The Nineteenth Byte

wizzwizz4

7:00 PM

@Tobi That is really inefficient.

New Sandboxed Posts

0

A: Sandbox for Proposed Challenges

Hello, World! (CnR) cops-and-robbers decision-problem Your challenge is to write a program or function that, with a certain input, prints the exact string Hello, World! and a newline. Capitalization, spacing and punctuation must be exactly as shown above. Your program cannot simply print whatev...

Tobi

exactly......

thats why im asking

Step Hen

Is there a CnR where you give code and output, and the robber has to find the input?

wizzwizz4

@StepHen Sort of.

No.

Step Hen

I'm assuming so

flawr

7:01 PM

@Tobi Please use something like pastebin or gist instead of pasting huge code blocks in the chat.

3

wizzwizz4

@flawr It's not that big, and big ones are automagically shrunk.

Tobi

that wasnt huge lmfao

wizzwizz4

@Tobi What does imfao mean?

Tobi

Laughing my fucking ass off

lmfao

Lembik

@EriktheOutgolfer formal defn added.. what do you think?

flawr

7:02 PM

@wizzwizz4 They are still quite big, and there is a reason why we have this point in the chattiquette

Tobi

So we know the problem, spacial grids or quad trees, anyone know?

trichoplax

@Tobi Grid seems a fairly natural fit for this, since the radii will tell you exactly how many grid cells to include in your check, and the objects can move around freely without having to recalculate much

wizzwizz4

@flawr Forgot about the chatiquette. :-/

Tobi

should I set the grid width to the max diameter?

and when checking and object for a collision, you check the grid and all grids surrounding it, right?

wizzwizz4

@Tobi Yes.

I don't know whether radius... I'm confused now.

Tobi

7:06 PM

same lmfao

u kept changing

i think radius makes sense, because it will leak out

and you will check all surrounding

grids

trichoplax

@Tobi Using the max diameter will mean the centre of any object that collides with it will be in one of the 8 surrounding grid cells (if it's a 2d square grid). That keeps it simple. However, is some of your objects are a lot smaller you might still have to check lots of objects, so you could use a smaller grid which makes deciding which objects to check slightly less straightforward, but will help with efficiency

totallyhuman

is . aliased to bash in linux?

Tobi

@trichoplax how would you deal with objects that are too big for grid

trichoplax

@Tobi If the centre of your main object is at the far left of the cell, and the centre of the other object is at the far right of a cell two to the left, they will overlap even though they are not in adjacent cells. Using diameter will correct this

wizzwizz4

@totallyhuman No.

. is current directory in POSIX systems.

Tobi

7:09 PM

i dont understand that @trichoplax

wizzwizz4

I assume you are referring to a standard GNU/Linux distribution such as Debian or Ubuntu, correct?

trichoplax

@Tobi If your grid is small so objects overlap multiple cells, you can either keep track of which cells they overlap, and store in each cell a reference to every object that overlaps it, or you can approximate this treated the objects as square, which is easier just means some false positives

wizzwizz4

@Tobi Imagine a Venn diagram. Now lay a grid over it with the width of the radii.

Can you get the intersection into a separate square to the two centres? The answer is probably yes.

totallyhuman

@wizzwizz4 as a file name, sure

wizzwizz4

False positives are better than false negatives.

@totallyhuman What do you mean?

totallyhuman

7:11 PM

But if it's being addressed as a command, it seems to be executing the argument as a bash script

Tobi

im so confused

wizzwizz4

@totallyhuman That's ./thingy.

Tobi

are there videos on this

wizzwizz4

@Tobi I can make you a picture.

My mouse battery is running low though.

totallyhuman

(trusty)totallyhuman@localhost:~/Downloads/Workspace/intrnt$ cat /bin/wtf
man $2
(trusty)totallyhuman@localhost:~/Downloads/Workspace/intrnt$ .
-su: .: filename argument required
.: usage: . filename [arguments]
(trusty)totallyhuman@localhost:~/Downloads/Workspace/intrnt$ . /bin/wtf
What manual page do you want?
(trusty)totallyhuman@localhost:~/Downloads/Workspace/intrnt$ . /bin/wtf is man
MAN(1)                                                          Manual pager utils                                                         MAN(1)

trichoplax

7:13 PM

@Tobi Imagine a square cell with no object centre in it, side length equal to your object radius. The cell to the left has an object which can reach past the centre of that cell. The cell to the right has an object which can reach past the centre of that cell. So the two objects can overlap even though neither of them has their centre in that cell. Making the cell side length equal to double the radius means they cannot quite reach from two cells with an empty cell in the middle

wizzwizz4

@totallyhuman Run where ..

totallyhuman

you mean whereis?

Tobi

ill just diameter

i cant visualise what youre saying

you stated that using smaller grid sizes may be more efficient, how would you then check objects that have a diameter larger than the grid size

totallyhuman

pastebin.com/Krb68Y1k

wizzwizz4

@Tobi You don't.

Tobi

7:18 PM

?????

wizzwizz4

The minimum grid size is the maximum diameter.

You want the grid to be as small as possible, so you use a grid size equal to the diameter.

Tobi

he said something about making it smaller than max diameter

wizzwizz4

And explained how that would lead to false negatives.

Step Hen

> Making the cell side length equal to double the radius means they cannot quite reach from two cells with an empty cell in the middle

Tobi

im not talking about that steph

wizzwizz4

7:19 PM

@StepHen Ninja'd.

Tobi

what does false negatives mean?

would uit be more efficient?

Step Hen

@Tobi false negatives is when it says it didn't happen but it did

false positive is when it says it happened but it didn't

wizzwizz4

13 mins ago, by trichoplax

@Tobi Using the max diameter will mean the centre of any object that collides with it will be in one of the 8 surrounding grid cells (if it's a 2d square grid). That keeps it simple. However, is some of your objects are a lot smaller you might still have to check lots of objects, so you could use a smaller grid which makes deciding which objects to check slightly less straightforward, but will help with efficiency

trichoplax

If you use a smaller grid then you may see some benefit if your objects are of widely differing sizes, but I'd recommend sticking to the simple version and getting that bug free before considering improvements

Tobi

ok, ill do so now. thanks, very helpful

trichoplax

7:20 PM

Did I just get ninjad by myself??

11

wizzwizz4

If you're using a smaller grid, you'll have to special case large objects.

Step Hen

and I thought writing a coordinate-based physics engine was complicated

wizzwizz4

@StepHen It's really simple, if you don't mind it breaking on more than 20 objects.

I wrote a physics engine like that once, with the added benefit of not actually having decent physics.

Step Hen

@wizzwizz4 hey mine had decent physics though, we even did corner collisions

wizzwizz4

Collisions only worked properly a quarter of the time, and only for one of the objects.

Maltysen

7:24 PM

@Mego do u know why python doesn't have right versions of any of the comparision operators, only the math, etc. ones?

wizzwizz4

Half the time it didn't work for either object.

Tobi

whats coordinatebased physics engine

Maltysen

im being forced to use << instead of <

Tobi

how does it differ to mine?

wizzwizz4

@Maltysen Those are completely different things.

DJMcMayhem

7:24 PM

@Maltysen What? Do you have an example?

Step Hen

@Tobi I don't really know how yours works

wizzwizz4

<< is a shift.

Step Hen

But coordinates is everything is in an xy plane

and you get centers of circles and radii

Tobi

mines that too, right?

wizzwizz4

@Tobi A physics engine that represents positions by coordinates.

Tobi

7:25 PM

oh

wizzwizz4

Ninja'd.

Tobi

how are they different?

Maltysen

@DJMcMayhem you have__rmul__ and __ror__ but not __rlt__ or __rge__

wizzwizz4

@Tobi I don't think they are.

DJMcMayhem

@Tobi Have you considered using Google?

Tobi

7:26 PM

my circles has positions and raadii that i calculate

Step Hen

@Tobi then what's the grid for?

wizzwizz4

@DJMcMayhem DuckDuckGo ftw!

Step Hen

( I don't know what I'm talking about fyi )

Tobi

to speed up collision detection??

wizzwizz4

@Tobi Optimisation ftw!

Maltysen

7:26 PM

2 mins ago, by Maltysen

@Mego do u know why python doesn't have right versions of any of the comparision operators, only the math, etc. ones?

DJMcMayhem

@Maltysen Ah. I heard python and thought Ooh, I know about that! Maybe I can answer! but then I realized that's over my head and I don't know what you mean. Good luck :P

HyperNeutrino

@Maltysen Wait what's the problem?

ppperry

@Maltysen DO you mean there is no __rle__ method?

DJMcMayhem

My python knowledge ends as soon as double underscores become involved. haha

wizzwizz4

@DJMcMayhem Double underscores are relatively simple. The magic methods are documented, and everything else is simple.

HyperNeutrino

7:28 PM

What do you mean by "no right versions"?

wizzwizz4

Where "simple" is defined as "undefined and subject to change".

Step Hen

Here's the line of code from the old project of mine that we used for collision detection:

ppperry

@DJMcMayhem how do you make a private method in Python?

wizzwizz4

@ppperry You don't.

DJMcMayhem

Uhhh.... I don't think you can

ppperry

7:29 PM

(I know, but am challenging the statement "My python knowledge ends as soon as double underscores become involved. haha")

you do, by prefixing the name with two underscores

DJMcMayhem

But I could google it

wizzwizz4

@ppperry No, you don't.

AdmBorkBork

Grats to Anders Kaseorg for winning the 500-rep TryItOnquine bounty!

DJMcMayhem

@ppperry Oh.

wizzwizz4

They're not private that way.

Maltysen

7:29 PM

@wizzwizz4 well private in this case measn it doesn't show up in docs

wizzwizz4

@Maltysen Single underscore does that.

trichoplax

@Maltysen Will python automatically switch the order of arguments for such cases? Do you have a situation where that wouldn't help?

wizzwizz4

Double underscore is for not conflicting with other double underscores of subclasses.

DJMcMayhem

> In Python, "privacy" depends on "consenting adults'" levels of agreement - you can't force it (any more than you can in real life;-). A single leading underscore means you're not supposed to access it "from the outside" -- two leading underscores (w/o trailing underscores) carry the message even more forcefully... but, in the end, it still depends on social convention and consensus

wizzwizz4

But it's by no means private.

Maltysen

7:31 PM

@trichoplax i'm overloading << right now, and it switches the order automatically (so the first arg is self)

AdmBorkBork

private static void __ThisIsn'tJava

Maltysen

but i can't find right < on anyone

Magic Octopus Urn

https://www.asciimator.net/asciimation/11692
^ Cool site, literally the worst UI I've seen since geocities.

Conor O'Brien

does python have closures?

ppperry

Yes

Maltysen

7:31 PM

@ConorO'Brien yup

Conor O'Brien

boom, private variables :P

Step Hen

> apple being ate

wizzwizz4

@ConorO'Brien No...

trichoplax

@ConorO'Brien You can still access their variables externally if you really want to though

wizzwizz4

func.__closure__

Magic Octopus Urn

7:32 PM

@StepHen makes for a decent challenge imho: codegolf.meta.stackexchange.com/a/13564/59376

DJMcMayhem

@MagicOctopusUrn I'm a simple man. I see Rick & Morty, I upvote

Magic Octopus Urn

I was going to do an assci-art abacus: codegolf.stackexchange.com/questions/1530/draw-a-suanpan-abacus

I STILL HAVENT WATCHED S3E2, NO SPOILERS.

Step Hen

@MagicOctopusUrn Title: Apple Being Aten

ppperry

@wizzwizz4 And I was about to post a TIO link showing that.

DJMcMayhem

@MagicOctopusUrn Of course not ;)

trichoplax

7:33 PM

@Maltysen I was thinking if the order is switched automatically you could use left > instead

Magic Octopus Urn

Lol the title was "nompf nompf nompf... nompf nompf nompf......... nompf"

ppperry

@Maltysen What are you trying to do

Step Hen

@Maltysen why exactly are you overloading operators? :P

Maltysen

@trichoplax the whole point of right overloads is that if the operation isn't implemented for the left operand, the right operand still gets a chance to make it work

ppperry

And you are saying those don't exist for comparisons, like < and <=.

Maltysen

7:34 PM

@ppperry repl.it/Juck/16

wizzwizz4

@ppperry They exist.

Maltysen

@ppperry i can't find them if they do

@wizzwizz4 really? i don't mean overloads, i meant the right side overloads

Business Cat

@DJMcMayhem +1

wizzwizz4

@Maltysen Basically just prepend r to the name inside __ and __.

Maltysen

@wizzwizz4 yeah but i can't get that to work for comparisons

trichoplax

7:35 PM

@Maltysen Does using << instead of < gives operator precedence issues?

Maltysen

no it just doesn't look as nice ;P

wizzwizz4

@Maltysen The other side should be raising a NotImplementedError iirc.

ppperry

returning NotImplemented, you mean

New Sandboxed Posts

0

A: Sandbox for Proposed Challenges

Hungry for Apples? This challenge is simple, given an integer 0 <= n or 0 < n, output an ASCII-apple with that many bites taken out of it. Here's the "ASCII-mation" of it happening: click player, then play. No bites (0): // .-.:|.-. .' '' '. ; ; : ...

Conor O'Brien

@AdmBorkBork @MagicOctopusUrn I know it's probably been said but holy cow your avatars are similar.

ppperry

7:37 PM

Is this what you mean?

Magic Octopus Urn

@ConorO'Brien it's been thought by me "damnit Adm, your answer faked me out again" like 100 times.

Maltysen

@wizzwizz4 it does

Magic Octopus Urn

Don't think anyone has said it outloud though. When looking for my answers I look for blue box.

Maltysen

@wizzwizz4 and it doesn't fall thorugh to my rlt

Magic Octopus Urn

If I were to change my avatar I'd never find my answers <by scrolling> again.

Step Hen

7:38 PM

@ConorO'Brien They've been mispinged before

trichoplax

@ppperry This is what I meant by switching the order automatically. Greater than is right less than. @Maltysen is this useful?

Maltysen

@trichoplax oh cool

thanks

Magic Octopus Urn

Also, dangit, I wish "New Sandbox Posts" put the image in the snippet lol.

wizzwizz4

@MagicOctopusUrn It puts what it gets in the feed.

AdmBorkBork

@ConorO'Brien Yeah, I've actually done a double-take going "I don't remember posting that challenge?"

Step Hen

7:39 PM

is there any time when !( < ) is different than ( >= )?

wizzwizz4

@StepHen Yes.

Maltysen

@trichoplax thanks so much

wizzwizz4

But then the unicorns cry.

Magic Octopus Urn

@AdmBorkBork it's funny how ACTUALLY different they are though, yet the colors just... confuuuse me/you.

ppperry

I posted that, not trichoplax

trichoplax

7:40 PM

@Maltysen I had a feeling python did that, but I wasn't sure until @ppperry gave a working example

AdmBorkBork

@MagicOctopusUrn Very true. They're just similar enough on a quick glance.

Magic Octopus Urn

I can go invert mine, I think you've been here longer xD.

Conor O'Brien

I mean if a == b is defined, but a > b is not, a >= b is still technically true. e.g. with complex numbers, 2 + 2i >= 2 + 2i

DJMcMayhem

@MagicOctopusUrn I think it's the color not the orientation

trichoplax

Just add some tentacles

Step Hen

7:41 PM

Or invert the color

Conor O'Brien

just remove the black background

Magic Octopus Urn

Invert the color is ahem what I meant... I don't think the orentation of a cube really... erm, matters?

Step Hen

Find a picture where Calvin looks exactly like Dennis's profile picture

Maltysen

does func<_(args) or func<-_(args) look better for partial application?

trichoplax

@ppperry Sorry for the confusion. Thanks so much for clearing that up with such a concise example

wizzwizz4

7:43 PM

@StepHen Calvin of Calvin and Hobbes?

Step Hen

@wizzwizz4 yes

flawr

HelkaHobbes?=)

wizzwizz4

@StepHen Can we find a picture where Hobbes looks exactly like Dennis' profile picture?

Magic Octopus Urn

I have NO idea how to change my avatar.

How did I even set it in the first place lmao

wizzwizz4

@MagicOctopusUrn codegolf.stackexchange.com/users/preferences/me

DJMcMayhem

7:45 PM

@MagicOctopusUrn codegolf.stackexchange.com/users/edit/59376

Step Hen

3

close enough

AdmBorkBork

@MagicOctopusUrn Hehe, no need to. It's not a big bother to me.

Magic Octopus Urn

That was so weird... "edit profile" wasn't under the first category when I was there before.

@AdmBorkBork I actually want to now, this is badass: imgur.com/a/uqQK9

wizzwizz4

@MagicOctopusUrn Different link.

AdmBorkBork

@MagicOctopusUrn OK, that is pretty sweet.

Magic Octopus Urn

7:48 PM

Okay, that's low res AF... lemme find a better way to invert it. The original image was like 900x600

wizzwizz4

@MagicOctopusUrn GIMP.

ImageMagick.

AdmBorkBork

Post a challenge ;-)

Poke

The guy who stopped the wannacry ransomware just got indicted for creating/selling the kronos malware

Step Hen

@AdmBorkBork "invert and hd-ify an image"

wizzwizz4

@Poke Ouch.

AdmBorkBork

7:51 PM

@StepHen Simple. Just bitmap it (not a rickroll, I promise).

Magic Octopus Urn

Having a legal person write the indictment for a computer virus is laughable.

"USED A COMPUTER SOFTWARE CALLED CRYPTING" - lol'd.

trichoplax

@ppperry Looks like this question on SO might benefit from your example too

wizzwizz4

@MagicOctopusUrn What's worse is having an unguided legal person write computer laws.

"You may not store the video on your computer."

How else are we to play it?!

Step Hen

Dennis gets creepy inverted:

Poke

sorry that indictment was last month... he was just arrested because he was in the US at defcon

because of that indictment

lulz

ppperry

7:58 PM

0

A: overloading less than in python

To do this, you can override the __gt__ method. class comparison: ... def __gt__(self, other): ... 7<comparison(2) will then get transformed in the call comparison(2).__gt__(7), which you can override.

Not that that answer is probably ever going to be seen by the OP, since they were last seen in May.

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