The Nineteenth Byte

@flawr "Animated GIFs use a lossless algorithm at this stage. Each frame can specify the updated picture region and the delay until redrawing, to avoid encoding whole and repeated frames. And that is about all that it does." I found that about inter frame compression

Anonymous

Yeah animated GIFs are horrible when it comes to file size

Anonymous

Each frame is stored in a stream format, individually compressed, but it doesn't take advantage of inter-frame compression (like MP4)

Lembik

@Mego thanks.. this is as I suspected

flawr

@Lembik Yeah about that. The problem is that you need more computing power the more you use inter frame compression.

Agawa001

9:25 AM

@flawr which kind of video codec that allows algorithmic pattern morthing ?

Anonymous

WebM is a lot better. Like MP4, it compresses the video into a sequence of key frames and deltas.

Lembik

@flawr all true.. but computer power is free these days :)

@Mego is there a simple tool to make webm like there is to make animated gif?

Agawa001

@flawr yes inter-frame compression

Anonymous

CPU time is a whole lot more abundant than bandwidth

Anonymous

@Lembik Gfycat works really well

Lembik

9:26 AM

oh cool!

Anonymous

Upload a video, select a slice up to 15 seconds, get your webm

flawr

What does imgur use for their gifv's?

mp4?

Anonymous

Also webm

Agawa001

it decomposes the image into segments using countour detection than move it upon the background thru an algorithmic process

kinof genuine sort of compression

Anonymous

For example: imgur.com/gallery/m8FE7wm

Lembik

9:28 AM

on another note.. I was thinking of posing a challenge for code to find efficient matrix multiplication algorithms (a la strassen)

does this sound interesting?

Anonymous

Raw video file is i.imgur.com/m8FE7wm.webm

Lembik

that's a big fish!!

flawr

@Lembik what do you mean, to find?

I think we'd have to rely on known algorithms???

Anonymous

@Lembik I was hungry; don't judge me

Lembik

@flawr so if you fix the size of two matrices that you want multiply together, say 2 by 2

you can search for the minimum number of multiplications needed to achieve this by any algorithm

in this case it is 7 which is Strassen's algorithm

Anonymous

9:30 AM

@MarsUltor That would be fantastic if it supported Python

Lembik

you can then search for the minimum number of additions too. I can't remember what that is

for 3 by 3 the answer is unknown

and for 2 by 3 I am not sure what it is

@flawr does that make sense?

Anonymous

Clearly the most efficient method to compute matrix multiplication is to use the builtin and not think about it any further. It's incredibly efficient, because you use essentially 0 brainpower on it.

Lembik

@Mego well :)

@Mego the game here is that once you have the minimum number of multiplications for small matrices you then apply it recursively to large ones

flawr

@Lembik I think I get it, but on the other hand I think this is a quite difficult challenge.

Lembik

so for strassen's algorithm you get n^(log_2(7)) complexity to multiply two n by n matrices

flawr

9:32 AM

I do not think it is exaclty n^(log_2(7))

I just recently had to calculate this=)

Rather like O(n^(log_2(7)))

Lembik

@flawr I was thinking of making the multiplication mod 2 which might make it very slightly better

flawr

You mean making the challenge about multiplying matrices over F_2?

Lembik

@flawr you are right.. I left out the O

@flawr yes. that might be slightly easier

I mean the code needed to search for the optima might be slightly easier

flawr

@Lembik Well the O makes a significant diffference here. There is the Coppersmith-something algorithm which is like n^2.3...

But has a huge constant factor IIRC

Lembik

@flawr yes, However this method won't give huge constants

Agawa001

9:35 AM

penguins arent allowed to flag when they are flaggable

Lembik

as you would get an explicit description of which multiplications and additions to do

Agawa001

hmmm lemme guess, that s not very nice !!!

Lembik

@flawr for Coppersmith-Winograd no one has ever even implemented it! :)

flawr

How can you be so sure about taht? :D

Lembik

which is always a bad sign

@flawr well the question has been asked and answered online. So only as sure as that

Anonymous

9:37 AM

The coverage package says my test coverage is 70%

flawr

@Mego It is lying.

Anonymous

I'm sure

Anonymous

It's either lying or confused

Lembik

@flawr see cstheory.stackexchange.com/questions/4491/… for example

Anonymous

19 mins ago, by Mego

My coverage is probably around 70% right now

Anonymous

9:38 AM

There is no way that guess was that accurate

Lembik

@flawr but I think it could be a fun and difficult challenge :)

flawr

@Lembik So you suggest making a challenge where given the size of two matrices, you have to find an multiplying algorithm that is as efficient as possible (considering the number of multiplications)

Anonymous

meta-fastest-algorithm

Anonymous

Alternatively, "write a program that generates a program that optimizes for a specific test case"

flawr

Still, I think that this is insanely difficult=)

@Lembik Nice link!

I thought about another challenge recently: Given two (unlabelled) graphs, determine whether the first one one is a sub-graph of the second one.

flawr

10:13 AM

This one:

Lembik

@flawr yes exactly. If the number of mults is equal you will then be judged on the number of additions (or subtractions)

@flawr isn't the subgraph isomorphism?

@flawr gregorybard.com/papers/early_release.pdf

VTCAKAVSMoACE

@CᴏɴᴏʀO'Bʀɪᴇɴ @EᴀsᴛᴇʀʟʏIʀᴋ RDFTD

[Dubstep] - Slips & Slurs x Mihka! - WiFi Tears [Monstercat Release]

►

It turns into Future Bass halfway through it. :ᴅ It's so good.

flawr

@Lembik I don't understand what you wanna say?

zyabin101

RIGFTD: None for today. :(

VTCAKAVSMoACE

@zyabin101 ʜᴡᴀᴛ ɪs RIGFTD?

zyabin101

10:20 AM

@VTCAKAVSMoACE Random infographic for the day.

VTCAKAVSMoACE

ᴏ

zyabin101

I choose an infographic from Imgur every morning to feature in chat every day. Sadly, I caught none this morning.

flawr

@zyabin101 Take this instead.

New Sandboxed Posts

0

A: Sandbox for Proposed Challenges

Determine whether one graph is a subgraph of the other mathgraph-theorydiscrete-math Given two unlabelled graphs as adjecency matrices with the same number of vertices, the goal is determining whether the first graph is a subgraph of the second one. Definitions A graph G=(V,E) comprises a set...

zyabin101

@flawr Oooooh, I've seen it on Imgur yesterday, too.

Lembik

10:29 AM

@flawr the link was just showing someone else who had done the same thing

except not over a finite field.. so not as good :)

El'endia Starman

11:16 AM

5

(Via Facebook.)

mınxomaτ

@El'endiaStarman JPEG'd to death? Comic f*cking Sans? It couldn't be from anywhere but facebook ;-)

zyabin101

@trichoplax o/

Keeping this room alive.

trichoplax

:)

Oct 15 '15 at 13:54, by trichoplax

There are other rooms??

VTCAKAVSMoACE

kek

That was a few days after I joined. O.o

trichoplax

And now you're an established part of the community with a type of vote named after you

VTCAKAVSMoACE

11:24 AM

;P

El'endia Starman

@mınxomaτ ¯\_(ツ)_/¯

Agawa001

penguins arent so nice

El'endia Starman

Ooh, today's the 100th anniversary of Claude Shannon's birthday, the guy that "Shannon entropy" is named after. Known as "the father of information theory".

3

trichoplax

How random is that?

VTCAKAVSMoACE

ಠ_ಠ

trichoplax

11:28 AM

:P

:D

:ᴅ :ᴘ

:d :p

SMALL CAPS EMOJIS ARE SO ADORABLE

They're like the poops in Binding of Isaac. :ᴅ

zyabin101

@VTCAKAVSMoACE D'AWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW--- throat

VTCAKAVSMoACE

11:30 AM

hwat

zyabin101

@VTCAKAVSMoACE I DO LIKE THEM, TOO

THEY ARE SO ADORABLE

:ᴅ

VTCAKAVSMoACE

^ That's what it reminds me of.

They're called small Dingles, right?

Apparently, they're called Dips

New Main Posts

12:00 PM

0

Q: exponential without exponential

Your goal is to calculate the exponential of a float (e**x) up to 2 decimal places for any float within 1 to 10. The accepted error range is 0.01. However, you must not use the built-in exponential function or the logarithm function. In fact, attempts to circumvent this by (2**x)**(1/ln(2)) are...

code-golf

flawr

@El'endiaStarman I do only understand 7,9,10,15

El'endia Starman

12:22 PM

1. Eskimos build igloos
2. Won is a Chinese soup
3. Scope is a brand of mouthwash
4. "Bananosecond" is a mash-up of banana and nanosecond
5. "Billigram" sounds like "Billy Graham", a very famous Christian evangelist
6. "Knotfurlong" sounds like "Not for long"
7. "Lite" is a category of beers and sounds like "light"
8. Rod Serling was an actor in the TV series "Twilight Zone" and is a pun on an archaic measurement unit: ?
9. "Semi" means half and "colon" means large intestine
10. A megahertz is 1,000,000 oscillations per second

@flawr: ^

flawr

Haha, thanks=)

I still do not get 1, but I do quite like 16,13 now that I get it=)

LegionMammal978

12:42 PM

First person to figure this out gets a cookie (looking at you, @MartinBüttner):

Count[Normal@SeriesData[x,0,Reverse@RealDigits[EulerGamma,10,#][[1]],0,#,1]~NRoots~x,_Real,{1,2}]&

Bas

@LegionMammal978 The answer is 6

LegionMammal978

@Bas Incorrect. It is a function.

Bas

@LegionMammal978 The answer is an anonymous function which returns 6 upon execution

LegionMammal978

@Bas For what input(s)?

Bas

@LegionMammal978 Every input :D

@LegionMammal978 Okay I give up, I was hoping you'd believe me for free cookies

LegionMammal978

12:44 PM

@Bas Incorrect. f[1] == 0.

Bas

I don't even know mathematica

LegionMammal978

Okay, from the OEIS:

> Number of real roots of the polynomial sum_{k=0..n-1} A001620(1+k-n)*x^k, whose coefficients are the decimal digits of the Euler-Mascheroni constant.

Bas

@LegionMammal978 Pronounce that entire sentence right and I'll give you a cookie

LegionMammal978

@Bas text2speech.org/FW/…

Kenny Lau

I'm quite sure text2speech doesn't know the word "Euler" even.

trichoplax

12:50 PM

@El'endiaStarman I think "a straight line" is just the non-funny line that sets up the next joke. Like the "straight man" is the one in a comedy duo who says something to set up the punchline for the other one.

Nothing funny, but makes the joke possible

urbandictionary.com/…

LegionMammal978

@KennyLau Fine, text2speech.org/FW/…

> Number of real roots of the polynomial produced by the sum of O E I S sequence A zero zero one six two zero applied to one plus K minus N all times X to the K with K going from zero to N minus one, whose coefficients are the decimal digits of the oiler mass care ony constant.

VTCAKAVSMoACE

1:45 PM

Holy crap, I just read the darkest Academia post

quartata

you should really turn on some lights then

VTCAKAVSMoACE

ಠ_ಠ

zyabin101

@VTCAKAVSMoACE Link?

VTCAKAVSMoACE

@zyabin101 Seriously, it's dark, so, viewer discretion is advised.

Agawa001

the cool thing bout ppcg, the challenges arent time-bounded

VTCAKAVSMoACE

2:14 PM

Welp. My outgoing firewall to help me work is officially useless.

github.com/SelfControlApp/selfcontrol/issues/359

Helka Homba

Anyone know what the "HP" might mean in this floor plan? liveluma.com/?floor-plans=2304

I'd guess water heater but the acronym doesn't make sense

Perhaps it's "Harry Potter" cupboard

New Main Posts

-2

Q: a recursive function for sorting a singly linked list?

Write a method which takes ONE PARAMETER only and does not use any auxiliary method to sort a singly linked list.

code-challenge

zyabin101

too late >_<

Kenny Lau

2:29 PM

what's our stance on challenges of creating a class (or its equivalent)?

meaning a bunch of methods and some variables

VTCAKAVSMoACE

@KennyLau Probably a little broad, since languages define classes totally differently.

Kenny Lau

@VTCAKAVSMoACE e.g. a matrix class?

that would include addition and transpose (only)

just as an example

VTCAKAVSMoACE

@KennyLau I don't follow.

Like, a code that generates a class?

Kenny Lau

a code containing two methods

VTCAKAVSMoACE

A class that is instantiable and has certain members?

Kenny Lau

2:40 PM

no need to be instantiable (how do you do that in esolangs)

VTCAKAVSMoACE

Oh, well, yeah, I guess. The language would be OOP restricted, probably.

I think I still don't follow. :P

Kenny Lau

just two methods basically?

I don't really know how to expand it to esolangs

code jam!!!!

in 1 hour 12 minutes

Maltysen

@KennyLau \o/

Kenny Lau

@Maltysen Could you help me golf this code?

0

A: Compute the Adler-32 checksum

Pyth, 25 bytes im%sd65521,mhsd._QhsQ^4 8 Try it online! Translation of my answer in Jelly.

zyabin101

@KennyLau Daaaaarn, I forgot. Don't worry, I'll take code together and build the "Friends of PPCG" leaderboard for the code jam when it ends.

New Meta Posts

2:54 PM

0

Q: Special method to sort linked list

Is it possible to write a recursive method which does not use any auxiliary method and only takes one parameter, sorts the singly linked list?

discussion code-challenge

zyabin101

Thanks to @MarsUltor's code jam leaderboard snippet, I'll be able to snapshot the leaderboard at several moments.

VTCAKAVSMoACE

Wait, so, question: what are code jams?

Helka Homba

It's like alphabet soup for bread

VTCAKAVSMoACE

@HelkaHomba hwat

zyabin101

code jam!!!!

in 0 hour 57 minutes

Helka Homba

3:03 PM

@VTCAKAVSMoACE code.google.com/codejam

zyabin101

@HelkaHomba He said jams, not one jam.

Maltysen

3

zyabin101

FRUITW'd /o\

Dr Green Eggs and Ham DJ

Good morning TNB.

Agawa001

bah, photoshock

zyabin101

3:06 PM

Competitive programming

Competitive programming is a mind sport usually held over the Internet or a local network, involving participants trying to program according to provided specifications. Competitive programming is recognized and supported by several multinational software and Internet companies, such as Google, Facebook and IBM. There are several organizations who host programming competitions on a regular basis. A programming competition generally involves the host presenting a set of logical or mathematical problems to the contestants (who can vary in number from tens to several thousands), and contestants are...

Maltysen

@Agawa001 gimp, actually

zyabin101

bah, gimp

VTCAKAVSMoACE

@zyabin101 Ah, okie.

zyabin101

@DrGreenEggsandHamDJ Good morning part of TNB

Agawa001

it is clear that is grape jam

Dr Green Eggs and Ham DJ

3:09 PM

@zyabin101 ¯\_(ツ)_/¯

I know it's not morning everywhere.

Agawa001

do anyone have the opening password for spoj challenges ?

Helka Homba

55 mins ago, by Helka Homba

Anyone know what the "HP" might mean in this floor plan? http://liveluma.com/?floor-plans=2304

Dr Green Eggs and Ham DJ

Health points?

Kenny Lau

@HelkaHomba heat pump

westerwelle.net/abbreviations.htm

Helka Homba

ah, thx

Eᴀsᴛᴇʀʟʏ Iʀᴋ

3:17 PM

@VTCAKAVSMoACE dude, up at 5 is my limit... yawns

monking

zyabin101

monring

Eᴀsᴛᴇʀʟʏ Iʀᴋ

no

monking

Agawa001

moaning

zyabin101

no

monring

PhiNotPi

Only 39min 8sec until Code Jam!

Dr Green Eggs and Ham DJ

3:20 PM

@EᴀsᴛᴇʀʟʏIʀᴋ Good monking!

Agawa001

mooring from moors

zyabin101

@PhiNotPi Daaaaarn!

Downgoat

@EᴀsᴛᴇʀʟʏIʀᴋ goom monking

PhiNotPi

good afteryesterday

Eᴀsᴛᴇʀʟʏ Iʀᴋ

shit, you people can code this early???

>.<

gtg, bai!

Downgoat

3:24 PM

bai

Hello @NeoKo!

Neo Ko

@Downgoat Hello

Dr Green Eggs and Ham DJ

@EᴀsᴛᴇʀʟʏIʀᴋ "This isn't a programming question. It is just a really unclear challenge" wat?

It's clearly a "gimme teh codez"

Maltysen

@EᴀsᴛᴇʀʟʏIʀᴋ not really

Eᴀsᴛᴇʀʟʏ Iʀᴋ

@DrGreenEggsandHamDJ but it is a challenge, nonetheless.

Dr Green Eggs and Ham DJ

I disagree.

What's the winning criteria?

TheNumberOne

3:30 PM

@PhiNotPi CodinGame also has a contest starting at that time.

And codechef had one start 1.5 hours ago.

Agawa001

those machines are picky

Helka Homba

> A weasel shut down the world's most powerful particle smasher when it wandered onto a 66,000-volt transformer and caused a short circuit - Pop goes the weasel

Downgoat

> caused by the weasel, which did not survive

flawr

8 hours ago, by flawr

It only took one weasel to shut down the LHC

Downgoat

I thought a weasel roaming in the Large Hadron Collider would be alive and poop out avocads...

flawr

3:44 PM

Anyone know a way of visualizing graphs?

Without having to position every vertex by hand?

Eᴀsᴛᴇʀʟʏ Iʀᴋ

@DrGreenEggsandHamDJ unclear, but phrased as a challenge and obviously is asking for one.

I think meta says 'pls send teh codez' are allowed ~~as long as they also ask for avocad~~.

Maltysen

@flawr networkx

Eᴀsᴛᴇʀʟʏ Iʀᴋ

@HelkaHomba read about that. :P

Dr Green Eggs and Ham DJ

@EᴀsᴛᴇʀʟʏIʀᴋ Link on that? If that is true, then it needs to change immediately.

flawr

@Maltysen Trying that, thanks!

Dr Green Eggs and Ham DJ

3:50 PM

"Gimme teh codez" are the garbage dump of SO. Why should they be on-topic here?

Maltysen

@DrGreenEggsandHamDJ I agree with Riker on this point. If "Gimme teh codez" was well-speced and everything, with an objective winning criterion, then it should be on topic here

however, there is a very high correlation between those and being low-quality for other reasons

aditsu

good luck to code jammers :)

Kenny Lau

3 minutes

Maltysen

@aditsu did you make it last time?

aditsu

you mean 1A? no, I'm participating now

Maltysen

3:58 PM

@aditsu oh, good luck to you too

aditsu

thanks

mınxomaτ

Ever wanted to give a TED talk? Now you can do it anonymously.

Sherlock9

Hey @zyabin101? How does the leaderboard look currently?

TheNumberOne

about to start

Sherlock9

Sorry for the multiple pings

Kenny Lau

4:00 PM

started

flawr

@Maltysen Looks great

Agawa001

which contest is on the way now ?

Kenny Lau

@Agawa001 code.google.com/codejam

flawr

4:16 PM

@Maltysen Can't seem to find how to plot?

Agawa001

@KennyLau it says registrations are closed!

Kenny Lau

@Agawa001 too late lol

Agawa001

why m i late allll the time ?

quartata

10

Q: Should homework be allowed?

Recently, browsing questions of PPCG, i have found a lot of questions that are simply for the purpose of offloading their homework assignments, due to lasiness or easiness of this platform. For this reason, i believe we should ban homework questions. Any input? Some examples: Factor numbers fo...

discussion challenge-quality

Dr Green Eggs and Ham DJ

@quartata That's not really relevant because all of the questions linked were code-trolling.

quartata

4:31 PM

True, but the answers cover what you're asking

Dr Green Eggs and Ham DJ

The top 2 answers are both semi-joke answers. The third answer I think nails it.

>"So I lean toward banning homework questions when it seems obvious that they are looking for someone to do their assignment for them. E.g. if their request is language-specific, that would be a red flag that they have to write something in Scheme or Java or whatever for class. Or if it has the kind of silly constraints that indicate an arbitrary aspect of a class assignment.

However, I'd be open to accepting homework questions when the questioner honestly tells us it is such, and lets us know what language(s) they are doing the assignment in. We could have a standard policy to submit answ…

quartata

Did you see this? meta.codegolf.stackexchange.com/a/1129/45151