7.2 Tuesday, December 16, 2014

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Top new questions this week: 
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[Buying a new computer (specifically for Mathematica)] http://mathematica.stackexchange.com/questions/69404/buying-a-new-computer-specifically-for-mathematica

My current computer is a MacBook Air, the mid-2011 version: 4 GB RAM, 1.7 GHz Intel dual core. It runs Mathematica 9 smoothly, but a bit too slowly for my taste. I use Mathematica almost exclusively ...

- asked by Kim Fierens (14 votes), answered by halirutan (15 votes)

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[Difference between Association and Dispatch] http://mathematica.stackexchange.com/questions/69291/difference-between-association-and-dispatch

In the example below, Association has a different behavior from Dispatch:

{1, 2, 3} /. Association@{1 -> "test",2 -> "test" , _Integer -> 
Null} 
{1, 2, 3} /. Dispatch@{1 -> "test" ,2 ->  ...

- asked by Murta (13 votes), answered by Leonid Shifrin (15 votes)

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[Real Numbers in the Wolfram Language] http://mathematica.stackexchange.com/questions/69525/real-numbers-in-the-wolfram-language

This is more of a request for advice and input than a solution to a programming challenge, but I thought it might be useful to raise here nonetheless.

I am wondering if Mathematica and the Wolfram ...

- asked by David Carraher (11 votes)

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[InverseFourierTransform of simple function takes forever] http://mathematica.stackexchange.com/questions/69477/inversefouriertransform-of-simple-function-takes-forever

i’m quite new to Mathematica. I’m trying to do something along the lines of:

InverseFourierTransform[1/(w^2 - I*w*b + c) , w, t, FourierParameters 
-> {1, -1}, Assumptions -> {b > 0, c >  ...

- asked by pnjun (9 votes), answered by bbgodfrey (8 votes)

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[Divide all but the maximal element in a list by 10?] http://mathematica.stackexchange.com/questions/69547/divide-all-but-the-maximal-element-in-a-list-by-10

I have a list of numerical data, and I want to write a program that will keep the maximum as it is, but reduce the rest by certain factor (such as 10). For example:

input = {2, 3, 1, -3, -5, 9, 2, 6,  ...

- asked by Paul (8 votes), answered by WReach (10 votes)

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[Select a particular rules out of a list] http://mathematica.stackexchange.com/questions/69299/select-a-particular-rules-out-of-a-list

rule = {beta -> 4, alpha -> 2, x -> 4, z -> 2, w -> 0.8} 
Select[rule, beta] 
Select[rule, beta &] 
Select[rule, beta -> _ &]

How would I select the rule that applies to beta ...

- asked by Chen Stats Yu (8 votes), answered by kguler (12 votes)

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[10.0.2 another Dataset type system (inference?) warning] http://mathematica.stackexchange.com/questions/69542/10-0-2-another-dataset-type-system-inference-warning

Bug introduced in 10.0.2

The warning below seems unrelated to these issues: Did 10.0.2 break some forms for named slots? and 10.0.2 mapping Association to Dataset warning.

First noticed w/ ...

- asked by alancalvitti (7 votes), answered by Stefan R (11 votes)

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

[How to find all the local minima/maxima in a range] http://mathematica.stackexchange.com/questions/5575/how-to-find-all-the-local-minima-maxima-in-a-range

I want to find :

all local maxima in range all local minima in range

>From those points I can interpolate and combine functions upper and lower boundary. What I am really interested in, is the ...

- asked by Margus (45 votes), answered by Daniel Lichtblau (43 votes)

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[How to create animated snowfall?] http://mathematica.stackexchange.com/questions/16881/how-to-create-animated-snowfall

Well, the title is self-explanatory. What sorts of snowfall can we generate using Mathematica? There are two options I suggest to consider:

1) Continuous GIF animations with smallest possible number ...

- asked by faleichik (30 votes), answered by Simon Woods (35 votes)

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

[How to execute code on FrontEnd quit?] http://mathematica.stackexchange.com/questions/69385/how-to-execute-code-on-frontend-quit

I would like to execute a block of code whenever the FrontEnd quits. I know about $Epilog, but it seems that this would execute every time the kernel quits, which is not what I want. Does anyone know ...

- asked by rdjain1 (4 votes)

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[Logarithmic vertex placement in large tree graphs] http://mathematica.stackexchange.com/questions/69555/logarithmic-vertex-placement-in-large-tree-graphs

This question about graph layout is fairly general, but can be illustrated in the case of the Collatz Conjecture. Collatz created the following function over positive integers: If the integer n is ...

- asked by David G. Stork (1 vote)

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[Background color does not display in InputField unless Appearance option is also specified] http://mathematica.stackexchange.com/questions/69446/background-color-does-not-display-in-inputfield-unless-appearance-option-is-also

I get the same behavior for v.10.0.2 and v.9 with OS X (10.9.5) :

No background color is displayed in InputField if I just set properly the option. For example, the background just remains white if ...

- asked by SquareOne (2 votes)