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I'm the little trashcan that could!


Mar
22
accepted Sort Unicode characters
Mar
22
comment Sort Unicode characters
That seems workable. Thanks and +1! I'll await 24 hours to accept just in case there are other answers.
Mar
21
comment Sort Unicode characters
Thanks for the help. Unfortunately, this only sorts words up to their first letter, and does not sort properly after that. For example, FromCharacterCode[SortBy[ToCharacterCode[{"ɝz", "ɝaz", "ʃ"}], First]] gives {"ɝz", "ɝaz", "ʃ"}, which is not sorted, since ɝaz alphabetically comes before ɝz.
Mar
21
comment TimeConstrained[Delete[Range[1],1]] causes kernel crash
Can confirm crash on Windows 8.1 Mathematica V10.0.2.0.
Mar
21
revised Sort Unicode characters
deleted 2 characters in body
Mar
21
asked Sort Unicode characters
Mar
17
answered How do I color an Image generated from data such that one range of values is one color gradient and the others another color gradient
Mar
17
revised Creating a random make matrix with a particular rank
added 352 characters in body
Mar
17
answered Creating a random make matrix with a particular rank
Mar
4
comment How to invert a matrix with 100 trillion elements?
M.R.: "I have petabytes of storage." WAT
Mar
2
comment Finding and plotting roots with parameter
I guess the crux of what I'm trying to say is that because each term in the summand is separable, it is not necessary to compute the value of the term over an entire $(x,t)$ grid, and you can use TensorProduct instead, which ought to reduce computation time by an order of magnitude or so.
Mar
2
comment Finding and plotting roots with parameter
At the moment I don't have time to test this (probably won't be free until tomorrow evening), but this might be one possible avenue of approach.
Mar
2
comment Finding and plotting roots with parameter
I guess the question is equivalent to "can I create a function which efficiently returns a list of the small positive roots of $\epsilon\lambda=\cot\left(\lambda\right)$?". If you're fine with generating a 3D cube of data (might need a lot of RAM?), then you can add together the tensor products of the sinusoids for each of the root frequencies, and then save the array to disk. By doing this, you generate slices of the 3D cube for each value of $\epsilon$. Finally, stitch them together and call Interpolation on it, giving an InterpolatingFunction $u(x,t,\epsilon)$ as you desired.
Feb
28
comment Elements inside arrays seem to be strings rather than signed numbers
I think what bills is trying to say is that instead of using Subscript[a, ##] you should use a[##]. It doesn't look as nice, but subscripts are really annoying to use in Mathematica, and should ideally be avoided.
Feb
28
answered Replace elements in matrix to make it symmetric using automated procedure
Feb
23
comment Simple Sin plot generates unexpected output?
Yup, it's a PlotPoints issue. To fix, just increase the number of points sampled.
Feb
23
comment Discrete Fourier Transform of a vector defined on a 3D lattice
@user3810266: So what you're saying is that you have three lists, listX, listY, and listZ, each of which are of Dimensions {Nx, Ny, Nz}? In that case, the original answer still stands, and you can simply call Fourier /@ {listX, listY, listZ} (/@ means Map). Alternately, you can do it list by list, ie recipX = Fourier[listX], recipY = Fourier[listY], recipZ = Fourier[listZ].
Feb
23
comment Integral does not converge (when it should)
Works fine in 10.0.2 for me as well, so probably a 10.0.0-specific bug.
Feb
22
comment Discrete Fourier Transform of a vector defined on a 3D lattice
@user3810266: What are the explicit dimensions of your data? If you could edit your answer to provide that info, it would be easier to give a useful answer. Presumably it is a four-dimensional array, so the question is what each index physically means.
Feb
22
comment Discrete Fourier Transform of a vector defined on a 3D lattice
@user3810266: For more info, search for Fourier in the Documentation Center. Several of the examples illustrate multidimensional FT's, which are all of the form Fourier[arrayInQuestion].