5.33 Tuesday, May 17, 2016

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Top new questions this week: 
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[Speedup matrix number multiplication] http://mathematica.stackexchange.com/questions/115087/speedup-matrix-number-multiplication

Consider this simple matrix number multiplication:

lth = 200; 
mtx = RandomReal[{0, 1}, {lth, lth}]; 
ls = RandomReal[{0, 1}, {lth}]; 
 
Et = Function[{t}, Sin[(Pi t)/20] Sin[2 t]]; 
Etc = Compile[{{t,  ...

- asked by xslittlegrass (15 votes), answered by xslittlegrass (5 votes)

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[Fit a function with an unusual side condition] http://mathematica.stackexchange.com/questions/114864/fit-a-function-with-an-unusual-side-condition

I have a set of measurement data and I try to fit there a function (a Exp[b x] + c Exp[d x] - o). I have two problems:

The fit function does not converge nor after \(500\) iterations. The fit function ...

- asked by Lutscher (12 votes), answered by Anton Antonov (15 votes)

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[Tips to move from functional programming to GUI-based applications] http://mathematica.stackexchange.com/questions/114984/tips-to-move-from-functional-programming-to-gui-based-applications

Even though this forum has some questions related to Mathematica programming tips I think that we still don’t have specific help for those who want to learn to efficiently create GUIs in Mathematica. ...

- asked by Ariel Sepulveda (11 votes), answered by Brian G (0 votes)

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[Longest common substring for multiple strings?] http://mathematica.stackexchange.com/questions/114979/longest-common-substring-for-multiple-strings

I’m looking for a way to get the longest common substring for multiple strings such as

  {home/dir1/dir2/jmoasd.txt,home/dir1/dir2/ivbnoxcihv.txt,home/dir1/dir2/siuhgiuchv.txt}

should yield

...

- asked by nqduy (10 votes), answered by xslittlegrass (9 votes)

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[How does a Pringle lose its curvature?] http://mathematica.stackexchange.com/questions/115231/how-does-a-pringle-lose-its-curvature

Nom!

As part of a bigger project, I’ve was writing some code to calculate the scalar curvature of surfaces of the form \(z = f(x,y)\). This uses a general calculation of the scalar curvature to produce ...

- asked by Lucas (9 votes), answered by KraZug (9 votes)

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[How to make datasets display correctly?] http://mathematica.stackexchange.com/questions/115246/how-to-make-datasets-display-correctly

NB: The problem illustrated below is truly ubiquitous. I hope the examples given below are sufficiently different to demonstrate this fact, and to discourage answers that hinge on the details of the ...

- asked by kjo (9 votes), answered by Stefan R (9 votes)

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[How do I translate a list of English words into another language using an online translation service with Mathematica?] http://mathematica.stackexchange.com/questions/115141/how-do-i-translate-a-list-of-english-words-into-another-language-using-an-online

As far as I know, there are two posts on this topic: Can I use Mathematica to translate a English word to a Chinese characters? and *How can I use Mathematica to get the translated result from the ...

- asked by matheorem (9 votes), answered by Rashid (11 votes)

================================== Greatest hits from previous weeks: ==================================

[What is the best Mathematica tutorial for young people?] http://mathematica.stackexchange.com/questions/733/what-is-the-best-mathematica-tutorial-for-young-people

As Conrad Wolfram said at the TED conference, in the future kids should focus more on new technology. Computers compute better than humans, so we should focus more on thinking and getting the ...

- asked by noisy (43 votes), answered by Vitaliy Kaurov (23 votes)

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[How to make use of Associations?] http://mathematica.stackexchange.com/questions/52393/how-to-make-use-of-associations

I have been curious about it for long. Now that Mathematica 10 arrives, I think it’s time to ask the question: How the new Association data structure would be used to improve Mathematica programming?

...

- asked by Yi Wang (110 votes), answered by Leonid Shifrin (128 votes)

================================== Can you answer these? ==================================

[PearsonChiSquareTest for count/frequency data?] http://mathematica.stackexchange.com/questions/114905/pearsonchisquaretest-for-count-frequency-data

I read with interest a previous question on the PearsonChiSquareTest from a few years ago, and one answer was very helpful:

Performing a chi-square goodness of fit test

Have there been any updates ...

- asked by Jim (3 votes)

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[ParallelDo issue with SQLExecute (SQLite)] http://mathematica.stackexchange.com/questions/115263/paralleldo-issue-with-sqlexecute-sqlite

This code run as expected if I use Do[...], but if I use instead ParallelDo[...], as in the code bellow, the SQL INSERT statements seems to be completely ignored.

In both cases, the filename is ...

- asked by jss (2 votes)

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[Why does Kernels[] produce this error?] http://mathematica.stackexchange.com/questions/115100/why-does-kernels-produce-this-error

Most of times, on my PC, when Kernel[] is launched for the first time, produces this error:

Executed again returns .

Is it a clue of malfunctioning or is, for reason I’m unaware of, the way it ...

- asked by mitochondrial (3 votes)