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Oct
14
comment 2D Fourier transform of a few (4) disjoint discs on a plane
@DumpsterDoofus (+1) In case anyone wants to reproduce the plot in a Mathematica version that doesn't have TensorProduct yet, it's also possible to just do the monochrome image first and then wrap it in Colorize[%, ColorFunction -> (Blend[{Black, RGBColor[1.0, 0.3, 0.1]}, #] &)].
Oct
13
comment How can I create a plot like this in mathematica?
There's also BoxWhiskerChart
Oct
12
comment How to create a reliable natural integral operator?
I voted to close as a duplicate originally, but it may be better to close because it's unclear what the question is asking. "Natural integral" is not a thing.
Oct
12
comment How to create a reliable natural integral operator?
My point is simply this: Integrate takes your integrand and finds, if necessary, an appropriate transformation that allows the integral to be calculated. That may involve any number of transformations, among them potentially series (such as that on which your question relies). But it's important to realize that the choice of appropriate transformation is limited by the type of integrand, and there is no one transformation that could be used as a definition of natural for all integrands. In that sense, Integrate already finds a reasonably natural result.
Oct
12
comment How to create a reliable natural integral operator?
If a definition of a natural integral involves so many case distinctions, as in your question, then it is almost "by definition" not a natural definition. So in cases where the most general of your attempts doesn't work, you should just ask: why not simply use Integrate? By the way you forgot an $i$ on the right of the first equation.
Oct
12
comment How to create a reliable natural integral operator?
It should be mentioned that this question is based on an earlier question (and my answer to it). To explain what exactly makes this question different from that one, it would be good to show what Mathematica code you have already tried, and what your expected input and output looks like in some examples.
Oct
12
comment Calculate inertia tensors
Maybe of interest: I used the inertia tensor to identify symmetries of an object in an image in this answer.
Oct
11
comment How to create an hexagonal lattice structure
Also related: Wolfram Demo
Oct
10
comment Very serious multiplication bug when subscripts are used
@physicsphile Good to know they acknowledged the bug.
Oct
9
comment exporting mathematica videos
The question at this point seems too broad because there are so many ways to make movies. The title suggests that you want to Export videos from Mathematica. In that case, you would have to be more specific about the source objects that you want to export, and the movie format that is desired. It's not efficient for someone who wants to answer, if they first have to download the iBook you mention, in order to see what you might mean.
Oct
9
comment stacking images
Unless we get more details about the images, and an explanation of what this has to do with "stacking" them, I would call this a duplicate of the question linked by @Kuba.
Oct
9
comment Non sequitur in documentation of MemberQ
That historical explanation of why they put the wording in the front section seems to make sense (+1).
Oct
9
comment Non sequitur in documentation of MemberQ
I'm going by my knowledge of what all the other functions ending in Q also do. They differ from tests such as Element in that they assign a truth value based on the immediate, explicit structure of the argument. Think of TrueQ: it's very quick to give False because it only gives you True if you give it True first. In other words, functions ending in Q don't ever give "maybe" as an answer...
Oct
6
comment Explanation for coloring of variables by code editor?
What happens when you check the definition of r by doing ??r ?
Oct
6
comment Explanation for coloring of variables by code editor?
The screenshot has a gap in between line 132 and 136. If you want a real explanation of why r is blue after line 132, you have to post the actual, copyable code sequence without gaps that leads to the coloring you are showing here.
Oct
6
comment Explanation for coloring of variables by code editor?
I can't tell from the screenshot what happened in your notebook between the point when r was defined and when it reappears later. It may have been cleared in the meantime. Once a variable is subjected to Clear, Remove or =. it will again be undefined and appear blue everywhere in the notebook, even at earlier points. But sometimes it does happen that Mathematica doesn't immediately recognize a previously defined symbol and incorrectly leaves it blue.
Oct
5
comment Mathematica exported movie quality
@JasonB is right - you may want to have a look at this answer where I discuss some other file formats for movie export, and at this answer for how to export image sequences to create the movie externally. However, you can get better result from within Mathematica, too, if you rasterize the image frames at the resolution you like before exporting them. That is discussed here.
Oct
5
comment Using an Image as the Fill/Texture (not background) of a Plot (not polygon)
I thought your main goal was to show the image only under part of the curve, like the colored regions in the sine plot you showed. If not, things are much easier (see other answers). To make the image fit the entire plot, you of course have to make sure that the aspect ratio of image and plot are identical. This could be done (a) by stretching the image, (b) by choosing an image with the right aspect ratio, or (c) by setting the aspect ratio of the plot equal to that of the image. You'd have to decide first which of these options you want. I mention option (a) in my answer.
Oct
5
comment Very serious multiplication bug when subscripts are used
@RolfMertig That's indeed good advice. Subscripts are in general full of pitfalls, especially for people who don't know anything about DownValues... But this seems to be a good test case showing a shortcoming of the parser that looks fixable.
Oct
5
comment Very serious multiplication bug when subscripts are used
@belisarius I confirmed this in version 8 and answered based on what I saw there. I strongly suspect that it's the same in version 10.