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8:00 PM
@QPaysTaxes I have regretted it every day. For five years.
 
I'm trying to do inscribed polygons, but I'm stuck trying to find a way to detect whether the center of the circle is inside the polygon.
 
As much as it's impossible to truly translate from one language to another by only translating word-for-word, it's even more impossible to "translate" by changing the letters from one alphabet to another. :P
 
 
@feersum I think the conditions of the question guarantee that? Lemme check.
 
No.
e.g. {3,4,6}
 
8:01 PM
True, true.
 
@El'endiaStarman its called a substitution cipher
 
@NathanMerrill A substitution cipher mixes up letters, not alphabets. And it's meant to obscure. :P
 
German's keyboard is not AZERTY, it's QWERTZ
 
regardless of the purpose, I don't see the difference between letters/alphabets
 
@feersum Right, I see that now. You can come up with more extreme examples easily. But anyway, do you need the center of the circumcircle to be inside? Hmm, I guess you do. Is there a test case that has the circumcenter outside of the polygon?
 
8:03 PM
That's what {3,4,6} was.
 
i'm not either, doesn't mean you can't know it
 
@feersum Hrm, shoot, I upvoted an answer without testing it. Eh well. orlp will fix it and then the upvote will be deserved. :P
 
@orlp didn't test the test cases?
 
@feersum I'm guessing he tested the more complex ones. I too do that sort of thing, where I don't usually try testing every test case.
 
I would have an answer by now too, if the center was always inside..
 
8:10 PM
@feersum I tested the long ones, not the short ones :)
 
This is one thing that would be vastly improved by a dedicated platform for PPCG: automatic testing of test cases.
 
We have Try it online!, but it's semi-automatic.
Not fully automatic.
 
And you can usually only test one case at a time. Also doesn't support Python. :P
 
@QPaysTaxes Nope, they aren't.
 
Wow curse is so much better than skype (not sponsored)
 
8:23 PM
^
I love curse.
 
I thought gamers used ventrilo
 
Don't watch a documentary on the vietnam war. It makes you not happy.
 
I've found a trick to make a function that has a zero at the correct radius value whether or not the circle center is in the polygon, but it keeps converging to the wrong zeroes...
 
@feersum I'm thinking about making a repulsive system
 
meh, the equation doesn't even work
 
8:37 PM
@QPaysTaxes watch this video, it might make you happy:
 
@orlp What do you mean?
 
@feersum a system in which stick are attracted to eachother, but repulsed by some force in the centrepoint of them
cool page
 
@Downgoat Is that one of your baby videos?
 
@DrGreenEggsandHamDJ no, it's my nephew's
 
Oh. This one is probably you:
 
8:50 PM
@DrGreenEggsandHamDJ sorry for not responding within 2 minutes, I fainted
 
@feersum any progress?
I'm kinda stuck
 
Same.
Still looking for a way to unify the two cases.
 
I'm trying to 'walk around the circle', so to speak
the problem is that with some n-gons, the next chord can have two intersections with the circle
 
I don't understand.. doesn't a chord always have 2 intersections with the circle?
 
sorry
I meant there are two possible radii for which the chord connects
the problem occurs when a prefix of the total set of segments is itself circular
I love it when people expect warnings for their personal phobias
 
8:58 PM
also why would they even put a warning like that on any book
Book Title [WARNING: HOMOSEXUALITY]
why would anyone think they would want that
 
@cat It was deleted as part of the effort to remove [underhanded] from the site. Some of the closed challenges are getting deleted, some of the well received ones are getting locked.
@poi830 Abstract Algebra, 3rd Edition [WARNING: MATH]
3
 
mathphobia is a serious condition
 
It afflicts 2 out of every 5 children and 3 out of every 5 adults.
It's an epidemic, really.
 
Is there any hope for a cure?
 
Not yet, I'm afraid. Though there is ongoing research.
Speaking of books, one of the best/worst pun titles for a textbook I've seen was my linear models textbook, Plane Answers to Complex Questions.
3
 
9:16 PM
thats perfect lmao
 
XD
 
9:32 PM
uh oh
we've reached a contradiction
wait i have a solution
by saying "XD" he was just stating that he found it funny, not that it was objectively funny
 
cat
@AlexA. Aha, I see.
 
9:49 PM
@AlexA. that's comedy gold
 
:P
 
I wish my textbooks had as much of a sense of humor as that
 
Believe me, the title was the extent of the humor in that book.
 
@AlexA. Oh, did we ever reach a consensus on that?
@AlexA. Still good
 
@quartata Yeah, a long time ago
 
9:52 PM
@feersum do you think a closed form exists?
 
@orlp if you mean a closed form for the area of the polygon
they are known up to n=7 iirc and they probably exist for higher ones
but they are absurdly complicated
 
assert_eq!(String::from("27"), run(String::from("NUMABCZPUT")));
assert_eq!(String::from("-1980"), run(String::from("NUMZDEFZPUT")));
assert_eq!(String::from("437/654"), run(String::from("NUMZZGHIZJKLZPUT")));
assert_eq!(String::from("-871/1088"), run(String::from("NUMZZZMNOZPQRZPUT")));
Numeric literals work in Babble now.
 
\o/
 
hooray
 
(try figuring out how they work :P)
 
9:55 PM
@poi830 but is there no pattern to their formulas?
 
@orlp nothing simple like that
 
@Doorknob \o/
 
does the order of edges matter
don't think so, right
 
it shouldnt
since you can just rotate them around the circle
 
@Doorknob clearly Z -> negative, ZZ...Z... rational where Z separates numerator and denominator in some order and ZZZ...Z... negative rational... (and it's always terminated by Z)
 
9:57 PM
@poi830 I think I'll ask on math.se, just to get an Q/A on the site
or maybe, if we're lucky, someone will dig up some paper
 
@orlp probably a good idea
if you look it up there isnt that much on the subject
it doesnt look like its trivial or anywhere near that
so the letters go up to R in the numeric literals
so if its a base n number n has to be at least 18
oh its base 25
because A=0 B=1 C=2... so ABC = n+2
so n=25
and yeah that works
 
yeah also works for the rationals
 
VjQ25pC+N65
doesnt do negative or rationals
probably not optimal either lol
 
irb(main):001:0> (0..1.0/0).all?
 
irb(main):001:0> loop{}
golfed that for you
 
10:06 PM
lol
 
I've got you a breathing exercise.
user image
14
 
im sure it can be improved
also it cant do rationals because im lazy
 
@flawr did you generate that? :)
 
Yep=)
I hope you are hypnotized by now.
 
I am
nice job :)
 
10:13 PM
yesterday, by Alex A.
11 mins ago, by Alex A.
@Doorknob pry
 
Now I can try to take over the world.
 
@AlexA. I'm gonna pry your limbs off if you say that one more time :P
 
oh jesus
 
Cheddar:T_REPL> set A scope
Cheddar:T_REPL> enter A
Cheddar:T_REPL> set B 123
Cheddar:T_REPL> get B
123
Cheddar:T_REPL> exit
Cheddar:T_REPL> get B
Symbol(KEY_NOT_FOUND)
\o/ \o/ \o/ Cheddar's scopes work!!!!!
 
@Doorknob gem install limbremoval
 
10:15 PM
0
Q: Closed form for the area of a convex cyclic n-gon, given the set of edge lengths

orlpLet's say we are given a set of positive reals, and we're told that these are the edges of a convex cyclic $n$-gon, and we must compute it's area. For $n = 3$ there is the famous Heron's formula: $$A = {1\over 4}\sqrt{4a^2b^2 - (a^2 + b^2 - c^2)^2}$$ For $n = 4$ there is Brahmagupta's formula...

 
@AlexA. O_O
 
@Doorknob Hey, you're the one who brought up limb removal. :P
 
1
A: Shortest infinite loop producing no output

coredumpOCaml, 17 bytes while 1<2do()done 1 byte removed thanks to @Mauris. Another one bytes the dust thanks to @feersum.

 
@AlexA. It was the only pun that worked with the name pry
 
> Another one bytes the dust
8
^ gold
 
10:18 PM
Another byte becomes one with the dust.
 
I think we've had that just yesterday or so.
 
@Cyoce Dennis must be a dust-blower then :P
 
@orlp You mean a regular n-gon?
Or what do you mean by cyclic?
 
@flawr that the vertices all lie on a circle
(not necessarily regularly spaced)
 
Oh ok.
 
10:22 PM
I'd say it should say 'inscribed in a circle' for clarity
Maybe cyclic means that but it's obscure..
 
its not a particularly obscure term and you could always look it up
 
@feersum afaik cyclic is not really obscure?
 
a link to the mathworld article could be nice
 
I never heard of that term before.
 
flawr is a math major but hasn't heard of it either :P
 
10:25 PM
@feersum Yeah I agree, I'd also word it that way.
 
If that's just too long, you could always call it circumscribed, lol
 
@flawr You've never heard "cyclic"? o_O Have you not taken any courses in group theory?
Cyclic groups, son
 
@AlexA. Obviously we mean this particular sense of cyclic.
 
That wasn't obvious to me from flawr's response
 
Yeah I do of course know "cyclic" but so far never in the context of the position of polygonial vertices.
 
10:29 PM
Okay
 
it comes up a lot in competitive math
but not that often outside of it
 
12.5k rep. link-only answer. what.
 
I've participated in one math competition so far, in hischool. And our class gloriously won the 2nd place. From behind.
 
Competitive math is as weird and randomly obsessive about certain topics as competitive coding, I suppose.
 
10:44 PM
@Doorknob I committed to Lojban Language SE, by the way
 
@flawr have you taken AMC
 
@quartata .ui
 
@poi830 What is AMC?
 
@flawr American Math Competition
You probably haven't done it. :P
 
its the first of many qualifiers for international math olympiad
 
10:48 PM
I guess not if you're not within the USA USoA=)
 
oh yeah lol
 
@quartata And not to Tatar ;-;
 
Does that still exist?
(the proposal, I mean)
 
Nope
 
:(
 
10:51 PM
It was auto-deleted because it had <5 example questions
I didn't know that was a thing otherwise I would have been more proactive in adding example questions
 
@AlexA. I'm sorry I don't know any Tatar
 
You could always create the proposal again
 
@flawr underwater society of america?
 
@Doorknob I might but I don't think there's much of a point. :/
 
Ununited States of America
 
10:53 PM
@quartata Me neither ∏.∏
@NathanMerrill Its members can't breathe very long
 
cinri zei .uinaibu
 
or the United States Ombudsman Association
 
@AlexA. PS: Christmas is great!
 
@flawr \o/ Favorite song?
 
@AlexA. I do not know the album well enough yet.
 
10:55 PM
Ah, okay. I love Gift, the first track.
 
Only played them about 3 times.
@AlexA. Yes, that's certainly a great one.
I generally liked how they packed so many different styles in this album, but it always seems to transition seamlessly.
 
Definitely :)
My favorite album of theirs will probably always be Seminar II though
 
I hope I'll get that soon too=)
 
It's gooooooood
 
Haha, I know that was the first you showed me!
I didn't listen to christmas before I received it on purpose=)
 
10:59 PM
Haha
For whatever reason I've never really gotten into Meditations in B, their first album.
 

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