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12:03 AM
22
A: Self-publishing academic book

Pete L. Clark Should I publish it traditionally or self-publish? Why do you want to publish at all? You answered I write the book to store down my research results and to spread my new knowledge. To make money is not the main aim, but it would be nice. Given that: the answer is that you should cert...

The last two paragraphs of that answer are one of the more polite smackdowns I've seen on SE in a long time
I love StackExchange for the seriously off-the-wall questions that come up:
15
Q: Would a mermaid be kosher?

Ely Beau EastmanTonight at religious school we were discussing Kosher laws and how to build/keep a kosher kitchen. While we were discussing different meats, one of the jokers in school asked if you could eat a mermaid, since it would have scales and fins. Would it be possible to eat one?

And the hot bar thing is cool cause I would never find them otherwise
 
@tpg2114 I'm always a bit disappointed when I see a question like "Why shouldn't I murder everyone I meet?" only to realize it is on gaming.SE
 
@ACuriousMind There are a lot of those... I've gotten pretty good at identifying the game from the title-only though.
I don't play most of them, but the trends are easy enough to figure out
Besides, it's better on gaming.SE than workplace.SE or academia.SE :)
Not sure how I feel about the worldbuilding.SE. It kinda just seems like "Hey, I made up a really random idea... tell me your really random idea on how it might randomly work!"
 
@tpg2114 Yeah, it's a weird place.
 
12:18 AM
Ie:
5
Q: What are the advantages of mutilating someone, rather than just killing them?

alexqwxIn Manhunt, I've just finished the tutorial level, where I am shown that, during a stealth kill, the longer I hold the action button for, the more gruesome the attack becomes. Now, there are several disadvantages to this: Performing a fully-fledged mutilation takes a good 5-10 seconds, during ...

At least WB is entertaining sometimes
Not sure I'd participate there, but it's entertaining. I don't know how every question isn't subjective
 
They often cite some facts or statistics or calculations as basis for their answers. I think it's about educated guesses, and that questions where there's not even a slight basis in fact in sight are closed as opinion-based?
 
12:57 AM
@tpg2114 That is pretty good. Note also that OP was duped out of $1000 to pay for a "life experience" PhD:
41
Q: Is a university that grants me a PhD for $1000 and a copy of my unpublished book fake?

portonI have paid $1000 for PhD in mathematics. And I have sent them my book to be considered as a PhD thesis. Now I suspect that I have lost the money. But as far as I know they are not accredited by the U.S. Department of Education. So, is it possible that I will find a job requiring a degree, usi...

 
 
2 hours later…
vzn
2:28 AM
hi sofia, thx for link re shimony/ Bell thm summary, nice. your profile says you are researching the fundamentals in QM. can you elaborate?
 
user54412
@tpg2114 Perhaps not so many. There has already been at least one cross post essentially.
 
4:54 AM
@ChrisWhite Yet another reason I absolutely love SE and the users... I have no idea how you found that, but it's pretty awesome
 
 
3 hours later…
8:21 AM
Hi Danu
 
Hey John
 
I don't think there's really much to discuss
 
I just saw that @DavidZ also posted a comment
 
I basically agree that a Google would have found the answer
 
do you not agree that it was quite clear what exactly to google, even to the OP him/herself?
 
8:22 AM
It's just that where a beginner seems to be genuinely interested I think we should cut them some slack
 
Okay, but I didn't downvote and did answer
 
Yes, I don't mean to criticise you personally
It's just that there seems to be a trend developing to be harsh on beginners
While we need to discourage lazy questions I worry that we will start appearing to be hostile and unwelcoming as a result.
 
Yeah... I guess we're back to that ol' debate
I think I stand by my initial judgement on this one though
 
what are we talking about?
 
1
Q: Are "uncertainties" in Heisenberg Uncertainity just standard deviations?

Illegal ImmigrantCan someone confirm that the uncertainties in Heisenberg's uncertainty relation are really just standard deviations based on the expectation values? For example, the $\Delta x$ can be computed by $\sqrt{(\bar x^2 - (\bar x)^2)}$, and the $\Delta p$ can be computed by $\sqrt{(\bar p^2 - (\bar p)^...

oops
 
8:31 AM
@SabreTooth: my bleeding heart liberal side is showing again :-)
 
huh wha?
 
Hehe, nice
 
There is definitely a balance.
 
8:54 AM
 
 
3 hours later…
12:03 PM
@JohnRennie 'liberal' has a quite different meaning here (th Liberal Party are the conservatives here)
 
12:19 PM
@JohnRennie I do think we sometimes appear as unwelcoming to new users, but it's hard to balance being welcoming and maintaining the policies of the site. If there is to be a change to address the former, the latter has to be changed.
 
@SabreTooth In the UK we distinguish between liberal with a small "l" and Liberal with a capital "L".
The latter is a political party and carries all sorts of baggage with it.
The former just means you're easy going and tolerant (ish)
@JamalS Generally speaking I think the site is pretty good and we get it mostly right. It's just occasionally that I think we can appear a bit fierce.
 
 
4 hours later…
Jim
4:14 PM
-3
A: How do we know that some radioactive materials have a half life of millions or even billions of years?

zakHow can you just conclude that half life is constant? We know the speed of light, gravity, and other "laws" have changed. Why is half life "constant"?

I didn't know that we knew the speed of light has changed
Learn something new every day
 
4:37 PM
So here's what just happened. A champion of the system, @JohnRennie, has expressed his discomfort with the present scheme of things. This is not some incessantly ranting folk like Horvath or bobie, this is the highest rep member on the site. I think we need to take these signs seriously. Just sayin'.

@Jim Well, you learn something new about *people* everyday.
 
@Jim you must not have paid attention as a kid. For example, we know time travel is possible. Superman did it. You just have to fly really fast in the opposite direction of the Earth's rotation.
 
@Gaurav Read "Generally speaking I think the site is pretty good and we get it mostly right. It's just occasionally that I think we can appear a bit fierce." again. That is not exactly "discomfort with the present scheme of things"
 
Nor it is particularly troubling -- I bet almost every (legitimate) user on the site has at least something they would like to see done differently. But obviously these are not blocking issues or we wouldn't be here
 
"It's just occasionally that I think we can appear a bit fierce." is part of "the present scheme of things".
 
I think the issue is with your choice of "discomfort" as the adjective
 
4:49 PM
I'd say that occasionally means precisely that there's nothing wrong with our general approach/scheme, but that there are specific instances where we can be a bit...overzealous
 
@tpg2114 What else is it?
 
This is wholly different from wanting to change any policy, or claiming a systemic failure, as PeterHorvath and bobie do
 
@Gaurav Just an observation? Recommendation? I don't know, I can't put words in his mouth (or his chat box as the case may be)
Not liking something is not equal to being uncomfortable with it
And there's plenty of things that I am uncomfortable with that I enjoy. I'm just saying I didn't (and still don't) reach the same conclusion you did
 
@ACuriousMind I remember bobie saying he is not against VTC but the abuse of it
 
It could also just be his personal philosophy in the sense "I am going to do what I can to be nicer to make it more welcoming, and I will recommend others do the same"
 
4:53 PM
@Gaurav Yes, but what they call abuse is actually conforming to policy.
 
@Gaurav He said it like 1000 times but never showed any actual evidence of abuse. His perception of the system is that it's abusive
@ACuriousMind I was actually thinking about that... so one of the claims he makes is that most of the times a question is closed as unclear and we say we can't understand the grammar, he can read it and see what the question is. So we're being unfair
Is it possible that for people whose first language isn't english, they miss potential ambiguities?
So something that is grammatically incorrect, they still only see 1 way to read it (which, if the asker is also not a native speaker may be the intended way)
But for native speakers, we struggle to figure out the meaning because we can see many ways to interpret it
 
Hm, my first language isn't English either, but I close plenty of these questions for being unclear
 
Maybe "first language" is too strong. Let's just say fluency?
 
Mainly because, even if I see a possible interpretation, I'm still not sure if that's what they really wanted to ask
 
A downvote seems harsh. I'm not sure why the question was posted in an "answer your own question" form, but a lot of effort has gone into it. Will downvoting and/or closing it really make the world a better place? — John Rennie 2 days ago
 
4:57 PM
@tpg2114 Okay, maybe you're right about the incorrect usage of 'discomfort'. I was never proficient at it. :)

@ACuriousMind & @tpg2114 So you say evidence is tantamount ?
 
@Gaurav Tantamount? I'm not sure what you are intending to say there
 
Whatever you think about this specific remark, Kyle Kanos was in "great form" yesterday.
 
For the record ...
If I think a question is lazy or careless I will instantly vote to close it and, if the opportunity presents, also set fire to the perpetrator's nasal hair.
But ...
We get new members who aren't familiar with the way we do things and sometimes ask questions that probably shouldn't be here.
In that case I may or may not vote to close, but I would at least try to leave a nice comment as encouragement.
 
..tantamount to proving the case that down votes to questions by new users is harmful for the site.
 
Taking quotes out of context is always good fun, but overall I'm happy with the way the site works.
I'm reluctant to downvote anyway, but I do agree that downvoting new users should be approached with caution. Look at:
0
Q: Why is beat described as a "relatively slow amplitude-modulation of oscillation"?

user36790Excerpts from A.P.French's Vibrations & Waves: . . . It may be seen that the combined displacement can be fitted within an envelope defined by the pair of equations$$ x = 2\mathit{A} \cos\dfrac{(\omega_1 - \omega_2).t}{2} \cdots (2-6)$$ because the rapidly oscillating factor i.e. $\mathit{A} ...

 
5:03 PM
@Gaurav Tantamount means "equivalent to" or "virtually the same as." So I'm not sure what you're asking -- your question as posed is "Is evidence [of abuse] virtually the same as to prove the case..."
 
The user (actually not a new user on this case) was clearly dismayed by a drive-by downvote, and in their place I'd probably feel the same.
 
I think perhaps you mean something like "required." As in "Evidence of abuse is required to prove..." but even then, I was referring to no evidence of abuse in the vote to close system (the only presented evidence was how quickly people voted in a few instances, which isn't really sufficient evidence to prove any abuse)
 
@tpg2114 exactly.
 
So I'm still confused -- your clarification was about "down votes to questions" being harmful but I was talking about evidence of VtC abuse
I don't think we're talking about the same thing
@JohnRennie I approach new users with some caution. I will still vote to close but try not to downvote unless it's also lazy. I don't foresee the ability to set nasal hair on fire any time soon, so downvoting is my close 2nd choice
 
@tpg2114 My previous few comments are poorly worded and thus don't make sense. The essence of my argument is that what evidence is sufficient to prove that there is indeed abuse.
 
5:08 PM
@Gaurav I'll know it when I see it. But just saying "It takes me 1 minute at least to review a question and these guys are reviewing questions in 20 seconds" is not it.
Of course, somebody could go and compute some statistical model of voting patterns and when the p-value is < 0.05 call it a significant finding of abuse and then it might be evidence. But it turns out the SE system already has algorithms in place to capture and undo those kinds of things
 
@tpg2114 Yes, and the same "I'll know it when I see it" argument is made by those who think that down votes to questions by new users drives them away.
 
@Gaurav Sure, and I don't buy it there either.
At no point have I said those people are wrong. Just that they haven't proved they are right
@Qmechanic Funny you popped in... is there some maintenance going on right now or something?
My messages keep trying to send twice. And then I was magically given access to the offensive/spam chat flags for a few minutes there
 
@Gaurav What possible motive could there be for 3k users to deliberately and systematically downvote or VTC? None of us are paid to be here, we're here because we're willing to spend our own time helping other people for free.
 
@tpg2114 But I thought you agreed with Rennie when he said
"It's just occasionally that I think we can appear a bit fierce."
 
@Gaurav Sure. But that doesn't mean we lose/gain membership because of it
There's no evidence anybody can point to one way or the other
 
5:13 PM
@tpg2114 : No maintenance that I know of.
 
@Qmechanic Okay. Well my access to the flags disappeared almost as quickly as it came.
 
@tpg2114 You do think it's unfair don't you? So you're essentially on my side. (?)
 
Although it is still trying to send all my messages twice
 
@Gaurav is that aimed at me?
 
@Gaurav Unfair that we seem fierce? Not really.
I actually don't have any idea what side you're arguing actually
 
5:15 PM
@tpg2114 the, um, flags disappeared also as quickly as they came
Sure that having >10k overall doesn't grant you access to them, anyway?
 
Jim
@JohnRennie It's exactly for that reason why I do less moderating tasks than some of the others (except flagging new answers to old questions, that's fun) and why I only answer a few questions that I really enjoy. I imagine it's also the reason that you answer 1 out of every 3 questions posed and why you do practically no moderating compared to equally active users
 
@ACuriousMind Nope, it doesn't (at least it never did before about 1 minute ago)
 
Jim
Not that there are other users as active as you, John
 
@Qmechanic is doing some chat room calisthenics... jumping in and out all the time
 
@Jim I'm semi retired and have time to kill. Most of the other high rep users have to work for a living :-)
@tpg2114 He's in a superposition, but someone keeps observing him
 
5:18 PM
Haha, I like that one
 
@JohnRennie : Ha-ha. Yes, in fact I wanted to leave, but I keep getting notified of unread replies in the hbar. Maybe the software glitch @tpg2114 is talking about...
 
user54412
@tpg2114 Well, chat flags are extremely rare. But I suppose if 10k overall were sufficient, then 200 rep + joining every site on the network would give that privilege
 
@ChrisWhite I have a new goal...
 
@tpg2114 I'm arguing (not actually) that it is indeed unfair to down vote a newbie's question.

@JohnRennie That's a good one.
 
@Gaurav In that case, no, I don't think it's unfair to downvote them. I think it's very unfair a person new to the site makes no effort to read our help pages about how to ask good, on-topic questions.
But just because it's fair to downvote them, doesn't mean it's always a great idea to do it.
 
5:21 PM
@Gaurav don't confuse unfair with unkind
 
Jim
@Qmechanic *Unread reply that drew you back to hbar*
 
@Qmechanic There's definitely something going on. This is kind of Twilight Zone-y chat room today
 
@Jim : Ha-ha. Don't test me!
 
So if it's unkind, there are many users who do down vote such questions. Is it not possible to control it?
 
Jim
@ChrisWhite I think the rep from other sites only counts towards your chat total once it's at least 200 on that site. I have several account on other sites but only one other has above 200 and my chat rep seems to only be a sum of physics and that site
 
5:23 PM
@Gaurav In fact, the site policies (for better or worse) say that regardless of who asked a question or posted an answer, if it's bad it should be downvoted into oblivion. The mouse-over for the downvote button tells you as much
 
@Gaurav Being unkind isn't against the site rules. It's just bad karma. In any case I think you're exaggerating the problem.
 
Jim
@Qmechanic *this is not a test*
 
@Jim : I guess I had that one coming.
 
Jim
@Jim * this is your brain. Stop being stupid!*
 
I agree with @JohnRennie on that one. Not every "problem" is something that needs immediate remedy. The way SE sites are set up work. We know they work because they're so damn successful. We know they work because we're here in a room talking to total strangers about the intricacies of the system, because we want it to keep working
 
Jim
5:26 PM
@tpg2114 I like to think it's because we really like the strangers
 
@Jim But that would mean we're not all downvoting, closing, argumentative jerks :)
 
@tpg2114 So you're saying it's unfair but nothing can be done about it. Fair enough.
 
Jim
@tpg2114 We aren't all that. Only some of us. There's got to be at least one that isn't one of those
 
@Gaurav When have I said in any of this that I think the SE system is unfair?
I've said quite the opposite
 
@Gaurav Are people never rude to you in real life? It happens - get over it. I think it happens less in the Stack Exchange system than on Internet forums in general. A lot less in fact.
 
5:29 PM
It's very fair. If you want to participate, be respected, and have influence over the community, you must be part of the community. Know how it works, be supportive of it, etc..
@JohnRennie I think it's also a perception problem. I don't think of downvotes on my questions/answers as rude, nor do I think of them being closed as rude. On the contrary, I see them as "Oh crap, I messed up and said something inaccurate or was being stupid" or "Oh crap, I didn't look closely enough at what is good to ask"
2
So I don't get offended when they happen to me, I feel bad that I didn't do a better job
 
@tpg2114 If someone downvotes me and leaves a comment saying "you got this bit wrong" then that's fine. It happens to me more than you might think - it's just that I hurriedly delete the offending answer :-)
But I have to say I really don't like drive-by downvotes
 
@JohnRennie I very quickly delete mine too :)
 
@tpg2114 Okay, let's agree to disagree and end it at there. I'm against unfair down votes while you aren't.
 
@Gaurav That's a very pointed way to say it that isn't representative of the discussion. But it really isn't worth arguing about that either.
 
@tpg2114 Okay, I agree with that. I wasn't trying to insult you, it's just that I've not fully understood your argument. Anyways, it's a long thread, and good time pass, thanks for that. Bye.
 
5:42 PM
@Gaurav No insult taken, don't worry.
 
I think the root of my concern with the unfair down votes lies elsewhere, I'll talk about that later.
 
6:20 PM
@tpg2114 Exactly. One of the aspects of being a scientist (and for that matter of being an adult) is being able to take on board evidence or suggestions that you may have been wrong, process it and respond.
The thin channel of internet sites makes this a little harder, of course, but it is still expected of us all.
 
@dmckee Only because the internet makes it so much easier to be a jerk with no consequences.
 
Of course no one likes drive-by down votes, so the proper and polite thing to do is explain the deficiency you see. Diplomatically to help compensate for the thin channel and the internet-jerk effect.
 
I often wonder if the people who are so argumentative online are just as argumentative in person
 
@tpg2114 Of those that I've known in both realms (a small sample), its a mixed a bag.
Some are just jerks full-time, and the others seem to be taking out the frustration the accept in person on their e-correspondents.
 
It still all goes back to the conversation we were having in here yesterday about social skills.
 
6:26 PM
I so wanted to join in that. Only I didn't get there until hours later.
 
Sometimes, even if you are right, it's just not always worth arguing :) Anybody who has spent any time in a long-term relationship with somebody else would understand that one
It was actually one of the more interesting discussions I think we've had in here
 
I've known work groups to handle a colleague with really bad social skills by protecting him against the buffeting of the crazy world. But he had the befuddled rather than belligerent kind of bad-social-skills.
@tpg2114 I've also know collaboration to knowingly accept a jerk because he could herd scientific cats.
 
Yeah, how to handle people who get easily overwhelmed/intimidated/etc is very different from how to handle people who are belligerent. But to the point I was making before, it takes groups with good social skills to identify and manage people who lack the same skills
 
@tpg2114 Yep.
 
vzn
hi all the talk re psychology/ social reminds me of emotional intelligence. also called "ppl skills" ages ago when went thru college myself... very similar speech by the engr dean mirroring some of the dialog here. eg re graduates that get high grades but dont work well on teams.
 
6:37 PM
I've been tar babied again :-)
1
Q: Do electromagnetic fields are already present all over the space?

SubhraA general solution for electromagnetic wave equation is as follows: $$ E=E_0 \sin (kx-\omega t) $$ $$ B=B_0 \sin (kx-\omega t) $$ Then at time t = 0 at any distance x the values of E and B are not zero except at the nodal points. To me this means Either the electromagnetic fields are alrea...

 
vzn
another topic, see there is a lot of simulation experts around... does anyone here ever do physical experiments?
 
@JohnRennie Downside of not being fierce enough ;)
 
@tpg2114 :-)))))
 
@vzn I work closely with experimentalists to generate data for comparisons with simulations
 
vzn
yep saw your profile. interesting. "turbulent combustion"? do you (like KK) use a supercomputer?
 
user54412
6:40 PM
@vzn I don't, but a number of people in my department dabble in them. That's right: controlled laboratory astrophysics ;)
 
vzn
sorry oops got you 2 mixed up
 
user54412
who was that directed toward?
 
@vzn Yeah -- so I've worked on ground-based power generation systems for Siemens, a scramjet engine for the Air Force, and now I'm actually working on condensed phase explosives (multi-scale simulations integrating experimental data and molecular dynamics)
And I have access to many supercomputers, mostly at the DoD and NASA
 
vzn
condensed phase explosives is that DoD?
 
I get access to some national labs once in awhile to do some testing there but don't use them for actual research
 
vzn
6:42 PM
weaponry?
 
My funding now is from the Office of Naval Research
 
vzn
CW were you talking about supercomputers or physical experiments?
 
Looking at multiscale techniques to evaluate replacements for traditional energetics. They are used for bombs, but also for solid rocket motors
 
vzn
tpg "testing" sounds pretty similar to research....
 
user54412
@tpg2114 do you have a general sense of whether it's easier to get time via national labs vs. DoD?
 
6:43 PM
And used in the civil world for mining, blast forming, etc. Some of the explosives are actually used in medicines also (PETN and nitroglycerin are vascodialators)
@ChrisWhite DoD is much easier to get time
@vzn No, it's scalability or evaluating new hardware
basically making sure our code works on whatever crazy new interconnect Cray comes up with
 
user54412
@vzn I use computers. Some others do physical experiments, which usually consist of some sort of plasma in a box doing... plama-y things I guess
 
vzn
yeah its probably pretty hard making sure the nodes are utilized efficiently
 
@ChrisWhite The DoD actually runs what they call "open" clusters where you don't have to be on a DoD funded project for access
 
vzn
CW high energy experiments?
but the open clusters are typically used by academia/ university prjs?
 
@vzn I run on all the unclassified machines here: centers.hpc.mil/systems/unclassified.html
@vzn Yes. A "regular" person couldn't get time on a supercomputer
 
vzn
6:46 PM
got to bang on a cray many yrs ago.
 
My lab also has 3 in-house clusters
With a total of 6000 cores
 
user54412
@vzn Sort of. I guess some experimental astrophysics is concerned with fusion (we need networks of reactions to plug into stellar models). Other experiments measure opacities of various gases. But also just studying (magneto)hydrodynamics is useful. It's very hard to do in the lab, since real astrophysical plasmas have Reynolds numbers of millions.
 
@ChrisWhite Which Reynolds number? The hydrodynamic one, or the magnetic one (or the turbulent one or...)?
 
user54412
@tpg2114 Yes.
 
Good answer :)
We do some MHD work in our lab (I say we, but it's only 1 guy)
He's been doing RMI studies under various magnetic fields
 
user54412
6:49 PM
RMI?
 
Oh yeah, I think I sent you his proposal before
The Richtmyer–Meshkov instability (RMI) occurs when two fluids of different density are accelerated. Normally this is by the passage of a shock wave. The development of the instability begins with small amplitude perturbations which initially grow linearly with time. This is followed by a nonlinear regime with bubbles appearing in the case of a light fluid penetrating a heavy fluid, and with spikes appearing in the case of a heavy fluid penetrating a light fluid. A chaotic regime eventually is reached and the two fluids mix. This instability can be considered the impulsive-acceleration limit of...
 
user54412
ohh -- I suck at acronyms
 
user54412
I was just having a detailed conversation with my adviser about that today too
 
Yeah, I know you knew it
It's an interesting problem
 
vzn
its like a big lava lamp lol
 
6:52 PM
@vzn That's actually a Rayleigh-Taylor instability
The Rayleigh–Taylor instability, or RT instability (after Lord Rayleigh and G. I. Taylor), is an instability of an interface between two fluids of different densities which occurs when the lighter fluid is pushing the heavier fluid. Examples include supernova explosions in which expanding core gas is accelerated into denser shell gas, instabilities in plasma fusion reactors, and the common terrestrial example of a denser fluid such as water suspended above a lighter fluid such as oil in the Earth's gravitational field. To model the last example, consider two completely plane-parallel layers of...
 
user54412
Yeah, they're sorta different names for the same thing, but sorta different.
 
vzn
hah no kidding ok. have a bunch of lava lamps luv em :)
 
Or a Rayleigh-Bernard:
Rayleigh–Bénard convection is a type of natural convection, occurring in a plane horizontal layer of fluid heated from below, in which the fluid develops a regular pattern of convection cells known as Bénard cells. Rayleigh–Bénard convection is one of the most commonly studied convection phenomena because of its analytical and experimental accessibility. The convection patterns are the most carefully examined example of self-organizing nonlinear systems. Buoyancy, and hence gravity, is responsible for the appearance of convection cells. The initial movement is the upwelling of lesser density fluid...
 
user54412
Number 1 rule of fluid instabilities: must be named after 2 people, separated by a hyphen.
6
 
RMI is impulsively started while RTI is buoyancy related
 
vzn
6:56 PM
tpg you say in profile you use massively parallel algorithms do you use a msging library for that?
 
MPI
 
vzn
once used that on a beowulf linux cluster. yrs ago. dotcom...
 
Yeah, it works the same on homogeneous clusters
I've played with shared memory on the Cray systems, but it's architecture specific
 
vzn
so is cray still building machines? they had a "near death experience" yrs ago...
 
Yes, but it's far less specific than it used to be
They've moved away from their own version of Linux, away from their own hardware, etc
They are more a support vendor now
 
vzn
7:06 PM
support vendor for clusters?
there are a lot of crays on that page you list.
are they older?
heard that supercomputers do not have very long lifetimes....
 
No, they are all relatively new
They get rebuilt or commissioned every two years or so
Cray is kinda like Red Hat -- they provide packages of software and setup/design the cluster
They still have their Compute Node Linux that is (supposedly) optimized
But it's a pain in the ass
 
@ChrisWhite: Thoughts on the Illinois GRMHD code?
 
vzn
commissioned? like passed back to vendor or something?
 
Commissioned meaning "built from scratch"
For instance, Garnet has been around for like 6 years. But they keep replacing nodes or merging new machines into it
As opposed to Kilrain, which was brand new and so "commissioned" not long ago
Spirit has been around for awhile too, but that just got a complete overhaul recently
 
vzn
china seems to be very aggressive in this space also (supercomps) last few yrs.
its too bad it seems hard to read lists of prjs running on the machines, it would be very interesting.
am interested in clusters esp wrt emerging/ developing deep learning field...
 
7:13 PM
@vzn If you are on the machines it's kinda easy to figure out what people are doing
If you look at the jobs in the queues, it's pretty easy to figure out what they are simulating. Either from the job name or the folder name.
 
vzn
yeah. interested in higher level descriptions. scientific papers/ proposals etc.
overview(s) / survey(s)...
awhile back was just reading a mods blog on his move to china. quite an adventure.
(DavidZ)
 
Ever heard of Cray Chapel?
 
vzn
? nope
 
user54412
7:39 PM
@KyleKanos My adviser and I had a good long discussion on it today. I haven't seen the code itself yet, but I've read the paper.
 
user54412
One thing we both noticed conspicuously missing was absolute performance -- all they ever give is relative performance to a couple other codes.
 
user54412
Also, we're not even going to attempt dynamical spacetimes (not before I finish my thesis anyway), but when it comes to stationary spacetimes I think Athena++ can do better MHD (on the Riemann solver end).
 
@vzn am an experimentalist
 
vzn
cool
 
@ChrisWhite It seems to be based on the Einstein Toolkit frame work, which is based on Carpet
 
7:51 PM
well, that was odd
 
I have yet to find Carpet very, um, easy to follow
 
user54412
@KyleKanos And it's not the only GRMHD code based on ET. It's quite an industry these days.
 
user54412
I really want to see "before" and "after" versions of the code, to see how they fixed the lack of "sufficient documentation and code comments, fine-grained modularity, a consistent coding style, and regular, enforced code maintenance"
 
And you probably won't because the previous edition is closed source
What kinda bothers me about GRMHD code papers I see is that they only show results for 1D (as far as I can recollect, I'm sure someone's shown a 2D solution)
 
vzn
re GRMHD think/ suggest they should use an open source repo like sourceforge or github, there seems to be no ref & its stored at their own servers. (re open science)
 
user54412
8:01 PM
@KyleKanos The Harm paper has a couple 2D results. The real problem is there is no analytic solution to anything beyond 1D.
 
@vzn I'm an experimenter by training. Though I'm at a teaching college now, and so have limited access to lab facilities and assistance.
Still I have a couple of students working on a cool demo project this semester. It will show up in one of my answers when we have data to display and the paper is on its way.
 
user54412
@vzn My group uses github, but we don't release everything publicly at first. For example, if my particular new code were freely available, other groups could use it to get the low-hanging science fruit, and I wouldn't get a degree.
 
vzn
dmc neat/ great to see all the applied bkg in this room/ site & its not so obvious at times looking at the profiles. a "hidden variable" so to speak ;)
 
@ChrisWhite Aha. Thanks for that. I do have the HARM code too, actually. Not sure why, but I presume it was for S&Gs
 
vzn
CW that seems a surprising sentiment. somewhat dubious of that. but maybe there is a way to separate out the sensitive IP into separate scripts/ configurations or something etc.
 
8:10 PM
@vzn In computational hydro/MHD work, semi-open source is really the norm
The code I use is GPL'd, but you have to request it from the dev team
There are a few good HD/MHD codes out there that are immediately usable and freely available
(Athena is one of them, ramses is not)
A lot more codes are in-house only and not shared at all
 
user54412
We definitely want full open-source eventually. But money (and PhD's!) are given for science results, not codes, so without some exclusivity rights the several years of code development risk becoming charity that is repayed with unemployment.
 
^ That
 
user54412
Our code is actually modular enough to make rolling releases easy: We'll release Newtonian hydro/MHD first (soon? no promises), then GR and radiation, then GR-radiation, then particles, etc...
 
And all the while, let other people build off your (original) work
 
8:27 PM
-1
A: How many colors exist?

chrisscrew you all. life is a consipracy

^wat
 
^ Ooooooookay.
 
Some people have problems
 
 
2 hours later…
10:17 PM
@dmckee yeah, right...
@alarge I see you have change your avatar, at first, I didn't notice you...
@alarge did u see my two site Hamiltonian?
is there a way to have private chatrooms?
12
Nanoscience and Nanotechnology

Proposed Q&A site for students, professors, and researchers to ask questions about nano-science and nanotechnology

Currently in definition.

@MarkMitchison u there?
@MarkMitchison what do u think about what I have done.. have u seen my two site Hamiltonian?
 
10:42 PM
@TAbraham no
 
@DavidZ I hear mods can do so?
 
Well, yes, we can, but only for moderation purposes.
 
@DavidZ that's sad.. why?
 
Because everything on SE is supposed to be public, except for sensitive information related to moderation. The whole purpose of the network is helping the internet at large, and private chats don't contribute to that.
 
@DavidZ but if I want to talk something private with somebody else, I can't? how sad..
 
10:45 PM
@TAbraham This is not intended as a social network :P
 
@vzn let's talk in toy models of qm ;)
 
@TAbraham no you can't, not on Stack Exchange. Go somewhere else if that's what you want
 
@DavidZ fine..
 
vzn
CW/KK, it may be the "folklore" that open source messes up scientific credit, but there is probably little solid evidence of that. think its virtually an urban myth. unf there are not good established policies on scientific source code re "open science". some ideas on all that see reinventing discovery/ networked science by nielsen
 
@vzn who's CW and KK ?
 
vzn
10:49 PM
regulars dude :p
 
@vzn their names?
 
vzn
dude youve probably chatted with both. chris white / kyle kanos
TA so what are you studying right now in school?
 
11:03 PM
@vzn oh yeah...
@vzn math, biology, and chemistry and some others...
@vzn we should talk in toy models...
sad that the chatroom is so empty...
I wish I could talk to @alarge right now...
anything u want to talk about @ACuriousMind or @dmckee ?
 
Nah, I'm good
 
@DavidZ no, I have noticed that some people (don't want to mention names) avoid me...
@ACuriousMind want to talk abot qm biology? u know about memristors?
@ACuriousMind sorry if I'm bothering you...
 
Well, I'm pretty busy right now, so if someone else wants to make good on my promise to sort out the relationship between beam momentum and probed scale I'd be really happy.
 
@dmckee wait, what?
 
@dmckee That's...a good question, actually
Somehow, it has never bothered me that the uncertainty principle is not about the actual size of the momentum
 
11:11 PM
helllllllllllllo
 
@usukidoll hello?
 
hi.. greetings
do you know how to nondimensionalize an equation?
 
@usukidoll oh, you're from biology chatroom...
 
umm how u know?
 
@usukidoll I'm a member of the biology stack exchange...
 
11:13 PM
oh ^_^ yeah I posted the question from last night
I sort of get it but ......... wow why is t* = I/P instead of what the book said which is scale time by 1/I?! -_-
 
@ACuriousMind And I'm convinced that I knew the answer and that it's not really that complicated, but I can't bring the reasoning to mind and my copy of Leo got lent out and never returned and ...
 
@usukidoll sorry, don't know...
 
hmmmmmm
that's ok
it seems that depending on the problem it's more or less obvious
like the other problem with the days and animals... that was easy
 
I see @Qmechanic is here... hey @Qmechanic ! want to talk QM?
@usukidoll seems like a math problem, not physics...
 
I know it is
it's Mathematical Biology
 
11:27 PM
@usukidoll yep...
 
but when I searched about it online, I was given bad results so it's kind of frustrating
and my book only features a few pages per section
 
@usukidoll what's the problem about?
 
1
Q: What is the process of nondemensionalizing an equation?

usukidollQuestion: I need to scale time by $\frac{1}{I}$ and species by $P$ for the following equation $\frac{dS}{dt}=I(1-\frac{S}{P})-\frac{ES}{P}$ where P - Size of the source pool of species on the mainland S - number of species on the island E - Extinction Rate for species I - Immigration Rate...

 
@usukidoll whoa, differential equations in biology... that sounds interesting, only if I studied differential equations...
@dmckee u into QM?
 
this is just about matching units though
and making it dimensionless.. nothing to do with finding the first order ode
even though I already know how to do it and know the answer :P
but the dimensionless part...I'm a noob :(
though my prof told me that the entire equation has to match.. like for that problem it's species/time
 
11:31 PM
since nobody's available to talk with, bye!
 
I almost have the answer in that question but apparently 1/I is a poor choice and I could cancel out had I chose I/P for t star... why though because that's time/species
 
@TAbraham You never wrote it out explicitly. I appreciate your enthusiasm, but I am not going to take you step by step through the derivation. Mark Mitchison in particular already gave you a lot of references to look at, and I too suggested some topics you should review. I can't do the reading for you. Once you think you have the two-site Hamiltonian, and have at least attempted to solve the Schrödinger eq, then I'm sure there will be lots of people happy to help you.
 
-.-
 
@alarge u available.. then let's talk...
@alarge I wrote the first term out...
 
@TAbraham I'm actually doing something else at the moment. I told you earlier that you can ping me with your questions and that I'd get back to you later.
 
11:35 PM
@alarge then join that room and I'll ping you there... I need a more systematic way of talking with you, this asynchronous communication thingy is not working for me...
 
@TAbraham Right. So you've spent one week figuring out what $\sum_{i \neq j}$ means. If you had read any of the references I'd given to you (Ising model etc.), you would've seen this explained on the first page.
 
@alarge what?
@alarge you know, people have lives.. I don't spend every hour of my life to figure out what it means...
@alarge i searched up heisenberg model and briefly looked at ising model..ok fine.. I'll look at it again.. just please join that room...
 

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