Wolfram Mathematica - 2012-02-12 (page 1 of 2)

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12:12 AM

@CHM The best way to think of it: # (Slot[]) is, as the name implies, a slot (dummy variable, if you will) that is intended to be replaced when the function is applied to something. & (Function[]) just indicates that you are using a pure function.

@JM or accepted

blegh, speaking of bloatware. The latest upgrade for OS X was 1.3 GB but at least I now have Catalan, Croatian, Greek, Hebrew, Romanian, Slovak, Thai, and Ukrainian language support. If only I spoke any of them.

There's no way to opt out of those updates?

12:28 AM

@JM I don't think so (unless you don't upgrade at all)

You can't pick updates? Eww...

you can't pick parts that you want to upgrade no

i just switched it to greek. can't decode what the menus say at all! very funny

(greek is my mother tongue, otherwise it would be neither surprising nor funny...)

It's quite the problem when you can't understand something that was intended to be completely understandable for you...

@acl you can actually

@Heike upgrade parts of the system? eg I could have decided not to install greek? how?

12:32 AM

No, I meant chosing not to install the whole upgrade

@JM i suppose 20 years of computer use in english are hard to forget. it's like physics, I can't discuss even basic concepts in physics in greek. when I talk to greek colleagues, half the discussion is in english

@Heike how?

@acl But you initially learned physics in Greek, no?

@JM please define "initially"

(I understand the sentiment, though. My native language is completely unsuitable for technical discussion...)

@acl I don't know... university? Undergraduate?

@acl By unselecting the little box in front of the update in the Software updater?

12:35 AM

@JM no, I did both my undergrad and phd in the uk

@Heike oh I see, you meant choosing not to install the upgrade at all. yes that's what I thought i told jm

@acl Ah, that's the rub...

@acl yes, that's what I meant

@Heike I see, but you can't say "upgrade this, but don't upgrade that", right? At least that's how I understood acl.

@JM you can't partially upgrade the OS if that's what you mean (at least not as far as I know)

As I said previously: eww...

12:41 AM

@acl I have a friend who has set the default language on his computer to Welsh.

@JM on the other hand, in the System Preferences one can set the caps lock key to be instead the ctrl key. furthermore, ctrl-a and ctrl-e do the emacs thing in most GUI text windows. as far as I am concerned, this cancels out all the negatives

@Heike not welsh, I suppose?

(the friend)

@acl he is. An very proud of it.

@Heike well that's not so unreasonable then I guess

I once insulted him by suggesting he didn't have a strong welsh accent.

by pretending to understand him?

12:44 AM

@acl No, by commenting that a mutual scottish friend had a stronger accent than he.

@acl :D

hm, os x does not seem to support welsh. terrible

@acl That would have been another 500 MB

@JM (actually, in the terminal at least, you can kill and yank text a la emacs, and it goes to a kill ring separate from the clipboard--someone must have had a laugh at that)

@acl you can choose a welsh keyboard layout

12:48 AM

sounds useful

@acl I always thought that ctrl-a ctrl-e etc. came from wordStar

I don't know where it came from, but it's the default in emacs

I'm not familiar with emacs, but I remember WordStar and Joe from the old days, and they used ctrl-a and ctrl-e as well.

that was somewhat before my time I'm afraid... or at least I never used them

Probably the first.

12:58 AM

I did use edlin though... and debug. had lots of time and nothing to do when I was younger

Don't know those.

DOS utilities, edlin is the "line editor" and debug.com was/is this

Debug (command)

debug is a command in DOS, MS-DOS, OS/2 and Microsoft Windows (only x86 versions, not x64) which runs the program debug.exe (or DEBUG.COM in older versions of DOS). Debug can act as an assembler, disassembler, or hex dump program allowing users to interactively examine memory contents (in assembly language, hexadecimal or ASCII), make changes, and selectively execute COM, EXE and other file types. It also has several subcommands which are used to access specific disk sectors, I/O ports and memory addresses. Background Traditionally, all computers and operating systems have included a main...

this was on dos 3.3

looks scary

looked mysterious and intriguing at the time (I had not yet worked out that not everything that can be understood has to be understood)

@acl I went through that phase as well, but luckily for me I never came across assembler when I was young.

1:05 AM

@Heike well, I only grew out of it when I discovered that I really wanted to do physics, and then I directed the monomania there. probably not so clever move in retrospect

Probably not. You could have been a multi billionaire by now if you had stuck to computer science.

But it's getting late here. Time to go to sleep.

night

1:27 AM

@MrWizard Honestly, I have not read through any of the answers to that question, nor have I upvoted any for that reason.

1:50 AM

I don't know what system is used to rank the sites (it must be some aggregate), but Mathematica.se is now ahead of both of the other two betas I'm "participating" in. Both, of which are older. If DSP isn't careful, we'll surpass them soon, too, despite them having twice the number of users. We have more at 200+!

@rcollyer did you compile ELK yet? If not, don't forget to edit src/zfftifc.f90 if you want decent FFT performance. I usually forget...

@OleksandrR No I have not yet compiled it. What's the issue with zfftifc.f90?

The default FFT implementation is FFTPACK5 (slow). If you want FFTW or MKL, you have to edit the source.

Elk's website gives the impression that FFTPACK (or at least their version) is pretty fast.

FFTPACK is one of the fastest FFT implementations that's licence-compatible with pretty much anything. It's not fast compared to FFTW3 or MKL.

1:59 AM

ah.

We only have mkl 7.1 on the cluster I'm using, so fftw it is.

Wow. If I were you: download a new version of Intel Fortran (comes with MKL) from the Intel website, install it, be happy.

(Mathematica 5.2 even came with MKL 7.2.1.0, so I don't want to even think about how outdated your cluster's software must be...)

problem: licensing fees

Though having used a cluster so old I had to compile binutils from source, I feel your pain.

The hardware is about 8 years old and held together with chewing gum and bailing wire.

My reading of the noncommercial licence terms for the Intel products is, you can use it if you're a student not being paid for your work, but not if you're an actual employee of the university. As such it might be feasible for you to get yourself a noncommercial licence even if it's not for your cluster administrators to buy a proper licence.

2:06 AM

But, at one point, it was part of a cluster that made it into the top 100 fastest in the world.

Well, I think we've all been there. :) At one point my university's was also in the top 100 (well, in 2008, actually). But now it's showing its age.

@Heike monolingual.sourceforge.net check it out.

I've had nodes drop out on me while running a calc never to be heard from again.

Considering I am its primary administrator, it could be worse.

These machines increased the groups cpu count by 10 times.

Well, it happens in big clusters... I would probably just install some decent checkpointing software and compile an MPI library set up to use it, and not worry about it too much.

I generally use Wien, and the scripts I have wrapping it aren't to bad.

2:16 AM

Never used wien2k myself. It's pretty annoying with whatever software though if you're running a job that'll take a week or two over 256 CPUs on however many nodes, and one process stops talking for a while because some insensitive clod decided to parse through 500GB of scratch files using a bash script on that node, so the job crashes...

@OleksandrR the minimum price I'm seeing is $169 for the student development suite, but the I'm seeing is $400 for academic pricing of just the Fortran compiler. I can't tell if it comes with mkl.

Never had that happen, at least on the main clusters at my university. Once we liberated this one, the set up became home grown and accompanied by a gentleman's agreement not to use each others allotment. With at most 3 people using it, it works. I get a whole rack to myself as I'm the heaviest user.

@rcollyer well I'm not an administrator for our clusters nor am I in any way an employee of my university so I've tended to use the noncommercial licences: software.intel.com/en-us/articles/…

@OleksandrR as I receive a stipend, I am technically an employee... :P

@rcollyer depends on your situation I suppose. I receive a stipend too, but in my case legally and for tax purposes a stipend isn't considered to be income or compensation so technically I'm still not an employee.

0

Q: Monitoring the progress of ParallelTable

How could I get a sense of the progress made when running large computations ? Specifically, how can I determine which index is ParallelTable[] currently evaluating? I have look into the help but ProgressIndicator[] or EvaluationMonitor[] are either opaque or not appropriate.

evaluation parallel

looks like an exact duplicate of this

2:25 AM

@OleksandrR I've forgotten, are you attending an american university?

10

Q: Monitor doesn't work with ParallelTable

I can't monitor ParallelTable: Monitor[ParallelTable[Pause[3]; i, {i, 1, 10}], i] just displays i until it is finished. Do you guys know of alternatives?

@rcollyer What I can say for sure is that in the noncommercial download versions, whenever you download Intel C++ or Intel Fortran, MKL is included in that download. (No, I'm not in the US. No clue how it works in America.)

@acl different question, same answers.

@acl agreed. I voted to close as well.

@OleksandrR for tax purposes, I'm an employee.

@OleksandrR So, did I. In this case, since it is a variant of the original question, it is worthwhile just closing, not deleting it.

2:29 AM

it looks like an exact duplicate to me to be honest

@acl I'm on the fence about that, so I won't fight it.

@OleksandrR looking at their compiler page, I see your right: mkl is included with them all.

@OleksandrR the academic licensing approaches $1000, and I don't think my adviser has that much. I could possibly swing the student license, though.

@rcollyer OK then. I guess that rules out using the noncommercial licence. Although I was under the impression that universities (in general) prefer not to consider their students as employees as it reduces the liabilities they have to them? For instance (as regards the US situation) OSHA only has jurisdiction where employees are involved, not students.

@OleksandrR Academia is given quite a bit of license (pun intended) in this area.

I hate flaky internet connections. My connection to the cluster just hung. Now I have to wait ...

@rcollyer it works both ways, IMO. The situation of not being an actual employee with career development targets etc. gives you quite a bit of freedom, which I have used on occasion when I've felt like making comments critical of the competence displayed by higher-ups in the university administration.

@rcollyer once, when something like that happened to me, my supervisor at the time happened to come into my office and saw my expression.

she suggested yoga

2:37 AM

@acl lol!

@OleksandrR I had a friend at my undergrad institution who was partially an employee (the astronomy lab instructor), partially a student (working on 10 years plus when I knew him), and he used his student status to get a meeting with the President of the college regarding the building of an observatory. He had priced it all out, and now the college has a small observatory.

@rcollyer 10 years?

Reading through the Elk make file reminds me of why I switched to using boost-build.

@acl he was on a long term plan to work while getting his degree.

So, he only took 1 - 2 classes per semester.

must be tough. 10 years ago I was learning QM, GR and so on. I hardly remember anything now (except QM)

@rcollyer hm. Personally I don't mind makefiles. They're simple. Complicated build processes have a lot of opportunity to go wrong. (Ever tried building NumPy with Intel C? It's not fun, mainly due to the horrendous build system.)

@acl I remember two things from GR: the difference between an upper and a lower index (sort of), and that I was able to use an otherwise absurd approximation on a hw question. I was proud of the approximation.

2:46 AM

@rcollyer I only remember my final exam (last of my undergraduate career). I hurled a 25 page manuscript at the examiner

@rcollyer here's my make.inc for the Intel compilers/MKL: pastebin.com/nCceXjMZ

@OleksandrR Personally, I hate tracking source files and dependencies between them. In make, you have to do that by hand, so, as you said, beyond a certain point it becomes nightmarish. boost-build will do dependency checking for you, and, to a large extent, you don't have to actually track the files yourself.

@OleksandrR thank you, that helps.

@rcollyer yes, I can see the advantages for package maintainers. But when the build system comes to embody a lot of extremely complicated logic and basically guesswork that might or might not have worked for any given person at any given time, then we (as users) have problems when we want to build in a slightly different way. That's the situation with NumPy, anyway.

@OleksandrR can't disagree with that. The primary reason I switched is I kept getting annoyed that I had to update my makefile whenever I added or removed a file, and since the project was in a lot of flux at that point, I hit my "I must automate this" point very quickly. My scripts to automate this process in make were buggy, at best, and completely useless at worst.

3:03 AM

Time to see if I can get this up and running. Thanks for the help @OleksandrR, and good night.

3:18 AM

blogs.discovermagazine.com/loom/2009/05/23/…

It's old, but... funny.

"As a biochemist and molecular biophysicist I studied a lot of this stuff and I must say, Schroedinger was my favorite and well, I had to do it." - Joe

@CHM that's indicative of quite some dedication to have all of that tattooed... and of a skilled tattooist not to drop a factor of 2 or change - to + ...

Yep. I would have stopped at $\hat{H}\Psi=E\Psi$

I saw one a while ago in which someone had tattooed the Y combinator on themselves. A bit more aesthetic than those three long and rather specific expressions, if you ask me.

yes rather too specific to be elegant

Especially considering he's a biochemist... :P

@OleksandrR The Y combinator... I saw that mentioned in a question today. I will have to read about it. Is that basic computational science knowledge?

3:28 AM

@CHM I would guess not. Actually when I saw the tattoo I recognised it but didn't know what the name of the construct was until I'd looked it up.

ok

However, I've never formally studied computer science, so there may be degrees of "basic" in this case.

@CHM I love the second comment: "Physicists dream of the day when a Theory of Everything can be reduced to tattoo that will fit on one bicep." Of course, the formula already exists: $\frac{\text{d}U}{\text{d}t}=0$. We just don't know the form of $U$.

Haha

I'd say $\delta L=0$ (with unknown $L$) is more elegant (if equally useless)

3:37 AM

point, on both counts.

I love working in condensed matter. we're one of the few fields in physics that can completely write down the equations of motion for our field, and it is completely useless.

@rcollyer for example in quantum hall systems, H looks trivial: there's no kinetic term, just interactions

@acl and we both know that interactions, however simple they may look, are the bane and beauty of condensed matter.

Damned self-interactions!

They wouldn't be "condensed" if the particles weren't interacting, y'know... ;)

exactly.

I thought a BEC counted as condensed?

3:51 AM

@JM Did you ever look at that blog: Thing's I Won't Work With?

(sorry)

@acl interesting question.

@acl for what?

@rcollyer Oh, sure. Fun. :)

@rcollyer stupid jokes :)

@acl no apologies necessary.

as long as I can make them, too.

3:52 AM

as long as laughing is optional, sure... ;)

with puns, laughter is always optional, the groans are sort of mandatory.

@acl It does say so in the name, doesn't it...

@JM since we see you here a lot, do you have an academic or industrial job? (i.e. when do you find time to work?)

@rcollyer probably while you're writing your thesis :)

@rcollyer Yes, I work at some chemical plant I won't name. I'm the chemist's equivalent of a sysadmin.

3:55 AM

@acl that's mean, and rather funny ... :)

When they call me, something has gone terribly wrong.

That explains it.

@JM sounds fun

@JM define terribly wrong.

and I have to agree, it sounds fun.

@rcollyer There was the time it turned out that a bit too much catalyst was added to the reaction vat, resulting in a polymerized goop that I had to think deeply on how to dislodge...

3:57 AM

@JM I think the word, ick, fits quite nicely.

Pretty much, yes.

@JM I am picturing Rodin's Thinker next to some polymerized goop...

@JM and the explosives option wouldn't have been appropriate, would it?

@acl :)

...the fact that one of the reactants had an, uhurm, interesting odor did not make the job any more fun...

@rcollyer I briefly considered it, but then I remembered that I had to write a report too...

@JM This mythbuster's episode came to mind when you mentioned you had to dislodge it.

4:01 AM

@rcollyer I eventually figured what to mix for solvent, so it ended up okay. I did chew out the lab tech for a half hour, after...

@JM I would imagine.

@MrWizard Weird that it worked without the shared variable for me

I'm off for a bit. Later.

4:28 AM

@David yes, that's a problem with version 7.

I'm kind of surprised why it is not a problem for 8

I mean the variable really shouldn't be known to the kernels

1 hour later…

5:30 AM

I'm plotting this function: primePercent[x_Integer] := Module[{a},
a = Count[PrimeQ[Range[x]], True];
(a/x)*100
] to know if the percentage of primes in a certain Range takes a steady value

The plot evaluated in under a minute for the first 10K naturals, but it's been 5 minutes and a lot of heat, but still no sign of the 100K plot.

Is there a way I could predict the time needed for evaluation?

Its dependence on set size obviously isn't linear.

5:47 AM

@CHM primePercent[x_Integer] := 100 PrimePi[x]/x is a vastly better way to do it...

Obviously, now that I know PrimePi exists.

Thanks lol.

@JM BTW, what was the problem concerning my acceptance of an answer in this question (mathematica.stackexchange.com/q/1633/73 ) ?

I've seen the discussion in the comments, but I'm not sure what mistake I made, or even if it concerns me.

@CHM It's really your prerogative, as OP. (Can't pressure you into accepting something you're not comfy with, see.) Just that an answer which is not fundamentally different from an earlier one getting something doesn't sit well with me. But hey, if you're fine with it, and Mr. Wizard is fine with it, I'm not pushing. I'll let you guys be the judge.

That's something I have thought about - whether or not it's ok NOT to accept any answers.

I thought one had to choose.

*I* would have done "please accept X's answer instead of mine".

@CHM Please do not NOT accept answers.

If indeed one was the most helpful, accept it.

If all are equally helpful, toss a coin or something.

Well, accepting an answer is subjective. There could be some "community accept" button, so that situations like this one would not reoccur

5:59 AM

@CHM Yes, it's subjective, precisely because it's up to you. ;)

You're the one asking questions after all...

Say, 5 people prefer another answer, they "community accept" it, and whichever answer gets the most accepts, after receiving at least 5, for example, gets tagged as "community accepted"

If you will: think of yourself as the client, and we're providing you services.

@CHM I think that's been broached in meta.SO a number of times...

@CHM I think "community accept" is redundant because what the community likes is indicated by the number of upvotes, but only you know for certain whether an answer addressed your question.

That, too.

Hmm. It might be redundant in the visibility the answer is granted, but doesn't accepting a question give some points to the answerer?

6:02 AM

@CHM yes; 15 rep for answerer, 2 rep to you.

Ok. Then there could be a small rep bonus for a "community accept"?

Also, voting is subjective. It can be entirely possible for n people to be confused... ;)

Ha. Ha.

(i.e., don't take rep *too* seriously.)

I don't. As long as I have 200, to help with the beta stats, I'm fine. Lol.

@JM Using PrimePi is A LOT faster.

6:06 AM

@CHM Much mathematical analysis (by Gauss, Legendre, Riemann, etc.) has been done on the matter. It would be a shame for you to not use it... ;)

Hehe.

I'm trying to export the plot, but my computer is dead slow.

user image

=)

@JM My interest in mathematics used to be very dim. When I was a kid, I found the math they taught us in primary/high school too... mechanical. Then came college, and I started to enjoy it more, probably because the teachers finally knew what the hell they were teaching, and liked it.

6:21 AM

Uhm guys

How do I access the options editor without using Mathematica?

I developed a respect for math, along with the interest.

I set some option and now it won't start anymore. (Changed default window appearance to borderless.)

@David me no knows, sorry. best of luck.

@David edit/delete init.m for the front end (most likely in your user directory)

Thanks, just found that

6:27 AM

for me on Windows it's C:\Users\USERNAME\Application Data\Mathematica\FrontEnd\init.m#

Problem: It opened with mathematica by default

and now i've got user interface problems.

this is one annoying bugger!

i'm going to unleash the linux on you, init.m

@CHM The math taught to kids is quite boring compared to what is actually done in mathematics. Sadly most people grow up thinking math is all about the crap they did as kids...

If only I remembered the option's name

I need to be off. Later.

@JM thanks. bye

6:32 AM

HA! Computer, your weapons against me are useless! Thanks @OleksandrR :-)

Time to make a backup of init.m and continue messing around in the options.

@David one alternative to the manual editing would be to start the kernel, then use Developer`UseFrontEnd[...] to fix the options.

Is that a function that sends stuff directly to the frontend?

(On a side note, I'm a dummy for editing the global options and not the ones for the current notebook only.)

It's for use from the kernel that's not being controlled via the front end to begin with. I think you're thinking of FrontEndExecute which is for sending commands to the FE in the form of FrontEndTokens.

Without Developer`UseFrontEnd, Options[$FrontEndSession] gives an error from the kernel, though.

@OleksandrR You wouldn't happen to know how to evaluate something each time a new nb is created, would you?

As in "I want the first cell to be 1+1 and evaluate it when I hit Ctrl+N"

(Goal is to set options for each new nb opened)

6:49 AM

@David not off the top of my head. To be honest I rarely do anything of consequence with notebooks or the front end in general so I'm not the best person to ask. Maybe post it as a question?

Already did that more or less. mathematica.stackexchange.com/questions/1641/…

What I'm asking right now is meant to solve this problem, but would have of course have many more useful applications.

David Zaslavsky

7:26 AM

I've been getting "scatter-pinged" a lot tonight ;-P

@DavidZaslavsky oh dear. Does the system ping you for a partial name match?

David Zaslavsky

7:41 AM

Yeah, every time someone types @ABCDEFGH it apparently pings everyone whose display name starts with ABCDEFGH

8:38 AM

@DavidZaslavsky @H Good morning everyone whose name starts with H

9:01 AM

@halirutan a ping needs atleast 3 letters :)

which is why J. M. can never be explicitly pinged (periods and spaces are stripped out)

2

@yoda hmm, than this wont work of course.

9:15 AM

but you can always temporarily change your name to something similar to the person you wish to annoy =)

9:25 AM

@yoda I feel so special... :D

9:49 AM

@DavidZaslavsky You could change your name. I heard that @Spartacus is available again.

10:02 AM

Hello

hey hey

I voted close on this one, what do you think? --> mathematica.stackexchange.com/questions/1657/…

I'm on the fence with that one. Are we supposed to be cool with questions on the philosophy of Mathematica?

"Why does Mathematica do it this way?"

I don't think asking it this way is good. Some people might "ask" the same question just because they are annoyed with Mathematica's behaviour. Perhaps "how to use it effectively" would be a better way to ask.

It can be hard to differentiate between genuine curiosity and garden-variety griping in text, I'll grant...

...and sometimes the two are conflated.

10:07 AM

This question feels more like "Why can't Mathematica do it the way <other program> is doing it?"

I'm not sufficiently annoyed to cast my super vote on this particular question, but if you guys feel strongly about it, you could consider telling the OP why the question does not sound too appealing to you. ;)

I'm glad I'm not a moderator! :D

@Szabolcs :D

No really, there are two close votes thus far; it would be nice to tell OP what you guys told me...

OK, I wrote a comment

10:22 AM

Thanks Szabolcs. :)

Nice comment. How much rep does a user need to be able to talk in a chat room?

@Heike 20 rep.

@JM Thanks. I just wondered because of @Szabolcs' comment.

10:36 AM

@Szabolcs which one?

@Heike Sorry, I'm the stupid one

10

A: How can I create a function with optional arguments and options?

I voted for Rojo's answer. I believe it is the best way. If for some reason you cannot be that specific about your arguments you might use the converse: nr = Except[_?OptionQ]; f[x_, y : nr : 2, z : nr : 3, OptionsPattern[]] := OptionValue["g"][x + y + z] If for some further reason you need...

: signs are both for default arguments and named patterns

he gets a vote from me too

Funny to see all the different ways people misspell my name :) this time it's "Szabacks"

@Szabolcs My name gets misspelled quite often as well.

My former landlady knew me by my official first name. I think she used a different spelling on every note she left me.

I think your name is easy to remember. But I have to admit that for a long time I did not know it was a girl's name.

There's also "Heiko" which seems to be a boy's name (but I don't know in what language)

It's used both as a boy's and a girl's name

Heiko sounds German, but I could be mistaken

11:00 AM

@ Szabacks and @ Heike; Thanks for re-directing me to this site.

@ Szabacks you can delete the question I posted there. Apparently I cannot do until two days...

@Heike I only knew of the physicist Heike Kamerlingh Onnes previously...

Coming from Mathcad, why does mathematica have separate cells for inputs? What is the advantage of this?

@yCalleecharan even though they're called "notebooks", the idea is to be able to produce publication-quality output using stylesheets for books, papers, reports, etc., so a more structured document is helpful. I've not used Mathcad, but I understand the intention there is to basically reproduce the totally unstructured, pencil and paper-type environment?

@yCalleecharan You've read this already?

@Szabolcs hey, it's not "starbucks" yet :D

11:16 AM

Thanks for the explanations (and for the useful link). I understand that this gives structure to a notebook and this is a very convenient feature. I am browsing through the book Mathematica by example by Abell/Braselton and it does not discuss notebooks as such.

@Oleksandr I have used Mathcad only for a short time but it is more like Word...so you can add sections and so on. The book that I was reading for Mathcad had a chapter dealing with creating templates for the worksheet (notebook for Mathematica) and I could not find a similar discussion (until now) for Mathematica.

@J.M The guide "Notebooks and Documents" is great. Thanks.

@yCalleecharan I'm not familiar with Mathcad, but a quick google search suggests that the Mathematica equivalent of a template is a Stylesheet

There are some predefined stylesheets in the menu section Format > Stylesheet you can play with.

@Heike Thanks for the information.

11:57 AM

@yCalleecharan You can think of notebooks as an extension of the interactive command line. Except you can go back and change input lines or save the whole session. This way of working interactively is becoming increasingly popular. MATLAB now has "cell mode" (which in essence is the same thing) and the latest ipython has a htmlnotebook interface.

@Szabolcs Yes mixing text and calculations is becoming part of what is called as reproducible research. I do this already with LaTeX and R.

12:18 PM

Well, for me it's not about mixing text and commands. It's about building up calculations incrementally instead of writing a whole program and running it.

Yes, I am ignorant:

0

Q: What is a "Paclet"?

I often see references to "paclets", for example the PacletManager` context, the PacletInfo.m file in some packages and next to downloaded computable data, $UserBadeDirectory/Paclets, etc. What are "paclets", what is their relevance to end users, and how can one use them with packages?

package system paclets

@Szabolcs (there is a typo in $UserBaseDirectory)

fixed!

Why does this question confirm your arrogance?

12:35 PM

@Heike I am sorry if it is an inappropriate question ... can you please explain?

@Szabolcs Oh, sorry, I completely misread your comment. I thought it said "Yes, I am arrogant" instead of ignorant.

I was puzzled why asking a question about paclets would make you arrogant (unless you had planned to write a 10 page answer to your own question explaining the ins and outs of the paclet manager).

I really don't know what the paclet manager is, but I notice it is used in all kinds of packages, not only the ones by WRI

I don't know what the paclet manager does either.

1:15 PM

I abused a near-extinct tag and I made a new one for this question. Feel free to retag.

1 hour later…

2:24 PM

What does Strunk & White mean?

maybe this?

The Elements of Style

The Elements of Style (1918), also known as Strunk & White, by William Strunk, Jr. and E. B. White, is a prescriptive American English writing style guide comprising eight "elementary rules of usage", ten "elementary principles of composition", "a few matters of form", a list of forty-nine "words and expressions commonly misused", and a list of fifty-seven "words often misspelled". In 2011, Time magazine listed the writing style-guide as one of the 100 best and most influential books written in English since 1923. History Cornell University professor of English William Strunk, Jr., wrot...

Got it.

Really wish I had a Good Answer ..

2:50 PM

@Szabolcs I'm 4 upvotes away from one

Me too, but I really wish it wasn't *that* answer for me... damn bikeshed.

@JM Is it a bike shed? I always thought it was a fence. And should it be blue or red?

@JM But I feel the same about my top scoring answer.

@Heike Heh. :) Something like that, yes.

It was a bike shed: en.wikipedia.org/wiki/Parkinson's_Law_of_Triviality

user image

This is the cumulative questions graph

A linear fit from jan 23 to today gives a 13.9 questions per day

3:02 PM

@Szabolcs That a lot better than the 8-9 we used to get on SO.

@Szabolcs It says 12.8 questions per day on area51 at the moment. I wonder where the difference comes from.

@Heike A51 doesn't update in real-time, for starters.

Maybe they don't count closed and/or deleted questions.

@JM No, but the average number of questions shouldn't vary too much over time.

or is the number of questions per day on area51 not calculated over the whole time period?

@Heike They are probably averaging for a shorter time span. If I count posts/day since february 8 til the last post we had, I get 11.2 posts per day.

@Heike the grid lines on the graph are weekly, starting Sunday midnight. We probably have fewer posts because of the weekend now. I guess it would be reasonable to average for one complete week, so let me check the average since last Sunday ...

@Heike the average is 11.5876 for this week, 14.2574 for the week before and 14.8243 for the week before that

3:21 PM

Looks like they took the average over the last 2 weeks

I hope the rate picks up again.

3:59 PM

I'm surprised (or should I not be) 500 keeps asking the same questions

@yoda Apparently searching ability is not part of his skillset...

@JM well, I won't blame users for not being able to find some specific posts (wordings are not always helpful)... but.. he asked the original!

Vastly annoying, nevertheless... *sigh*

4:19 PM

I didn't realise he had asked the exact same question before. Otherwise I would have left a comment instead of posting an answer.

No fault of yours, Heike.

Thanks @JM

By the way, you seem to change avatars more often than I change my socks.

Eh? It's been four days I think... :D

It feels more frequent.

I like the latest one. It looks like an upside down snake

@Heike That was the intended effect. Thanks. :)

4:28 PM

@yoda yes this had been a trend before... annoying (although it shouldn't be, really)

Oh, I didn't even see the new avatar

reload needed

@acl It shouldn't be a trend, or it shouldn't be annoying? :)

@JM annoying :)

@JM I'm curious, what is it actually that you do?

Chemistry?

@Szabolcs Yes, chemistry. Math's the hobby.

(and if it's not already obvious, I'm also a frustrated sculptor :D)

4:44 PM

who's the feed master here @Szabolcs? Could you add a meta feed to the room?

@JM That would explain the hexagonal theme in your avatars

@Heike Actually, no. The actual inspiration was old code by Mark.

...which I decided to update and enhance for version eight.

Found it.

@JM The link doesn't work for me but I think I've found the right page

hmm... perhaps we could request Mark to add a link to this site on his webpage...

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