@acl Leonid's answers are always very informative.
@rcollyer Excel does a decent job at being okay. :P
I used to generate graphs in Excel, but I use another program now. I still use Excel to create my tables, that I then convert to LATEX. I find it too laggy for any other use.
If anybody's interested, the graphing tool I use is called Plot. It is an OS X app, available here
Just before Christmas, my HDD failed, a bunch of pixels on my screen discolored, and a couple of keys on my keyboard went loose.
Went to the Apple Store, they asked for my name and birthdate, took my computer, replaced the parts, and I had my laptop back - in one evening.
1000$ worth of reparations. Now.. yesterday my battery gave me a "Service Battery" alert. That's not good news though, because the battery I have to pay.
But meh, to me it's worth it, not having to worry about customer care.
If I do back to back calls of Eigenvalues[] and Eigenvectors[] can these be assumed to order the values and vectors the same, or is each independent?
Related to this is a curiousity about the performance of a pair of calls like this. Are mathematica optimizations done at an expression level, or...
@CHM If we must be precise: SchurDecomposition[] is what actually returns the "spectral decomposition". Eigensystem[] returns what it says. The deep theorem is the correspondence of the outputs of those two functions...
Given a directed acyclic graph, there is always a possibility to plot the graph as layers, where nodes always send edges into one direction (usually down), to successive layers, and never backwards. The "LayeredDrawing" option value for GraphLayout fails miserably. There is the built-in (but some...
via ColorSeparate[Image[...]][[1]] // ColorNegate.
@Verbeia We're slowly moving up the rankings. Currently, we appear to be in a dead heat with DSP. With luck, the influx of questions will mean we'll stay ahead of them.
I've been really slack on dsp... questions and views are zooming up, but no one's picking up the slack in editing and tidying... normally, I'd do that routinely, but got bored and burnt out on gardening
@rcollyer making undergrads run away screaming is a badge of honour isn't it? I reckon the minimum effort way to do that is to go through a proof of the Hohenberg-Kohn theorems. Undergrads just love that stuff!
@rcollyer yeah, H-K theorems are OK at an undergrad level IMO. But I'm in a chemistry department, so often they balk at simple calculus. I managed to name-drop Tikhonov regularization in a talk I gave the other week.
@Andy: I'd say that's why books like Wagon's are popular. Often the examples in the help file are minimal. Those books show off the power of these functions.
@AndyRoss I guess control theory and wavelets could benefit from some longer writeups. Those aren't areas I've got any familiarity with and without getting out a textbook or three it seems a bit difficult to find a way in even though they almost certainly do have uses in more general contexts.
What I'd really like to see is a short demonstration comparing, say, QRDecomposition[] and SingularValueDecomposition[] with LeastSquares[]. I could write one myself, but such things really should be in the help file...
I agree. Even when it's documented, there are no references for the methods used. One thing I really like about MATLAB's documentation is that they meticulously include references to literature, so if you so desired, you can actually re-implement the algorithm yourself
this is another one of those man power issues. We are sort of limited in what we put in the home page for a function. For links and such we need advanced documentation which takes a lot of time.
Most of the time is spent creating new functionality. I think most probably prefer it that way :) Then there is the time writing the docs which take a lot more time than I would have guessed. Advanced documentation keeps lingering on the todo list and never seems to rise to the top.
@AndyRoss So now you know how we feel when we all get Internal`Blindsided[] with all the undocumented functions that get thrown around like candy on Halloween =)
@JM well... I can think of several times when I was in the midst of some project and "invented" some new function only to find a better version already existed in some buried context.
@JM one you are probably familiar with is Internal`PartitionRagged. I reinvented that wheel many times.
So on another topic... I actually liked the question 500 posted that was deleted. It had to do with creating labels with names, email addresses and icons (I don't know how to link to it).
@AndyRoss I mean, combine Internal`PartitionRagged[] with PadRight[]...
(Full disclosure: the code in that question was a modification of a "Mathematica Programming Competition" winner in the early '90s. Silly me forgot to note the year in the documentation.)
@MrWizard I really don't know. OO's spreadsheet is less than stellar; Excel is a steaming turd; and I haven't really needed to use spreadsheets in the last three years to bother shopping around. If you find a good one, please let me know, too...
@Wizard I've been using Excel for the last 15 years (standard calculation tool where I work). From 2003 to 2007 there are substantial improvements. From 2007 to 2010, not so much. I recommend you see these two articles: add-ins.com/Excel%202003%20versus%202007.htm
Have little experience with the openoffice equivalent, but when I tried it (2 our 3 years ago), I felt it was a product of a rapid development project, trying to get it close to the functionalities of Excel as fast as possible, but where no time was taken to soften edges (for me, being obliged to use a spreadsheet all the time, it clearly justifies paying the small price of Excel)
@Szabolcs I use larger-than-default fonts (size 15) in GraphicsBox so I would not be the best one to ask. Also, regarding the filled curve answer I was slowed down because I don't actually have FilledCurve. It appears that my post-and-then-update approach is annoying however, and I will try not to do that as much. In this case I was going to leave out code and illustration entirely because I cannot generate it, but then I decided to copy from the documentation.
Recently I have been posting an answer that is not yet complete and then continuing to make additions over the next few minutes. Undeniably I enjoy getting first post, but there is another reason that I have been doing this: to get some ink on the page so that others know what is coming.
I pers...
If I do back to back calls of Eigenvalues[] and Eigenvectors[] can these be assumed to order the values and vectors the same, or is each independent?
Related to this is a curiousity about the performance of a pair of calls like this. Are mathematica optimizations done at an expression level, or...
Recently I have been posting an answer that is not yet complete and then continuing to make additions over the next few minutes. Undeniably I enjoy getting first post, but there is another reason that I have been doing this: to get some ink on the page so that others know what is coming.
I pers...
