The h Bar

0celo7

13:00

@JohnRennie ok, I probably seem really paranoid, but cut me some slack please

John Rennie

Overclocking is all good fun as a way of passing the time, but I'm not sure it's worth it. You're going to get small improvements at best, and from what you've said the CPU hasn't been maxing out anyway.

0celo7

there are LEDs on the mobo that are now off

wonder why they were on in the first place

John Rennie

@0celo7 which LEDs?

What does the mobo manual say about them?

0celo7

reading right now.

it was right above the CPU socket

not the EZ debug lights

nothing in the manual

@JohnRennie I restarted and it came back on.

John Rennie

You could ask on the MSI forums I suppose. Or you could just ignore it, which is what I'd do :-)

Is there anything written on the mobo by the LED?

@0celo7 does this look relevant?

0celo7

13:08

@JohnRennie there are three LEDs

also there's one under the GPU that is constantly on

I'm only curious because it turned off over night

John Rennie

If MSI can't even be bothered to document what the LEDs are for I wouldn't be too worried about them.

0celo7

ok

0celo7

13:30

@ACuriousMind is it not a little suspicious that Ciri was able to just kill two of the crones?

Why couldn't Geralt kill them in the swamp?

ACuriousMind

@0celo7 Although her fight don't show it that much, Ciri is much more powerful than Geralt could ever be.

(Also, it's not really clear to me whether they are dead, or just their corporeal form destroyed, possibly only temporarily)

0celo7

@ACuriousMind Much more powerful? Why didn't she fight the Hunt general?

I thought she couldn't control her powers at this point

ACuriousMind

@0celo7 Well, the setup was kinda made so that both had to happen simultaneously - fighting one before the other would have warned the other.

So Geralt and Ciri each had to fight one

@0celo7 She can't control all of them, but she has some measure of control - Avallach taught her, after all.

0celo7

@ACuriousMind But the general (can't remember his name exactly) said he was expecting them

Well, expecting Geralt at least

ACuriousMind

@0celo7 Imlerith, and yeah, I didn't quite understand why he'd expact them. IF they were expected, splitting up to fight him and the Crones separately doesn't make much sense to me

0celo7

13:47

I was thinking Irileth but that's Balgruuf's housecarl :p

@ACuriousMind he said the Crones saw it in the water

ACuriousMind

@0celo7 Ah, well, that doesn't undercut my reason for why G&C split up - they couldn't know the Crones could prophezise that, and hence wanted to maintain the surprise

0celo7

@ACuriousMind I'm not disagreeing. But wasn't Imlerith the stronger foe?

ACuriousMind

@0celo7 I don't think so. The Crones were a set of ancient spirits that had controlled Velen for centuries. Imlerith was "just" an elf, albeit a powerful one.

0celo7

Yeah, wtf is with the Hunt being just elves

Latest plot twist ever

ACuriousMind

@0celo7 Not...actually a twist, since Geralt actually knows that from the beginning of the game (it's written in the character entry for Eredin or in the glossary for the Wild Hunt, I think)

0celo7

13:58

@ACuriousMind I know, I read the glossary.

BUT the opening cinematic calls them wraiths

Everyone calls them wraiths

ACuriousMind

Yeah, because most people have no idea the Aen Elle exist

0celo7

No spoilers pls. I just got back from the Aen Elle world for the first time (maybe I go back, just clarifying if that's the case)

Physics Meta

14:14

0

Q: View counter: which is correct?

I noticed one of my questions has a different view count from the main Physics.SE homepage? Which view count is correct? The one displayed in the question itself or the one on the homepage? For e.g. the question in question (nice!) says 2K views on the homepage and 1,544 views when you open the...

0celo7

@ACuriousMind so what's with the symbolism?

Why do these super advanced elves wear creepy ghost armor?

ACuriousMind

@0celo7 I'm not sure whether it is ever explained, but I think they're wearing them for the effect it has on their opponents - they know that it looks creepy and will make at least some run away in fear of "wraiths"

Kiarash

hey guys

does anybody offer me a good reference on Fock space?

ACuriousMind

14:32

@Kiarash I'm not sure there are references specifically for Fock spaces, but at least some of the books on QFT and/or condensed matter will certainly explain them. Is there something specific you want to know about them?

Kiarash

@ACuriousMind please take a look at the topics of this book (which has not yet released): worldscientific.com/worldscibooks/10.1142/10367

I have almost the same thing in mind

and this article: math.univ-lyon1.fr/~attal/Fock_Spaces.pdf

but it's not comprehensive

ACuriousMind

Ah, I see

0celo7

@JohnRennie So...I'm gonna have money again in a week. SSD or second monitor?

Or should I chill

Kiarash

@ACuriousMind do you something in mind?

Sid

14:57

@0celo7 If you have money again, you should save them.

0celo7

@Sid I think that would depend on how much money

Jaime Gallego

Buy an SSD and install Arch in it

Sid

Well, saving money isn't a bad thing...

0celo7

15:15

@Sid I could save 2/3 of the money and still have enough for an SSD. Maybe a monitor too

Depends on the monitor too

Sid

You could save all the money and buy your thing later when its price falls.

0celo7

@JaimeGallego Bernardus was saying I should get one of those SSDs that plug directly into the mobo

Jaime Gallego

The PCI Express ones, yeah

0celo7

@Sid Wha? It's not something you want to wait. I'd have to move the OS

That probably gets harder the longer I use the PC

If the PC dies now it's not a tragedy

If something catastrophic happens to the current hard drive, that is.

@JaimeGallego Uh, no

M2 or something

My small mobo only has one of the large PCI slots. I have a small one free, but it's right by the GPU, would block cooling.

Jaime Gallego

¯\_(ツ)_/¯

0celo7

15:23

amazon.com/Samsung-850-EVO-Internal-MZ-N5E250BW/dp/…

I'm assuming you just stick it in there...

@JaimeGallego a nice 500GB SSD...

Imagine the power

John Rennie

An SSD makes a huge difference to the speed of the PC.

Jaime Gallego

250 GB SSD + HDD is sufficient. You would regret spending extra for a 500 GB one.

0celo7

It's only $80 more. Why wouldn't I get it?

John Rennie

@JaimeGallego Remember modern games are big.

0celo7

@JohnRennie I have a very fast SSD in my laptop

I notice the difference

John Rennie

15:29

A 256GB SSD is going to fill up pretty fast.

Jaime Gallego

Ah yeah, the games

0celo7

I think I am using ~800GB on my current HDD.

My laptop has around 900GB

John Rennie

@0celo7 I wouldn't build a PC without an SSD these days. It makes such a big difference to the speed that it's always worth it.

All the computers I use (even my servers) have SSDs.

0celo7

@JohnRennie Are you telling me I should get it sooner than later?

ACuriousMind

@JohnRennie I keep only my OS on the SSD and the games on the HDD, I don't think it's necessary to have the games on the SSD. It might improve startup times but the disk is generally not the bottleneck.

0celo7

15:30

Is OS swapping feasible?

Jaime Gallego

Still, I only have four demanding games or so which benefit from being installed on the SSD.

Sid

@0celo7 Swap to what?

Jaime Gallego

Dual-booting?

0celo7

@Sid Read the conversation

John Rennie

If you're going to fit an SSD you really need to wipe the PC and start afresh.

0celo7

15:31

wtf

I was told you can swap

Jaime Gallego

What do you mean?

0celo7

what do you think I mean?

Jaime Gallego

Choosing to load one OS or another.

0celo7

No, why would I do that?

Why can't I just put everything from my hard drive onto the SSD, then boot from the SSD and make it the primary drive?

Jaime Gallego

Hmmm

Copying files is easy, but an OS is not just copy-and-paste.

I assume you would have to unplug the HDD prior to the installation of the SSD.

Because of the Windows license

Back up the files and uninstall Windows on one, then install it on the SSD and copy the backup.

Jaime Gallego

15:58

@0celo7 Yeah, as I am reading, it would be fine with both drives connected as long as you don't have Windows installed on both.

0celo7

16:12

@JaimeGallego Who are these people on r/PCMR who use 144Hz monitors?

I have one of the best GPUs out there and get nowhere close to that

Jaime Gallego

Partly bragging rights, partly because games like Counter-Strike are much more lightweight.

So you can push them to 200 frames or more

0celo7

My laptop has a 120Hz screen, I think. I played Morrowind for a while and got 120fps. It was something.

@JohnRennie I might buy an SSD right now if I can figure out the OS thing. Are you sure I have to uninstall Windows first? I spent a lot of time downloading shit on the current PC.

I will lose literally days of downloading time if I have to delete everything.

John Rennie

It might be possible to get windows transferred to the new disk, but you risk ending up with an unstable system, and Windows is rickety enough at the best of times. If you want a stable reliable PC the best way to achieve this is get the installation perfect from the start.

Jaime Gallego

^

0celo7

I guess I won't get an SSD then

Wonderful

John Rennie

16:18

The effort you put in doing a full new installation now will repay you over the years you'll be using the PC.

0celo7

No, I just lost a week of work if I have to delete everything.

John Rennie

If you're happy with the startup and game loading speeds then the simplest solution is not to bother with an SSD.

0celo7

I'm not happy, but I'm even less happy that I was led to believe this would be an easy thing.

ACuriousMind

Who led you to believe that?

Jun 25 at 19:45, by Jaime Gallego

Do not wait for an upgrade to buy an SSD. It's a bitch to uninstall the OS on one disk and reinstall it on the other.

0celo7

Key word "uninstall."

We are now not talking about an uninstall, but a complete delete.

Anonymous

16:22

@JohnRennie In classical mechanics friction can't be classified as an applied force as it does not satify the condition $$\begin{align}
\sum_i \mathbf F_i^{(a)} \cdot \delta\mathbf r_i = 0
\end{align}$$. Am I right or missing something?

ACuriousMind

We are?

I think there's some miscommunication going on here, then.

0celo7

To install my copy of Windows on a new hard drive, it has to be removed from the old one, no?

ACuriousMind

@Blue Uh...what are the $F_i$ and $\delta r_i$ there, and what is your definition of "applied force"?

John Rennie

@0celo7 you can leave the Windows files on the old disk. They won't do any harm - just take up space.

0celo7

@JohnRennie What about programs like Mathematica, Matlab, etc. that I had to get licenses for?

John Rennie

16:25

@0celo7 They will need to be reinstalled and relicensed.

0celo7

Fucking hell

Anonymous

Anonymous

@ACuriousMind As in here ^

John Rennie

In your place I would leave things as they are for now, let my bank balance recover then revisit the disk swap in a year or so.

0celo7

@JohnRennie My bank balance is fine

In a year it will be an even bigger pain in the ass

John Rennie

16:27

Anything could happen. You might decide you don't like the new PC or you might decide to get a faster CPU or video card.

In a years time SSDs will be cheaper, and bigger.

Getting a 1TB SSD will allow you to put all the games on the SSD, but right now 1TB SSDs are pretty expensive.

Jaime Gallego

Ryan is right on that point, though. The more time, the more effort needed for a full migration.

John Rennie

Or, if you eventually get an SSD bigger than your current hard disk you can simply clone the existing disk onto the SSD. It's easy to clone a disk to a bigger disk but much harder to clone it to a smaller disk.

Anonymous

@ACuriousMind Any idea?

ACuriousMind

@Blue I'm not sure what your question is - the paragraph explicitly says that the principle of (zero) virtual work does not hold for sliding friction. What's the question about that?

0celo7

"let $f\in C_0^\infty(K)$, where $K$ is a compact subset of $\Bbb R^n$"

What does that even mean

Anonymous

16:35

@ACuriousMind Yes, so it that the only reason that friction cannot be classified as an applied force? What about other kinds of friction other than sliding friction?

ACuriousMind

@Blue I'm not sure what it means to "classify a force as an applied force" - if your definition of "applied force" is that the principle of virtual works holds for it, then sliding friction obviously is not an applied force, but I don't know what your definition of "applied force" is.

And yet, the principle holds for rolling friction (as the text you quoted say explicitly) and for static friction (for the same reason it holds for rolling friction).

Danu

@0celo7 Probably vanishing on the boundary?

0celo7

@Danu I think it's $\{f\in C_0^\infty(\Bbb R^n):\mathrm{supp}(f)\subset K\}$. Now, that could be a $\subsetneq$...not sure. It's the boundary I'm worried about, yeah.

Danu

Vanishing at the boundary is the obvious way to make sense out of things to me

John Rennie

16:50

@Blue friction is a non-conservative force.

Emilio Pisanty

@JohnRennie how much cheaper and how much bigger, d'you reckon?

John Rennie

It converts work into heat in an irreversible way, so you can't integrate frictional forces and expect to get a potential energy.

@EmilioPisanty No idea. 1TB SSDs are pretty routine these days, though expensive in the UK thanks to the fall in the pound (thanks BREXIT), so in a years time I'd guess 2TB SSDs will have descended from their current stratospheric pricing.

Anonymous

@JohnRennie Ah, makes sense :)

Anonymous

@ACuriousMind Thanks. I think I got it now!

Emilio Pisanty

@JohnRennie goodness, yes, that 1TB to 2TB price increase is quite remarkable

John Rennie

16:54

I keep hearing rumours of new memory technologies that will reduce SSD prices, though I haven't seen anything concrete yet.

Jaime Gallego

3D NAND sounds promising

Emilio Pisanty

@JohnRennie and c'mon, it's not that bad, at least in the formal conversion

xe.com/currencycharts/?from=GBP&to=EUR&view=2Y

you could even argue that brexit marked the end of a fairly steep consistent decline and led to a reasonable stabilization

John Rennie

@EmilioPisanty How would you like it if all the tech you wanted to buy was suddenly 20% more expensive?

Emilio Pisanty

@JohnRennie that bad, huh

it's hard to gauge how bad the on-the-ground stuff is doing from abroad

John Rennie

@EmilioPisanty I haven't done a rigorous study, but it feels as though things have gone up a lot more than 20%. 256GB SSDs were approaching £50 before Brexit and they are approaching £80 now.

Emilio Pisanty

16:59

@JohnRennie =/

John Rennie

Possibly my memory is misleading me on this, but they have certainly shot up a lot.

0celo7

Brexit is the gift that keeps on giving

John Rennie

There you go. That's an order I placed just before Brexit.

Emilio Pisanty

@JohnRennie yeah, that's just before the whistle blew

0celo7

@JohnRennie Lay it on me straight

What should i do

Jaime Gallego

17:03

@JohnRennie Censor that address John

John Rennie

That's Amazon right now.

0celo7

@JaimeGallego wow what a creeper

i didn't even notice it

John Rennie

@JaimeGallego My address isn't secret. I'm in the phone book so anyone can see it.

0celo7

@JohnRennie if an analysis book shows up at your door, will you read it?

John Rennie

No

3

My remaining lifespan:no. books I want to read ratio is beginning to look scarily low.

Balarka Sen

17:06

@JohnRennie Modulo the beards and the weird-man-mustache, your face looks like Shinichi Mochizuki's

Jaime Gallego

@0celo7 I'm an infosec guy :P

0celo7

@JaimeGallego you're in high school

you're a high school guy

Jaime Gallego

That too

Emilio Pisanty

Ah, excellent, the lego Saturn V is not in stock but there is a notification site for when it comes back isinstock.com/lego/…

John Rennie

Anyhow, the point is that in the UK SSDs have gone up 40%

0celo7

17:08

@JohnRennie what do I dooooo

John Rennie

@0celo7 just leave it for now.

If the disk speed starts really bugging you then come back to the issue. Otherwise carry on enjoying the gaming.

0celo7

@JohnRennie Well, the disk speed doesn't bother me. It's just the overall responsiveness is much better with an SSD

opening programs, etc.

John Rennie

If it was me I'd get the SSD and resign myself to the pain of reinstallation. But then I quite enjoy reinstalling PCs.

I probably reinstall my main work laptop at least once a year.

0celo7

@JohnRennie Sigh.

I'll do it.

John Rennie

Hmm, this looks like an awfully good deal

0celo7

17:14

500 or 250?

John Rennie

If it was me I'd buy a 1TB SSD.

0celo7

Ugh, a 1TB SSD is expensive.

John Rennie

Yes, it's expensive, but 500GB disks fill up surprisingly quickly.

Maybe wait for either the 1TB SSDs to get cheaper or your bank balance to go up.

0celo7

I have a 1TB drive in my laptop with two 500GB partitions.

@JohnRennie Ok you can stop talking about my bank account

I have enough money for many SSDs, that doesn't mean I want to spend it...

@JohnRennie I think 500GB is good, assuming I can use my 2TB as backup storage. Is that possible?

John Rennie

@0celo7 In this context bank balance means freely disposable income. Even I don't spend all my money on computers :-)

0celo7

17:22

@JohnRennie Can I use Keynsian economics to justify spending $400 on a hard drive?

John Rennie

Free your mind! You don't need to justify spending $400 on a hard drive :-)

0celo7

@JohnRennie I could justify $180 for the hard drive, then $XXX on a 144Hz g-sync mofo monitor

(I would wait on the monitor)

Jaime Gallego

@0celo7 Absolutely. Use the HDD for files and the SSD for MATLAB et al. and some games.

0celo7

@JaimeGallego In theory I would put the three or four that I currently am playing on the SSD

Jaime Gallego

How much space do they take?

0celo7

17:28

Witcher 3 is like 50, Ass Creed Unity is like 50, Far Cry 4 is 30 (?)

I might get Battlefield 1 if I can find people to play with, that's 60

Jaime Gallego

That's 200 GB of games right there

0celo7

So I would need the 500GB.

Fallout 4 is 100GB

I want to replay that

Jaime Gallego

Then put it on the HDD

0celo7

@JaimeGallego The loading times are measured in minutes with my current setup

4k textures are no joke

Jaime Gallego

You gotta choose

Pick the ones that need the performance boost most

Then throw the rest on the other drive

Either that or a) not playing games, b) spending $$$.

0celo7

17:35

Eh, the $80 more for the 500GB drive doesn't bother me.

But the $180 jump for the 1TB drive is a lot

$180 more than the 500Gb, that is.

John Rennie

I certainly wouldn't get the 256GB disk. That's too small and you'll quickly regret it.

Secret

17:53

O great, I cannot read german

degruyter.com/view/j/znb.1953.8.issue-11/znb-1953-1120/…

user228700

18:05

@JohnRennie Says the man who owns 27 laptops.

Anonymous

18:17

14

A: Are there examples in classical mechanics where D'Alembert's principle fails?

Given a system of $N$ point-particles with positions ${\bf r}_1, \ldots , {\bf r}_N$; with corresponding virtual displacements $\delta{\bf r}_1$, $\ldots $, $\delta{\bf r}_N$; with momenta ${\bf p}_1, \ldots , {\bf p}_N$; and with applied forces ${\bf F}_1^{(a)}, \ldots , {\bf F}_N^{(a)}$. Then...

Anonymous

"sliding friction, that we (for some reason) don't count as applied forces of type 1."

Anonymous

Is the reason = sliding friction is non-conservative?

Anonymous

18:30

@ACuriousMind Need some help with this: "The principle does not apply for irreversible displacements, such as sliding friction, and more general specification of the irreversibility is required." Which are the forces which produce irreversible displacements? Do all non-conservative forces produce irreversible displacements ?

DanielSank

19:52

Hi, everybody.

@0celo7 This is why I stick to Nethack and Super Nintendo.

For a few MB I get some of the best games ever made, and can play them on my phone!

igor

i want to revise my physics knowledge

any sources you would recommend ?
,

Anonymous

@igor At what level?

Anonymous

Middle school, High school, undergraduate, graduate, etc...

igor

i am a highschool student studying for ipho

Anonymous

@igor Start with the physics galaxy website then. It's great.

igor

19:57

ok

Anonymous

@igor Change to "global accent" if you can't understand the "Indian accent".

igor

i would prefer a read

Anonymous

@igor I used the Resnick Halliday book during my high school. Not really upto the mark.

Anonymous

I don't really know another theory book at the Olympiad level

igor

you can recommend undergrad

Anonymous

20:02

Undergrad physics topics are mostly way beyond the Olympiad level.

Anonymous

In IPhO the major topics are Newtonian Mechanics, Fluids, Thermo, Electromagnetism, Optics and Modern Physics

Anonymous

And some Relativity also

Anonymous

Look up MIT's undergradute physics syllabus along with their book recommendations if you want. But remember that you will be mostly wasting your time with those books as they are mostly beyond IPhO level.

DanielSank

21:12

@igor What are you trying to learn?

"I want to revise physics" is rather broad.

Slereah

21:29

Start at the beginning, obviously

with Archimedes

Levers and pulleys!

Anonymous

21:49

The start is unit and dimensions :P Followed by error analysis XD Good topics to deter one from studying Physics...lol

0celo7

22:30

@Slereah I need a programmer

Slereah

I'm in bed

It will have to wait tomorrow

0celo7

22:46

@Slereah I need you to teach me how to code for GPU

i want to run a simulation on my gpu

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