The h Bar

12:01 AM

@ACuriousMind Well, I used my newfound power to look at those rants saying this whole site is a sock-puppet show run by me.

All I can say is, wow. That person was upset.

ACuriousMind

@DanielSank Yeah. Still not sure why they picked you as the puppetmaster, though

guest

Friendly people are easy targets :P

ACuriousMind

@DanielSank Maybe you find this deleted post funnier (I like the combination of the original title, dmckee's edit and the "non-mainstream" close reason)

guest

Have you guys heard of the unit of beauty needed to launch one ship?

dmckee

Hurrump. I'd never seen a Putnum before. Those are reasonably evil. I can see where the exam's reputation comes from. I can see possible ways to start A3 and B3, but it's not clear how either of them finishes.

@guest The millihelen. A classic.

guest

12:16 AM

:D

The reputation of math 55 is worse.

dmckee

It doesn't help that I'm not particularly strong on sets of series. But they look like at least some are done by induction which I'm usually giddy about.

DanielSank

@ACuriousMind wtf?

@dmckee I tried one long ago. I got half a problem right.

user507974

hey guys, what did we call it when you used a metric such that your constant was equal to one

like when we use c=1 for relativity calculation

ACuriousMind

We call that "clever" :P

@user507974 But it's one part of what is called natural units, to give a serious answer

@DanielSank That's not even the most disturbing one.

user507974

thanks

i wanted to play around a little bit and create a modified metric system based on natural units

see what it would kind of look like

guest

12:30 AM

Sounds like a great exercise in dimensional analysis.

GBeau

12:45 AM

@FenderLesPaul It looks like Tuesday things pick up big, and really big on Wednesday

DanielSank

@ACuriousMind I absolutely loathe that this is called natural "units".

ACuriousMind

@DanielSank I know, we've already talked about that, and I mostly agree

guest

1:04 AM

A "unit" is what a mathematician calls 1 :P

user507974

1:16 AM

btw, for some reason trying to ask a question on firefox triggers a mathjax script error and freezes the browser. Any idea on how to fix that

DanielSank

@user507974 Use Chrome?

user507974

well yea...but i like firefox

guest

I have the same "browser freeze" problem with Mathjax

DanielSank

@user507974 I like it in principle, but it doesn't work :\

I keep wanting it to be better than Chrome but it's not.

guest

Chrome is very "robust."

Kyle Kanos

1:19 AM

Chrome rusts

DanielSank

It is.

Kyle Kanos

Well, I guess it flakes

DanielSank

@KyleKanos Only it it's plated badly.

Kyle Kanos

And then the metal underneath can rust

guest

Slowly :P

DanielSank

1:20 AM

@KyleKanos You must own a crappy chrome plated item.

Kyle Kanos

I don't think I have any chrome plated anything

DanielSank

@KyleKanos Just flaky impressions?

Bernard Meurer

Waiting on the airport on my way to CA. Just now I remembered how I hate airports

Kyle Kanos

@DanielSank Probably

Where's my book?

Bernard Meurer

They've changed my boarding gate more times than I changed my choice of major

Kyle Kanos

1:23 AM

arxiv.org/abs/1307.7291

DanielSank

@KyleKanos excuse me, what book?

Bernard Meurer

@ACuriousMind you around?

Kyle Kanos

Jan 17 at 4:16, by Kyle Kanos

Hmm. Physics probably should just be taught entirely using bra-ket notation linear algebra

Jan 17 at 4:17, by DanielSank

I actually wrote a book doing this.

DanielSank

@KyleKanos Oh right.

Yes fixing that up is on my todo list. Let me see...

Bernard Meurer

Never got around understanding bra-ket

Never tried too hard either to be honest

DanielSank

1:26 AM

@KyleKanos I have to submit some interview feedback and make some slides first.

Kyle Kanos

@DanielSank My email won't be moved from my profile, so whenever you're ready for it, I still aim to read the shit out of it

I'm in no rush

DanielSank

@KyleKanos Ok. I'll probably just put it on Github when I fix the really obvious holes.

Kyle Kanos

Github...I've almost forgotten about my stuff on there

Bernard Meurer

@DanielSank, talking about GitHub I've been wanting to show you this for a while: wtfpl.net

Kyle Kanos

MIT license is pretty good...

DanielSank

1:32 AM

@KyleKanos Ahhhh excellent.

It's like MIT but more in your face.

Bernard Meurer

I used to be a GPL guy, but then I changed my mind and decided it was anti-freedom and overly restrictive

I use MIT now mostly

Kyle Kanos

@DanielSank Seems that way. But I'm not sure I like the changing it is allowed as long as the name is changed. bit

DanielSank

@KyleKanos I balked at that too, but that's for the license itself, not the licensed software.

I agree that any such rule is sort against the intended spirit.

Bernard Meurer

BSD is nice too

Kyle Kanos

I think that if I wrote something & someone else used it for their own project, they should include the original author's name somewhere (for historicities sake or something)

DanielSank

1:36 AM

I think it would be truly awesome to have a license which requires good deeds on the part of those using the software.

For example, you can use this library in your project, but you have to go hug your mom each time you compile.

Bernard Meurer

Let's make one @DanielSank

I'm totally for that

DanielSank

What do we call it?

Kyle Kanos

Hmm, what about the case that your mother has passed away?

Bernard Meurer

Hmmm

Kyle Kanos

Good Deed License, GDL for short

DanielSank

1:37 AM

@KyleKanos zomg that's so good.

Bernard Meurer

Sounds good to me

I can draft it on the plane!

DanielSank

@KyleKanos Then you have to say something nice to a stranger.

@BernardMeurer Go for it. We can use it in cappy.

Bernard Meurer

The more complex the code is (McCabe) the more kind your deed must be hahaha

Awesome @DanielSank!

Kyle Kanos

You know, being the only Fortran guy to answer questions on Code Review can be a little frustrating.

Bernard Meurer

@KyleKanos FORTRAN? Yikes

I signed up for a course in a couple of weeks

Not very excited

Kyle Kanos

1:42 AM

Not FORTRAN, Fortran

Bernard Meurer

Is there a difference? Or did I just write it wrongly?

Kyle Kanos

The difference is about 13 years (the latter indicates the 1977 standard, the former indicates the 1990 standard)

Bernard Meurer

Oooh

Well I don't I'd like either

But God it's a fast language

It only gets better if you're writing bloody assembly

Kyle Kanos

F77 only sucks when the user starts writing with goto and writing spaghetti code

Bernard Meurer

Spaghetti code is my middle name

Just kidding I'm actually paranoid about code standards

Kyle Kanos

1:45 AM

1990 is pretty damn good; easy to read & write and still hella-fast

Bernard Meurer

I don't know how @DanielSank hasn't murdered me yet over me complaining about PEP-257

Kyle Kanos

2003 & 2008 standards allowed for more OOP concepts (biggest hurdle is whether runtime polymorphism would be added, most are against it)

Bernard Meurer

I think km going for C++ tho. It's fast enough for what I do and I feel it will be far more useful

Want to mess with fortran tho, just to beat my deadly fear of it

My uncle worked with it, I grew up listening to tales about the evilness of fortran

Kyle Kanos

Yeah, one can be evil with it, abusing memory mostly

But good programmers don't do that

Bernard Meurer

Good programmers are a legend in Brazil :p

FenderLesPaul

1:56 AM

@GBeau ah

Bernard Meurer

Gotta board my plane now. You guys have a good one

FenderLesPaul

yeah I think UChicago and all the big guys are coming out this week.

@BernardMeurer Have a safe flight!

DanielSank

2:22 AM

@BernardMeurer Coding style is important.

Kyle Kanos

user116211

2:53 AM

@FenderLesPaul @BernardMeurer: Are you going somewhere?

FenderLesPaul

@user36790 not me, no

user116211

@FenderLesPaul: Nope!

user116211

Is Bernard going somewhere? The plane??

dmckee

@BernardMeurer Fortran is like a lot of old systems languages: unforgiving. It does what you tell it to do without making any allowances for human frailty. But it's not out-n-out evil like tcl/tk or perl.

Well, I may make an exception for the array sub-set processing hack. That's pretty much evil

Secret

4:00 AM

This game has some interesting physics in it

If you turn the red region into green, thus removing that boundary in the middle, sometimes the squares will redistribute and end up pushing the orange region as indicated so that the region end up fused

I am suspecting some kind of energy minimising principle is at play here, simialr to how fludis tend to reduce the surface tension by reducing the surface area

should read up more about fludis in order to model this game more properly

I wonder how the "minimising surface tension" phenomenon arise from just the forces between each fluid particles

user54412

@Danu I just realized that question, which I was going to link to you for getting 10k, is one of the ones @ACuriousMind recently linked. And now ACM is showing DS all the good stuff. Lesson learned: never try to beat ACM at this chat.

Secret

@ChrisWhite Why do many small oil droplets on water will fuse into a larger droplet?
Isn't that for a fluid to minimise surface energy, it will try to minimise surface area thus the fusion of two droplets into one will go against this since the resulting droplet surface area is larger?

user54412

4:16 AM

@Secret recheck your surface area computation

user54412

or maybe the misunderstanding is that it's total surface area that matters for the system's energy

Secret

@ChrisWhite
I see
in that case:
Before fusion
$$4\pi r_1^2+4\pi r_2^2=4\pi (r_1^2+r_2^2)$$
After fusion
$$4\pi r_f^2$$
where $r_f^2$ has to obey $\frac{4}{3}\pi(r_1^3+r_2^3)=\frac{4}{3}\pi r_f^3$
Thus
$$r_f^2=(r_1^3+r_2^3)^{\frac{2}{3}}$$

And since the surface area is minimised, $r_f^2 < r_1^2+r_2^2$ (though I am not sure how to prove that...

user54412

4:34 AM

$(x^3+y^3)^{2/3} < x^2 + y^2$ iff $2 x y < 3 x^2 + 3 y^2$ (cube and cancel)

user54412

solve the equality for positive $x$ given positive $y$; conclude there is no solution and thus the inequality is either always true or always false; test for any choice of numbers

Secret

$$2xy < 3x^2+3y^2 \Rightarrow 0<(x+y)^2-\frac{8}{3}xy$$
Minimum when $(x,y)=(0,0)$ thus inequality has no solution

I see, thanks!

Secret

5:06 AM

typo" Maximum

user507974

6:44 AM

oh, that looked like a fun talk i missed

Danu

7:38 AM

@DanielSank Congrats!

Danu

8:02 AM

I'm afraid you'll soon overtake me!

user116211

@DanielSank: Carry on! Feed us with your answers; we would take you over Motl and Rennie:P

Shing

10:19 AM

@ChrisWhite I am learning python on edX now, it seems to be a very good starting point for programming, pretty easy and intuitive so far (yet I still keep making mistakes :/). Thanks for the advice months ago :D