Introduction I’ve just uploaded a new package to CRAN based on a stimulus generation algorithm that I use for my experiments on vision. The FourierDescriptors package provides methods for creating, manipulating and visualizing Fourier descriptors, which are a representational scheme used to describe closed planar contours. The canonical reference ... [Read more...]

Computer creations are perfect by design. We put in numbers, and if all goes well we get out an exact result. If we want a line, we want it perfectly straight. If we want a circle, it should conform to the platonic ideal of a circle. From a mathematical standpoint, ... [Read more...]

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Transitions are often used in presentations to break up the presentation and to keep the audience awake, but often the outcome is irritation/distraction with text or other objects flying on or off the screen from different directions. As such they should be used sparingly if at all in a ... [Read more...]

In the first part of this series, I discussed some standard debugging techniques, like the use of the browser function. One of the limitations of browser is that it isn’t much help if the problem is somewhere higher up the call-stack. ... The function I’m going to show you ... [Read more...]

Following my discovery of two surprising inefficiencies in R, I’ve been inspired to spend much of the last two weeks looking for ways to speed it up. I’ve had quite a bit of success, both at finding ways to speed up particular functions, and at finding ways to ... [Read more...]

Now that SST has been processed with raster we can return to the land processing and put that on the same footing. To get there I’ll rebuild from scratch making some minor adjustments along the way. As we go foward the amount of code we have to write should ... [Read more...]

The ggplot2 package for R is an amazing system for creating entirely new visualizations of data. It allows data analysts to tell a detailed, meaningful and yet easy-to-interpret story about complex and/or unusual data sets. To promote more data stories being told, ggplot2 author Hadley Wickham has organized a ... [Read more...]

In the wake of the main machine learning NIPS 2010 meeting in Vancouver, Dec. 6-9 2010, there will be a very interesting workshop organised by Ryan Adams, Mark Girolami, and Iain Murray on Monte Carlo Methods for Bayesian Inference in Modern Day Applications, on Dec. 10. (And in Whistler, not Vancouver!) I wish ... [Read more...]

So if you had a robot that was an expert at botany - would you have a bot botanist?  Among other things, it would need to to distinguish flowers through vision and image processing, and be able to classify various kinds of plants based upon specif... [Read more...]

Folks in the New Jersey area no longer need to trek over to New York City to meet other R users. Now there's NewJerseyR, a new R user group put together by Mango Solutions. The first meeting will in Iselin on September 16, with speakers from Mango, Pfizer, and Bristol Myers ... [Read more...]

A collective blog has been started by the statistics students and postdocs at CREST, in the wake of the Valencia meeting. It is called Statisfaction. (The Rolling Stones of Statistics?! Actually, Andrew Gelman also has a post with that title… And it is even part of the Urban Dictionnary!) Since ... [Read more...]

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There has been a lot of attention paid to the role of US guns exacerbating the violence in Mexico. The assault-weapon ban expired on September 14, 2004, but with the recent spiraling of violence in Mexico the ban has attracted renewed attention. Just recently the Mexican President stood before the American Congress ... [Read more...]

Hello dear followers of R-bloggers.com Today (and probably in the next few days), R-bloggers will be down part of the time due to maintenance work. (Technical stuff: I am [Read more...]

When I did a brief post three days ago I had no plans on writing two more posts on correlated random number generation. But I’ve gotten a couple of emails, a few comments, and some Twitter feedback. In response to my first post, Gappy, calls me out and says, “... [Read more...]

This is very short notice, but for those in the vicinity and not at the RSS conference, there is a highly interesting workshop taking place in Bristol in ten days (I would certainly have gone, had I not been at the same time in Banff!): We would like to invite ... [Read more...]

Over the past 10 years, I have been torn between building a new stat. computing environment or trying to overhaul R. There are many issues on both sides. But the key thing is to enable doing new and better things in stat. computing rather than just making the existing things easier ... [Read more...]

A few weeks ago, I posted the Rffi package on the Omegahat repository. It is an interface to libffi which is a portable mechanism for invoking native routines without having to write and compile any wrapper routines in the native language. In other words, we can use this in R ... [Read more...]

We've covered how to generate random numbers in R before, but what if you want to go beyond generating one random number at a time? What if you want to generate two, or three or more random numbers, and what's more, you want them to be correlated? JD Long lays ... [Read more...]