@skillpatrol who's Oakland playing this weekend

hello

Baltimore @0celo7

Hi pal

@0celo7 it may be better phrased as who is oakland losing against this week... :-P

-_-

Ignore yuggib (everywhere)

On the fast track you are pretty competitive...

What's the "fast track" mean?

like in a 100 meters competition

your draft usually is (or at least was): "who's the fastest guy in the combine still available? Draft him"

Any real Okland fan can shank a competitor fan at 100m in 5.76 seconds. It's crazy.

Yah, right. I didn't watch the combine.

Yah Aaah

I like watching the bench press competition.

:-D

Raw power.

a bit boring though

Not those last few reps.

you want to see people suffer

That's what the old school raider defense does.

@0celo7 You seem a bit focused on shanking people lately...

and since you're a raiders fan masochistic as well...:-P (that was the last joke on the raiders, I promise)

Np pal ;-)

Who's your team @yuggib?

I have no preferred team

just played for a few years...but at the veeeery low level my european country can provide

Are you ready for rugby tomorrow

no, I am a football (american one) and basket guy

rugby is boring

Basketball is cool now that Oakland are champions :P

Ahahahah

Does anyone have experience with the code in "numerical Methods in C" by Press et al? On the one hand it gets bad reviews on amazon, but it seems to cover good ground. Can anyone suggest an alternative? Many thanks :)

you mean numerical recipes?

it gets bad reviews because of it's insane copyright

which basically says you can only use the code/example algorithms for pedagogical purposes

if you reproduce it in your own code for non-pedagogical use you have to pay some amount

:O that IS insane.

for pedagogical purposes numerical recipes is basically "here's the algorithm, here's how to use it"

@FenderLesPaul yea thats the one, ... but I mean as a book for learning how to code and that..

i see

it doesn't give much insight into how to actually go about writing similar algorithms by yourself

Oh :/ any suggestions for books that do? (on similar topics)

I'm not sure really

I used it in a numerical methods class here

and it was taught by one of the authors of the book

oh nice

I'm not really sure what else to recommend because 1. I think it's somewhat dependent on what physics applications you are writing code for and 2. I don't have much experience in computational methods

@ChrisWhite is an infinitely better person to ask

I'm trying to generate an algorithm for some MCMC parallel tempering style work ... but have little experience in actually writing algorithms etc

thanks for the help :)

don't get me wrong though numerical recipes is probably a good resource to have

I just personally didn't find it pedagogically useful

okay, it looks fairly inexpensive on amazon here in the UK so I'll pick a copy up.

I also took QM from the same author

it was...quite an experience

haha I bet! It looks a pretty good book actually, but little on global optimisation methods

pretty interesting paper on arXiv today

for those interested

arxiv.org/pdf/1509.04645.pdf

it's also super short

@FenderLesPaul So I take it you play guitar then? What gear do you have?

@AngusTheMan I usually play a Taylor for acoustic and I have a les paul 60s neck traditional through a vox AC 15W tube amp

that I use for electric

I have a PRS SE that I also use

trying to save up for a Fender American Strat

I mostly play acoustic finger style though

on the electric guitar side I used to play blues and classic rock mostly but I've been getting into jazz recently

oooh very nice is your LP a custom? I'm a bit of an SG freak tbh... inverness green custom with korina body and a couple of standards, one of which i put a lyre vibrola and swapped for the angus you pickup in the bridge. put it through a marshall class 5 (but has an awful rattling problem) and a fender 100W solid state

same, all about the blues-classic rock vibe

it's not a custom unfortunately

Who is "Angus"? In AngusTheMan

;)

I'm a big AC/DC fan

Aaah, right.

We use AC/DC at our home games as an opener

I was going to go see them when they just did their tour of Uk but couldn't get the time off work :'(

:,(

Regarding physics.stackexchange.com/q/207432/26969 - am I the only one that thinks that it got a bit too much of a frosty reception (@ACuriousMind)? I hate it when a new user comes in, posts a not-too-terrible question, and then gets put off. It didn't seem like a "check my work" question to me - just a "I tried this, and the result is obviously wrong. How can I fix it?"

Cool intro @skillpatrol ! we have nothing like that here, best we have is for like .. boxing matches and that. I used to be a boxer but never fought properly, just trained then sparred and that. But I convinced my sparring partner to go in the ring to Evil walks... (he won)

If every time you "show your work", but your work is wrong, the question gets closed - how would we ever answer any questions? If people don't post their work, we complain; and if their work is wrong, we also complain? What's the new user left to do...

I realize that the question is now deleted by the OP - in response to said frosty reception. This means not everyone will be able to see what I am talking about. Sorry about that.

@Floris I agree with you. I saw one guy a while back asking about how to get first integrals from a Hamiltonian and he said he had no idea. His question was closed. I felt under suspicion just for giving him a hint. That being said some people do take liberties

I need to downvote something so my rep goes to 3,666

yesssssss

@Floris Well, I think the question is off-topic. As written, it's check-my-work, and if asked as "How do I calculate this correctly", it's homework-like. But I don't think simply voting to close is a "frosty reception" (after all, what else am I supposed to do when I think it's off-topic?). A frosty reception is when I downvote, vote to close, and leave a comment indicating that I think the question is bad (not just off-topic).

@AngusTheMan thanks. Looking at John Rennie's answer on meta for a related question, it seems I'm not the only one who think we should err to include for marginal cases

I also know some people have less strict views on such questions. That's why I don't make a fuzz when they don't get closed in the review queue after all.

@ACuriousMind - the comment from the OP suggests that he/she felt your reception was "frosty". Perception and all that. Bit miffed because I had started an answer, got distracted, finished it later - then found "you can't post the answer because the question is deleted". Which is a nasty feature of the interface.

Aye.

So in this case I am making a fuss (fuzz is a bad hair moment) just because "my hard work" went to waste

On Super User that leads me to post quick answers and then edit them extensively

May I suggest: Only put good effort onto good questions @Floris

Just a suggestion :-)

@skillpatrol - it started as one of those "here is a link to an earlier answer that may help you" comments that spun out of control. And before I knew it I had spent 10 minutes.

But I get your point

@Floris Well, I understand that frustration, but I can't predict that OP is going to delete their question after a single close vote, can I? That's not how it's supposed to work! If I leave a comment saying why I think a question is off-topic, I expect OP to explain to me why it's not, or to edit it appropriately.

I didn't even get notified of their response comment because they deleted it so shortly afterward.

@ACuriousMind yes, and I am not blaming you. I should have made a counter point in the comments when you posted your downvote, but as I said - I got side tracked and returned later. The interface gives no hint that the question was deleted unless you refresh - which I didn't want to do since I had a half-written answer...

I just felt a need to vent my frustration. Going back to other things now.

@Floris I think there are quite a few meta.SE posts complaining about that interface "feature"

One should try their best to be "gentle" in the first comment to avoid "frost biting" the OP :D

@skillpatrol - well said.

But apparently it'd be too difficult to implement a notification for deletion/closure while writing an answer since it doesn't happen that often.

@ChrisWhite Thanks for the reply :). I have ordered the 3rd edition of Numerical Recipes and it's on it's way. I am trying to find a similar style book that covers global optimisation (preferably with code in C) but specifically detailing parallel tempering. Do you know of any that would do this?

I see that NR has simulated annealing which is quite related.

@ChrisWhite It is an excellent reference, but indeed the "in C" part of the Numerical Recipes is a token gesture (it was originally "in FORTRAN", I believe). They use base-1 arrays, and have the most convoluted way of allocating memory to create something that pretends to be arrays with arbitrary bounds (meaning you could have an array that starts indexing at 5, if you wanted). That said - the algorithms are pretty good, and the code is mostly quite efficient. But written in a horrible style.

I need UH stories!!!

@ACuriousMind Denzler is also a UH grad :O

@ACuriousMind this cannot be a coincidence

@ACuriousMind better watch out then

@ACuriousMind something I've noticed about speaking to Germans multilingually: when speaking English and a German word comes up, you'll say the word in perfect German; when speaking German and an English word comes up, you make an effort to say it with an English accent

but I speak both without foreign accent, but when a word in the other language comes up, I make no effort to say it perfectly

like I will still say an English word with a German accent when it comes up in German speech

@Floris I have had a brief look through a coworkers 2nd edition copy and it seems a really strange way to code. He said it has a lot of errors in, which initially put me off. But it is as good a place to start as any :)

@0celo7 Well, one has to pronounce the word properly

@ACuriousMind I don't do that. I don't say the word perfectly/properly when speaking the other language.

I'll keep the accent that I'm speaking in.

Who can judge pronunciation?

I can.

Me too.

According to ACM, I speak German w/o accent.

And I speak English natively.

Although apparently not spelling because that word is underlined.

w/e

@ACuriousMind You did say that, right? I don't want to misrepresent my German cred.

@0celo7 Yes. (Although one can detect you learned it somewhere around the Pfalz ;) )

@skillpatrol I can.

How?

Rhineland-Palatinate is best Palatinate

@ACuriousMind When speaking English, is it Munich or Munchen.

screw dots

Trump still ahead in the polls!

@0celo7 Hmmm...depends on whether I can remember fast enough there's an English version, but if I do, I tend to use the English versions of names. (No point in using the German ones if the other person is likely more familiar with the English ones)

See? Familiarity governs pronunciation

@skillpatrol Using the English version of a name is not a difference in pronounciation, it is using a different word.

E.g. Cologne is surely not a "pronounciation" of Köln, it's a different name.

The same word can sound like two different words, no?

@ACuriousMind That's the one I was thinking of

I spent about 5 minutes trying to figure out why I thought Bonn was pronounced differently in English

@skillpatrol One smells better than the other, in this case :^)

@skillpatrol Under certain circumstances, yes. But I still maintain that the English versions of foreign names, while often originating from the English person's difficulty in pronouncing the actual foreign name, are different words.

I thought e.g. Cologne was a result of the former Latin name.

There are some that are strange, like Trier.

It's a perfectly normal word in English but it's two syllables in English vs. one in German.

@0celo7 In that case, may be true (but Köln also derives from it, we just butchered it more :P)

I love seeing the Senate hearing rooms on CNN and I know I've been in them.

And you'll never look at another library the same, right?

@0celo7 Can you gauge the difficulty of this problem set?

After being in the LoC

@skillpatrol They're all so...inadequate.

The lack of 22k gold on the ceiling in my university library ruins the whole atmosphere.

@obe gl lol

busy

Is it that bad?

haven't looked at it

1. isn't bad at all

1. is standard, you should have done that in Carroll, actually

maybe

1 is ok.

@obe Looks fine to me, but I don't have a reference to evaluate it against.

The rest though.

(I.e. I don't know what you would consider "easy" and "difficult" in this context)

although off the top of my head idk how to do the boost one...that's just me being dumb

@ACuriousMind For me.

@obe How is anyone else but you supposed to assess what's difficult for you?

Right, my bad.

indeed

I should look it over.

@ACuriousMind to be fair, I'm sure we can decide what is difficult

e.g. that one problem in Weinberg where he tells you do reproduce chapter 8 but with selectrons is kinda hard

you have to do a lot of work

I can only do 1.

@obe I looks fine to me as an "before we start QFT recap sheet" in general, though. If you find these problems difficult (as opposed to tedious, which I grant some of them might be), you'll likely not have fun in QFT.

I can do some of 2.

I should know how to do 3.

4, 5, 6 clueless.

They didn't teach it yet.

oh gosh

@obe 3. is really just plugging in and chugging through

how on earth do you do the infinitesimal boost one :O

@ACuriousMind indeed

@ACuriousMind Though there are people there who didn't know 4-vector notation or generalized schrodinger equation.

I should be fine.

@obe teach me how to do the infinitesimal boost part

I didn't do it yet.

It looks simple.

@obe 4. should not require much teaching. You do know what dimension the action has. You know how the action is obtained from the Lagrangian density, and it's easy to figure out the dimension of the integral measure. From there, one can deduce the rest.

@0celo7 They say "write down". So one looks up the matrix somewhere and writes it down :P

(Alternatively, take the full boost matrix and Taylor expand it in the velocity or something)

@ACuriousMind well I can do that

@ACuriousMind well yeah, what is that one again

@0celo7 idk, I don't memorize such things.

I don't memorize much of anything, tbh :P

Why not?

too much other crap that he likes

all the B__M stuff

@skillpatrol Why should I? If I need the explicit form of such matrices, I can always look them up, and having them memorized contributes nothing to my understanding

I wonder if that's ban worthy

@0celo7 All bets are off after the thing with the lady of pain, eh?

yeah, I'm worried now

@obe Cahill has 1.

Just looked up the matrices

He "guesses" them from the commutation relations

I was about to look at cahill.

I meant in general. @ACuriousMind

that's one way of doing it

I'll worry about this later.

@obe chapter 10

section 10.31

"The Lorentz Group"

wait a minute.

2 is in shankar right?

I learned this I think.

@skillpatrol Well, "of anything" was a slight hyperbole, obviously (how would I do physics if I didn't memorize anything?). But, if it is something that can be looked up quickly and is just bare information as opposed to a technique or idea, don't expect me to know it off the top of my head.

dunno

I don't think Shankar brings up the concept of coherent states

He does I remember.

4. should be trivialish

Right I learned lagrangian density in carroll.

have to review it though.

@obe 5 is straightforward if you recognize what the added term is and what it does when integrated. 6 is very tedious. But it prepares for the battles of indices that are to come ;)

Thanks, I'll work on them this weekend.

5. is trivial!

5. is less trivial in GR!

I think, great now I've confused myself

There's something important about boundary terms in GR actions

@Slereah what am I thinking about

@ACuriousMind think of any UH stuff?

@obe 6. is done in Zee

both books IIRC

@0celo7 Of course.

so that's not bad at all

if you're clever enough to guess the 3-direction boost generator that is

I don't really care about finishing it, It won't be graded.

I only want to learn, by practicing myself. (or learning from you guys)

or did they give those in class

@0celo7 "You can probably find this worked out in lots of places, but it's good practice with working with four-vectors, so I strongly encourage you to do it yourself"

@ACuriousMind I can read...I'm just giving him a specific source

I can find page numbers

@0celo7 But...that sounds as if you encourage him to not do it himself.

Is it important to do myself?

I wanted to stress that that is not an empty phrase there, as much as I hate indices, one has to get used to working with them.

He wants to learn.

@ACuriousMind indices are trivial

@0celo7 Analysis is trivial.

take that for what you will

Relax

Time out.

It's all my fault.

@ACuriousMind Denzler thought I was shitting him when I said I couldn't do the problems in chapt 0 of Jost