The h Bar

I want to write down the most general second order PDE on a Riemannian vector bundle (what I mean by that isn't clear) and try to get existence and regularity

Sir Cumference

What would be the cause of sore throat and a little fatigue?

0celo7

@SirCumference aids

Sir Cumference

I'm praying I'm not sick right before finals

0celo7

12:33 AM

@Semiclassical dissertation or paper?

Semiclassical

Dissertation

Sir Cumference

@0celo7 ಠ_ಠ

0celo7

@SirCumference i know your secret

Semiclassical

Which is mostly just me jamming the papers I contributed together

0celo7

right

skull

12:34 AM

He is secret?

Semiclassical

I sorta despise it but to hell with it

0celo7

I'm trying to take some old notes I wrote and vastly generalize them to stick in the thesis

Writing down the problem is an obstacle

Semiclassical

Once I have a chance next week I’ll probably go back and do more format tweaks

skull

Sir secret cumference

Semiclassical

But I need the working version tonight

0celo7

12:36 AM

I can work with equations $$\nabla_i(A^{\mu ij}_\nu \nabla_j u^\nu+b^{\mu i}_\nu u^\nu)+c^{\mu i}_\nu \nabla_i u^\nu+d^\mu_\nu u^\nu=f^\mu -\nabla_i F^{\mu i}$$

Semiclassical

Which basically means: remove some stuff in the last chapter which is a distraction, move some stuff into footnotes, and write a conclusion

0celo7

is a conclusion really necessary?

Semiclassical

It’s a bit perfunctory

skull

Yes.

0celo7

right now I can only work with $u$ a section of some tensor subbundle, but I think this should generalize

the problem is writing down some invariant equation

@skull I doubt it

skull

12:39 AM

What?

0celo7

basically I need the most general thing possible that lets me integrate by parts globally

and this makes sense to me as long as I have an orientation

I really don't want to have to deal with orientability though, it gives me a headache

Semiclassical

I think the tack I’ll take with the conclusion is “if I were to go back to these projects, here’s what else I might explore”

I can spitball that pretty easily

Huh, I was just looking at the conference that’ll be here next week talking about holography stuff

And one of the speakers is Verlinde

0celo7

I have to admit I know nothing about holography

Semiclassical

Same

bolbteppa

Number of bosons in a photon vector field equals the number of fermions in the dimensions division algebras exist, obviously

G. Bergeron

12:49 AM

That was a really hard question to answer... It blended so many different things together...

0

A: Ion Wind Thruster? What is the theory behind it?

Your two questions concern entirely different devices/approaches to electric propulsion. Also, ion thrusters as used on satellites have little to do with those two approaches. With regard to question 1: You seem to have in mind the conventional setup in a ducted jet engine. This is not the case...

0celo7

@G.Bergeron You should be happy, there's more algebraic topology in my thesis

G. Bergeron

How did I do?

skull

Which department is hosting it? @Semiclassical

G. Bergeron

@0celo7 Ha!

Semiclassical

Physics

skull

12:50 AM

sounds cool

0celo7

@G.Bergeron relative de Rham cohomology on manifolds with boundary

Semiclassical

The conference is on “Holographic quantum matter”

0celo7

because why not at this point

G. Bergeron

@0celo7 relative?

0celo7

@G.Bergeron basically with forms supported away from the boundary

bolbteppa

12:51 AM

To me, stupidly, holography is Stokes theorem, apparently that's really wrong

Semiclassical

ftpi.umn.edu/workshops/2017-2018/HQM/index.html

0celo7

there's gonna be a commutative diagram

G. Bergeron

@0celo7 So like compact support in the variety \ boundary?

0celo7

no, not compact support

I said it wrong

you just assume they're zero on the boundary

G. Bergeron

The \ meant setminus...

but ok

@0celo7 yay!

0celo7

12:54 AM

I know, and that's not right

that would be compact cohomology of the interior

which is another thing

the challenge is to generalize the Hodge theorem to a manifold with boundary. I think I discovered a proof of this by accident

G. Bergeron

@0celo7 I'm just not sure what a 2-form being non-zero on a 1D boundary really means, without additional structure and/or embeddings...

0celo7

um, it's a thing defined on the manifold

so it's zero on the boundary

Semiclassical

Hmm, on further inspection it looks like Verlinde won’t be talking about entropic gravity

So less unusual

G. Bergeron

@0celo7 Yeah, so how come assuming it to be zero there introduces any additional constraints?

0celo7

@G.Bergeron it's a Dirichlet boundary condition for the Poisson equation

G. Bergeron

1:01 AM

@0celo7 Ah right, so by Hodge theorem, you mean the decomposition one, right?

0celo7

yes

I have the proof of the usual one written up. Currently doing it for boundaries. It's not a new theorem but this seems to be a nice proof

@G.Bergeron admittedly I don't have a good application in this mind that's easy

Joe Stavitsky

Howdy folks. Stupid question: can't I write v=int(2t-6)dt?i.imgur.com/9cgDhQ5.png

G. Bergeron

@0celo7 So to you cohomology is all about harmonic solutions and Poisson solutions? :p

0celo7

@G.Bergeron of course

it's an analysis thesis :P

G. Bergeron

@JoeStavitsky yeah

@0celo7 Yeah well in my diff geo course the Laplace operator was defined as $\Delta = \delta d + d \delta$. You can cast everything in differential equations, but we mostly worked abstractly by using the inner product $(\alpha,\beta) = \int_M \alpha \wedge * \beta$.

0celo7

1:18 AM

My proof of the hodge theorem is one sentence because it's a very specialized form of a very general result

G. Bergeron

@0celo7 Is it something along the line of poisson solutions = harmonic + special part?

Joe Stavitsky

@G.Bergeron ok so why the heck is this wrong please? i.imgur.com/esVKlJQ.jpg

G. Bergeron

Actually, I'm looking at those notes and he did introduced some elliptical analysis notions to do the proof...

@0celo7 Like weak solutions, regularity theorem and then using the scalar product above...

0celo7

The version you'd see in something like Gilkey or Lawson-Michelson is that any elliptic self-adjoint operator $L:\Gamma(E)\to \Gamma(E)$, where $E$ is a Hermitian vector bundle on a closed Riemannian manifold satisfies $\Gamma(L)=\im L\oplus \ker L$

@G.Bergeron someone actually proved all of that in a geometry course?

G. Bergeron

@0celo7 Yeah well it was my graduate diff geometry class, for some theorems, he cited Warner. In general some proofs he just sketched, but it was in depth enough to my satisfaction, like the deRham isomorphism theorem, but he could only introduce the Atiyah-Singer theorem and didn't have the time to fully prove it...

0celo7

1:24 AM

lol Atiyah-Singer would take a month to prove

I'm vastly generalizing what Warner does.

I strongly dislike his approach as well.

G. Bergeron

I really liked that class starting from analysis in R^n and gradually accelerating the pace up to Atiyah-Singer

@0celo7 Of Warner or of doing only sketches of some proofs?

0celo7

Warner

The approach is $\Psi$DO without $\Psi$DO and there's no good reason for it

G. Bergeron

@0celo7 Yeah well the professor had to off-load some proofs in order to cover so much material in only one semester

0celo7

I understand that

But Warner's proof isn't good imo

The second order Garding inequality rubs me the wrong way

I'm doing my proof with a first order Garding inequality

This is more in line with the classical Morrey proof

And is has the advantage of allowing for boundary conditions

G. Bergeron

You know after introducing the basics rigorously, it then went on to talk about Riemannian geometry & Hodge theory, integration and Stokes theorem, de Rham cohomology and a bit of singular homology which required some homological algebra so he could prove Mayer-Vietoris and deRham's thm... Finally, Hodge thm, some stuff about Green's operator, connections on vector bundles, Chern's classes and its link with Hodge theory, finishing with Atiyah-Singer.

@0celo7 He only referenced a theorem on Cauchy subsequence existence in n-forms and the regularity one: For $\alpha \in \Omega^k(M)$ and $l$ a weak solution of $\Delta \omega = \alpha \implies \exists \omega$ s.t. $l(\beta) = (\omega,\beta), \forall \beta \in \Omega^k(M)$.

@JoeStavitsky $dv = a dt$ does NOT imply $\int v dv = \int a dt$...

0celo7

1:39 AM

@G.Bergeron the cauchy one is the strange one

it's not typical

it's a combination of a second order Garding inequality and the Rellich theorem

Joe Stavitsky

@G.Bergeron, but I thought thats what the book says? How else then to compute velovity from accceleration?

0celo7

I know the proof pretty well

G. Bergeron

@JoeStavitsky You did not fix the constant of integration, you did not evaluate your expressions at the given times, etc. etc. Was I grading this, I would probably have given zero on the basis of mathematical inconsistency, but also because you didn't actually answered the question.

@0celo7 I haven't looked it up to be honest... Garding inequality and Rellich theorem does not really ring any bells for me...

0celo7

read my thesis when it's done

Joe Stavitsky

@G.Bergeron Yea I got as far as the missing constants and missing evaluation, but what is the correct derivation of v from a?

G. Bergeron

1:42 AM

@JoeStavitsky It's $\int dv = \int a dt$ But you actually did the computation right, just not what you wrote...

no extre v

Joe Stavitsky

ok ty

G. Bergeron

@0celo7 Fair enough, as long as you're gentle at the beginning.

Joe Stavitsky

ty all and good night

0celo7

@G.Bergeron I treat epsilons like topologists treat tubes

I am substantially less careful in this chapter because the stuff is already well understood I'm just doing a generalization

G. Bergeron

@0celo7 Fair enough, it's just that elliptical analysis is getting far from my specialisation, I use algebra in physical contexts...

@0celo7 That's the thing with being in mathematical physics: mathematicians think you're never rigorous enough and physicist say you're shoveling clouds... (that last expression has been literally translated from french, so I hope it invoke the same imagery...)

5

0celo7

1:46 AM

I'm a mathematician

with PDE you can sometimes play very loose because you eventually get really good at inequalities

skull

and the engineers probably think you're shovelling sh*t

G. Bergeron

@skull Yes, but then when I help my engineer friends after reading the first equation of a book (that's then converted in the rest of it in useable rule-of-thumbs) they appreciate that shit makes plant grows...

skull

:-D

G. Bergeron

@skull Also, if you entirely remove the difficulties coming from the math from, say, electronics, the topic becomes vastly more approachable (I do that as a hobby).

G. Bergeron

2:42 AM

Oh now SE wants to mess with the UI?!? What's up with companies fucking around with UI constantly?

user187604

Please somebody see my question on main site

G. Bergeron

3:00 AM

@user187604 You're question is highly unclear... What exactly is the motion, why does gravity suddenly appears, etc. But the point is that in the frame of the ball there is only the tension and the (pseudo/false) centrifugal force, while in the frame of a static observer, there is only the tension, always applied orthogonal to its motion

G. Bergeron

3:38 AM

Am I crazy to think this is asking way too much of me?

2

A: Homework questions physics

To summarize the myriad of homework meta questions that dmckee linked to, as well as to editorialize a little, I think the issue that most of us have is with no-effort homework questions. There is a help page on the main Physics.SE site that includes an explanation of what's considered on topic....

Secret

4:11 AM

1

Q: Entropy : subjective lack of knowledge that leads to objective conclusions

There is something I really don't get about entropy. Let's consider a newtonian system (not quantum mechanics here). We can compute the entropy of a system via the formula $S=-\sum_l Pl Log(P_l)$ where $P_l$ is the probability to find the system studies in the configuration $l$. If we work at ...

It is cool that information has a more physical effect as some experiment shows. It makes it much easier to understand information entropy

Secret

4:39 AM

Last night dream:

Grabbing the computational chemistry book to read again as I ponder about the correlation between the electron density of the molecules and the reactivity, Slereah (represented as some boy with short hair) and
I compare the contents with me saying the chinese one has less content than the english one. Slereah then checked and said they are exactly the same and nothing is missing (the back cover of the chinese one which is thinner, has the words sobereva.com written on it). I then checked again, and confirmed that indeed nothing is missing

skull

-_-

Secret

4:58 AM

nature.com/articles/s41598-018-25028-0

These binary materials sure give interesting electronics

Captain Bohemian

6:53 AM

Last night I dreamt of visiting Beijing again.

I do wish I am there now.

skull

7:10 AM

News update:

232

Q: Does Stack Exchange really want to conflate newbies with women/people of color?

The Stack Overflow Isn’t Very Welcoming blog post says: Too many people experience Stack Overflow as a hostile or elitist place, especially newer coders, women, people of color, and others in marginalized groups. There have been accusations of elitism against SO since time immemorial. Basic...

discussion etiquette blog behavior welcoming

3

John Rennie

To be honest I didn't read the original blog post very carefully, but I agree with the sentiment that it shouldn't be mixing up reaction to poor questions and reaction to posts from specific groups.

It is frustrating when OPs are lazy i.e. they haven't bothered to do even basic Googling before asking their question, and I dont think I'm the only one who feels this way. But I have never seen sexism or racism on the PSE and I would be horrified if I did.

Well, not deliberate sexism or racism anyway.

skull

7:26 AM

I heard deliberate racism, specially nazism, was a big part of the reason why Chris White left.

welcoming-behaviour could be a tag to discuss on meta

John Rennie

7:48 AM

@skull nope

We have had a few trolls discuss Nazism in the chat room, but they were never serious users and they have been swiftly banned. Chris White left for personal reasons that are his own business.

skull

yeah, probably a rumour started by those trolls

the owners of the math room wrote up these guidelines for that room

I think I showed you them before, no? @JohnRennie

when you first became room owner iirc

John Rennie

I'll have a scan through the Meta to see if we have a similar post. If not I'll suggest we make one.

skull

thank you, sir

Cows

8:10 AM

I've been in the cloud via ssh for 10 hours straight. I think I need to sleep now

Симон Тыран

8:33 AM

LOL there is indeed a video of some crackpot on youtube, claiming "stackexchange sucks", but in my opinion that rather speaks for stackexchange and not against it. Facts are more important than feelings.

Balarka Sen

@JohnRennie I think it's sloppy SJWness on the original blogpost's part to say "uhhh if you disagree, IMPLICIT BIAS TESTS"

It's very very controversial that the IATs have any correlation whatsoever with racist behavior.

Симон Тыран

How should one even know about the gender or the color of someone asking a stupid question? That blog post is a real Buzzfeed article, a pity one can not downvote it

Balarka Sen

That's accurate I'd say

(To be clear, I meant the adjective of it being a buzzfeed article is accurate) For what it's worth I agree with the premise of the blogpost. I think SO and many of the SE sites have developed an active culture of hostility. I don't see this too much in MSE, but PSE definitely has this.

Now, it's completely imaginable that a large part of that hostility comes from trying to regulate effortless and homework questions.

Симон Тыран

8:59 AM

It would rather be sexist and racist to encourage stupid questions just because the one asking could be a woman or a person of color. Only a real SJW would do that.

Balarka Sen

I think one should be careful about making a statement on, at least publicly, whether a question is "stupid" or not. If a question is unsuitable for the site, or doesn't put enough effort in it, obviously homework-help, the community would point that out regardless of whatever associations of the asker, and downvote it to oblivion/flag for closure.

It's also possible that the judgement of the community on the question's unsuitedness is not accurate (I have come upon many many questions on MSE which are great questions that got closed for no reason)

Симон Тыран

a funny quote about stupid questions: youtube.com/watch?v=uYT-ObGFly0

Balarka Sen

But yes, privately I think some questions are just downright stupid :D

Симон Тыран

The same goes for some blog posts [:

Balarka Sen

@СимонТыран It's funny (psst: and true), but pointing that out publicly (eg, in a comment below the post) is also totally not suitable for the site, IMO.

ACuriousMind

9:05 AM

@BalarkaSen Reminder: Off-topic is not the same as downvote-worthy is not the same as a stupid or bad question. These things overlap but they are not the same.

Balarka Sen

@ACuriousMind Yeah I was making a general case. This is true.

I think a major section of the blogpost ponders on the hostility of the community that comes from being "technical": If you ask a question, it'll either be upvoted/answered, downvoted/flagged, get some comments pointing you the backdoor. That's just a downside of being a Q&A site and not a forum.

ACuriousMind

This is a large source of perceived hostility, I think: Many think of downvotes and closures as aggression, as hostile actions against the author of the post. And, well, in a certain sense they are - they're usually not meant to be, it's not their primary purpose to upset the author, but of course they'll always bear some connotation of "the author of this question did something wrong".

Balarka Sen

The right solution to that is to put more attention to the chats: where people can come to seek discussion and not just answers.

Симон Тыран

I just don't get how the author of the Buzzfeed article correlates that with gender and color

Balarka Sen

@ACuriousMind I think we have similar things in mind, just from different angles.

ACuriousMind

9:12 AM

@BalarkaSen Nonononono - chat's don't become top Google hits, they are ephemeral and as horrible to search as the fora of old and their moderation and curation does not scale to the size of something of SO

Симон Тыран

Meta would be the place for that I assume

Balarka Sen

@СимонТыран Neither do we, so we say it's obviously a false correlation and convince ourselves that it's obviously SJW-inclined from the various sentences present in the blog, and move on to extract the constructive part of the blog.

Симон Тыран

Ok then first rule: never downvote my posts [:

Balarka Sen

@ACuriousMind I don't see why one would need to search discussions. That's the (primary) purpose of the chat.

To move extended discussion in the comments to somewhere

And any such discussion gets linked in the comments below the answers anyway

ACuriousMind

But...we already do that. So what do you mean by focusing more attention on chat?

Balarka Sen

9:15 AM

Maybe I don't understand your point

ACuriousMind

@BalarkaSen I was just thinking I don't understand yours :P

Balarka Sen

@ACuriousMind Only a nominal fraction of the community knows and actively uses the chat, which itself is filled with moderation bugs of various sorts. We should (1) popularize the chat as a place for discussion more actively (2) put more attention moderating it.

That's all my point was

skull

does SAP have built-in employee internet chat rooms?

ACuriousMind

@BalarkaSen Well, my point was that even getting rid of all the buga chat currently has, that doesn't scale. Get 200 people (a significantly larger but still tiny fraction of the PSE user base) talking in here and it'll move so swiftly it becomes useless. So you have to do lots of rooms dedicated to specific topics. Each room then probably with their own room owners, and people who oversee who gets to be a room owner, and then moderators moderating what the room owners can't...

That just doesn't work, I think.

Balarka Sen

Hm, perhaps true.

Slereah

9:32 AM

Maybe we can just make STEM less appealing

We'll get less questions

Balarka Sen

@ACuriousMind I thought about this for a bit: I am not sure if this is entirely a fault of the downvoting mechanic. I mean, most anybody perceives a criticism of their question or answer as, however little in proportion, hostile. If a professional mathematician posts a paper in a journal and it gets bashed by the reviewer hard, they'd probably go "damn, this fellow is an ass"

ACuriousMind

@BalarkaSen I did not claim this problem is solvable ;P

Balarka Sen

Lol

skull

the insult to the injury comes when people take it too "personally"

ACuriousMind

Best we can all do about downvoting/closure being perceived as hostile is not to additionally leave snarky or rude comments on people's questions, and make an effort to explain to well-meaning new users what exactly they did wrong.

Balarka Sen

9:35 AM

But yeah just this discussion should be enough to justify how complicated the problem of hostility that's being raised is, and how much dilution the blogpost does to it.

@skull The point is any sufficiently personal curiosity, from which questions and answers originate, have to have personal connotations with it.

@ACuriousMind That's the more constructive approach, but I suspect many will disagree on it (a careful tutorial/walkthrough on what the OP did wrong) being a crucial part of a Q&A site - which, tbh, it's not.

It's a crucial part of a community, though

I think SE's trying to balance between those two ships at this point.

ACuriousMind

@BalarkaSen True enough

@skull You're not going to come across as less hostile by saying people are just taking it too personally :P

Balarka Sen

@ACuriousMind Don't take what skull says personally, bruh

(Gotteem)

skull

::runs for cover::

Balarka Sen

But I agree, on the more serious note.

@Slereah This.

STEM are for broke ass people like us

skull

Don't take this personally, but your question shows me you're not very bright :P

Balarka Sen

9:44 AM

LOL ^

bolbteppa

I think people seriously seriously undervalue relativistic quantum mechanics and it's power

Slereah

@bolbteppa its only use is for practical applications

Disgusting!

bolbteppa

I am getting so into these dirty waters I want to view particle physics as starting from Fermi's theory of beta decay :(

and then tinker with it to get it right instead of some magic Lagrangian

Anonymous

@JohnRennie Morning. You around?

bolbteppa

But seriously, it offers an explanation for charge renormalization with the Dirac sea and electrostatic repulsion, how are you supposed to understand it without this?

It's very weird using a differential equation to get a qft scattering amplitude, way way easier

Mithrandir24601

9:51 AM

@bolbteppa I'd agree with that all right

skull

how goes the quantum computing site?

Slereah

There are many paths to QFT

Except the Royal Road, as Euclid would say

skull

but there is a royal roads university

Slereah

I assume they don't teach geometry there

bolbteppa

In fairness few places do (yee-olde/royal Euclidean) geometry anymore

Slereah

10:00 AM

We learned euclidian geometry in elementary school

And I assume you learn it in some uni math modules

Synthetic geometry or axiom systems or whatever

John Rennie

@Blue Hi

Sorry for the slow response. I'm playing wit a new PC :-)

bolbteppa

'it is said that Abraham Lincoln memorized the first six books of Euclid'

Slereah

The axiomatization proclamation

Anonymous

@JohnRennie Hi! :D Could you check this C question I asked on SO? I seem to stuck with an issue that apparently shouldn't be too difficult to handle. But I just can't seem to think of any way around. If you wish, you could answer it there too (so that I can upvote/accept)

Mithrandir24601

@skull Slowly gaining momentum - we're up to an average of 4.4 questions per day from maybe 3.6-3.8 a week or two ago. This is normal for beta sites, so it's fairly promising. We've got a few experts, although it would be nice to have more expert level questions

skull

10:04 AM

cool

Anonymous

@JohnRennie Hah. New laptop again ? :P

Slereah

So when will a quantum computer run DOOM

John Rennie

@Blue no, a PC this time. I want a PC to use for remote working i.e. I shove it in a corner somewhere and RDP into it when I'm away from home.

Anonymous

By the way, my main problem with that program is the runtime. In its current form it takes hours to execute

Anonymous

So if you have any ideas to reduce the complexity etc. let me know

Anonymous

10:06 AM

@JohnRennie Oh nice. It's been a long time since I used a PC

Anonymous

Desktop i.e.

skull

@Slereah here

John Rennie

The way I'd probably approach this is:
- initialise the array with 0 and -1, where -1 means black
- start at the top left and find the first -1
- change this to 1 and search for all connected cells and set them to 1 too
- carry on through the array, find the next -1 cell and this time set it and connected cells to 2
- then 3, you get the idea

Mithrandir24601

@Slereah While people like claiming things like 10 years, it'll probably be a few decades yet :P

Anonymous

@JohnRennie Ah, finding connected cells is not the problem. My program already does that

Mithrandir24601

10:10 AM

(a reasonable estimate would actually be about 30 years)

Anonymous

I'm sorry that I didn't add comment lines

Anonymous

My program labels all black cells belonging to the same cluster with the same number. Say 1, 2, 3 and so on. Anyhow, take your time. It's nothing urgent but would be helpful to find an efficient solution

John Rennie

@Blue I bought a cheap low spec Dell Optiplex 7010 because I reckon I can buy a replacement mofo i7 CPU for it cheaply. Hopefully I'll end up with a cheap but seriously powerful little PC.

ACuriousMind

@Blue By the time I got to the end of that "introduction" I had forgotton this was an SO question and was surprised to see a code block :P

I suggest you trim down the intro considerably, or at least put the actual question in front of it

Anonymous

@ACuriousMind Ah, you're right. Trying!

Anonymous

10:14 AM

Such a big intro is probably not necessary

John Rennie

@Blue why wouldn't you write out the cluster size data once per run, then process it separately after you've done all your runs?

Anonymous

@JohnRennie Wow. That would be a great combination. For Desktops using assembled components is a good idea

John Rennie

If you do that you always have the raw data in case you decide later to do a more sophisticated analysis.

So you only need one LxL array.

Anonymous

@JohnRennie Well, umm I was thinking of that but there are some issues. Say for p = 80 and L = 100 the largest cluster size could be 8000 (say) while in the second run it could be 8500. I could output all of that into a data file but then using Gnuplot to make an averaged graph would be another pain. For Gnuplot what is suited is i) some x-axis values (possible cluster sizes) ii) corresponding y -axis values (number of clusters of each size for a given p).

Anonymous

But if all the runs produce a different set of x-axis values I'm not sure how to use Gnuplot for that

John Rennie

10:21 AM

Have your first program write out the raw data, then write a separate second one to crunch the data into a form GNUPlot can handle.

Anonymous

@JohnRennie Ah. Using the "read files" technique in C? Interesting. I could use the r+ or w+ mode for that

John Rennie

For example you might need to experiment with different size bins. Once you have the raw data in a file you can run your analysis app with different bin sizes to see what works well.

@Blue Huh?

Oh, you mean open the file for append and write each fresh set of data to the end of it?

Anonymous

@JohnRennie Well, not "append". I just need to access the output files in r+ mode and calculated the required averaged data and create another set of output files in the desired format in the w+ mode (containing the averaged data which Gnuplot can later be used to plot)

Anonymous

I'm referring to

Anonymous

30

Q: Difference between r+ and w+ in fopen()

In fopen("myfile", "r+") what is the difference between the "r+" and "w+" open mode? I read this: "r" Open a text file for reading. "w" Open a text file for writing, truncating an an existing file to zero length, or creating the file if it does not exist. "r+" Open a text file for up...

c fopen

Anonymous

10:26 AM

@JohnRennie Anyhow, I think your idea is good. I should definitely try that

John Rennie

This is the new PC. Cute little thing isn't it? :-)

Anonymous

That's probably the tiniest CPU I've ever seen

Anonymous

:P

John Rennie

If I can get one cheaply I'll cram a 3.4GHZ quad core i7 into that!

Anonymous

Haha. Cool

John Rennie

10:31 AM

It's a Dell ultra small form factor case. They are remarkably small.

skull

your laptops are going to be jealous ;P

John Rennie

@Blue yes, open the file with "r+" then use fseek to move to the end of the file before writing the new data. That way you'll append the new data each time.

Slereah

Please

Check out my sweet rig

John Rennie

I have a friend who collects old PCs.

Slereah

Is it me

John Rennie

10:37 AM

Old as in Commodore 64s, BBC micros, Sinclair QLs etc

Slereah

Or are we not friends

John Rennie

I have (at least) two friends who collect old PCs :-)

Slereah

Nice save

skull

indeed, the parenthetical statement was done with mathematian like skill

skull

10:54 AM

6

Old and Middle English

Proposed Q&A site for students of the predecessors of English: Old English, the language of Beowulf, and Middle English, the language of Chaucer in the Canterbury Tales. Accepts questions about learning, translation, and tales in this language.

Currently in definition.

skull

11:16 AM

how's the sore throat? @SirCumference

Sir Cumference

@skull 100x worse D:

Now a stuffed nose

Slereah

How does one get a sour throat

Sir Cumference

Goddammit all

Slereah

Drink a lot of lemon juice?

Sir Cumference

Why does this happen to me when I need to study for finals

skull

11:17 AM

fatigue weakens your immune system

John Rennie

@Slereah apoptosis

Slereah

makin' a roast for lunch

John Rennie

I'm having :: drum roll :: beefburgers!

skull

in your new place?

John Rennie

Followed by stem ginger icecream

Then some sweeties, but I haven't decided what sweeties yet

Slereah

11:22 AM

I get the new place in one month

And I move there mid june

You're an old man, get one of those old man candy

Like a werthers or some hard candy

John Rennie

There's a local shop does a sweet called mint crumbles.

I think they are icing sugar that has been pressed into a ball, presumably under some considerable pressure. They are firm but crumble in your mouth when the saliva touches them.

And as they crumble they release a terrific burst of peppermint oil.

Those are my current favourite sweet. And since they crumble in the mouth even we toothless old wrecks can eat them.

skull

toothless already?

John Rennie

I've lost two teeth so far. Not too bad I suppose.

Mithrandir24601

@JohnRennie I had ginger and lemongrass candy floss once - it was the final course of a mind blowing meal

John Rennie

@Mithrandir24601 Wow, where was that? In China?

Mithrandir24601

11:34 AM

@JohnRennie Nope, in Nottingham :) Horrifically expensive, but the best meal I ever had, not (just) in terms of sum of the parts, but everything I ate then was the best of that thing I've ever ate :)

Slereah