The Nineteenth Byte

1:50 AM

0

Shorthand Combined Functions I was doing some investigation into trig functions using compound angles recently, and noticed that the results are really long and tedious to write: $$ cos(A+B) = cosAcosB - sinAsinB\\ cos(A-B) = cosAcosB + sinAsinB\\ sin(A+B) = sinAcosB + sinBcosA\\ sin(A-B) = sinA...

Jonah

3:33 AM

why do certain questions appear faded?

Anonymous

4:01 AM

@Jonah Got an example?

Jonah

@Mego: i.imgur.com/N2Va7SL.png

Anonymous

@Jonah I've never seen that. Maybe CSS styles not getting loaded right?

Jonah

huh, weird

Bubbler

4:39 AM

Is it OK to use a char array for "list of integers" input, even if the language's default int is 32 or 64 bits?

Anonymous

@Bubbler For C/C++? Probably yes, since char is an integral type, unless you run into issues where only having one byte instead of 4 or 8 causes over/underflow or restricted range.

Bubbler

It's Forth, and there's no array access, just raw address manipulation.

The challenge is this, there's no mention about input value range but some test cases have values over 256...

Anonymous

Then probably no

Anonymous

I'm not familiar with Forth, but given that the default int is 32 or 64, and there are > 256 test cases, it's probably not acceptable to use a smaller int

Anonymous

Arguably it could fall afoul of codegolf.meta.stackexchange.com/a/8245/45941

Bubbler

4:54 AM

I see

dzaima

5:40 AM

@Jonah have you ignored (on the right sidebar) a tag on that question?

Unrelated String

6:29 AM

If there's something clever you can do with a char array feel free to post it within the body of a more compliant answer

Stewie Griffin

11:28 AM

I haven't written many challenges recently so I probably won't be missed. Nevertheless, I want to thank you all for the fun I've had here over the years. I hope I'll return one day, but for now I'm suspending my activity network wide as I no longer have trust in the Stack Overflow executives.

11

Sherlock9

Take care, Stewie. Thank you for being here while you were here

(Dang, now I want to take another crack at the factor tree challenge XD)

Stewie Griffin

I won't actively contribute to the network, but I will still drop by the site out of habit, so don't hesitate to contact me.

Sherlock9

In that case, best of luck and see you around o7

Stewie Griffin

@Sherlock9 Thanks for the effort you put into that challenge! I really enjoyed what you managed to get out of the rough draft I had written :)

New Sandboxed Posts

0

A: Sandbox for Proposed Challenges

Can Jimmy escape the ghosts? code-golf grid decision-problem path-finding It is Halloween and Jimmy (/o\) has gone into a mysterious neighborhood for trick-or-treating (ask himself why). Now some evil ghosts are chasing him. Can Jimmy escape the ghosts? Challenge: Input: A board showing po...

caird coinheringaahing

12:36 PM

@Dennis Out of interest, why did you decide that Ġ should group the indices rather than the elements themselves?

Unrelated String

Since it's grouping by value rather than an arbitrary function, I'd suspect there's just more utility to be expected from the indices, which can be converted back to values fairly easily

Actually since it's not by an arbitrary function it might be a bit difficult to get the indices from the values since you couldn't even group Ė by head

Also you can use the indices to simulate grouping by a function by just mapping the function over the input, grouping the indices, then indexing back into the original input

caird coinheringaahing

My point is that I've seen Œg be used much more often in code golf than Ġ, so it seems as though it would've been better to have Ġ group elements

New Sandboxed Posts

0

A: Sandbox for Proposed Challenges

Intersect the integer ranges Integer ranges take one of four forms: A start, a step and an end. Both ends are included in the range. The difference between the end and start is guaranteed to be a multiple of the step. The step is guaranteed to be positive, even if the start is equal to the end...

Jonah

@dzaima: thanks, you were right. I must have accidentally ignored one somehow.

New Main Posts

1:02 PM

0

Q: Letters associated with prime numbers

If we assign each letter a respective integer, starting from 1, then a is 1, b is 2, c is 3, and so on. After z, the letters loop back around, but with a in front (aa, ab, ac). It then goes to ba, bb, bc... After this is completed, as you may have figured, another letter is added (aaa, aab, aac)....

New Main Posts

2:04 PM

1

Q: Subtract two numbers with Rule 110

Background : It is known that Rule 110 is Turing complete, but in general, I have seen a lack of actual programs that utilize this property of Rule 110, so I propose that we do something about it ;) Some explanation Rule 110 is a one dimensional cellular automaton, consisting of cells on/off,...

cellular-automata

caird coinheringaahing

3:18 PM

CMC: Given a complex number z, determine if it's a Gaussian prime

Anush

@cairdcoinheringaahing nice question.. although you know mathematica will have it built in :)

@cairdcoinheringaahing related to codegolf.stackexchange.com/questions/35881/is-gaussian-primez ?

caird coinheringaahing

@Anush That bans builtins

Anush

got you

caird coinheringaahing

Which is annoying given that Verbosity has one :/

Anush

:)

in code, what is the simplest way to record the time and size of every tcp packet going to/from my PC?

maybe I could make it a challenge

Veskah

3:46 PM

@Anush ./wireshark.exe

Anush

@Veskah thanks.. I think the answer is tcpdump -s0 , at least on linux

Veskah

No problem :^)

New Sandboxed Posts

4:08 PM

0

A: Sandbox for Proposed Challenges

Doing something with Haifu Haifu is an esoteric programming language by David Morgan-Mar, which, in addition to having a very weird control scheme also has the requirement that each program should be in the form of Haiku. Maybe it would be possible to do a cops-and-robbers-like challenge with i...

New Sandboxed Posts

4:28 PM

0

A: Sandbox for Proposed Challenges

Verify that \${}^ni\$ is complex I've conjectured over on Math.SE that \${}^ni\$ is complex (i.e. has a non-zero imaginary part) for all \$n \ge 3, n \in \mathbb{N}\$. Now, as programmers, we have no need for mathematical proofs when we can instead write a program that enumerates all possible va...

caird coinheringaahing

@NewSandboxedPosts 'Bout time :P

Krzysztof Szewczyk

4:43 PM

r,c;main(){while((c=getchar())!=-1){if(isspace(c)) putchar("+-<>[].,"[r%8]);else r++;}}

any ideas on golfing this bad boy?

other language proposals openly accepted

DJMcMayhem

@KrzysztofSzewczyk while(~(c=getchar()))

dzaima

@cairdcoinheringaahing i find it a bit strange you define n≥3, n∊ℕ, but not ⁿi :p

caird coinheringaahing

@dzaima The definition is in the linked Math.SE question, but I should probably add it here :P

DJMcMayhem

@KrzysztofSzewczyk Untested: r,c;main(){for(;~(c=getchar());r++)if(isspace(c))putchar("+-<>[].,"[(--r)%8]);}

I think should do the same thing though

Veskah

4:59 PM

@cairdcoinheringaahing Dang, just added a comment saying that

caird coinheringaahing

@Veskah And I just added it in :P

I'm adding in your other suggestions as I type

Veskah

hoo ray

Krzysztof Szewczyk

neat, lgtm

DJMcMayhem

@KrzysztofSzewczyk Minus 2 bytes I think? r,c;main(){while(~(c=getchar()))if(r+=isspace(c))putchar("+-<>[].,"[r--%8]);}

I don't know if r--%8 is valid

caird coinheringaahing

@Veskah Also, you didn't happen to downvote it, did you?

Veskah

5:02 PM

Nyet

ngn

@DJMcMayhem is r guaranteed non-negative there? (--r)%8 -> 7&--r

caird coinheringaahing

Ugh, that's irritating

DJMcMayhem

@ngn Oh nice one

C golfing is fun, why don't I do it more often?

Veskah

@DJMcMayhem Because pointing is rude

Krzysztof Szewczyk

paradoxally enough I spent around six years of my life on C and I had all of these at the end of my tongue :p

well done

ngn

5:04 PM

@DJMcMayhem because you're already in love with vimscript :)

caird coinheringaahing

@DJMcMayhem It's weird, I couldn't imagine you enjoying golfing :P

DJMcMayhem

lol

caird coinheringaahing

If only there was a symbol after your username that indicated just how much you like it :P

DJMcMayhem

@ngn Oh yeah, I'm just crazy about comparison operators that depend on user settings

Veskah

Heh, I'm so used to seeing "tip of my tongue" that "end of my tongue" looks odd

Krzysztof Szewczyk

5:07 PM

a polishism probably

I didn't know simillar idiom

Veskah

S'all good. I speak gibberish and obscure references most of the time anyways

Krzysztof Szewczyk

<< A tape-based language, where the tape can be unrolled, cut, stick to itself, be stuck to other things, scribbled on, pulled off, and thrown away. >>

Seems like a challenge

ngn

poor tape

Veskah

Never know when you'll need the ThrowTapeAway Opcode

AdmBorkBork

Halt and Catch Fire

Anush

5:19 PM

does anyone know how you can numerically find two roots of an equation?

I feel I am missing some knowledge on this front :)

ngn

@Anush quadratic equation?

Anush

@ngn sadly not.. can we use mathjax here?

or I could paste it in plain text

\lambda_1 e^{y - \lambda_1 e^y} (1 - \lambda_1 e^y ) + \lambda_2 e^{y - \lambda_2 e^y} (1 - \lambda_2 e^y ) where \lambda_1, \lambda_2 > 0

Krzysztof Szewczyk

newton's algorithm?

AdmBorkBork

Chinese Remainder Theorem. ;-)

Anush

@KrzysztofSzewczyk ah.. can that find all the roots? The thing is there might be 1 or 2, it seems to depend on what \lambda_1, \lambda_2 are set to

Krzysztof Szewczyk

5:23 PM

iirc yes

but i'm not a very good mathematican

Anush

so basically, for a whole lot of lambda_1 and lambda_2's that are > 0, I would like to find how many values of y make the formula equal to 0

Krzysztof Szewczyk

i had a calculator that used newtons method to calculate roots of equation

Anush

e.g. lambda_1 =1 and lambda_2 = 20

Krzysztof Szewczyk

it was able to compute a few of these

Anush

that would be a good start

Krzysztof Szewczyk

5:24 PM

therefore its certainly able to do that

Anush

in code, what's the simplest way to do that?

Krzysztof Szewczyk

but it didn't calculate the domain so division by zero and square root of -1 crashed the calculator

I mean, not literal division by zero

but something like 2/x=0

J. Sallé

5:42 PM

@KrzysztofSzewczyk buddy of mine crashed a software in production because one of the hundreds of variables involved in some tax calculations was reducing everything to a 0 in the denominator of a division

Boss was not amused

Krzysztof Szewczyk

robust solutions (TM)

J. Sallé

All of that because it never ocurred to them that the client could just ignore one of the Tax % fields before clicking the button

Krzysztof Szewczyk

well, I'm not making my software idiot-proof in 100%, so I'd better shut up :p

Neil

@KrzysztofSzewczyk r,c;main(){while(~(c=getchar()))isspace(c)?putchar("+-<>[].,"[r%8]):r++;}

J. Sallé

Hahahahah yeah, we all had a good laugh after spending a few hours debugging that

DJMcMayhem

5:46 PM

@J.Sallé Yesterday I discovered a bug that past me made in a GUI. I did do_something(callback(foo)) instead of do_something(lambda: callback(foo)), and that made it so that if the user clicks a certain button they get a popup that never leaves and softlocks that entire section of the GUI

Anush

6:13 PM

maybe I should turn it into a challenge somehow

Anonymous

Root-finding algorithm

In mathematics and computing, a root-finding algorithm is an algorithm for finding roots of continuous functions. A root of a function f, from the real numbers to real numbers or from the complex numbers to the complex numbers, is a number x such that f(x) = 0. As, generally, the roots of a function cannot be computed exactly, nor expressed in closed form, root-finding algorithms provide approximations to roots, expressed either as floating point numbers or as small isolating intervals, or disks for complex roots (an interval or disk output being equivalent to an approximate output together...

Anush

@Mego thanks

J. Sallé

6:35 PM

@DJMcMayhem the product we sell has a feature where you can mark any component window as a favorite, and the system will open that window when you log in. A client managed, somehow, to favorite every single one of the >600 windows,and some of those aren't even available for that option because of dependencies from other components.

Bottom line, their software took a few minutes to stop loading every window, and a few of them caused some access violations. It was a nightmare to fix.

DJMcMayhem

:'D

I'm not exactly sure what they expected to happen

Veskah

@J.Sallé Just means the entire application is their favorite

J. Sallé

6:52 PM

Hah, I'd love to see someone tell that to the very angry manager that called the company demanding the fix

Anonymous

7:13 PM

@J.Sallé I've had my fair share of "I broke it, now you fix it" tickets :P

El'endia Starman

@Mego Sometimes feels like this is QA's reason for living (at my company anyway).

I mean, we do want QA to find bugs. Still, doesn't feel great when they go "Hey, I found a bug...". :P

Veskah

The only thing worse than QA is smug QA

Anush

who is QA?

do you mean the company called QA?

El'endia Starman

Quality Assurance. Specific people whose whole job is to try and find bugs. (Well, they also make sure that features are working as intended in other ways.)

E.g. there are three QA testers at my company, compared with 10+ devs.

DJMcMayhem

There are two QA testers on my team.

They're also the only two devs :P

Veskah

7:27 PM

My QA is pretty much angry emails

Anonymous

We have 1 QA that's worthless

Anonymous

I find more bugs than the QA does

ngn

true story, once long ago a QA fellow filed a bug report for me: "i tried to do [this] and [that] happend, and your mistake is in [filename.jsp], line [123]"

wizzwizz4

7:45 PM

ticket closed as "give this QA tester a raise"

Anonymous

@ngn jsp? (gags)

ngn

@Mego yeah, i'm old :)

Anonymous

I can't wait for programming to cycle back around to using Java instead of JS for a React Native-like mobile framework :P

wizzwizz4

Well, BT's writing their new web mail interface in JSP.

Anonymous

On purpose?

wizzwizz4

7:56 PM

I think so.

It's a reimplementation designed to look like Yahoo!'s.

Anonymous

Each sentence gets worse

wizzwizz4

(They've been "migrating away" from Yahoo! for several years, but they're actually at a point where they can, now.)

Sherlock9

Oh God, you've reminded me that Yahoo! is completely wiping Yahoo! Groups in a month very very little warning

What a completely stupid decision

DJMcMayhem

Apparently I'm part of a class action lawsuit against Yahoo because I somehow managed to forget I had an email with them years ago

J. Sallé

Yahoo! was never a big thing in Brazil, I haven't heard of it in years. Didn't know they were still around

wizzwizz4

8:01 PM

@Sherlock9 That is one of the few reasons Yahoo! is still around – very poor choice.

New Meta Posts

8:37 PM

0

Q: How can we clearly define "Must work for theoretically large values"?

This doesn't seem immediately like an issue, but I've encountered it once in a challenge already, and recently again in a Sandboxed challenge, and is getting tiring to find the correct wording. For example, for this challenge, the biggest struggle in the Sandbox was making it clear that programs ...

discussion asking-questions specification