@yoda, hmm. I have not really a positive opinion about that, since I rarely use greek letters and when posting code, I always use smth like phi. Btw, yesterday I sent Rebecca the stuff.
I can't seem to flag using the reason "other" with a message. I keep getting a message that my message has to be more than 10 characters, even though it clearly is. Probably a IE7 problem. Anway the asker and the editor on this question need to be merged. He says in his edit comment that he is the same guy.
I am trying to solve a system of equations which is dependent to an parameter alpha. So I iterate over alpha via a Table call and try to back substitute the solution found in iteration i into the FindRoot call. My example leads to an infinite recursion.
sols = {x->0, y->0}
Table[ {sol = Fi...
@OleksandrR I have a question for you: Why do some people write it Aleksandr and some Oleksandr (like you and sasha)? Shouldn't Александр start with an A?
One reasoning I came up with was that the difference was based on whether the person's origin was Ukranian (O) or Russian (A), but I'm not sure if that's right
@yoda that's right, it's Ukranian. However, this is not my real name; I just chose it to use on MathGroup for anonymity and because it is (AFAIK) unique (thus searchable), and carried on using it here.
@yoda I mean, for example, if I wanted a button that makes the cell that contains it selected, Button["Select this cell", SelectionMove[ButtonNotebook[], All, Cell]] wouldn't work
I would like that, as an example, to select the cell of the button
@yoda @halirutan @Rojo I can see how it could be challenging for a beginner. (I'm not too sure how I would do it). But he's asking for someone to do it, not for help.
SE is not a rent-a-coder place - and it doesn't look like it either, I wonder why he thought so. Funny
@Rojo Yeah, belisarius was the first (maybe second, Leonid may have edged him out) to get a gold Mathematica badge on SO. He's also the only one in contention for a gold Math badge, primarily due to this answer. Produced using mma, of course.
@rcollyer yup, they can be. The cranky thing is that there is no way to lock every damn thing in the question... locking the question does not lock the answers, and mods have to do them one by one if that's the intent
except if they've slapped a "historical question" banner, in which case everything goes limp
@yoda But that requires a lot of manual editing :-( It's too much work. Also, \[Greek] is highlighted in special bold blue, which makes the situation much better.
I am trying to compute symbolically a n-fold integral (n is a parameter of a function) over, say, the cube [0,a]^n. My code looks like this
intCube[n_, a_] := Module[{xvars, range, expression},
xvars = Table[Symbol["x" <> ToString[i]], {i, 1, n}];
range = Table[{xvars[[i]], 0, a}, {i, 1, n...
3D surface rotation in Mathematica 7 with anti-aliasing turned off is very fast and smooth. However, turning on anti-aliasing, even at a moderate level, drastically reduces the rendered frame rate, making rotation very choppy. This happens to a much greater degree in Mathematica than it does in...
@MrWizard I was thinking about writing a meta post with links to all the tutorial-style answer that we might commonly want to reference. Just to have a handy list so I don't have to search so much. Like this one: mathematica.stackexchange.com/questions/1959/… The primary reason I want it is to have the list for myself, but I think it can be useful for others too. Do you think it's appropriate to post it?
@MrWizard I'm worried some would take it as an "official" list that we are supposed to reference, or there would be big debates about what to include an what not to include. So maybe it's better to keep it private for personal use.
@Szabolcs Perhaps it would be better to make an index of questions. That way there is not a bias for a particular answer, yet a good answer should still be apparent.
On second thought I'm not sure it would be a problem. I would hate to see it cause contention, but I think the community could manage to select helpful answers. Only if someone edits the list to include theirs, and then someone else deletes it do I see a problem.
I think we would have to let the situation unfold to find out.
@Heike I need a "null graphics object", something I can include in a Graphics or Graphics3D but it doesn't display as anything at all, it just gets ignored. Null works sometimes, but not always (especially not with Dynamic things). Do you have any better suggestions? Here's my use case.
@Heike I am really sorry, of course {} will work! Why is that I only find the solution after I tell someone about the problem.... ?
It it, but the only noticeable thing in the graphs is the increase in Q/day. Moving medians are notoriously stable so the Visits/day doesn't say much ... (why couldn't they just use a mean??)
I never studied any statistics, so I'm really not good with this.
But I think the result would depend on whether they use a question rate calculated for periods of 1-hour when taking the median or a question rate calculated for periods of 1 day.
@Heike Well, if there are any improvements, feel free to post. Mine has the problem that it keep calculating as the mouse moves even if it is not over the graphic. That's pretty wasteful but I was lazy and didn't want to complicate the code.
There was another question that complained that assignments with subscripts lead to recursion. Was is closed and deleted? I'd like to mark as duplicate.
Duplicated shouldn't be deleted, I think. They increase the chance of the site being found by google. Just leave them closed.
I am absolutely sure there was a question just like this, and someone posted an anwer showing exactly what happens.
@Verbeia No, I know the person I referred personally, and she's a novice user :) Also, she would have told me if she started posting.
@MrWizard This one: mathematica.stackexchange.com/questions/3020/… This keeps coming up again and again, and I clearly remember one answer where someone showed (with a screenshot too) why there is a recursion and what happens.
There's a regular on MathGroup whose names is also Helen, but I doubt it's the same person.
BTW I think she's the only person I referred whom I know face to face (i.e. not only online). I don't know anyone closely who uses Mathematica extensively.
@MrWizard This is closely related: mathematica.stackexchange.com/questions/1004/… Do you remember when J. M. sugggested a set of canonical question with very well worked out answers that we can mark faq as duplicates of? I think soon we can start doing that.
Taking a page from this meta.math.SE discussion, and in light of this question, I wonder if it would be worthwhile for us to maintain a community wiki post like this one in meta.math.SE that lists questions that a.) are likely to be asked, in ever so different variations, again and again; and b.)...
@Verbeia There is Helen Read on MathGroup, but I doubt it's her because the person who started posting here recently seems to work at DigiArea. See this. It's close to an advertisement, but I think it's an appropriate answer here regardless of that.
@Szabolcs Perhaps I should add a comment about avoiding recursion to my answer in that thread. I make a search for questions relating to Subscript but I could not find one that is a duplicate of the first question you referenced.
@Verbeia People often insist that it's appropriate to disclose. But is it really necessary? I think it's a very appropriate answer. The OP asked for differential geometry tools. She showed one and described in detail what it can do and why she considers it to be an excellent choice. There's nothing wrong with that. ... well, it is true that if she works there, she might not be as ready to mention possible disadvantages as an end user. But it's still a useful answer.
@helen We have just been wondering if you work at DigiArea If you do, maybe a one-line note would be appropriate in the answer about differential geometry packages.
@helen And welcome to Mathematica.SE! :-) We're always glad to have new active people here
@MrWizard You deleted before I got the chance to read it ...
I often import several long time series to analyze something about a city. When I have multiple cities, I use contexts. As a simple example,
Begin["paris`"];
dataRaw=Import["Paris.csv"];
data=Differences[dataRaw];
dataMax=Max[dataRaw];
End[];
Begin["madrid`"];
dataRaw=Import["Madrid.csv"];
data=...
May be someone can explain why I can't use Begin[context],End[] inside Manipulate expression, or inside Manipulate Initialization section?
When I use it in the Manipulate expression, and close the notebook and restart, I get the error This file contains potentially unsafe dynamic content
here...
If we evaluate these lines one-by-one, x will be created in the context cc.
Begin["cc`"];
x = 1;
End[]
However, if we evaluate them together,
(Begin["cc`"];
x = 1;
End[])
then x will be created in Global. This is despite the following printing cc`:
(Begin["cc`"];
Print[$Context];
End[])
...
@Szabolcs Yes, I am working in DigiArea. Initially I put short/one-line answer with a link in the post about differential geometry. But in the comment I was asked to give more descriptive answer. If you think that it is necessary to return the link, I can do that, no problem.
@helen No, don't change your answer, the long version is excellent. What seems to be the usual practice is that you either disclose your employer in your user profile, or mention that you work there at the bottom of the answer.
@MrWizard You're very kind. I have been working in this field for a long time, worked my way up. The last four years have been very busy and very interesting.
If you go to the web site of my employer, you can even download MP3s of my dulcet tones ;-)
But you can understand that I try to keep at least a bit of separation between here and my real life.
One of these days people will work out that I sometimes answer questions in my lunchbreak.
@MrWizard Oh Project Euler. If I started on that, I would get mired in it. Best not to start.
@helen As Verbeia said, it's very good that you gave a detailed description. A link is just a link, but to decide what package to choose, I need to know what they can do. :-)
@Heike I am pretty fluent in English, and use it daily, but word games always remind me how inadequate my English is compared to my Hungarian :-(
@MrWizard The comment will also cause the link to show up in the right hand side column ("Linked questions"). But on the other hand comments are supposed to be volatile ... I used to write "related:" comments often
@MrWizard and all: I remember this Tim guy from MATLAB on SO and looking at his profile for other accounts, seems to be a help vampire. So please keep in mind and nip things in the bud before it gets out of hand (it's not there yet)
We have had so many good questions and answers in the last day that I have run out of votes for the first time. Now I have to leave an extra pile of tabs open to remind myself to vote.
@MrWizard Seriously? You haven't run out of votes before today? I have to call BS, you got the suffrage badge a while ago. But, the next one, VoxPopuli, is actually a little difficult to get because of the way they calculate the voting limit. You have to burn your votes on questions, first, before voting on answers to easily hit the 40 vote mark.
It's weird, because we already have an agreement about almost everything, EXCEPT about the work that must be done by our counterpart ... and nobody else can do it
I was never salaried (although a grad student stipend is like that), but yeah, I understand that.
@yoda speaking of the c++ tag, on my careers.stackoverflow profile it lists me as being in the top 20% of the c++ answerers. That is a very, very scary statistic as I've only answered 27 non-wiki questions with 64 upvotes. If I'm in the top 20%, then I completely understand why the top echelons are going completely crazy with the questions.
@Heike c++ is one of the most trafficked tags on SO, if I'm in the top 20%, it means something is seriously wrong, and likely that is leading to the viciousness that is often seen with questions/answers on that tag.
Last night there was some discussion about highly voted answers. While the examples brought up are scary unto themselves, the most interesting results are in this data query: top 500 answerers by avg score. The top rated person has only answered 13 questions!
How can it be? Isn't the memory of a local variable inaccessible outside its function?
You rent a hotel room. You put a book in the top drawer of the bedside table and go to sleep. You check out the next morning, but "forget" to give back your key. You steal the key!
A week later, you retu...
A lot of the C++ folks were pissed about that one because Eric is not a C++ guy
For a long time, I couldn't display that answer correctly... the diacritics would just fly about everywhere, and i had to ask for screenshots to appreciate it. It's now fixed though
During undergrad, I beat the snot out of an 1800+ rated player, and I could see the structure of what he was doing and how to circumvent it. Now, I couldn't en passant my way out of a paper bag.
@Heike Not sure. I feel Mma has a very steep learning curve
@Heike Clap!
@Heike I used to prepare my math exams with a friend. (math.nyu.edu/faculty/avellane) working with him was a permanent remainder of how deep you can think on a simple subject
@EliLansey May I suggest posting a question with a few features and then "upgrading" in other questions? If you post a huge list it's harder to find someone with enough time to answer ...
@EliLansey It has a fairly steep learning curve as it has a different way of evaluating then standard mma. So, I completely understand. But, I agree, CustomTicks needs to be absorbed into the kernel.
I know this is really late to the game, but the expression used to generate the first n colors in ColorData[1] is:
Table[Hue[FractionalPart[0.67 + 2.0 (i - 1)/GoldenRatio], 0.6, 0.6],{i, 1, n}]
@rcollyer do you really think it's important to explain = vs := yet again ... ? I felt it's necessary to draw attention to it in case the distinction is not absolutely clear to the OP. If he needs more explanation, he should ask. If he doesn't ask, today I just don't feel motivated enough to try to explain.
@rcollyer Of course if my answers are not clear enough, I always appreciate feedback. I',m quite tired these days, so it might easily happen.
@Szabolcs The answer is clear. Just HH[kx_] = H /. {μ -> 1, Δ -> .3, L -> 11, ky -> 0} seems a little surprising, at first, and why Set is necessary there. It is your call if you wish to add anything additional, or not. The fact that you pointed it out is useful, by itself. Sufficient? I don't know. I agree, though. If the OP asks, tell him then. I'll remove my comment.
Taking a page from this meta.math.SE discussion, and in light of this question, I wonder if it would be worthwhile for us to maintain a community wiki post like this one in meta.math.SE that lists questions that a.) are likely to be asked, in ever so different variations, again and again; and b.)...
@Searke I know it is easy in theory, but it is a mental burden that distracts me from my task and it takes time. And I knew there had to be something. Thanks for the pointer'
Also DepthFirstScan is not a function I am happy to use ... it's not easy or convenient. I'd rather implement the search manually than use it ..
I am trying to solve a system of equations which is dependent to an parameter alpha. So I iterate over alpha via a Table call and try to back substitute the solution found in iteration i into the FindRoot call. My example leads to an infinite recursion.
sols = {x->0, y->0}
Table[ {sol = Fi...
3D surface rotation in Mathematica 7 with anti-aliasing turned off is very fast and smooth. However, turning on anti-aliasing, even at a moderate level, drastically reduces the rendered frame rate, making rotation very choppy. This happens to a much greater degree in Mathematica than it does in...
If we evaluate these lines one-by-one, x will be created in the context cc.
Begin["cc`"];
x = 1;
End[]
However, if we evaluate them together,
(Begin["cc`"];
x = 1;
End[])
then x will be created in Global. This is despite the following printing cc`:
(Begin["cc`"];
Print[$Context];
End[])
...
How can it be? Isn't the memory of a local variable inaccessible outside its function?
You rent a hotel room. You put a book in the top drawer of the bedside table and go to sleep. You check out the next morning, but "forget" to give back your key. You steal the key!
A week later, you retu...
I know this is really late to the game, but the expression used to generate the first n colors in ColorData[1] is:
Table[Hue[FractionalPart[0.67 + 2.0 (i - 1)/GoldenRatio], 0.6, 0.6],{i, 1, n}]
