icon for actively playing audio pops up

*doesn't pop up

i could see someone wanting to specifically preemptively mute chat

Rydwolf Programs

It's under the right click menu on the tab right?

I didn't even know the little icon for audio could be interacted with

Unrelated String

...that it is

yeah i don't think anyone would have issues with overriding ctrl+m

Rydwolf Programs

Oh and it'd only be when the text box is focused and Ctrl+K is already overridden, so I'm definitely good to override it I think

Unrelated String

yeah lmao

Joao-3

20:25

jsyk, this is the most downvoted loophole (lol) codegolf.meta.stackexchange.com/a/1078/111471

mousetail

Is it? There may be others with more negative points but also more upvotes

caird coinheringaahin g

Well, it has 122 downvotes

mousetail

What's the most downvoted post in all of meta?

Joao-3

20:41

-42

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

CMC: code anything remotely interesting in typescript type system

mousetail

@Joao-3 That's not even close to the no builtings loophole

Joao-3

no that loophole has more downvotes

mousetail

Exactly, so it's not the lowest post on meta

Joao-3

loopholes are answers not questions lol

mousetail

I said posts

Aiden Chow

22:44

so yall there is a little bit of a conundrum with coding in desmos with actions that id like some feedback with. so basically the only "meta-compliant" way (at least that im aware of) to take input if you are going to use actions is to use \ans, which is an allowed I/O method.

but they recently took out that functionality as it wasnt meant to be used on the main graphing calculator and that it was too inconsistent

so now there are no "meta-compliant" ways i can think of to take input while still conforming to the agreed-upon default I/O methods.

the only other way to take input for actions is to hardcode an input variable, which as yall know, isnt allowed

lyxαl

It is for languages where there is no STDIN

eg ///

Aiden Chow

i was about to mention that

lyxαl

You can't get input any other way except for hardcoding it in the header

So there's some leeway there

Aiden Chow

but the difference here is that desmos does technically have a form of acceptable I/O, namely functions, except actions cant act on functions

they act on variables directly

now if u allow hardcoded variables for desmos then it would also be golfier to not use functions at all

and that would be an even bigger conundrum

so whats the solution here? can we not do any challenges requiring actions?

u can also say that hardcoded variables are only allowed for solutions using actions, but then there are many challenges that can be solved with both no actions and actions

and also it seems like a super specific rule just for one lang, i would preferably like a more "general" solution that isnt desmos-specific

theres also another issue of my old "desmos with actions" answers utilizing \ans that are now broken becuz that functionality was removed

hmm ok i was commenting with another user @fwoosh on one of their posts (which is where I noticed the issue) and they suggested the following:

would (byte count aside) having a function initialize the variables, and then starting the ticker, work? — fwoosh 7 mins ago

as i said in a reply to that comment, i dont immediately see an issue with that form of I/O (albeit not too byte efficient) tho i would like yalls opinions on this

Ginger

23:43

ugh

Unrelated String

lovely

you... could start by putting that bit in a function :P

also wait is there a particular reason the cast and pipeline get actually have to be repeated

like per name

Ginger

@UnrelatedString no, I just wanted to make a point :p

Unrelated String

:p

Ginger

this is my hail mary for getting catfm working

if this fails I'm out of ideas

and I will weep

profusely

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