The h Bar

user228700

09:00

Um..?

John Rennie

@Kaumudi Yes?

user228700

Oh, u were done?

John Rennie

Yes.

user228700

:-| I don't think I understood ur point, exactly. I found this:

user228700

> What if you distil a mixture containing more than 95.6% ethanol? You should find that you get:
1) A distillate containing 95.6% of ethanol in the collecting flask (provided you are careful with the temperature control, and the fractionating column is long enough)
2) Pure ethanol in the boiling flask.

John Rennie

09:07

Yes. If you start with 99% ethanol in the liquid phase then boiling will preferentially remove water. The vapour contains more water and the liquid less water. You end up with pure ethanol in the liquid phase.

So I suppose at that point boiling produces pure ethanol since there is no more water to boil away ...

user228700

The water is boiling away?

John Rennie

Yes.

That's what makes it an azeotropic system.

If you start with almost pure water with just a bit of ethanol then the ethanol boils away to leave pure water.

If you start with almost pure ethanol with just a bit of water then the water boils away to leave pure ethanol.

Somewhere in the middle (at 95.6% ethanol) is a composition where the water and ethanol boil away at the same rate to leave the composition unchanged.

user228700

Hang on, in the first case, this point will be somewhere on the left side of the azeotropic point, yeah?

John Rennie

@Kaumudi Yes. And in the second case the composition will be to the right of the azeotropic point.

user228700

It looks like the vapour should be richer in ethanol!

John Rennie

09:12

If you start at the left side i.e. on the water rich side, then the vapour has more ethanol than water.

If you start at the right side i.e. on the ethanol rich side, then the vapour has more water than ethanol.

user228700

Oh, crap, right.

user228700

OK, last question?

John Rennie

Yes?

user228700

This is the graph for a max. boiling azeotrope:

user228700

user228700

09:16

Please don't be mad, because this might sound like an impossibly dumb question, but...

John Rennie

OK

user228700

Say we start at a point to the left of the azeotropic curve. We travel up, up, up and hit the bubble-point curve.

John Rennie

OK

user228700

To the find the composition of the vapour at this temperature, do we go left/right? (Ik we go left but we could right and get a completely nonsensical answer too)

John Rennie

user228700

09:20

Yeah, but I mean:

user228700

Damn. Alright, no, I mean going from that point on the blue curve all the way to the right and hitting the pink curve.

user228700

Is that kinda movement prohibited? :-P

John Rennie

That line would cross the blue curve twice.

user228700

Yes, and that would have what kind of implications?

John Rennie

So it would suggest there are two liquid phases present with different compositions.

The two points where the horizontal line meets the pink line give the vapour compositions that would be in equilibrium with those two different liquid phases.

user228700

09:24

Of course. Alright, I think that's it for now. Thanks very much Sir :-) How's ur Sunday going, BTW?

John Rennie

But in practice the solution doesn't separate into two different liquid phases.

Actually there are systems that do separate into two liquid phases.

user228700

Yeah, I realize that now...

user228700

@JohnRennie Wait, what?

John Rennie

I spent a while working on them. Absolutely fascinating, but not really relevant to this problem.

I could explain, but I suspect it would be an unnecessary distraction.

user228700

That's very interesting, hmm.

John Rennie

09:27

I now need to work for an hour or so. Good timing really :-)

user228700

@JohnRennie Sadly, me too :-( Also, what did koolman ask about these diagrams the other day? I was going to see if there's any point in going through that discussion..?

John Rennie

I can't remember what koolman asked. I find his questions a little hard to understand sometimes.

user228700

@JohnRennie Alright, have a great day, Sir! :-)

user228700

11:33

Alright, Henry's Law gives the dependence of solubility of a gas on the composition of the mixture and Raoult's law for the same, but where liquid is dissolved in solvent. Does Raoult's law give this for solids too?

user228700

^ Oh God, that sounds terribly sketchy, but please bear with me :-/

John Rennie

A solid doesn't have a vapour pressure. However it makes sense to ask about the change in the vapour pressure of the solvent as you dissolve a solid in it. For example does dissolving salt in water change the vapour pressure of the water.

user228700

Yes, it does, for the vapour pressure of the volatile solvent changes due to the presence of the solute molecules in it.

John Rennie

Is that what you were asking about?

user228700

Yes. I was asking if Raoult's law may be used to describe this lowering.

rob

11:39

@JohnRennie Hmmm. I always thought vapor pressure of a solid was the way to explain sublimation.

John Rennie

@rob most solids have a negligably small vapour pressure under most conditions. Better? :-)

rob

@JohnRennie Much, thanks.

user228700

Raoult's law is used to describe the dependence of the vapour pressure of volatile liquids to their compositions in a mixture. I was wondering if the same formula can be applied to a system in which the mixture consists of a volatile solvent and a nonvolatile solute.

John Rennie

@Kaumudi I'm not sure if there's a separate law to describe vapour pressure depression by a solid solute. Let me dig out my copy of Moore and I'll have a look ...

user228700

^ Do scream if that's a terrible question!

user228700

11:43

@JohnRennie Thanks sir :-) I've done some Googling to find that Raoult's law is used to describe this case as well.

user228700

Gas→Henry's Law, Liquid/Solid→Raoult's Law

John Rennie

Yes. Moore agrees with this.

user228700

OK :-) Has this been explicitly stated whilst explaining Raoult's law in the book?

John Rennie

Moore says Raoult's law applies to any ideal solution.

user228700

Oh, wow. So OK, Henry's Law can be arrived ay from Raoult's law as well?

John Rennie

11:46

However I'd suspect that many solutions of solids, especially in water, are significantly non-ideal.

user228700

Hmm. But:

John Rennie

@Kaumudi I'm sure I remember telling you that Henry's law was a special case of Raoult's law some days ago ...

Nov 12 at 10:56, by John Rennie

Raoult's law is effectively the same as Henry's law

user116211

Henry's Law is valid for ideal-dilute solution.

user116211

@JohnRennie, asked the vector potential query; waiting for any response.

John Rennie

@MAFIA36790 I saw the question. Sadly my interest in electrodynamics remains low.

user228700

11:49

@JohnRennie Yes, of course! So ur memory isn't that bad, after all :-)

user228700

@JohnRennie Yes, they have derived this for the general case, u see.

John Rennie

These various cases are, of course, all best understood by considering the Gibbs free energy changes involved ...

user228700

@JohnRennie Nooo (:-P)

user228700

Anyway, I was just remarking that while u said:

user228700

> "However I'd suspect that many solutions of solids, especially in water, are significantly non-ideal."

user228700

11:53

My textbook has derived it for the general case.

John Rennie

@Kaumudi For now I'm sure it's best to learn this stuff in the form the exam will ask it. But generally speaking as you learn physics you discover that more and more things can be explained using fewer and fewer basic assumptions. This makes life simpler to understand.

@Kaumudi has it? If you mean the picture you posted I can't see that it derives anything. It just states that Raoult's law applies.

user228700

@JohnRennie Yes, it does. In that box.

user228700

Anyway, if my textbook has done it this way, I will accept it for the sake of my exams. Thanks for telling me about Raoult's law again. This is proving to be like that time I couldn't shut up about Thermodynamics and I'm sorry :-P

John Rennie

But that starts with $P_S = x_{solvent} P^0$, which is the assumption behind Raoult's law.

So the whole working assumes Raoult's law applies.

user228700

Oh, I see that they have implicitly stated that the system must be ideal. Oh, well :-/

user228700

12:01

They wrote a completely new statement of the Law than before, for the case of a liquid solution and that's why I was confused. Thank you :-)

Qmechanic

13:42

@JohnRennie : Plank!...there's a good woody word. Also Plank on main site.

Bernard Meurer

@JohnRennie Give me a linux server plox thx

heather

hello @BernardMeurer

Bernard Meurer

@heather Howdy

Slereah

@ACuriousMind why is the condition $\Phi(x) |\Omega \rangle = c |\Omega\rangle$ enough to declare a theory trivial

heather

14:00

sweet, I was able to figure out what I was doing wrong and set the branch up completely and push something from it such that it showed up on the github page

=D

is there any way you can completely delete a branch, not even merge it because a test file was made?

Bernard Meurer

@heather Local or remote branch?

heather

@BernardMeurer, local, but I figured it out, nevermind =)

git branch -D branch_name

Bernard Meurer

Yeah :)

user228700

Hey, guys :-) Does anybody here own a Lenovo phone?

Rajath Krishna R

14:47

I have a query. It is just to clarify something and I am not sure whether it could be put up as a question. Given a set of vectors v_1,v_2,....v_n are there infinite number of matrices with v_1,....v_n as eigenvectors?

heather

now I've got a weird error in my latex bibliography

darn

David Z

15:24

@RajathKrishnaR I think that could be put up as a question on Mathematics. It would be off topic on Physics, of course.

Rajath Krishna R

@DavidZ Yes, I will be doing that. But then I was trying to get some insights through the chat rooms. I had put up this query on mathematics chat rooms and no one responded. As you said I guess it will be best to put up a question on this on mathematics stackexchange.

David Z

Yeah, it's kind of random whether anyone responds to you on chat. Sometimes it's quicker and easier than putting a question on the main site, and sometimes not.

Rajath Krishna R

@DavidZ ok, thank you.

John Rennie

15:46

@BernardMeurer What's a linux server plox?

Bernard Meurer

@JohnRennie plox=please

I got one for testing my chat server with Dan

but I only have it for a month :P

after that my free student credit dies

ACuriousMind

@Slereah Because your algebra of observables is generated by the fields, and if all fields act trivial, then you have the trivial representation of your algebra of observables, hence your Hilbert space is one-dimensional, so there can't be any dynamics.

Slereah

But does the fact that it happens for the vacuum mean that it happens for all states?

ACuriousMind

I think the vacuum is required to be cyclic vector, no?

Slereah

What is cyclic vector

ACuriousMind

15:52

One which when acted upon by each element of the algebra being represented gives a set of vectors that is dense in the representation space

Well, I guess you don't need to assume its cyclic, but if $\phi\Omega = \Omega$ for all $\phi$, then your state of space always decomposes into the one-dim. space with the vacuum and the rest.

Slereah

Hm

Now the question is how to prove that thing

ACuriousMind

And there will be no interacting between these two parts, so you either can have dynamics where there's the vacuum but nothing to do or dynamics that can be non-trivial but which effectively know nothing of the vacuum, violating the assumption of existence of the vacuum.

Slereah

Hm

I think by what's his name theorem that probably means my hyperreal idea won't work

So much for that

Los theorem

John Rennie

16:13

I normally spend my Sunday lunchtime browsing the half dozen or so physics blogs I follow, but they all seem a bit boring today. There just doesn't seem to be much happening in physics. Maybe they're winding down for Christmas ...

Bernard Meurer

@JohnRennie I'm just having beer

Come join :P

@ACuriousMind About what we were discussing yesterday, so you think I was right in interrupting someone who'd teaching bullcrap to others?

John Rennie

@BernardMeurer this linux server, could it be a Hyper-V VM.?

ACuriousMind

@BernardMeurer Yes, although I certainly can't assess how diplomatic you were about it :P

Bernard Meurer

@JohnRennie As long as I can SSH into it, and it's on a network where we can use some random port to send out messages through it can be on any VM I think

@ACuriousMind Well, all I asked was for him to show me the maths behind what he was saying

not that I would understand it if he did, but because I knew he couldn't

and he dismissed me saying "It's ideas that matter"

John Rennie

Microsoft are building a quantum computer

ACuriousMind

16:21

@BernardMeurer Well, that sounds sufficiently diplomatic

Bernard Meurer

At which point I said without the maths to base and support his ideas he might as well be writing a sequel to back to the future or harry potter

Sigh, everyone is working on QC's and I'm a useless freshman

heather

@BernardMeurer, do a research project on QC's or something - I don't know how this all works but you can still write a paper as a freshman I think.

ACuriousMind

@BernardMeurer Don't know the person, but a more...hopeful approach might have been to ask him how to distinguish the good ideas from the bad ones without the math. The ridicule is perhaps deserved, but not suited to persuade people who might've already been inclined to listen to him

Bernard Meurer

@ACuriousMind I just really don't understand how someone can say that travelling to another dimension through a wormhole and then back in order to reverse time is a good idea

John Rennie

John Schwarz's 75th birthday. Scraping the barrel now ...

Bernard Meurer

16:25

Like, come on man

@heather You can write a paper, but that won't free you from the lab reports and exams you need to do still :)

I might do something come the break

heather

@BernardMeurer, yay middle school, where there are no big tests and no big projects =D

ACuriousMind

@BernardMeurer That's why I said "the ridicule is perhaps deserved". Doesn't change that you tend to come off as arrogant to the people listening if you jump straight to ridiculing him.

Not to mention that you won't actually convince him that the math should matter that way.

Bernard Meurer

@heather I'd miss middle school if it hadn't been horrible

@ACuriousMind Indeed, good point. It just angers me when someone is willing to spread misinformation like that

@ACuriousMind Can you even imagine my face when he said "NP just means complexity grows exponentially"?

It's the closest I've been to having a stroke so far

heather

@BernardMeurer , well, my last two years of middle school weren't too hot; my science teacher was pretty bad and other stuff happened my first year of middle school. But this year's not too bad. =)

Bernard Meurer

Meh, I hated middle school, and I hated high school too, and also whatever came before middle school.

I had two very good science teachers that made two of the years be worth it

ACuriousMind

16:31

@BernardMeurer Oh, you'll have to grow a far thicker skin. :P People are wrong all the time, sometimes maliciously, but most often innocently because they just believe what they heard somewhere.

Bernard Meurer

@ACuriousMind I even showed him the big-O complexity of an NP problem that was not exponential and he said "This doesn't matter" :(

ACuriousMind

Well, that's another level. Actively ignoring facts you're being told is the hallmark of the crackpot :P

Anyway, you'll also have to get over that because this won't be the last time that happens :P

Bernard Meurer

Sigh, complicated

Slereah

I guess I could use hyperreal distributions, but then that is even less fun D:

even if it does form an algebra

Bernard Meurer

@Slereah Boolean algebra does not form a field

or a ring

it forms a semi-ring if you allow the XOR operator

and a boolean ring otherwise, which is a weird, weaker version of a ring

Sad :(

Slereah

16:39

Who gives a damn though

Bernard Meurer

savage

I do

If they formed a field I could've solved a question in my exam very elegantly

DanielSank

@BernardMeurer <3

Bernard Meurer

But I'm still a bit intrigued by how the toroidal k-map works

@DanielSank <3

koolman

heather

@DanielSank, hello! I was able to fix the problem I was having last night. =)

koolman

16:43

In the above question can we solve it if instead of rod it is string

@JohnRennie

Any idea

Bernard Meurer

I wish I could pull off wearing nigerian ethic clothes, like look so badass

ACuriousMind

@koolman 1. You might try posting a picture that's easily legible on all screen sizes next time. 2. Don't ping people to help with your exercise questions unless they have explicitly said they are interested in it - if someone wants to help you with your question, they will even without a ping.

@BernardMeurer Are "ethic clothes" those worn by judges? :P

Bernard Meurer

@ACuriousMind Lol, that was a good typo

*ethnic

John Rennie

@koolman Using a string makes the calculation much, much harder.

koolman

@JohnRennie so can we solve it or not

John Rennie

16:53

The problem is that the end and middle mass have the same gravitational acceleration so in general the string won't stay straight as it moves.

koolman

@JohnRennie yeah

Anonymous

@ACuriousMind 1. The picture is visible/legible if you open it in a new tab even on a small screen mobile phone (I tried just now) 2. chat.stackexchange.com/transcript/message/33657578#33657578

John Rennie

Offhand I don't know how to solve it if the rod is replaced by a string. I'm sure it can be done, but I'd have to go off and dig out my olf mechanics books which I don't want to do.

What is it with the spate of recent questions about Bohmian mechanics?

Has there been some pop sci article on it recently?

koolman

@JohnRennie ohk fine

DanielSank

@heather What was the fix?

ACuriousMind

16:58

@JohnRennie What spate?

Anonymous

@JohnRennie Can Koolman's question be modified somehow in order to ask it on the main site ? It seems really interesting...

heather

@DanielSank, I wasn't in the tex-files folder, so it didn't see the file.

koolman

@S007 @JohnRennie yeah is there any way

ACuriousMind

I count three questions containing "Broglie-Bohm" this month and none containing "Bohmian". Doesn't seem out of the ordinary to me

DanielSank

@heather That'll do it.

John Rennie

17:04

@ACuriousMind that's a spate

For a topic that people have been working on for 80 years with no progress :-)

ACuriousMind

wtf Vafa: "Let us denote M-theory by $Q[V_M]$, then $Q[-V_M] = Q[V_M]$ in this background" , that makes about as much sense as saying "Let $C[V_M]$ denote classical mechanics". What does that even mean?

DanielSank

@ACuriousMind ::shrugs:: sounds about as ridiculous as when y'all write down a Lagrangian and call it a "theory".

@JohnRennie what was that software for managing mp3 tags you mentioned?

ACuriousMind

@JohnRennie Eh, I think there there's been some prograss (I think they're close to reproducing scalar QFT? :P) and also the hydrodynamic analogue won't cease to be misinterpreted :P

heather

would anyone mind looking at the references branch on a github repository and helping me figure out what's wrong with the way I set up the bibliography (relevant files: main-file.tex and resources.tex)?

ACuriousMind

@DanielSank Well, but there's a clear meaning to that: A Lagrangian suffices to determine a QFT fully. I have literally no idea what Vafa means by this passage

DanielSank

17:10

@ACuriousMind Mehhhh, sort of grump grump grump

@heather Hahaha bibliographies are such a PITA.

heather

@DanielSank, if pita is not referencing the (delicious) food, then, yes, they are =)

DanielSank

@heather Indeed, the bread is considerably more delicious than the task of writing TeX.

Bernard Meurer

Pita is a food?

heather

especially with hummus? I could live on that =D

@BernardMeurer, you didn't know this?

DanielSank

@heather You are aware that making hummus is very easy, yes?

(My mom's family is Lebanese)

heather

17:12

Pita

In many languages, the word 'pita' refers not to flatbread, but to flaky pastries; see börek. Pita or pitta (/ˈpɪtə/ or US /ˈpiːtə/) also known as Arabic bread, Lebanese bread or Syrian bread, is a soft, slightly leavened flatbread baked from wheat flour, which originated in the Near East, most probably Mesopotamia around 2500 BC. It is used in many Mediterranean, Balkan and Middle Eastern cuisines and resembles other slightly leavened flatbreads such as Iranian nan-e barbari, Central and South Asian flatbreads (such as naan), and pizza crust. == Etymology == Pita is a Modern Hebrew word (pittāh...

@BernardMeurer, ^

DanielSank

^ delicious

ACuriousMind

@heather What error do you get?

heather

@DanielSank, I guess I sort of did, but I don't think what I could make would come out very well

Bernard Meurer

@heather We just call it Syrian Bread in Portuguese

or Arab Bread

not Pita

DanielSank

...and we Lebanese call it "bread" or "Syrian bread".

heather

17:14

@ACuriousMind, "something's wrong - perhaps a missing \item" <- 3 of those, and 1 "misplaced alignment tab character and missing <argument>"

ACuriousMind

@heather the [9] after the \begin{thebibliography} should be in curly braces.

heather

...and we "cultured" Americans call it what no one else calls it: pita

@ACuriousMind, oh, okay, let me see if that fixes it

DanielSank

@heather would you be interested in a PR that uses a proper bibtex bibliography so you don't have to type this stuff in by hand?

heather

@ACuriousMind, now there's no item errors, but more weird errors, like "missing $" and "command item invalid in math mode" (and no, I double-checked, I didn't type a dollar sign)

ACuriousMind

I was about to recommend biblaTeX instead of this explicit bibliography :)

heather

17:17

@DanielSank, that would be nice

Bernard Meurer

Yes, bibTeX

DanielSank

@heather Ok, then I'm going to make a pull request on the branch we were just talking about.

ACuriousMind

@heather where does that error occur?

heather

@ACuriousMind, line 2, 3, and 4

i found a missing }, but added it in, and it still gave errors (the missing } was at the \end{bibliography}{9}

ACuriousMind

@heather The urls contain $ and & which must be escaped as \$ and \& in text.

heather

17:23

okay, I'll fix that and see if it works

ACuriousMind

Also, you don't need the 9 behind the \end{bibliography}.

DanielSank

This is good, @heather you might have to do a real merge in a few minutes :)

heather

I did the \& but for some reason I can't see any dollar sign, even though there's an error and I know there must be one, I'll keep looking

ACuriousMind

Also, @heather, your third item has texit instead of textit and if you want to link urls, just use the package hyperref and use \url instead of \texttt. You also need to escape _ since those are only for subscripts in math mode (which is what creates the "missing $" error.

heather

okay

Secret

17:33

0

Q: Does Quantum mechanics imply "Determinism" comes from "Randomness"?

I'm not sure it's a philosophical question or a scientific question but I know in science we have a term named "Randomized controlled trial" or "Randomized experiment" which refers to those kind of experiments/trials in which we "Randomize" the (not under study) initial conditions of the experime...

Rather, it is randomness is deterministic

i.e. wavefunction evolves determinstically under SE

DanielSank

Oh, ha. @ACuriousMind how do I make entries of a bibliography show up if they're never (\cite)ed?

ACuriousMind

@DanielSank Do \nocite{label} before the bibliography.

(where label is of course the label of the uncited bib object you want to have appear)

DanielSank

^ ty

@heather check your pull requests

heather

okay

DanielSank

17:48

I see you merged the PR. Everything working?

heather

eh...i'm not sure, it's not going completely smoothly

DanielSank

No?

Do you have local changes on that branch?

heather

it's upset when i tried to pull because the change doesn't keep resources.tex

DanielSank

Indeed.

heather

yes, i've got local changes

DanielSank

17:50

Heheheh

Ok, now it's git-fu time.

First, make sure we understand what's gong on.

heather

so i tried to fix it by deleting the file myself because i was following the hints (just an fyi)

DanielSank

You have two different repos: the one on github and the one on your computer.

heather

okay

DanielSank

The repo on github has the commits you merged from me.

If the repo on your computer had not been modified, the pull would work fine because it would just be adding new commits.

However, since you changed stuff locally, it's impossible to just add the commits from me.

In particular, you modified a file that my commits removed (because I renamed that file).

Make sense?

heather

yeah, seems a tad problematic

DanielSank

17:53

Well, it's exactly the kind of problem git is designed for.

vzn

18:09

@Mew try this for some ideas that "go beyond" maslow, started to get into it recently en.wikipedia.org/wiki/Logotherapy

heather

@DanielSank, hmm, I've done some googling around, but I'm still not completely sure what I need to do (mainly because I don't want to complicate it further =P)

DanielSank

@heather sorry was in conversation

heather

@DanielSank, oh, no you're fine, I didn't mean to rush you or anything

^just noticed that

=)

DanielSank

lol

Anyway...

You have a few options:

What is the error message if you try to pull?

heather

"pulling is not possible because you have unmerged files"

DanielSank

18:20

oh

git status?

heather

"your branch and origin/references have diverged..."

"you have unmerged paths"

DanielSank

Ok, so I guess you made some commits on your local repo?

heather

yes

i think so

DanielSank

Hmmm, wish I could see the screen.

heather

wait, i have an idea, one moment

DanielSank

18:26

I have a recommendation but I'll wait for you.

heather

hmm, is there any way i can enable java script for net surf? (I'm trying to access chat on the linux side, so then I can take a screenshot/save/upload it all on one side of the computer.

your idea is probably better, though

DanielSank

I'm not sure what you mean.

In a normal desktop environment you'd just take a screenshot and upload it to chat.

You must be in a different environment than I'm used to.

In any case, when you do git status, does it say you're in the middle of a merge or anything like that?

heather

it does have a section that says you have unmerged paths, use such and such command to abort merge

DanielSank

ok, abort the merge.

heather

okay

DanielSank

18:31

Then do git status again.

heather

okay, i did, and it no longer has that section

DanielSank

What does it say?

heather

"your branch and origin/references have diverged, and have 1 and 3 commits each, respectively. (use "git pull" to merge the remote branch into yours.)" then it lists those untracked files that tex creates

DanielSank

ok

cool

Ok, so the 3 commits are the two from my PR, plus the "merge commit" you made when you merged the PR.

The 1 means that your local branch has a commit that is not on github's version of that branch.

If you do git log you can see what that commit is.

Could you do that, please?

("q" closes the log viewer)

heather

it was me trying to fix the issue by following the hints git gives - i thought i just had to commit the file again and it would be saved, so it contains the url changes and everything

because git said i needed to add/commit the file for the pull to work because changes i made weren't committed or something like that.

DanielSank

18:45

@heather ah ok

So your local branch has a commit where some URL's and stuff are fixed up.

heather

yes

DanielSank

The github branch has the changes I made, which, unfortunately in this case, completely rewrote the file where you made the URL fixes.

heather

right

DanielSank

Also (and this is why the merge conflict was complicated in this particular case), I renamed that file from .tex to .bib.

Ok now we know what's going on, so we can decide what to do.

In this particular case, if I were you, I'd ditch the most recent local commit you made.

...simply because the changes from my PR are rather large and the ones you made are easy enough to redo.

heather

okay, right

DanielSank

18:47

This isn't standard operating procedure, but it makes sense here.

So just drop the last commit on your branch. There are a few ways to do this. I think the easiest in this case is:

$ git reset --hard <SHA of the commit you want to go to>

To find the SHA, just do git log and look at the big long string of characters for the commit prior to the latest one. You only need to use the first four or five characters though.

heather

okay

DanielSank

After you've done that, git pull again.

actually, git status first :)

heather

i git pull ed before i did status, but the pull worked and the status gave "your branch is up to date with origin/reference"

so i think the issue is fixed

DanielSank

cool

yep

I asked you to do git status so you could see that the merge would work before you actually did it.

I have some advice to simply your life: don't use git pull.

git pull does two things:
1. git fetch
2. git merge

git fetch simply gets all the commits and branches from the remote (in this case, github).

heather

and then merge merges those with your own branch?

DanielSank

18:55

git fetch does not attempt to update your local branches. In this sense, git fetch is a very "safe" command.

@heather yes

I always do get fetch, and then git status to see where I'm at.

If my local branch has diverged in some way from the remote, git status will tell me that!

heather

hmm, okay

DanielSank

If the remote has simply added some commits that can be merged with no problem, git status tells you that explicitly!

It's really nice.

heather

that sounds much less dangerous than git pull

DanielSank

So my workflow is this:

heather

^well, not dangerous

DanielSank

18:57

$ git fetch
$ git status
Check that everything is good
If the histories have diverged, go to github and find out why/how
$ git merge origin/<name of branch>

Some people think this is overly cautious/annoying, but for me it's great.

heather

hmm, that makes sense, I think I'll start using that

DanielSank

If the conflicts are just conflicts within files, like you changed a line and the remote changed the same line in a different way, than git pull is ok and you just resolve the conflicts as needed.

Anyway, that's my two cents.

Also, I wouldn't normally have recommended throwing away your commit. There are better ways to handle divergent history (that's the point of git) but here I was looking for a simple solution (it's just hard to narrate anything beyond simple over internet chat).

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