The Nineteenth Byte

In this challenge, you will be given a matrix A, a vector v, and a scalar λ. You will be required to determine if (λ, v) is an eigenpair corresponding to A; that is, whether or not Av = λv. Dot Product The dot product of two vectors is the sum of element-wise multiplication. For example, the do...

user165474

Wait so after you've posted more than once you can't delete your account?

wizzwizz4

@HyperNeutrino And got a single vote.

ais523

@HyperNeutrino you can, but it involves contacting SE staff; at that point you can't do it in an automated way

actually I think a diamond mod has the technical power to do so, but I don't think they can do so on request (not sure on that)

wizzwizz4

2:11 PM

There was a user who got their post migrated but didn't want it linked to them. They recreated their site-specific account so I could submit a CM flag, but somebody had voted on their question so they got the extra rep and couldn't auto-delete it any more.

@ais523 We can do it on request, but there's a 24-hour delay.

During which time the account is (iirc) fully functional, and the user can cancel it from their profile.

user165474

This seems a bit confusing >_>

ais523

huh, somehow I didn't realise you were a diamond mod

some of the mods are much higher-profile than others

wizzwizz4

@HyperNeutrino It's there so that a rogue mod can't delete all of teh accountz in a fit of rage whilst still being able to moderate without CM supervision.

@ais523 Most don't have "I'm a moderator!!!" plastered all over their user profile.

I must change that sometime.

seshoumara

some of my answers have been edited by some script, are those really necessary?

wizzwizz4

@seshoumara I don't understand what you mean.

user165474

2:13 PM

@seshoumara Was it by Community?

seshoumara

yes

not the first time happening

wizzwizz4

@seshoumara That means a user who wasn't logged in did it.

It went into the suggested edit queue, then was approved.

Somebody had to own it, so Community (-1) did.

There have been suggestions to attribute them all to Jon Skeet, but those have not (afaik) been put through.

seshoumara

I think it was a script, because a lot of answers have been edited at once.

user165474

@seshoumara Community owns a lot of edits that don't have a registered user assigned to them but it also sometimes modifies your posts a bit.

ais523

it's also worth noting that quite recently, Community did a mass edit to fix URLs

because Stack Exchange's URL scheme changed, so pretty much any post that linked to somewhere on Stack Exchange got edited by Community

user165474

2:16 PM

Oh that might explain some things...

ais523

you can click on the "edited by Community" bit at the bottom of the post to see what it did

hmm, IMO Community should get 2 rep every time it edits a post

it'd make up for all the rep it loses from owning downvotes

wizzwizz4

@ais523 Community never has reputation calculated.

user165474

@flawr This is why I wanted to ban builtins for matrix-vector multiplcation

wizzwizz4

It used to, but people noticed that its reputation started becoming positive.

user165474

@ais523 Community is a weird thing because its userID is -1, so that's weird enough, and it has 1 rep always. It just never bothers to get its rep updated because it's not important

seshoumara

2:18 PM

so who executes these scripts?

exactly

wizzwizz4

@seshoumara The servers.

It's a cron job.

user165474

@seshoumara Community is a script run by StackExchange; it owns things like unnamed edits

user165474

ninja'd

wizzwizz4

I'd been developing a system for reliably impersonating Community ♦.

But then I threw it out of the window when I realised I could just not sign in.

Riker

@HyperNeutrino saw and upvoted the challenge :D

@HyperNeutrino if you've given a vote or made any post (even a comment), you can't delete your acct automagically

SE will do it, but it most often involves rescinding all votes you've cast, losing some rep for people

ais523

2:21 PM

the vote stays if it's more than 60 days old, plus one other condition that I can't remember offhand

might need to be on a post at +3 or higher? something like that

wizzwizz4

@ais523 I think that can be customised.

I've only ever deleted an account once though, so my memory is hazy.

The account needs to have more than 500 reputation too! How did I forget that?

ais523

aha

I think the customization is for vote manipulation compensation, i.e. if a sockpuppet account has been upvoting the original owner, you'd want to wipe all its votes even if they've been longstanding

wizzwizz4

Speaking of vote manipulation, the system says that I've been being naughty.

I've approved too many edits from the same person. >40%!

(Note that this person has submitted a disproportionate number of suggested edits.)

Kritixi Lithos

@wizzwizz4 how do you know that?

wizzwizz4

@KritixiLithos I looked.

Kritixi Lithos

2:28 PM

where?

oh wait, it must be a secret mod thing

quartata

@Downgoat update CE:SP

wizzwizz4

@KritixiLithos User profile -> mod -> info -> votes -> ↑ ↑ ↓ ↓ → ← → ← A B start -> Given To

user165474

@wizzwizz4 0/10 It's B A

quartata

TF2Goat hs been broken for over a month because of the HTTPS move

Kritixi Lithos

$ cat .bashrc
alias kkjjhlhlab="unalias rm"

wizzwizz4

2:33 PM

@HyperNeutrino Don't ping me. Prepend your message with @@team instead.

Kritixi Lithos

Isn't it left right left right instead of right left right left?

Downgoat

@quartata is this chatexchange

wizzwizz4

@KritixiLithos Yes.

But, again, you'll have to bring it up with @@team.

This URL... retrocomputing.stackexchange.com/users/history/…

/users/history/278?type=User+switched+profile+image+to+Gravatar+Identicon

It looks a bit... verbose.

user165474

Wait there are badges for getting your chat messages starred???

wizzwizz4

@HyperNeutrino Yes.

ais523

2:40 PM

only one badge

ten of your messages need to be starred IIRC, and by ten different people

Riker

there's 2

user165474

Yeah. I just got it and I was confused >_>

ais523

oh, huh

Riker

talkative = 10 or more msgs in chat, at least 1 star

outspoken is 10 msgs starred in chat, with 10 starring users total

New Meta Posts

0

Q: Do we need some extension softwares? (Ex. TIO Chrome/Firefox extension)

We currently have a Graduation script, which adds some utilities. However, we do need (or want) some more utilities, like a TIO Chrome extension. Do we need more? If we need more, How would we host them?

discussion

New Sandboxed Posts

2:44 PM

0

A: Sandbox for Proposed Challenges

EVERYBODY DO THE FLOP! code-golf audio music This is a song challenge and I know that they are discouraged as they are normally closed as dupes of the rickroll challenge but this is slightly different. My absolute favourite song is called EVERYBODY DO THE FLOP by TomSka and I think it would be ...

0

A: Sandbox for Proposed Challenges

Embedded Rectangles! Your task: given an integer n, print the embedded squares to the nth depth, using #. Standard methods of input and output, input in any convenient format, output should be as a string. Examples are 0-indexed, you can use 1-indexed if you want. The length and height of each...

0

A: Sandbox for Proposed Challenges

Embedded Triangles! Your task: given an integer n, output an embedded triangle to the nth depth. Standard methods of input and output, input in any convenient format, output should be as a string. Examples are 0-indexed, you can use 1-indexed if you want. The left and right sides of each figur...

wizzwizz4

Ouch.

user165474

...

Riker

?

wizzwizz4

Lots of sandboxed posts to go through.

At once.

Riker

ah

quartata

2:57 PM

@Downgoat ChatExchange Source Python.

Riker

@EriktheOutgolfer fwiw, I'm fairly certain I figured out what happened with that ninja edit (on the sundays question): the code-golf tag was already there, OP added the KG tag.

the revision for adding that tag isn't hidden, and it's around the right time

Erik the Outgolfer

@Riker Then how do you explain 3 CVs and a comment about an objective winning criterion not being there?

Riker

I dunno

but I do note that 2 more CVs have come in after that

Erik the Outgolfer

1 more CV.

Oh, I get why they come: it's because people think that the winning criterion must be specified in the question body as well.

I dunno if I should edit that in though...

wizzwizz4

3:13 PM

@EriktheOutgolfer Wait until after it's closed or otherwise out of the queue, then add it.

For some reason, people sometimes get cross if people fix the question before it gets closed.

New Main Posts

0

Q: Cheeky bus driver

The bus driver picks up the children from their homes every morning for school. All the homes are positioned around a circular street and the bus driver has to stop at every home exactly once. One monday morning the bus driver decided to only pick up every second child he encountered along his w...

code-golf number logic

trichoplax

I thought a winning criterion tag was sufficient, since they come with default settings

Geobits

Most don't, really, but [code-golf] does for sure.

[code-challenge], [king-of-the-hill], etc would need something.

trichoplax

Oh right. Yes I suppose even fastest-code needs more detail, so only code-golf is sufficient alone

I really shouldn't do my thinking and talking in alphabetical order

New Sandboxed Posts

0

A: Sandbox for Proposed Challenges

Number Lockers! Given a positive integer < 100 (from 0 to 99, including those numbers), output that many lockers. A locker is defined as the following: +----+ | | | | | | | nn | +----+ where nn is the locker number, in base 10. If there is 1-digit number, it is expressed with a 0 in...

mbomb007

3:27 PM

@NewSandboxedPosts As much as I like AsdfMovie, this isn't a good challenge

flawr

@HyperNeutrino what's wrong with it?

mbomb007

Hasn't speech-to-text been done before?

Riker

*text-speech, and yes I think so

>_> this was too easy for Mathematica. +1 :P — HyperNeutrino 1 hour ago

I think he's saying it trivializes the proble

flawr

Well it is a trivial problem

Riker

shrug

flawr

3:31 PM

there are just languages that make it more complicated

I just advised against banning matrix multiplication built ins, as in languages that support linear algebra it is very easy to circumvent this restriction with other functions that do similar things

mbomb007

3:43 PM

Can someone help me find the post that was created from this Sandbox post? I can't find it, but I want to add a hyperlink to the Sandbox post.

Was the question deleted?

I can't find it with the Review Tools either.

Riker

codegolf.stackexchange.com/questions/116256/ascii-fractals

mbomb007

Ah, it was. Thanks.

Comrade SparklePony

@mbomb007 I deleted the post, it was not that good.

New Main Posts

3

Q: Fold Some Towels!

I heard somewhere that one thing that technology cannot do yet is fold towels. So it is now your job to prove that statement false! Given a string as input, made up of rectangles (towels), like the following, fold each towel in half twice. For example: +------+ +------+ +--+ | | ...

code-golf ascii-art geometry

user165474

@flawr I was looking for some golfed implementations of the multiplication but oh well >_>

mbomb007

3:54 PM

@NewMainPosts Bonus if someone solves it using fold :D

ais523

fold is basically the functional programming equivalent of a for loop, you can solve basically anything with fold if you really want to

but normally there are more readable primitives

user165474

Does Sparkle have side-votes in his profile picture???

betseg

ye

mbomb007

Idk, it could go either way. XD

user165474

...:P

Comrade SparklePony

4:00 PM

@HyperNeutrino Yes, I have side-votes.

user165474

@ComradeSparklePony Interesting. That would be an interesting concept though I have no idea what it would do. :P

mbomb007

@HyperNeutrino If there aren't enough right-votes, he won't make the star board. XD

ais523

I think Reddit should add side-votes as one of their April 1 social experiments

and that they should be counted, and the distance left/right that a post has been voted should be displayed on the post, but otherwise have no effect

mbomb007

because starboard side is the right side

4

ais523

also that there should be no guidance on when to use them

user165474

4:04 PM

@mbomb007 hah I see what you did there

user165474

@ais523 Political spectrum?

ais523

I'm sure that's something that people would try to use them for, but they'd be used for other things too

and likely factions, etc. would spring up

oh, you should also be able to sort posts by leftmost and rightmost

once a pattern starts being established, people would start following it

user165474

Probably, yeah

Kritixi Lithos

Wow, 40 tabs. Writing a polyglot in obscure languages always results in this sorta thing

user165474

wow...i only had like 20 open when i was working on 4 projects at the same time.

Kritixi Lithos

4:16 PM

tbh ~10 of the tabs are from another project

user165474

oh XD

Basic Sunset

How do you print a string in ><>?

I see that you have to print one character at a time but how do you loop until the stack is empty

flawr

@HyperNeutrino Why don't you make a challenge about implementing the matrix multiplication then?=)

Geobits

@BasicSunset ><>----

user165474

@flawr wow you're a genius. yeah i'm going that :P matrix-matrix multiplcation i guess, without matrix-vector builtins. i guess just basic math operators.

Basic Sunset

4:25 PM

I think that's been done before

user165474

Probably.

user165474

11

Q: Do Matrix Multiplication!

In mathematics, matrix multiplication or the matrix product is a binary operation that produces a matrix from two matrices. The definition is motivated by linear equations and linear transformations on vectors, which have numerous applications in applied mathematics, physics, and engineering. In ...

code-golf math matrix

user165474

And of course a way too short Jelly answer from Dennis:

user165474

4

A: Do Matrix Multiplication!

Jelly, 7 5 bytes Z×þḅ1 Takes B and A as arguments and returns A × B. Try it online! How it works Z×þḅ1 Main link. Left argument: B. Right argument: A Z Zip; transpose B's rows and columns. ×þ Table multiplication; multiply all columns of B (rows of B's transpose) by all ro...