Description:
Mathematica discussion group. (Moderated)
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simple question
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Dear List: I have the following list: ejemplo1={{1,0,2,2,0},{0,1,1,1 ,2},{2,0,0,1,1},{1,1,0,2,2},{1 ,0,2,0,1},{2,2,0,1,1},{2,1,1,1 ,2},{0,1,1,0,1}}; I want to group it, so that the sublists of ejemplo1 that have identical values at positions 4 and 5 are gathered together. So I did the following code: Split[ Sort[ejemplo1,#1[[4]]>=#2[[4]] && #1[[5]]>=#2[[5]] &],Take[#1,{4,5}]==Take[#2,{4, 5}]&]... more »
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newbie q-n about FinancialData
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Hi, I would appreciate some pointer on how to use FinancialData API to retrieve fundamentals (e.g. PERatio ) on a list of tickers (all US) and export it to a file. One hour of googling did not help! Thanks a lot, max.
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how to find a function
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Dear Math Group:- Suppose we have:- x = a * e + (2*b - 3*a^2) * e^2 Now let us find such functions: F(x) = 1 + a * e + (2 * b - a^2) * e^2 + ...... we are just interested in the first three terms. Now two such functions can be: F1(x) = 1 + x + 2 * x^2 and F2(x) = (1-x)/(1-2*x) How can we find all such functions F(x)?... more »
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Bug in Plot3D?
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The two plot commands in the notebook below should give identical outputs, but they don't. The notebook is posted at [link] a := 9; b := 18; ff[x_, y_, z_] := x + y + z gg[x_, y_, z_] := 2*x - 2*y - z f[x_, y_] := z /. Solve[ff[x, y, z] == a, z] f[x, y] g[x_, y_] := z /. Solve[gg[x, y, z] == b, z]... more »
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compositions with the restricted set of integers
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...The above can be made more efficient by using the form of IntegerPartitions that only generates partitions of a given length. That is outs[sum_, thr_] := Total[Factorial[Length[#]]/ Times @@ Factorial[Tally[#][[All, 2]]] & /@ IntegerPartitions[sum, {thr}, {1, 2, 3, 4, 5, 6}]] does the same thing a bit more efficiently... more »
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Is it possible to make NIntegrate faster?
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Good point, DrMajorBob; I seem to have underestimated the telepathic powers of Mathgroup. As you will see below, the problem with my NIntegrate was that Mathematica tried to do SymbolicProcessing where it didn't need to. ...Using this suggestion, and playing with AccuracyGoal settings, I was able to get a factor of 30-40 performance improvement. This is still... more »
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how to read in a number in hex and convert it to
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You can't fit 256 hex digits into 27 binary digits, but other than that... Here's an example. First I'll create a much smaller "hello.txt" file... 30 numbers, each with exactly 5 hex digits: str = OpenWrite["hello.txt"]; Scan[WriteString[str, # <> "\n"] &, IntegerString[RandomInteger[{1 6^4, 16^5 - 1}, 30], 16]]... more »
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Bug associated with Graphics3D???
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Can anyone explain why the disk that corresponds to x = 5.1 (see the last line of the code below) isn't red---like the others? ------------------------- Rho[Psi_] = 2/(1 - Cos[Psi]); Para = ParametricPlot3D[ Rho[Psi] {Cos[Psi], Sin[Psi] Cos[Theta], Sin[Psi] Sin[Theta]}, {Psi, Pi/3, Pi}, {Theta, 0, 2 Pi},... more »
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Mathematica and LabelME
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The LabelMe is project created by the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL) which provides a dataset of digital images with annotations. The dataset is dynamic, free to use, and open to public contribution. [link] It is a very interesting way to research and experiment with computer... more »
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Importing fonts into Inkscape
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...Try adding the following option to your graphics before exporting them... BaseStyle->{PrivateFontOptions ->{"OperatorSubstitution"->Fal se}} I'm not sure whether it'll fix all of the problems you're seeing or not (since you didn't provide an example, it's impossible to say), but it helped with the... more »
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