Wolfram Mathematica - 2012-08-22

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2:36 AM

Can anyone tell me whether we have the advertisement banners and logos from here

21

Q: Design for Mathematica.SE

I'm Jin, I work on the designs for the Stack Exchange sites as they graduate from the beta phase. Each site will have its own unique theme that will reflect its topic and culture. However, all sites will share common elements so they feel like they're part of the Stack Exchange family. I have to...

discussion design

in an updated version so I can include them on a webpage and link to Mma.SE?

@halirutan Yes, Jin gave an updated one for the blog... hold on

user image

As for the logo... well, it was created with Mathematica and the code is on the site :)

There's also this blogpost that condenses it and you can simply download the notebook

@R.M But ready to use web-banners for including in different sizes are not available?

@halirutan oh, what did you have in mind?

I don't know what advertisement banners you're talking about

I don't think we have any right now, but if you have some standard advertisement sizes, then you could just ask Jin for it and he'd make you some

@R.M Some websites (and SE or SO are really big) provide some banners you can include into your own website to bring people to the site.

But when you never heard about something like that it is very likely we just don't have such stuff.

I'll create my own.

2:51 AM

@halirutan I know what you're talking about but we don't have that. It would be nice if we did. Area 51 has these for its proposals though... maybe they just haven't thought of doing it for the site yet

@R.M Anyway, thanks very much. Have to go now. It's very very late here.

Or very early. Depends.

Good night :)

Thx ;-)

They do have a personalized badge called the flair (not sure if you know about it) that you can use to show off your participation

Yours is here: mathematica.stackexchange.com/users/187/halirutan/flair

10 hours later…

1:07 PM

3

Q: Is there a way to facilitate the copy&paste process for code samples?

Code samples are easy to recognise, but I wonder if there is a more convenient way to copy all contents of a gray sample box into the clipboard for pasting into Mathematica. Right now I select all content in a given cell with the mouse (which can get fiddly for long scrollable cells), but I´d ver...

discussion feature-request

2:05 PM

Dang, kinda quiet.

2:38 PM

user image

...so I'm leaving that in the meantime.

coooooooooooooooool.

It's @Mana!

@Tim!!!

I got Mathematica.

I have no clue what I'm doing with it!! But it's really cool.

I don't either, I'm mostly just here to meddle in unrelated things. looks around shiftily I actually have more experience with MATLAB than Mathematica, heh. But the content on this site is pretty impressive, clearly people are putting it to good use.

@TimStone I need to check out the site more. I've mostly been reading through one .pdf to get a feel for the syntax of the language.

2:56 PM

@Mana It has a pretty steep learning curve. But it's very powerful

@J.M. Are you designing collapsible soccer balls?

@Verde I'm debating how best to apply it towards my upcoming multivar calc course, besides the obvious use of plotting out the functions we're given

@Mana You can do almost anything, from vector analysis, derivatives, integrals, you mention it

My main fear is coming to over-rely on it, though.

I'll see how it goes.

@Verde Wooden collapsing soccer balls.

@Mana Mma is a helpful assistant. You shouldn't rely on it :)

3:03 PM

@Mana That's when you can ask questions.

@Verde Right, it's a tool, and not a brain substitute.

@J.M. Well ... and then sometimes ... :)

oh, if I only had a brain...

@Mana try Import["ExampleData/head.dcm.gz", ImageSize -> Small] in your notebook

Nice.

hahaha I just drew squiggly lines all over a human brain. I am the best mathematician ever.

@Verde One of my favorite answers on SO was in how to use it as a tool in exploring a solution.

@Verde doesn't verde mean green?

3:15 PM

@rcollyer That's quite likely the joke...

A bit like the time I named my childhood dog with white fur "Blackie".

@J.M. I'm am just checking that I understood. Those Argentinians aren't like the rest of us, you know. :)

Now try `MorphologicalComponents[
EdgeDetect@
Import["ExampleData/head.dcm.gz", ImageSize -> Small]] // Colorize`

@J.M. I didn't do that. My black cat: chocolate. White cat with black spots: chip (as in chocolate chip).

@rcollyer Yes

@rcollyer Nice theme. :)

3:18 PM

@J.M. Later I had a dog named pepper, his coloring looked like ground black pepper.

@Verde Holy crap, I hadn't realized Mathematica can now handle DICOM...

@J.M. I was 5 when I named them, and i liked the food theme.

I should go. Good luck with your explorations, @Mana.

@J.M. help ref/format/DICOM

I think DICOM is far too complicated. They surely had not implemented it all

@Verde Yes, I did look it up in help after I saw your code...

@rcollyer thanks!!

3:22 PM

@Verde Well, that's what happens if you have doctors design a file format instead of... well, you know. :)

@J.M. yeah yeah. I worked a lot with a diagnosis cataloging system a few years ago. They can drive you nuts ...

I wonder why we haven't closed this already

0

Q: Find formula for general term

such as: {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1} it seems that need use Floor or Mod etc IntegerFunctions. I am sorry my english is very poor

function-construction integer-sequence

@Verde I'm kind of meh on it, but I don't want to exercise my unilateral vote. But I certainly won't vote to reopen if it got closed...

@J.M. Don't be shy

@Verde Well, if you can pull in three more people, I can cast the executioner's vote.

3:41 PM

hello: quick (meta)question: is it possible to render e.g. Subscript[x,i] on SE?

@chris nope

ah... too bad!

@TimStone how are you in all those rooms (barely active in this one) and yet aware of who drops in/says something as soon as it happens?

I know you're some secret SE ninja, but do you have scripts that alert you about activity in all rooms?

another quick mathematica on mac os question: every now and then when I cut and paste an input,output group of cells and re execute it, instead of replacing the old output by the new one it duplicates it. Anybody encounters this (minor) problem?

Since there are people around now... here's a quickie: MATLAB's filter2() is Mathematica's ListCorrelate[], right?

3:46 PM

@R.M Nah, I'm just very attentive, heh.

@J.M. I believe so, although it typically takes me several tries with ListCorrelate/ListConvolve's options and arguments to get it to do what I want

@R.M Thanks; I'm trying to translate some old MATLAB code I found, and this part was a sticking point...

ok since you didn't like the last one, a couple more :-)

@J.M. I know you probably would do this anyway, but I'd start with some known kernels and matrices and get ListCorrelate to produce the same output as filter2 for several test cases.

is there a way to change the default size of the mathematica frontend documentation center? can it be set up so that all cells are opened by default ?

and finally, is it possible in a given notebook to collapse down alls cells but just at the top level?

3:58 PM

@chris don't know if there's a point and click option, but it should be possible programmatically

@R.M Yeah, it's what I've been doing the last few hours. :D Anyway, at least I know I'm looking in the right direction, so thanks.

@J.M. Depending on the needs and actual usage ImageCorrelate[Image@matrix, kernel] too might work

@chris You mean the size of the window? I remember there's a 'remember window position' or something like that

@R.M yes the size of the window.

@R.M Nah, the old MATLAB code was using filter2() on an array of height values, as opposed to an image, so I think ListCorrelate[] is the ticket.

@chris Look up the options under HelpBrowserSettings (Global) in your option inspector. I believe you could set the window size there.

@J.M. ah, then yes. I've seen lengthy code written with basic functions because the OP didn't have the proper toolbox that would've done it in a line

@TimStone Do you remember the site to check if one's experiencing CDN issues?

4:11 PM

@R.M Actually, after staring at the blasted thing for a long time, the guy who wrote the thing seems to be doing something like a discrete derivative...

@R.M Hmm, unfortunately not

Oh, there is the NetDNA status page and the Data Center locator page, but I'm not sure if that's what you were referring to.

4:27 PM

@TimStone hmm.. I must've misremembered. The images in the site design aren't loading here, but I'll just wait. That usually solves most issues

Hey

Anyone knows how InterpolatingFunction work?

I want to save one for other sessions. When I dump save it and reload it it doesn't work properly

nor if I save it hidden in the notebook. However, in some smaller simple examples it seems to work

@Rojo the solution is to not use dumpsave, but simply >> the file

2

A: Problems with DumpSave and memoization

The reason this isn't working is that DumpSave expects a symbol as the second argument. The doc page says: DumpSave["file.mx",symbol] writes definitions associated with a symbol to a file in internal Mathematica format. With ClearAll[y] y[a_, b_, c_] := y[a, b, c] = NDSolve[{y''[x] == a...

@R.M Let's see... Thanks @R.M

4:59 PM

@R.M, it's not working :S

Nasser M. Abbasi

5:10 PM

@J.M., I have web page on Matlab/Mathematica examples (i.e. same problem is solved in Matlab and Mathematica). The page is here 12000.org/my_notes/mma_matlab_control/index.htm , I just looked and do not have filter2 in there, I should now go add it, but many others are there.

Any one knows if it will be hard/easy/expensive to get a hotel room for the Mathematica conference in oct 17 at student budget? should one reserve in advance or can I just drive there and find a room when I get there? like motel 6 and such? or will it all be booked up by then?

5:23 PM

@NasserM.Abbasi I don't know the rates in U-C, but places like motel 6/super 8 etc should have rooms available at the last minute too.

I would suggest that you also answer here and try to get SE to sponsor you to attend the conference

6:02 PM

Any better way to partition a string than StringJoin /@ Partition[Characters["alskdjflasdf"], 3] ?

@Rojo StringCases["alskdjflasdf", Repeated[_, {3}], Overlaps -> False]

Overlaps!

Niiiiiiiiiice

@OleksandrR. Thanks

@OleksandrR. Isn't overlaps false by default?

6:18 PM

@R.M yes... just making it explicit.

You never know if you go to the toilet and the dog comes and types SetOptions[StringCases...

2

3 hours later…

9:24 PM

I am trying to work out why this is still open

0

Q: Find formula for general term

such as: {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1} it seems that need use Floor or Mod etc IntegerFunctions. I am sorry my english is very poor

function-construction integer-sequence

(notwithstanding the fact that I've posted an answer)

Is there something particularly interesting about this? To me this seems normal, but I don't know if there's some CS terminology for the evaluation scheme

9:56 PM

@R.M I think understanding the evaluation sequence better will help him/her understand this

Yeah... I guess it's second nature to most of us that we don't stop to think. I guess Vitaliy's answer covers the bases

My litmus test is: if I can do the same thing in MATLAB, then it is not something unique to Mathematica :P

10:26 PM

@R.M sounds like a tautology to me :)

(two people have upvoted my joke answer to this !)

haha

10:45 PM

@acl Haha

I'll upvote it now

and give my alternative

@Rojo What he means by a ternary square word is "abcabc" but not "abcdabcd" ,right?

Right, because the second has 4 symbols, not because the repeating sequence has length 4. That's what I got

@R.M

oh, I see. I thought it was the latter

PRobably it's the latter, I just got home and saw that

I'm googling

No, you're right. He says in the very beginning that it's a ternary alphabet

10:54 PM

@R.M Yeah... I'll give it a shot how and see what happens

no big deal... just 3^111 possible words to test :)

Haha

11:26 PM

@R.M He is an online acquaintence of mine, joined the site early on at my suggestion. He actually emailed me with the question first and I suggested he ask it here. I've been at a conference the first half of the week and my head is full of my day job, so I just couldn't think of the answer myself. I thought the answers were awesome, so I am glad I suggested it.

11:37 PM

@Verbeia I wasn't dismissing the question... just that this is a syntax that I've seen and used from day 1, and because of my general lack of familiarity with other languages, I don't know if someone should be surprised at this

@R.M Well, I don't remember being able to do that in MATLAB or FORTRAN or C... :D

x{1} = @plus;
x{2} = @times;
x{1}(3,5)
x{2}(3,5)

@J.M. ^^ (MATLAB)

11:53 PM

:/ my first code on the square free stuff seems too slow

Well, I wouldn't konw after a week in 24 cores

@Rojo For[i = 1, i <= 3^111, i++, squareFreeQ[number]]?

@R.M Wow, I don't remember that at all. Since when? :)

Hahaha

(I've used function handles in MATLAB a bit before, but I honestly never knew that one can have indexed function handles.)

@R.M That code at least is correct

11:58 PM

@J.M. Sorry, I don't remember since when or if it was not possible in very early versions. Cells are relatively newer (since v5), so I would presume if you went far back, you wouldn't have been able to at some point

@J.M. you can't have function handles as regular arrays, but cell arrays are OK

cells are heavily underused in MATLAB

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