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00:21

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Q: Is physics stackexchange limited to answering questions?

I am not allowed to create a new tag, please make an appropriate one. I ask a question someone answers it. The design of the stackexchange sites (the reward system of earning points) ensures that good answers and even more importantly correct answers are distinguished from all the other answers ...

discussion

Physics Meta

03:22

0

Q: Why is math not being rendered here on my browser?

I am using Firefox 26.0 on most recent Ubuntu. Math formulas surrounded with the dollar sign are not being rendered as formulas, just as plain text. I can't pinpoint when it stopped working, because I am just an sporadic user of math enabled StackExchange sites, but some time ago they used to be ...

support mathjax

Kyle Kanos

03:51

Man applications for liberal arts colleges suck

This is what I have to write about: This position has responsibility for working with students from many different ethnic and cultural groups. Please give three examples that describe how your past experience has prepared you to do this effectively

And within 1200 characters

tpg2114

Ouch

user54412

ouch

user54412

lol

Kyle Kanos

How about, "Everyone's a person and deserves to be taught the same as every other @#$&ing person in this world, regardless of what they look like. Asking me to write an answer to question like this enforces a belief that there is a difference between people of different ethnicities."

tpg2114

Did the kids enjoy the snow?

Kyle Kanos

03:56

The boy did. Little Miss got too cold and started crying after about 45 minutes

But we didn't have gloves

So we improvised

With socks

That didn't work nearly as well as we thought it would

tpg2114

Yeah, they don't work very well

But we did that up north when we didn't have gloves

Kyle Kanos

I seem to recall using plastic lunch baggies (not the zip-lock types, the foldable ones)

tpg2114

Hrm... I don't know if I ever did that

Would make sense though

We did that on our feet for sure, mostly while cycling cause it's cheap windblocking

Kyle Kanos

Didn't really work for keeping your hands warm, but it certainly kept them dry

user54412

@tpg2114 is there a cutoff below which you don't cycle?

tpg2114

04:00

@ChrisWhite Now that I live in Atlanta and am lazy? Like 60 :)

But when I was in PA, not really

I did one ride where it was in the low 20's when we started and there was slush all over the ground. The spray from the tires froze the cables together on the downtube of my bike

And my shifters broke when I tried to shift, had to ride the last 10 miles home stuck in the hardest gear

user54412

So it hasn't gotten much higher than 20 all week here, yet half the profs in my department are still taking bikes to work

tpg2114

There's actually enough cold-weather clothing to ride all the way down to negative temperatures

I don't own enough clothing to do that anymore. And I don't like being cold

Kyle Kanos

Everyone takes the bus around here

They don't ride bikes much

tpg2114

My mom is supposed to get 10-14 inches of snow outside Philly from this same storm

Kyle Kanos

We've got two Bendy-Buses and they're awesome

tpg2114

04:04

@ChrisWhite You should probably get a lot of snow too, but you might be close to the ice transition

Kyle Kanos

I briefly looked at Princeton for post-docs. Then I thought that I wasn't good enough to be hired there, so I closed the browser

tpg2114

Well written C++ libraries make me happy

Kyle Kanos

@tpg2114 Because it's a rare thing?

:D

tpg2114

@KyleKanos It is very rare! But I think I can change my linear algebra solver without having to write everything. I can just create the matrix in the new library and give it the data from the one I already have

Without making copies or repacking etc

Kyle Kanos

Not copying is good

Because that wastes time

tpg2114

04:11

So is not re-writing everything to use the new library

Kyle Kanos

@tpg2114 Oh yeah, that's a big thing too

Me, I'd just write my own library that conforms to what it is I need to use at the moment.

user54412

@KyleKanos :(

tpg2114

@KyleKanos I'm trying to get a parallel BiCGSTAB solver as easily as possible

Writing my own isn't really the easiest way to do that...

Kyle Kanos

@ChrisWhite I look at some of the names listed as faculty and just think to myself, "Maybe after one post-doc I could be good enough to be hired there"

Plus, you're way smarter than me.

Clear example of Princeton vs Me :D

@tpg2114 Linear algebra solvers are lost on me. I try avoiding them if possible (and, in fact, I have done a remarkable job at avoiding it)

user54412

don't know what justifies that conclusion...

user54412

04:16

but I do agree this place is quite competitive for postdocs

tpg2114

@KyleKanos Me too, that's why I want to get somebody elses' library

And I want it to be threaded rather than MPI so I don't have to actually decompose the problem myself

Kyle Kanos

@ChrisWhite Which conclusion. There's like 3 there

Also: independent.co.uk/news/science/…

tpg2114

I have no idea what that photo is

But it's badass

Kyle Kanos

I'm pretty sure it's a rock wall for climbing

user54412

I thought it was Cerebro from X-Men

user54412

04:19

also, "Dr. Hurricane" - just... wow

user54412

clearly the NIF is a front for an evil genius aiming for world domination, with one dapper British agent all that stands against him

tpg2114

Totally random -- if you've never seen a pro bike race, the team managers drive in cars with the mechanics behind the race and this is pretty normal:

►

And super fun to do. I like driving the car better than racing

Kyle Kanos

So the drivers job is to swerve around other cars and honk his horn? Sounds fun

tpg2114

And not run over the riders

It's crazy fun. The men have radios so the manager talks to the riders from the car. The women don't have radios though so I don't get to do a lot

Unless riders come back to chat

Kyle Kanos

Why don't the women have radios?

tpg2114

04:35

I dunno really. Women get kinda left out of most of the things

I think they don't bring enough money into the sport so they don't get as much infrastructure

They've been trying to get rid of race radios for the men also

They claim the radios make the races more boring because the riders just become robots with somebody in the car calling the shots

Kyle Kanos

Hmm, seems to me they're more of cyborgs. But I can understand the confusion

tpg2114

Hah, fair enough

Kyle Kanos

Well, it's late and I'm going to be beat tomorrow if I don't go to bed now.

tpg2114

But it's coding o'clock

Kyle Kanos

Actually, I just finished putting in the Sedov solution into Pluto and am running a 2-core simulation on 3 AMR levels

Going to take hours to finish

dt is currently around 1e-7

tend = 0.5

Anyway, I'll catch you later

tpg2114

04:41

See ya

user54412

05:16

sigh - the stackexchange iOS alpha has been out for 2 days, and I haven't been invited to participate yet

user54412

and here I thought I could be one of the cool kids

tpg2114

Until you remembered you use iOS so you really aren't that cool

user54412

hey now

tpg2114

Android would be way better if it weren't just running Java... what a terrible language that is

user54412

yeah... silly high-level applications people

tpg2114

05:19

I played with writing stuff in native code but they make it way harder than it should be for developers to do that

Waffle's Crazy Peanut

13:26

5

Something I made for this Valentine's day... :D

dmckee

14:35

@KyleKanos There are two kinds of postdocs: institutional and research group. The institutional ones are more like being an independent researcher and generally pay better and are more competitive.

The research group ones are much more common and getting those it is about impressing one person (or a small group of people): impress the perspective supervisor(s) and you're in.

Do apply for a few that you think might be out of reach. You never know.

I know how much work goes into to an application so I won't suggest apply for a lot of them, but you really want to take a few chances on landing a dream job.

RhysW

15:17

@ManishEarth or other physicsy mods, you guys find this on topic for your site? astronomy.stackexchange.com/questions/1694/…

Waffle's Crazy Peanut

@RhysW That should probably be a dupe of a heck of questions here... ;-)

Kyle Kanos

@RhysW I'm no mod, but it looks like it'd be on topic here, albeit a duplicate of many

Waffle's Crazy Peanut

yeah...

RhysW

ontopic yes, duplicate yes,

slightly better than on ours, where its duplicate no, ontopic no :D

Waffle's Crazy Peanut

yeah :D

Rajath Krishna R

15:59

@Waffle'sCrazyPeanut Can i use this image in FB?

Waffle's Crazy Peanut

@RajathKrishnaR Sure! ;-)

Rajath Krishna R

Does physics in any way support the concept of God?

Waffle's Crazy Peanut

Dunno about that... (as we haven't observed any "God" yet!)

Rajath Krishna R

@Waffle'sCrazyPeanut In which software did you make the picture? It's really imaginative and beautiful.

Kyle Kanos

@RajathKrishnaR Well there's always the big bang.

Waffle's Crazy Peanut

16:10

@RajathKrishnaR Hand-made... Just pen (oh, and scales) -- And also, my dear LaTeX for the final wrap up :)

Rajath Krishna R

Does anyone know about the ISSYP camp by Perimeter Institute of Theoretical Physics? I have applied for it but really don't know about my chances of getting in.

Why most pictures of electromagnetic waves show same amplitude of electric and magnetic field where in reality the electric field is much more than the magnetic field?

David Z

@RajathKrishnaR physics has nothing to say about the concept of God

Rajath Krishna R

16:27

@DavidZ But, then why does people(mainly physicists or more precisely cosmologists) tend to think about the concept of God if physics doesn't imply anything about it?

ManishEarth

17:05

@ChrisWhite me either :(

user54412

17:59

@RajathKrishnaR do they? I've never seen papers like that

user54412

and if they do in their personal lives, well, as a physicist, I also think about computer games, youtube videos, and what I'm eating for lunch

user54412

we don't just think about physics

user54412

This question appears to be off-topic because it is about physics — Eduardo Serra 2 days ago

user54412

^ I'm really sad now

David Z

18:16

@RajathKrishnaR Like Chris said, physicists don't only think about physics

ManishEarth

@ChrisWhite I actually vtc'd it too; basically it's being migrated and the users don't know how. Being lazy, I selected the already-used freeform :p

jinawee

18:37

@Manish Would next week be ok to try mods not closing homework for a week?

ManishEarth

It's perfect. I won't even be around :p

David Z

@jinawee yeah, that's the plan, I'll post on meta about it

Mostafa

19:46

@RajathKrishnaR I think the main connection between physics and the concept of God lies in the (en.wikipedia.org/wiki/Teleological_argument)[Teleological argument].

Teleological argument

A teleological or physico-theological argument, also known as an argument from design, or from intelligent design, is an argument for the existence of God, or more generally of some kind of intelligent agent of creation, based upon proposed empirical evidence of human-like design or purpose in nature. The argument goes back to Greek philosophy but is today central to the creationist religious concepts of creation science and intelligent design which are presented as alternative scientific explanations in opposition to evolution theory. While the concept of an intelligence in the natural o...

David Z

20:43

@Mostafa there isn't really anything like that in physics though.

Mostafa

21:34

@DavidZ Surely physics *itself* has nothing to do with such metaphysical arguments. It is not *in* physics, rather it's *about* physics.
Actually if you *somehow* believe in the existence of (an intelligent) God, then you will observe the physical universe from that point of view (as in the teleological argument). I personally don't like and even accept teleological arguments as *proofs* of the existence of God.
Take a look at this section of Wikipedia's article to see what I mean: (about Abdus Salam)

jinawee

21:52

How can this kind of trolling be disputed?

-6

A: What experiment would disprove string theory?

What actually matters is if the universe is composed of strings (or contain strings in some way). Not the theory of it. Right? To see and feel these is a key factor. Otherwise it will be proposing earth movement to a medieval priest or convincing dogs the existence of rainbows. Strings are con...

Kyle Kanos

@jinawee What do you mean disputed?

jinawee

22:07

@KyleKanos The flag

Kyle Kanos

I definitely downvoted that thing, but I didn't get any option to delete it.

ManishEarth

@jinawee disputed means >=1 10k user marked the flag as invalid

note that we don't flag wrong answers here

...lemme have a look

@dmckee dammit

Hm, strange, I can't figure out why that flag was marked as disputed

Kyle Kanos

Slip of the finger?

jinawee

What a nice guest!

Jesus Christ

1

moon sun

ManishEarth

@KyleKanos no, it's impossible for mods to mark a flag as disputed

tpg2114

22:19

Sigh... 50% of my runtime is spent on the line:

return area*std::sqrt(area);

And area is just a double

ManishEarth

Well, maybe possible (we probably can use the invalid flags tool from the 10k interface), but not something we can directly do.

Kyle Kanos

@ManishEarth I have no idea how moderating works, it was purely a guess

ManishEarth

@KyleKanos disputed != declined. Disputed means a 10k user marked the flag as invalid, and I can't find any evidence of that

I know, just explaining :)

Kyle Kanos

If I had >10k rep, I'd have not disputed it

@tpg2114 you're returning $x^2\sqrt{x}$?

tpg2114

No?

Kyle Kanos

22:23

That's what it looks like

tpg2114

x*y*sqrt(x*y)

Kyle Kanos

That's the same thing. Except with $x=y$.

Wait

Nevermind

tpg2114

:)

You were missing half of a power

Kyle Kanos

You're returning x^3

tpg2114

Yeah

Except that x /= y

Kyle Kanos

22:24

That sucks for you.

tpg2114

To put it in perspective, solving an 1600x1600 linear system takes less time

Than returning that damn result

Kyle Kanos

I have no idea what line my code spends most of its time on, but I do know what subroutines it spends the most time on

tpg2114

VTune gives me the line

Kyle Kanos

@tpg2114 Ouch

I should try that vtune thing

ManishEarth

@KyleKanos It might be that the post also had an offensive flag

Kyle Kanos

22:26

I don't know that it was offense (maybe the Mr Suck my penis thing), but it definitely is not really worth keeping around

ManishEarth

offensive and spam flags have other consequences, so declining/invaliding them when they don't apply makes sense

But still, the entire situation is strange because I can't see any "invalid flag" flags. Bleh

tpg2114

Ah, figured out the problem

It's not the math

It's cleaning up the variables used in the routine at the return

dmckee

22:42

@ManishEarth What? Did I handle the flag out from under you or something.

ManishEarth

@dmckee yeah. No worries, was just startled :)

dmckee

Got it.

I don't know how to investigate why a flag was disputed.

It may even be that we are not supposed to know.

The team could find out it there was a pressing reason.

user54412

sometimes the mods are too efficient... like that time I entered the review queue a few seconds behind Qmechanic

3

ManishEarth

@dmckee I had basically opened the question and it said "deleted by dmckee 1s ago" :p

user54412

23:05

@ManishEarth aha! I'm chatting from the iOS app now :p

ManishEarth

@ChrisWhite Aha! I sent this from the terminal!

Unlike you, I can cronjob this

In fact, I already have a spam-detecting bot running that posts links possible spam to the Tavern

David Z

oh, I thought we were going to see you post the word "spam" to this room every minute :-P j/k

ManishEarth

in Tavern on the Meta on Meta Stack Overflow Chat, 5 hours ago, by Manishearth

[ SmokeDetector ] All-caps title: UNKNOWN NAME OF MOVIE

in Tavern on the Meta on Meta Stack Overflow Chat, 13 hours ago, by Manishearth

[ SmokeDetector ] Bad keyword detected,Phone number detected: love problem solution baba +91-7508870968

etc etc

Qmechanic

23:30

@ChrisWhite : Ha-ha :)

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