I love using TeXShop for GUI editing of LaTeX and particularly Sweave documents, but it is a pain not being able to get it to automatically generate the pdf output. Luckily I found this post which explains how to add a Sweave engine.Basically, make a f... [Read more...]

Following up on yesterday's Rcpp 0.7.0 release, here is a quick example of why the new feastures can be so useful. The following R code defines a character variable gslrng. This variable contains a short C++ code segment, which is then transformed by the function cfunction into a function of two ... [Read more...]

Drew Conway has a great list of 10 must-have R packages for social scientists. If you’re a social scientist (or really, any kind of scientist) who doesn’t use R, now is a great time to dive in and learn; there are tons of tutorials and guides out there (my ... [Read more...]

A new release of Rcpp awaits inclusion on CRAN and has also been sent as a .deb to Debian. It will hit mirrors over the next few days, in the meantime you can get it here as well. This release has a couple new features : inline support: the cf... [Read more...]

Here's a neat visualization of the decline of the British, Spanish, Portugese and French empires from 1800 to present day. It's definitely more art than stats -- judging by the relative size of India and Australia I think the circles are scaled to area, not population -- but it definitely does ... [Read more...]

This post is a continuation of my series dealing with matrix operations for image processing. My next goal is to demonstrate the construction of simple low-pass and high-pass spatial frequency filters in R. It’s easy enough to construct simple versions of these filters in R using the Fast Fourier ... [Read more...]

Using data from the INEGI I calculated the percentage of births who were born outside of marriage in Mexico and compared it to the Hispanic rate in the US. They are basically the same. There’s been a gigantic increase that’s slouching towards 50% a... [Read more...]

This tutorial with real R code demonstrates how to create a predictive model using cforest (Breiman’s random forests) from the package party, evaluate the predictive model on a separate set of data, and then plot the performance using ROC curves ... [Read more...]

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On December 3, 2009 I presented a brief talk at the NYC R meetup on how to create data visualizations with R using the immensely powerful ggplot2 package. The talk is very light on motivation but heavy on examples, so it may be more useful to those with some R and/or ... [Read more...]

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Over the next few posts, I’m going to be reviewing the use of R to implement the most commonly used matrix techniques for image manipulation. The code will be surprisingly simple to understand, because the real magic behind these techniques lies in the mathematics that R provides an abstract ... [Read more...]

There are many blogs on Statistics, R and other related topics scattered around the internet. The R bloggers website provides a central hub where feeds from participating blogs are collated so that they can be viewed from a single website. This resources certainly appears to be a good idea so ... [Read more...]

The "apply" family of functions in R (apply, sapply, lapply) is a very powerful suite of tools for iterating through structures of data and returning the combined results of each iteration. But with great power comes great responsibility (or something like that): these functions can sometimes be frustratingly difficult to ... [Read more...]

In 2006 UserR conference Jim Porzak gave a presentation on data profiling with R. He showed how to draw summary panels of the data using a combination of grid and base graphics. Unfortunately the code has not (yet) been released as a package, so when I recently needed to quickly review ... [Read more...]

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Lately, I’ve been running a series of fMRI experiments on visual perception. In the interests of understanding the underlying properties of the images I’m using as stimuli, I’ve been trying to learn more about the matrix transformations commonly used for image compression and image manipulation. Thankfully, R ... [Read more...]

In scientific discovery, the first three paradigms were experimental, theoretical and (more recently) computational science. A new book of essays published by Microsoft (and available for free download -- kudos, MS!) argues that a fourth paradigm of scientific discovery is at hand: the analysis of massive data sets. The book ... [Read more...]

Just about everyone is familiar with weather maps. There are many situations where it is useful to combine the underlying numerical weather data with other types of information. Accessing  the weather data is a necessary first step. The output from the U.S. National Centers for Environmental Prediction (NCEP) Global  ... [Read more...]

i usually run long simulations in R on a remote server. i’ve read an article on linux journal about emailing yourself after something happens…i forgot. since my jobs are long, and i usually have to run multiple jobs sequentially, it’d be nice to look at my results ... [Read more...]