The Nineteenth Byte

orlp

4:00 PM

'robber: the message is this' -> 'no it isn't' -> 'prove it'

Nathan Merrill

@orlp only by the OP

orlp

@NathanMerrill conflict of interest

Nathan Merrill

but if the OP says that it isn't, and then later reveals that it is

orlp

if a robber came to your house

and asked 'sign here to confirm my robbery'

would you sign?

Nathan Merrill

right, but the OP can't lie, because he'll eventually prove himself wrong (if he wants any points)

Anonymous

4:01 PM

Bureaucratic robbers, I like it

TùxCräftîñg

@orlp obviously

Cᴏɴᴏʀ O'Bʀɪᴇɴ

sighs

Anonymous

Simply knowing the decrypted message is not enough to determine the private key

orlp

@Mego you don't specify how to encrypt with RSA

there's various different schemes

Maltysen

@Mego just curious, why is this scheme done under a finite field? won't interpolating the polynomial still be computationally easy under Z (Lagrange)?

orlp

4:03 PM

@Maltysen because normally the finite field is large enough to be secure

but still be finite

which is fast to work with, and requires less memory

@Maltysen also

Anonymous

@Maltysen It's easy to interpolate the polynomial in Z, but gaining one secret in a GF doesn't give you any additional information about the polynomial, unlike in Z.

orlp

you need a lack of infirmation

Maltysen

@orlp so there's a faster way to do the interpolation if done under a finite field?

orlp

@Maltysen yes, because all the intermediate results are small, and also the secrets stay small

flawr

@Maltysen What do you mean by interpolation?

Anonymous

4:06 PM

Since your integers are bounded, addition is constant time wrt the length of the integer, rather than linear in Z.

Anonymous

@flawr Lagrange interpolation

Maltysen

@Mego oh

Leaky Nun

@Mego It's interesting

Anonymous

Wikipedia gives a much more efficient way to compute the constant:

Anonymous

wikimedia.org/api/rest_v1/media/math/render/svg/…

Leaky Nun

4:07 PM

when I input those numbers

the snippet tells me they are not valid

then I swap n and t

then the snippet warns me

but then it becomes valid

Anonymous

@LeakyNun What numbers are you using?

Maltysen

@Mego well, that's just the lagrange formula

evaluated at 0, so you get the constant term

Leaky Nun

@Mego 173, 95, 17 for n=3, t=5, s=7

Anonymous

@Maltysen It's the Lagrange formula, but without computing the other coefficients

flawr

(In case any haskell experts are here: I have a question)

Anonymous

4:09 PM

@LeakyNun Well your problem is that n must be greater than or equal to t

Leaky Nun

@Mego but then it returns valid

Anonymous

If you get the error that t > n, the bottom result is irrelevant

Leaky Nun

oh, alright

@Mego Thanks, I found the problem and fixed it.

Sherlock9

@orlp For which game?

Maltysen

@Mego no, its literally just evaluating the formula at x=0

see here: wikimedia.org/api/rest_v1/media/math/render/svg/… and here: wikimedia.org/api/rest_v1/media/math/render/svg/…

Sherlock9

4:13 PM

@flawr Why did you question get downvoted?

orlp

@Sherlock9 2 lines down

Anonymous

I've updated the snippet so that the verify button is disabled if t > n.

Anonymous

That should hopefully avoid some confusion

Sherlock9

Whoops, missed that

Leaky Nun

@Mego thanks

Sherlock9

4:16 PM

Tetris exhibition starts at 2 am for me so in about... 3 hours

Lasts till nearly 4

And I was hoping to sleep early tonight :/

Anonymous

Gah, all these people saying "I don't know how to verify my program"

Anonymous

I spent an hour last night putting together that verification snippet... Ungrateful people...

orlp

@Sherlock9 the page says 7:40 pm for me

which is in 1hr 20 min

oh

they moved it

guess there was delay

Sherlock9

Yeah, refresh regularly

Maltysen

@Mego you should have just redirected them to the inverse question that FryAmTheEggman posted :P

orlp

4:21 PM

@Sherlock9 It was accurate when I said it

and I had refreshed

Sherlock9

They update the schedule with the times that the games actually finished and how long the setups take as well

Weird

orlp

I think maybe some donation goal got met

and another run got put in

Sherlock9

Well, it's moved back to 2:21 from when I last refreshed, which said 2:27

orlp

doesn't matter

you have to watch it

it's not optional

Sherlock9

Orlp, I'm the middle of exam and project and hell month

It doesn't matter that this week is a national holiday. At some point, I need to fix my sleep schedule from that of London's

Maltysen

4:24 PM

@Sherlock9 its not the summer for you?

Sherlock9

My university ends two weeks after a lot of my friends' universities

orlp

@Sherlock9 irrelevant

Sherlock9

And we start back up right after our Independence Day in August

orlp

this is gamesdonequick

thou shalt not sleep!

mınxomaτ

@Mego BTW: Slightly more accurate SHA256 attack numbers for consumer CPUs: thepasswordproject.com/oclhashcat_benchmarking

Or, well, GPUs.

Anonymous

4:31 PM

@mınxomaτ Since the estimate was CPU cores and not GPU cores, that unfortunately doesn't help me

zʏᴀʙiɴ101

4:44 PM

@Downgoat github.com/cheddar-lang/Cheddar/pull/58 D: /o\

Please, don't merge it! D: D: D:

nooooo

Downgoat

@zʏᴀʙiɴ101 too late already closed it

zʏᴀʙiɴ101

:D

mınxomaτ

@Mego The estimate yes. But Google's probably using way more GPU power to process it's data. There are no reliable numbers either way. Especially this year, when Google is already using mixed-arch clusters, with CPUs, GPUs and TPUs.

Cᴏɴᴏʀ O'Bʀɪᴇɴ

what would you call the process of making a fraction like 1.5/2.5 without decimals, as 3/5?

TùxCräftîñg

> 12 Months @ FREE
> 1 Year @ EUR 8.22
.______________________________________.

Sherlock9

4:49 PM

Simplification?

orlp

@CᴏɴᴏʀO'Bʀɪᴇɴ an integer fraction

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@orlp yes, that's what the result is called, but what is the process called?

mınxomaτ

Oct 1 '15 at 23:21, by Doorknob

orlp

@CᴏɴᴏʀO'Bʀɪᴇɴ don't believe that has a name

TùxCräftîñg

lol cheaper in euros :D

Cᴏɴᴏʀ O'Bʀɪᴇɴ

4:50 PM

probably doesn't, but what would you call it?

El'endia Starman

@mınxomaτ Looks like something that came from The Daily WTF.

Anonymous

@mınxomaτ Without accurate numbers from Google (which they're not divulging), any estimate is probably far below the reality

mınxomaτ

Uhm no, that's a signature Doorknob freehand circle. Clearly.

El'endia Starman

@mınxomaτ Woah, TPUs.

Eᴀsᴛᴇʀʟʏ Iʀᴋ

@mınxomaτ TIL Doorknob is circle addict.

El'endia Starman

4:53 PM

I wonder what field has the most applications of circles.

Sherlock9

@CᴏɴᴏʀO'Bʀɪᴇɴ Simplifying the fraction?

TùxCräftîñg

@El'endiaStarman no, it's just a thing from freenom

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@Sherlock9 oo thanks

Sherlock9

I said that earlier though haha

mınxomaτ

3 mins ago, by TùxCräftîñg

lol cheaper in euros :D

That's how currencies work >.>

Cᴏɴᴏʀ O'Bʀɪᴇɴ

4:54 PM

google.com/…

still cheaper in euros than it was then

@El'endiaStarman Google could be switching to Power CPUs for all we know.

Eᴀsᴛᴇʀʟʏ Iʀᴋ

Fun gif of the day:

5

Cᴏɴᴏʀ O'Bʀɪᴇɴ

right shift and left shift discard the decimal portions of a number, right?

FryAmTheEggman

@CᴏɴᴏʀO'Bʀɪᴇɴ That depends on language, etc. Sometimes they carry around (often called rotate instead)

Downgoat

5:07 PM

;_; ono cheddar parser is borking on parsing: "->" ;_; how hard is it to parse two characters ;_;

Lembik

hi

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@FryAmTheEggman oh, I see

hiya!

quartata

@EᴀsᴛᴇʀʟʏIʀᴋ hurr hurr topologists can't tell the difference between a coffee cup and a donut

El'endia Starman

@EᴀsᴛᴇʀʟʏIʀᴋ Mmmm, delicious glazed mugs...

3

quartata

hilarious and original

Sherlock9

5:09 PM

Topologists say you can't comb a hairy ball or a hairy coconut, but hairy donuts, hairy coffee cups and hairy Klein bottles are all ok

El'endia Starman

@Sherlock9 Hmm. What about a double donut? An object of genus two.

TùxCräftîñg

@Downgoat just add -> as a token, after the parsing would be simpler

Eᴀsᴛᴇʀʟʏ Iʀᴋ

@quartata ....

@CᴏɴᴏʀO'Bʀɪᴇɴ HAI

Downgoat

no like it can't even parse the -> correctly

=== OUTPUT LOG ===
CheddarFunctionToken { Code: '-> (a,b) a + b', Index: 0, _Tokens: [] }
=== OUTPUT END ===

Index should be 3

Cᴏɴᴏʀ O'Bʀɪᴇɴ

@EᴀsᴛᴇʀʟʏIʀᴋ hai!

quartata

5:11 PM

@EᴀsᴛᴇʀʟʏIʀᴋ ?

Cᴏɴᴏʀ O'Bʀɪᴇɴ

doot doot

Sherlock9

@El'endiaStarman Looking it up

New Main Posts

0

Q: Implement parallel for

You know the typical for loop. For every i form 0 to some constant, you execute the block of code, sequentially. Today I will introduce you to another kind of for loop, parallel for. For every i from 0 to some constant, spawn a thread to execute the block of code given an iterator set to the cur...

Sherlock9

> From a more advanced point of view: every zero of a vector field has a (non-zero) "index", and it can be shown that the sum of all of the indices at all of the zeros must be two. (This is because the Euler characteristic of the 2-sphere is two.) Therefore, there must be at least one zero. This is a consequence of the Poincaré–Hopf theorem.

> In the case of the torus, the Euler characteristic is 0; and it is possible to "comb a hairy doughnut flat". In this regard, it follows that for any compact regular 2-dimensional manifold with non-zero Euler characteristic, any continuous tangent vector field has at least one zero.

uoɥʇʎPʎzɐɹC

Yeah got my challenge posted!

I have that question ban warning even though only one question was downvoted...

Sherlock9

5:17 PM

@El'endiaStarman Since the double torus has Euler characteristic of the double torus is -2, I don't think that it can be combed flat either, though I could be wrong

TùxCräftîñg

FontForge cant access the D: drive ._______.

El'endia Starman

@Sherlock9 I guessed so, but I wouldn't have guessed that the same would hold true for a triple donut as well, which is what your quotes seem to imply.

uoɥʇʎPʎzɐɹC

Darn, my question is the only one that's unanswered not on hold or closed and not super-hard (e.g. Domain Name Appraisal)

quartata

You posted it 7 minutes ago

Give it a bit

TùxCräftîñg

yes, my questions usually take 15min to be closed

uoɥʇʎPʎzɐɹC

5:23 PM

so used to PPCG answering questions so quickly

Dr Green Eggs and Iron Man

Cool SEDE query:

data.stackexchange.com/codegolf/revision/308882/400005/…

Sherlock9

@El'endiaStarman By the way, those quotes are from the Wikipedia page on the hairy ball theorem. There's another passage on the page for "Vector field" that says more or less the same thing, but you may want to check out all the same

Dr Green Eggs and Iron Man

TIL I have more V/vim answers than every other language combined.

Downgoat

@DrGreenEggsandIronMan O_O I have 3 cheddar answers

Dr Green Eggs and Iron Man

\o/ nice! I've only seen one of them.

I have 17 V answers.

uoɥʇʎPʎzɐɹC

5:28 PM

I have two answers - both for a JS-only challenge

TùxCräftîñg

._. i have 4 apl answers

Cᴏɴᴏʀ O'Bʀɪᴇɴ

I have equal score in JS and Jolf

El'endia Starman

Pytek answers: coming eventually.

Cᴏɴᴏʀ O'Bʀɪᴇɴ

\o/

uoɥʇʎPʎzɐɹC

Someday. Someday...

@El'endiaStarman

Helka Homba

5:30 PM

I just got a gold medal for a challenge about Hodor ._.

uoɥʇʎPʎzɐɹC

@El'endiaStarman this is really off topic and it might sound rude, but I'd just like to ask, what kind of christian are you? (catholic, methodist, etc.)

quartata

7 Rotor answers (what), 6 Perl answers, 6 Groovy answers, 5 05AB1E answers, 5 Cinnamon Gum answers

El'endia Starman

@uoɥʇʎPʎzɐɹC I usually call myself non-denominational. I don't really fit into any denomination of Christians.

Downgoat

@HelkaHomba wat

quartata

I have a few others I have 4-5 answers in but it seems I have a lot of languages I only did one answer in

Anonymous

5:32 PM

@HelkaHomba The fact that the gold badge isn't named "Hodor" makes me a bit sad

uoɥʇʎPʎzɐɹC

@El'endia I'd say same. I don't believe in any major religion, but I believe that there is a God (so I'm not an atheist), but I lean towards christianity and judaism.

quartata

@HelkaHomba We should have one for the reverse operation

Helka Homba

Oh well. It was about time. @Dennis was about to surpass my gold medal count :o

Dennis

> Your connection is not private.

Downgoat

what should be the splat operator? (I think its called unpacking in python and rest op in js)

I was thinking ... like JS

Anonymous

5:35 PM

@Downgoat *

Downgoat

but why

that's so random imo

Anonymous

Because it looks like a bug went splat

5

Downgoat

o_o

Anonymous

And that's the dream of every developer - making all of our bugs go splat

Dennis

Best justification I've ever heard.

Downgoat

5:36 PM

ಠ_ಠ

FryAmTheEggman

Err, isn't that the reverse of how those operations were named? I thought splat was named that long before "splatting" an argument list was a thing.

TùxCräftîñg

句_句

Business Cat

@Downgoat _

quartata

@Downgoat ... doesn't make any sense either

Downgoat

but it's like spreading

i could make it postfix if that makes more sense

Anonymous

5:38 PM

... is what C and C++ use, so clearly it's the wrong choice

Anonymous

github.com/paulcbetts/splat

quartata

C has a splat operator?

Maybe we're not talking about the same thing here

Anonymous

The logo: camo.githubusercontent.com/…

FryAmTheEggman

I think it's for varargs in C isn't it?

quartata

Yeah.

Anonymous

5:39 PM

C uses ... for variable arguments, which is somewhat close

Dennis

@Mego C language is best language.

Cᴏɴᴏʀ O'Bʀɪᴇɴ

I C.

Anonymous

C++ uses ... in variadic templates with varargs. Postfix means "this is a variable list", prefix means "splat this list".

Anonymous

(sort of)

Downgoat

=== OUTPUT START === 0
4
4
4
?
4
4
4
?
8
8
8
17
17
17
19
19
19
?
19
19
19
?
19
19
19
?
3
4
4
4
6
6
8
8
8
17
17
17
3
=== OUTPUT LOG ===

i have no idea what's even happening anymore ;_;

Anonymous

5:40 PM

I really want "because it looks like a bug went splat" to be the reason why * is splat in Python

Downgoat

why is tokenizer going backwards ;_;

TùxCräftîñg

@Downgoat ǝsnɐɔǝq

2

@uoɥʇʎPʎzɐɹC Where is your question ?

Anonymous

109 rep with 7 hours left in the day - I might just get my first back-to-back mortarboard

orlp

@Mego mortarboard?

Cᴏɴᴏʀ O'Bʀɪᴇɴ

200 rep in a day

Downgoat

5:46 PM

@MᴀʀsUʟᴛᴏʀ do you know what this bit of code does in the Cheddar lexer?:

                        if (Array.isArray(defs[i][j][0])) {
                            // TODO: not recommended; creates 2^optionals new rules
                            //slice(0) clones array
                            let def = defs[i].slice(0);
                            def.splice(j, 1);
                            defs.splice(i + 1, 0, def);
                            defs[i].splice(j, 1, ...(defs[i][j][0]));
                            i--;
                            continue main;

it's in the grammar parser's optional part

Dennis

Holy indentation, Batman!

6

FryAmTheEggman

@Mego I looked around a bit and it doesn't seem like it's officially called splat anywhere. It looks like the name was borrowed from Ruby by users.

Downgoat

@Dennis you must of not seen my sprintf implementation yet

FryAmTheEggman

Called *-operator here

Maltysen

i though it was unpack

and *args was pack

FryAmTheEggman

5:48 PM

60s Batman is best Batman.

Downgoat

                                    // Filter
                                    if (!(
                                        (
                                            result.constructor.name.endsWith('Alpha') ||
                                            result.constructor.name.endsWith('Beta')
                                        ) &&
                                        result._Tokens.length === 0))
                                        tokens.push(result);

oh wait no that's not sprintf nvm

Anonymous

@Maltysen *args is a variable argument list for positional arguments. **args is a variable argument list for keyword arguments (usually called kwargs).

Cᴏɴᴏʀ O'Bʀɪᴇɴ

there's a beautiful key stroke series called "Shift+Tab"

Helka Homba

Cool architecture for a science lab: