Monthly Archives: June 2011

Simple plyr/ggplot example of cummulative distribution plots

June 9, 2011
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Simple plyr/ggplot example of cummulative distribution plots

I’ve been a big fan of ggplot2 for a long time but plyr has been in my toolkit for less than a year and it is now one of my most-used R packages. It is how aggregate/*apply would have been if they were awesome. In five lines this code computes the cumulative distribution functions of

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Rejection Sampling

June 9, 2011
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Rejection Sampling

An interesting sampling method that was covered briefly in my Bayesian statistics course was rejection sampling. Since I have nothing better to do, I thought it would be fun to make an acceptance-rejection algorithm using R. FUN!The Rejection Sampling method is usually used to simulate data from an unknown distribution. To do this one samples...

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Image color palette replacement

June 9, 2011
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Image color palette replacement

Here is an example of a function I wrote to change the color palette used in an image. The above example comes from a black and white original, although color images can also be used. The function first converts the image to grayscale in order to have ...

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A Quantstrat to Build on Part 5

June 9, 2011
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A Quantstrat to Build on Part 5

Another iteration of the quantstrat system but this time with a sum of standard deviations instead of simple count and then some comparison charts.  Thanks for the comments and I welcome many more.  In my head and it seems like in others base...

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Automating R Scripts on Amazon EC2

June 9, 2011
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Automating R Scripts on Amazon EC2

Overview: How to setup R on an EC2 instance of Ubuntu 11.04 (Natty Narwhal) How to setup Apache Tomcat 6.0 web server and configuring it with basic authentication so that we can view our output from R on a password … Continue reading →

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We are now a part of R-bloggers.com

June 9, 2011
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R-bloggers is a site that aggregates many of the best R blogs on the internet. We're glad they've allowed our R-related posts to be aggregated there. If you mainly write in R, it's worth checking them out.

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R: Speeding things up

June 9, 2011
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R is many things, but it's not exactly speedy like a Patas Monkey. In fact, while it is much faster than many other solutions, R is notably slower than Stata (even inspiring talks that it should be rewritten from scratch!).Fortunately, Radford Neal ha...

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New patches to speed up R 2.13.0

June 9, 2011
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New patches to speed up R 2.13.0

I have now released a new collection of 30 patches to speed up R version 2.13.0. You can get them here Assessing how much these patches speed up R is difficult. First of all, the speedup varies tremendously with the type of program. It also varies quite a bit with the machine and compiler used

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The R-Files: Jeroen Ooms

June 9, 2011
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The R-Files: Jeroen Ooms

"The R-Files" is an occasional series from Revolution Analytics, where we profile prominent members of the R Community. Name: Jeroen Ooms Background: Ph.D. Candidate, Statistics, UCLA Nationality: Netherlands Years Using R: 3 1/2 Known for: Developing web applications for popular R packages including ggplot2, lme4, stockplot and irttool Jeroen Ooms is a statistical consultant and R enthusiast currently pursuing...

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Rotating disks

June 9, 2011
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Rotating disks

My neighbour is an half-retired entrepreneur who still runs his electric engine company. A few weekends ago, he came to me with the following physics question related with one of those engines: given a primary disk rotating at the angular speed of ω0 and a secondary disk located on the first one with a centre

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