The Nineteenth Byte

Sp3000

1:00 PM

The matrix wouldn't change, but the augmented vector would be [1, 0, 1, 1, 0, 0, 0, 0, 0]

Anonymous

Hmm

Anonymous

Suspicion is confusing me now

orlp

@Mego contradiction

Sp3000

(btw you were right about the determinant thing earlier, so sorry - explains the batch of zeroes at the bottom though)

Anonymous

@orlp ?

orlp

1:03 PM

@Mego let me put it into sage 1 sec

might just be my code borking again

Anonymous

Sage is saying no solutions

Anonymous

Which is verifiably false

orlp

yes

sage reduces it to

[1 0 0 0 1 1 1 0 0 0]
[0 1 0 0 1 0 1 0 1 0]
[0 0 1 0 0 1 1 1 0 0]
[0 0 0 1 1 1 1 1 1 0]
[0 0 0 0 0 0 0 0 0 1]
[0 0 0 0 0 0 0 0 0 0]
[0 0 0 0 0 0 0 0 0 0]
[0 0 0 0 0 0 0 0 0 0]
[0 0 0 0 0 0 0 0 0 0]

Sp3000

That right column makes no sense - did you complement the bits?

Anonymous

The issue is, there is a solution: f

orlp

1:05 PM

@Sp3000 oops

there we go

that was it

@Mego solve again using sage, but complement the bits

remember, either everything must be 1 or everything must be 0

Anonymous

Ahh

orlp

wait a sec

this is really easy to encode into the matrix

I must just add another column

that is all ones

which will be the 'all 1 or all 0' variable

Anonymous

sagecell.sagemath.org/…

Sp3000

@Mego Your prime pyramid needs more binomialling :P

Anonymous

@Sp3000 ?

Sp3000

1:16 PM

Take the relevant binomial row and dot product with the primes, e.g. [1 3 3 1] . [2 3 5 7] = 33

(basically, sum (n-1 choose k) * prime(k) for k in range(n))

Anonymous

That might be more bytes :P

Sp3000

I'd expect it to be shorter, give it a shot?

(I'm assuming Seriously has binomial here)

Anonymous

No, but I can use a clever property I think

Anonymous

It's supposed to have binomial, but the person who was going to write it never wrote correct code

Sp3000

:/

orlp

1:25 PM

0

Q: Finding solution to matrix equation over GF(2) with minimal true variables

I am looking for a general way to find a solution to a system of equations in GF(2) such that the solution has the least amount of true variables. After Gaussian elimination I get a matrix like such: $$ \left[ \begin{array}{ccccccccc|c}1&0&0&0&1&1&1&0&0&1\\ 0&1&0&0&1&0&1&0&1&1\\ 0&0&1&0&0&1&1&1

let's see what smarter people have to say

Sp3000

Hmm well Pyth has .c

orlp

@Lembik maybe the above question interests you as well

LegionMammal978

Is anyone else having problems logging in?

orlp

nooooooooooo

read only on math.se

LegionMammal978

and mathematica.se

and codegolf.se

orlp

1:30 PM

welp

LegionMammal978

nothing on the status blog

or twitter

Anonymous

Nope, neat property failed me

Anonymous

Phooey

Anonymous

It would have been longer anyway

Sp3000

Twitter says hurricane. Funtimes

Anonymous

1:34 PM

Oh dear

LegionMammal978

...

Sp3000

Also s*V.cLtQUQ.f}ZPZQ0 is also 18. shrugs enough Pyth for one day.

orlp

@Sp3000 what twitter

> november 30

LegionMammal978

that was several days ago

orlp

also

LegionMammal978

1:35 PM

all of them are

orlp

Hurricane Electric is the name of the company

not an actual hurricane

Sp3000

Oh. Well.

Wrong on two counts then oops :P

orlp

so double fail :P

A for effort though

you get that

Sp3000

(I have no idea why I still thought it was Dec 1)

FlagAsSpam

15 Sorting Algorithms in 6 Minutes

►

LegionMammal978

1:37 PM

@FlagAsSpam Sorry, saw that already :P

FlagAsSpam

Awesome, right? :D

Anonymous

I think everyone with a cs degree has seen it :P

Anonymous

Required watching in intro algorithms courses

Sp3000

Hmm I don't think we watched that in uni itself, although I do remember something about a dancing quicksort...

Dennis

> We are currently offline for maintenance

No!

Sp3000

1:39 PM

^^ there we go

Anonymous

:(

Anonymous

That's such a huge disruption in our golfing

Sp3000

At least chat's still up

Anonymous

for now

Sp3000

So we can still golf here :P

FlagAsSpam

1:40 PM

DON'T SAY THAT>

Anonymous

tempting-fate

FlagAsSpam

MINI-CHALLENGE: write a program or function that prints out "tempting fate" without any of those characters (only the lowercase) being in the code.

Anonymous

"TEMPTING FATE"ù

FlagAsSpam

...

Anonymous

Or are spaces not allowed?

FlagAsSpam

1:42 PM

^

orlp

@Dennis what will yuo do now

FlagAsSpam

@orlp Sleep - he hasn't in years.

Dennis

Hahaha.

Anonymous

["TEMPTING,"FATE"]`ù`M1╤2*cj

Dennis

I'm actually taking a break. I've posted two answers in the last couple of days, I think.

FlagAsSpam

1:45 PM

@Mego Chaîne?

Anonymous

@FlagAsSpam Seriously, obviously

FlagAsSpam

@Dennis The apocalypse approaches...

@Mego Oh. Well then.

Anonymous

Push the two strings in a list, convert to lowercase, push 20, pop 20 and push chr(20), join

Dennis

Haven't rep capped in a week. I think. I can't check. Oh god!

LegionMammal978

In Mma, this is impossible. Print and Symbol@Names[][[21122]] both use forbidden characters.

Wait no forgot Echo

FlagAsSpam

1:46 PM

... I just got this page when trying to connect to SE:

Anonymous

There's something slightly discomforting about watching the PPCG god have a mental breakdown

FlagAsSpam

@Sp3000 Use [`code`](link)

Sp3000

"dU]`dY^WVQdU"{H(+}%

there we go. About 3 things I was doing wrong there

FlagAsSpam

Woah, how does that work?

Dictionary lookups?

Sp3000

The first string is 16 subtracted from each char

FlagAsSpam

1:49 PM

Oh.

I see that with the "te" -> "dU" now. :D

Sp3000

Actually I can use 17 fine

... nope I can't

Anonymous

Seeing this Pyth code that I don't understand bewilders me

Anonymous

And then I think of how Seriously must look to people who don't understand it

FlagAsSpam

^ Same with Vitsy.

Anonymous

At least Pyth is nice enough to stay in printable ASCII

FlagAsSpam

1:51 PM

Side note: I found the origination for the name of Simplex.

LegionMammal978

@Mego When I see golfing languages, I just see random strings of characters

FlagAsSpam

It's a flag in ifconfig. c:

orlp

interesting idea

Sp3000

Er... that isn't the only meaning of "simplex" though

orlp

if you get poop anywhere on your body except your ass

do you wipe it off with water or toilet paper?

FlagAsSpam

1:52 PM

WTF?

orlp

it's a thought experiment

to show how weird it is that we only wipe our ass with paper

FlagAsSpam

@Sp3000 It's a logical place to start.

@orlp See: bidet.

orlp

if you get a chunk of poop on your arm, no way in hell you smear it out with toilet paper

Sp3000

@FlagAsSpam I think the more reasonable guess is simple + complex, but would have to ask Conor

FlagAsSpam

@CᴏɴᴏʀO'Bʀɪᴇɴ From where did you get the name "Simplex"?

Why did I use originate? That's not remotely what I meant.

Anonymous

1:55 PM

"FATE""TEMPTING"k`ù`M5╙cj I got it shorter!

FlagAsSpam

\o/

stackexchange.com/error?aspxerrorpath=

D:

LegionMammal978

Finally, Mma in 59 bytes: Echo@"\.74\.65\.6D\.70\.74\.69\.6E\.67\.20\.66\.61\.74\.65"

FlagAsSpam

\o/

Sp3000

So... we're allowed to use uppercase?

LegionMammal978

Yes

Sp3000

2:00 PM

Oh, then "dU]`dY^WVQdU"{G+}%

FlagAsSpam

> only the lowercase

Sp3000

Ah right

LegionMammal978

Finally

Stack Overflow is coming back online now.

Tweeted by Nick_Craver on December 5, 2015 at 2:01 PM

Anonymous

it-lives

Anonymous

Mini-challenge: print "IT LIVES" without alphanumeric characters

LegionMammal978

2:07 PM

@Mego Now that's impossible in Mma...

Sp3000

"§²~ª§´£±"{'^'Æ'~-'!+~-}% <-- I'm probably overthinking this

3

Cᴏɴᴏʀ O'Bʀɪᴇɴ

2:29 PM

So... Stack Overflow broken whilst I was gone? C'mon people! XD

@FlagAsSpam Where did the name Simplex come from? I was thinking of a good name for the language, and thought Hey! This has MULTIPLE tapes! Hm.... I wanted a cool name for it i.e. a unique one. I haven't seen one with "x" before... Simplex!

That is, a K-dimensional triangle

Anonymous

My headcannon: "this language is anything but simple, so I'll denote that by calling it Simple and appending an x for xtreme"

4

Sp3000

So actually simplex simplex, nvm :P

Cᴏɴᴏʀ O'Bʀɪᴇɴ

^

Cᴏɴᴏʀ O'Bʀɪᴇɴ

2:46 PM

@Mego -[------->+<]>.+++++++++++.[--->+<]>++++.++++++[->++<]>.---.>+[--->++<]>.--[----->+<]>+.>-[--->+<]‌>--.

@Mego Or ɪᴛ ʟɪᴠᴇs

:p

Stefnotch

3:02 PM

Any suggestions on what I should improve?
http://output.jsbin.com/cuzoxu

^A Labyrinth interpreter...

Also, who should I call if I want to golf my interpreter?

FlagAsSpam

3:18 PM

CodeBusters.

2

Anonymous

@Stefnotch @phase

Martin Büttner

@Stefnotch someone who can assure you that golfing the interpreter is not a good idea

so not phase

FlagAsSpam

@CᴏɴᴏʀO'Bʀɪᴇɴ The reason I ask is that Simplex is also a flag in network interface configuration. :P

Anonymous

@FlagAsSpam It's also an algorithm for solving linear optimization problems

FlagAsSpam

So many simplexes. x.x

Sp3000

3:32 PM

At least the linear programming one makes sense, since the solution space is a simplex (I think?)

Anonymous

59 mins ago, by Mego

My headcannon: "this language is anything but simple, so I'll denote that by calling it Simple and appending an x for xtreme"

Anonymous

s/language/algorithm

Sp3000

The algorithm is simple, finding its practical runtime complexity is the hard part :P

Lembik

hi @Sp3000

Sp3000

Hey

Lembik

3:35 PM

I am still not convinced by the p-1 factors problem :)

Stefnotch

@phase Can you golf that down: jsbin.com/cuzoxu/edit?html,css,js :P

Lembik

let's set x = 2

don't almost all numbers have more than 2 distinct prime factors when is large?

Stefnotch

"You have fully used your vote allowance for today"
Does that mean I can't star any messages anymore?

Lembik

do you have some nice code to list the number of distinct prime factors that will work for n > 1000000 say?

@Sp3000 ^^

Sp3000

Yes but the problem here is ratios between "good" primes, rather than the difference

Lembik

3:37 PM

@Sp3000 this is true

I suppose I could ask for the largest number of primes between two good primes

Sp3000

So they can get increasingly rarer proportion-of-all-numbers-wise, but the ratio can still tend to 1

Lembik

@Sp3000 this is true also..but is it obviously true?

I mean that the ratio tends to 1

Sp3000

Obviously? No - none of this is anything I'd be able to prove

Lembik

how about if I just change the score to the largest number of primes between two good primes?

Anonymous

@Lembik I don't believe this is true

Lembik

3:39 PM

@Mego which part?

Anonymous

@Lembik You're claiming that lim [n -> inf] (integers < n where omega(n) = 2)/n = 0, yes?

Sp3000

I fear you might have the opposite problem, where score gets arbitrarily large really easily

orlp

Hah

I've got you guys beat!

Anonymous

(omega(n) = # of distinct prime factors of n)

Lembik

@Mego I am not sure I did claim that :)

@Mego the cruel naysayers did I think :)

Stefnotch

3:43 PM

Would a digit sum catalog question be a good idea?

Anonymous

@Lembik You are claiming that, the higher you go in the positive integers, the less integers you find that have exactly two prime factors, correct?

Anonymous

@Stefnotch 9,%

orlp

0

A: Sum pyramid of primes

Pyth, 16 bytes s*V.cLtQQ.f}ZPZQ Very simple actually: s*V ; Multiply element-wise and sum .cLtQQ ; the binomial coefficients for n .f}ZPZQ ; and the first n prime numbers.

Lembik

@Mego oh yes I did claim they get rarer

Stefnotch

LOL (Is that a Seriously program?)

Lembik

3:44 PM

@Mego only because omega#(n) grows like log log n

@Mego can they really grow like log log n and omega(n)=2 stay equally frequent?

Anonymous

@Lembik So, given some positive integer n, you are claiming that (# of integers < n where omega(i) = 0)/n tends to 0 as n -> inf

Anonymous

I'm just verifying that I understand you before I try to go prove anything :)

Lembik

do you mean omega(i) <= 2?

I do claim that (# of integers < n where omega(i) <= 2)/n tends to 0 as n -> inf)

Anonymous

Err, omega(i) = 2

Lembik

<=2 :)

Anonymous

3:47 PM

I guess <= also works

Lembik

it is a known fact that primes get rarer

Anonymous

Yeah, but I'm not convinced that extends to omega(i) <= k for some k >= 1

Anonymous

I can see how it seems intuitive that it would, but I want to check :P

Lembik

@Mego do you agree that omega(n) grows like log log n?

Anonymous

@Lembik That seems correct

Lembik

3:51 PM

@Mego ok

then it seems natural that omega(n) =2 gets rarer doesn't it?

Anonymous

Yes, that makes sense

Anonymous

I had to logic out that omega(n) ~ log(log(n))

Lembik

it would love to see some number if anyone has code

for n > 1000000 say

Anonymous

Some number for what? omega(n)?

Lembik

yes

Anonymous

3:53 PM

,wl

Lembik

or really for good primes

Sp3000

I did check for x=2 empirically for the first few million and it was going down, if that helps

FlagAsSpam

Ω(n)?

Sp3000

Would check again but I'm doing some atm

Anonymous

@FlagAsSpam Lowercase omega

FlagAsSpam

3:54 PM

Or ω(n)?

Lembik

@FlagAsSpam the latter

Anonymous

Lowercase: # of prime factors; uppercase: sum of prime exponents

FlagAsSpam

Sum of prime exponents sounds horrifying. o-o

orlp

@Lembik did you take a look at my question?

Lembik

@orlp not yet sorry

Anonymous

3:56 PM

@FlagAsSpam It's not that bad. An integer n is prod(p_i^a_i). Omega(n) = sum(a_i)

New Sandboxed Posts

0

A: Sandbox for Proposed Challenges

Digit Sum of a Number Write a program that calculates the digit sum of a non-negative integer, in as few bytes as possible. Digit sum means the sum of every single digit. Test cases: Input: 10 Output: 1 Input: 3701 Output: 11 Rules: Your program must log to STDOUT or an acceptabl...

Lembik

could someone with high rep copy my deleted question to the sandbox please

orlp

sjQT

Lembik

I am not sure it should be completely dead yet

orlp

@Lembik link to question?

Lembik

3:58 PM

@orlp ummm...@Sp3000 help :)

@orlp how do you find a deleted question?

Sp3000

codegolf.stackexchange.com/questions/65814/…

(found via history)

FlagAsSpam

Side note: I have successfully created a virtual phone to allow me to use Fallout 4's pip-boy app on my computer. c:

I am a nerd.

:D

Anonymous

@Lembik I'll do it for you

Lembik

@Mego thanks!

orlp

gist.githubusercontent.com/orlp/437548b0f5f888cd0ac8/raw/…

question contents

Anonymous

4:01 PM

0

A: Sandbox for Proposed Challenges

Find the largest gap between good primes Following the fine tradition of questions such as Find the largest prime whose length, sum and product is prime , this is a largest prime challenge. Input Your code should take a positive integer x as input. This can be given in any sensible way you ch...

Anonymous

I made it CW so that you can edit it

New Sandboxed Posts

0

A: Sandbox for Proposed Challenges

Find the largest gap between good primes Following the fine tradition of questions such as Find the largest prime whose length, sum and product is prime , this is a largest prime challenge. Input Your code should take a positive integer x as input. This can be given in any sensible way you ch...

Anonymous

4:16 PM

Outputs (positive integers i less than n where omega(i) <= 2)/n: ,;RpX`wl3>`MΣ/

Anonymous

May need to run it locally for large n

Nathan Merrill

4:37 PM

@Mego reading your meta post about testing: unfortunately, I think its a culture problem than a rules problem

people are ok with posting code that looks valid

quintopia

Guess which denizen of this room has been seen hanging out in ##magic on Freenode

FlagAsSpam

4:56 PM

ಠ_ಠ The app for the pip boy doesn't last long enough for the PS4 to respond.

Anonymous

not me

FlagAsSpam

I wireshark'd the network, it waits .5 seconds for the PS4 to reply.

With a fairly complex message. ಠ_ಠ

sigh

VTC = annoyed

VTC ≠ happy with app

Anonymous

@FlagAsSpam Who is VTC? I thought you were FAS

Anonymous

5:39 PM

@NathanMerrill Maybe. I'll be keeping my trout ready for any future untested answers

ETHproductions

@Mego Trout?

Anonymous

Wikipedia:Whacking with a wet trout

The above is a WikiTrout (Oncorhynchus macrowikipediensis), used to make subtle adjustments to the clue levels of experienced Wikipedians. To whack a user with a wet trout, simply place {{trout}} on his or her talk page. For newcomers (or for a less spammy version), use a {{minnow}}, {{diet trout small}} or {{diet trout}}. For a styleable version that can, e.g., be floated the right of talk page posts, use {{minnow}}. For not-so-subtle adjustments, try a {{whale}}. Any Wikipedian who wants to advertise an openness to being trout-slapped can add {{trout me}} to the top of his or her user page. ...

ETHproductions

Ah

Anonymous

Slapping people with a trout when they post untested code

ETHproductions

Haha

Anonymous

5:45 PM

I can understand getting excited because your code "works" and forgetting a test case

Anonymous

But posting code that is blatantly wrong (fails for a center (not-corner) test case or has syntax errors)

Anonymous

That deserves a trout

FlagAsSpam

@Mego /slap Mego

ಠ_ಠ

ETHproductions

/slap FlagAsSpam's trout

FlagAsSpam

Double-Troutle.

Anonymous

5:50 PM

To save the world from devatroution

Nathan Merrill

I have a dvd I want to watch on my laptop while in a car. If I copy the DVD to my hard drive, and watch it there, will I save power?

aka, does an optical drive use more power than a HDD (not SSD)

Dennis

You watch movies while driving?

Nathan Merrill

lol

while I'm in the car

Dennis

Ah, OK.

I'm pretty sure the optical drive will consume more power.

@NathanMerrill This isn't exactly recent, but it lists HDD vs ODD power consumption as 2.78 W vs 5.31 W while reading.

Both values are bound to be lower with modern hardware, but the relation probably hasn't changed.

Nathan Merrill

its also likely that HDD power consumption has decreased much since then, while ODD hasn't

have there really been improvements in the ODD field?

orlp

6:02 PM

ODD?

Nathan Merrill

I feel like its simply becoming obsolete

orlp

optical disk?

Nathan Merrill

yeah

Dennis

The ODD from the test was a CD drive, which has to spin a lot faster.

orlp

ODD has one prime advantage over other storage forms

Nathan Merrill

6:03 PM

its easily transferrable?

orlp

it's cheap to make, if all the optical disks have the same contents

e.g. when distributing a film on blu-ray

while at the same time being small, resistant against shocks (both kinetic and electric) and light

FlagAsSpam

We need to establish a definite general etiquette for CG. I see way too many answers that are practically dupes.

Nathan Merrill

you're trying to define etiquette?

orlp

@Lembik I think there's a more useful function to study

@Lembik rather than omega(N)

Dennis

@FlagAsSpam The problem is that it's very hard to draw a line. An official policy should be objective.

orlp

6:11 PM

study f(n) = sum i=1,n omega(i)

FlagAsSpam

@Dennis Yes - etiquette mayn't've been the right word. Just a basic byte % difference or something.

orlp

I think the most useful definition for a dupe is if you can copy an answer from one to another with minimal modification

Nathan Merrill

@FlagAsSpam that's heuristics, not objective

orlp

I'm actually surprised how little answers this got

10

Q: Fully parenthesize expressions

Today your challenge is to produce all possible full parenthesizations of an expression. Your input is a single line of printable ASCII containing one or more terms separated by operators. The input might also contains spaces - you must ignore these. A term is [a-zA-Z0-9], an operator is [^ ()a-...

code-golf

I wonder if it was too difficult

it seems so simple

Dennis

@FlagAsSpam Like edit distance / byte count?

orlp

6:14 PM

@Dennis that terribly inefficient

unless someone is plagiarizing it's unlikely that the edit distance is going to be small

Dennis

Are you talking about answers or questions?

Nathan Merrill

wait, so what are you trying to prevent?

if not plagiarism?

orlp

@flawr are you from switzerland

@NathanMerrill duplicates?

you can ask the same question without ever looking at the duplicate

plagiarism is something else entirely

Nathan Merrill

duplicated questions have a defined procedure here.

if there are two answers that are similar on the same question, but were independently conceived, then I don't see the problem.

orlp

Ohhhhhhhh

this is for answers

not questions

either way, it's very subjective

it's not uncommon to independently discover a golf

I do it all the time

if it's an exact dupe of an answer, or 1/2 shorter I'll post a comment

otherwise I just post

flawr

6:32 PM

@orlp yes, why are you asking?=)

orlp

@flawr just saw your profile

was a riddle

flawr

6:49 PM

Haha=)

New Sandboxed Posts

7:17 PM

0

A: Sandbox for Proposed Challenges

Generate a graphical representation of a Stern–Brocot tree of depth n I am aware of this challenge. Would this be considered as a dupe?

quartata

Finally got my internet back

I've been without Internet since 5 A.M and I was starting to suffer from withdrawal

@FlagAsSpam Wait, what?

ETHproductions

@quartata Sheesh, and I thought the 15 minutes I had to wait after I woke up while SE was down was bad

quartata

@ETHproductions basically

PhiNotPi

I just came up with an idea for a new version of chess. I call it "real chess" because the pieces can move in distances of real numbers.

Doorknob

7:34 PM

Next up: imaginary chess

Thomas Kwa

Should all noncompetitive answers be CW?

On the one hand, getting votes is in a sense the reward for winning a code-golf. On the other hand, sometimes people work hard on noncompetitive answers and deserve rep.

orlp

@ThomasKwa no

flawr

@Doorknob Lets get non-commutative: quaternion chess

2

orlp

the competition is for the checkmark

the upvotes is for originality, enjoyment, interest, ingenuity, etc

quintopia

hands @Doorknob an imaginary pie

Doorknob

7:43 PM