The h Bar

12:04 AM

@ACuriousMind delet dis physics.stackexchange.com/a/360475/159423

12:31 AM

@IcEmybReaD From 15 rep, you can make flags. Click on the "flag" link below the post, so the nearest mod will intervene. Although it is possible, that they won't do anything saying that vote it down. It is also possible, that the post will go into the low quality queue and there will be deleted by community votes.

2physics

12:47 AM

Hi

I have a question in Electromagnetics, anybody to help?

IcE my bReaD

2:06 AM

@peterh I know. I already did that before I messaged him.

clearly it did nothing.

peterh

2:44 AM

@2physics Well, it seems most of us sleeps or going to work. Also me.

DanielSank

2:56 AM

Everyone, learn Rust immediately.

@heather

@heather when you at some point want to learn a compiled language, try Rust.

It's sick.

IcE my bReaD

@DanielSank do you know anything about haskell?

0ßelö7

3:26 AM

@DanielSank do I have a reason to learn any programming language?

DanielSank

3:41 AM

@IcEmybReaD Nah.

@0ßelö7 Yes. Presumably you want to do work.

0ßelö7

@DanielSank honestly, not if it involves programming

I hate it with a passion

IcE my bReaD

:o

@SirCumference hOwdy

Sir Cumference

@IcEmybReaD Howdy :)

DanielSank

@0ßelö7 k

IcE my bReaD

cool story bro

lol

DanielSank

3:53 AM

@0ßelö7 go learn about feedback in digital signal processing. Then you'll understand QFT better.

0ßelö7

@DanielSank ...why would I want to do that?

I don't know any QFT

IcE my bReaD

haha yeah

dmckee

@DanielSank Remind me why I want to learn rust. I seem to recall that I do, but I can't remember why.

2

Aside: I'm taking a machine learning course from coursera right now. Two things to say.

(A) This is mostly fitting and is old hat, only the business majors have given it all stupid vocabulary that doesn't agree with the use in any other field.

(B) I remember very clearly why I hate matlab's language.

0ßelö7

@dmckee why

dmckee

@0ßelö7 Because it feels like the bastard child of fortran, pseudo mathematical typewriter symbols, and ruddy /bin/sh.

Because the keywords are long and the important functions are strings of gobbledygook letters crammed into 8 characters.

0ßelö7

4:08 AM

I hate fortran but love matlab

so what you're saying doesn't make sense to me

dmckee

Because the matrix manipulation syntax is full of specials cases intended to be convenient but which actually serve to obsfucate what is going on an set traps for the occasional user.

0ßelö7

@dmckee mm, yes

Not putting .* breaks everything and it's annoying

dmckee

@0ßelö7 Right now you don't know enough language to understand that what you like out of matlab is run-time typing, type inference and the power of the abstract machine.

But there are other languages that have all that and don't have the crappy syntax.

0ßelö7

I don't think I want to ever get deep enough into a language to know what you're talking about

the thought makes my skin crawl!

I was born 60 years too late

dmckee

Those are all user-visible properties. You don't have to know anything about what goes on under the hood to understand them.

Matlab can change the type of a variable on the fly: run-time typing.

You often don't have to tell matlab what type it should be: type inference.

0ßelö7

4:12 AM

@dmckee indeed

dmckee

You can perform certain matrix operation with a single operator: powerful abstract machine.

0ßelö7

Fortran has this retarded thing where SQRT(5) is undefined

you have to write SQRT(5.)

dmckee

The last two are fairly unambiguously good. The first has its pros and cons.

@0ßelö7 That's numeric literals having rigidly defined types and there being no type promotion system. A 'feature' of the original era of fortran.

You'll find that c literals also have defined types, but the type promotion system means you rarely have to care.

rob

4:24 AM

I saw a car yesterday whose license plate was "F77 64G". I have been trying to decide whether it was a vanity plate making a subtle reference to high-performance computing with old tools, or whether I have a nerd problem.

6

DanielSank

4:35 AM

@dmckee C but modern and less terrible.

And yeah Matlab is a disastrous language.

Secret

6:27 AM

> We all got light and dark inside us. What matters is the part we choose to act on and there are cases where even the light and the darkness join force to form something powerful for a common purpose

Sid

@Secret What's that?

Secret

The front half is a quote from Harry Potter, the back half is my own extension

this is because there exists scenarios both in reality and fiction where there is a synergistic interaction between something good and something evil

John Rennie

7:07 AM

@Qmechanic: oops, our edits overlapped on physics.stackexchange.com/questions/360507/…

Mithrandir24601

7:34 AM

@dmckee It's nice to know that I'm not the only one

Abcd

@JohnRennie Please give me the link of your drawing tool.

John Rennie

Google Drawings

Google Drawings is a free, web-based diagramming software developed by Google. It allows users to collaborate and work together in real time to create flowcharts, organisational charts, website wireframes, mind maps, concept maps, and other types of diagrams. Google Drawings is also available as a Chrome app that works offline, available from the Chrome Web Store. Google Drawings is hosted within Google Drive and all files created with the application are by default saved to Google Drive. It was originally introduced on April 12, 2010 as Google Docs drawings, a tool for making drawings in Google...

It's part of Google Drive.

Abcd

Okay, thanks. Let me check.

John Rennie

Just open the Google Drive site and follow the links to create a new drawing.

Abcd

@JohnRennie docs.google.com/drawings/d/… ?

John Rennie

7:38 AM

It's quite a basic drawing app, but with a bit of practice you can construct quite sophisticated drawings.

Abcd

Ok.

John Rennie

@Abcd Is that a drawing you want me to look at? If so you'll need to make it public. At the moment I get an access denied error when I click on your link.

Abcd

@JohnRennie No. Btw isn't MS paint better?

John Rennie

What I usually do is screen grab the drawing, paste it into Paint, crop as necessary and save it as a GIF. Then I can insert the image into a post.

@Abcd MSPaint is not a vector graphics app so it isn't ideal for technical drawings.

Fawad

Sep 25 at 15:18, by Balarka Sen

England is my city, MS Paint is my Photoshop

Abcd

7:44 AM

@JohnRennie Okay.

John Rennie

Ah, you worked out how to change the line width?

Abcd

Yes

Qmechanic

8:40 AM

@JohnRennie : Interesting. there seems to be a minor bug: On the revision page your revision (v3) is listed after my revision (v2), clocked at the same time, but it's my revision that is the actual/current version. I guess it's because of mod superpowers. :)

Slereah

9:20 AM

It's a bit hard to write about the warp drive seriously because one of the major contributor is called Hiscock

Mithrandir24601

10:27 AM

It's not every day you see the phrase "and will provide insight into early life not only on Earth but also on other planets." in a nature paper... Someone's being a bit optimistic...

Wrichik Basu

How do I solve this?

@JohnRennie are you available now for once? ^^^^

John Rennie

@WrichikBasu you need to know the temperature in the Sun's core ...

Balarka Sen

@ACuriousMind Can you shed some light on the various different tangent bundles of a Riemann surface?

ACuriousMind

@BalarkaSen There are different tangent bundles? oO

John Rennie

@WrichikBasu Or what I'd probably do is use the supplied energies to work out the corresponding temperature and see which temperature looks most plausible.

ACuriousMind

10:30 AM

This may be the part of surfaces I never had to deal with ;)

Balarka Sen

@ACuriousMind Yeah, it seems like there's the usual complex tangent bundle (just the usual tangent bundle $TX$ with the complex structure coming from the complex structure on $X$), and the complexified tangent bundle, which is $TX \otimes \Bbb C$.

Wrichik Basu

@JohnRennie ok. I'll find sun's temp. What formula should I use?

Balarka Sen

And apparently $TX \otimes \Bbb C$ decomposes into two subbundles, $T^{1, 0} X$ and $T^{0, 1} X$, which are the holomorphic and the anti-holomorphic tangent bundles respectively.

ACuriousMind

Ahhh, that's what you mean

Wrichik Basu

@JohnRennie it's about 15 million kelvin.

John Rennie

10:33 AM

@WrichikBasu I would use my second suggestion. The question tells you that the energies given are $1.5kT$, so you can work out what $T$ is.

ACuriousMind

@WrichikBasu The question already gives you the formula.

Balarka Sen

@ACuriousMind I think I understand these various players of the game abstractly, but not hands-on.

Wrichik Basu

k is Boltzmann constant?

ACuriousMind

@BalarkaSen I'm not sure what a hands-on understanding would involve: The complexified bundle is vector fields with complex coefficient functions, and it has natural subbundles where these functions are restricted to be (anti-)holomorphic. What more do you want to know?

Wrichik Basu

OK, it's the last one.

Balarka Sen

10:40 AM

@ACuriousMind For example if I call the almost complex structure $TX$ inherits as $J$, I can extend that to an almost complex structure on $TX \otimes \Bbb C$ in the obvious way. Then $T^{1, 0} X$ and $T^{0, 1} X$ are merely the eigenspaces of $J$ corresponding to the eigenvalues $\lambda = 1, -1$. Is it immediately clear why this definition agrees with yours (i.e. vector fields w/ holomorphic resp anti-holomorphic coefficients)

I meant $\lambda = i, - i$

Wrichik Basu

@JohnRennie thank you a lot.

ACuriousMind

@BalarkaSen No, it's not obvious because I was talking non-sense :D

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