# Posts Tagged ‘ math ’

## multiplicitiesoffreedom demonstrates Chaos Theory in Excel. If…

June 29, 2012
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multiplicitiesoffreedom demonstrates Chaos Theory in Excel. If he filled in more initial values, you would see a thick bar—like a picture of white-noise. Butterflies flapping their wings in Vermont to change the wind in Hangzhou? A drop of water on ...

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## How do I Create the Identity Matrix in R?

June 27, 2012
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I googled for this once upon a time and nothing came up. Hopefully this saves someone ten minutes of digging about in the documentation. You make identity matrices with the keyword diag, and the number of dimensions in parentheses. > diag(3) [,...

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## How to outrun a crashing alien spaceship

June 11, 2012
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Hollywood movies are obsessed with outrunning explosions and outrunning crashing alien spaceships. For explosions the movies give the optimal (but unusable) solution: run straight away. For crashing alien spaceships they give the same advice, but in this case it is wrong. We demonstrate the correct angle to flee. Running from a crashing alien spaceship, Prometheus Related posts:

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## How Not To Draw a Probability Distribution

March 7, 2012
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If I google for “probability distribution” I find the following extremely bad picture: It’s bad because it conflates ideas and oversimplifies how variable probability distributions can generally be. Most distributions are not unimodal. Most dist...

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## Error Handling in Lyx & Sweave: using Quantmod (and R, of course)

November 8, 2011
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I do reports for clients with LyX and Sweave. It took me an extremely long time to get them working, but now that they’re working I can do more in an hour and thus charge more per hour. If you’re not familiar, here’s a rundown: LaTeX is the stand...

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## Error Handling in Lyx & Sweave: using Quantmod (and R, of course)

November 8, 2011
By

I do reports for clients with LyX and Sweave. It took me an extremely long time to get them working, but now that they’re working I can do more in an hour and thus charge more per hour. (Which is, like, the point.) If you’re not familiar, here’s ...

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## Hey! I made you some Wiener processes!

September 7, 2011
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Check them out. Here are thirty homoskedastic ones: > homo.wiener for (j in 1:30) {  for (i in 2:length(homo.wiener)) {          homo.wiener for (j in 1:30) {        plot( homo.wiener,           type = "l", col = rgb(.1,....

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## Prime testing function in R

August 20, 2011
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$Prime testing function in R$

I was hoping to begin tinkering a bit with the multicore package in R beyond some extremely trivial examples.  Thanks to a combination of R’s dumb quirkiness (for example, being worthless on loops), my poor planning, and general bad programming, my Saturday afternoon tinkering project is ultimately worthless in fulfilling that purpose. I was really

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## B*tchin’ six dimensional 6-cube. The rainbow colours and…

July 1, 2011
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B*tchin’ six dimensional 6-cube. The rainbow colours and glass panes really help this visualisation.  Examples of 6-dimensional things If it’s hard to envision 6 dimensions, consider this: the possible tunings of a guitar constitute a 6-dimensio...

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## B*tchin’ six dimensional 6-cube. The rainbow colours and…

July 1, 2011
By

B*tchin’ six dimensional 6-cube. The rainbow colours and glass panes really help this visualisation.  Examples of 6-dimensional things If it’s hard to envision 6 dimensions, consider this: the possible tunings of a guitar constitute a 6-dimensio...

Read more »