Monthly Archives: May 2011

R functions for Earth geographic coordinate calculations

May 29, 2011
By
R functions for Earth geographic coordinate calculations

Here are some functions that I regularly use for geographic data (e.g. binning, filtering, calculation of new positions etc.).#distance in kilometers between two long/lat positions (from "fossil" package)earth.dist <- function (long1, lat1, long2, l...

Read more »

Which R documents to read, and which R packages to use

May 29, 2011
By
Which R documents to read, and which R packages to use

There are lots of R documents and over 3000 R packages. Which documents to start with and which R packages to use are questions faced by many people. If you are new to R, an Introduction to R can be … Continue reading →

Read more »

Comparing HoltWinters() and ets()

May 29, 2011
By

I received this email today: I have a question about the ets() function in R, which I am trying to use for Holt-Winters exponential smoothing. My problem is that I am getting very different estimates of the alpha, beta and gamma parameters using ets() compared to HoltWinters(), and I can’t figure out why. This is

Read more »

An Application of boot() to IV regression

May 28, 2011
By
An Application of boot() to IV regression

Bootstrapping standard errors can be a useful technique when obtaining closed form for the standard error formula is difficult or intractable. In this post, I give an example of how to use R to create a bootstrap sampling distribution in the context o...

Read more »

An Application of boot() to IV regression

May 28, 2011
By
An Application of boot() to IV regression

Bootstrapping standard errors can be a useful technique when obtaining closed form for the standard error formula is difficult or intractable. In this post, I give an example of how to use R to create a bootstrap sampling distribution in the context o...

Read more »

RcppArmadillo 0.2.21

Following up Conrad's 1.99.2 release (in RcppArmadillo 0.2.20), we now have Armadillo 1.99.3 en route to the upcoming 2.0.0 release. Armadillo is a templated C++ library for linear algebra---which RcppArmadillo brings to R based on our Rcpp library...

Read more »

R for the web

May 27, 2011
By

There is a nice R module for apache: rApache. So you can easily publish statistics.

Read more »

Collaborative R coding using Dropbox

May 27, 2011
By
Collaborative R coding using Dropbox

I do like Dropbox. I’m a big fan of easy to use solutions to common problems. For me I work at two different sites and I do a significant amount of work at my desktop machine at home as well as on my laptop. Dropbox solved the problem of synchronising files between

Read more »

Handling Errors Gracefully

May 27, 2011
By

In R functions sometimes produces warnings or errors. In the case of errors execution of a function or a series of commands can get halted when an error occurs, which can in some cases be frustrating especially if we want to continue our calculations. There are various functions available in R for dealing with errors

Read more »

Norvig and the Nature of Modern Science

May 27, 2011
By

In this, Chomsky is in complete agreement with O’Reilly. (I recognize that the previous sentence would have an extremely low probability in a probabilistic model trained on a newspaper or TV corpus.)1 Anyone who considers themself an intellectual should be required to read this new essay by Peter Norvig. It’s the best summary I’ve ever

Read more »