I wrote this post months ago but never hit 'Publish'. But, the subject has changed little since then. So, here's to cleaning out the draft folder... R's connections are the heart of data/code/text input and output. Without connections, R would be crippled. Additional connections make R more ... connected ... [Read more...]

Gompertz Model Visualization # Gomperz growth function gomp [Read more...]

This post describes some preliminary results from a compatibility study of the SAS sas7bdat file format. The most current results stored in a github repository here: sas7bdat The ultimate goal is a native solution to the incompatibility between open-source statistical software (e.g. R) and sas7bdat database ... [Read more...]

It's been a year since I began keeping a web log. This post presents some thoughts related to the experience. Blogging is Sharing Ideas Blogging is online self-publishing. There is no faster way to share your ideas so broadly. Last year at the useR! conference (in Gaithersburg, MD, just a ... [Read more...]

A recent R-help post asks for examples of Sweave use for web appliations. I think there is very little out there; maybe nothing. Below is a proof of concept for web-based Sweave-ing with rApache. But, it will soon be possible to do this with R's built-in web server. The idea ... [Read more...]

These graphics look familiar. From the Tor Metrics Portal: "The metrics website uses R to generate custom graphs on demand." See more here: http://metrics.torproject.org/graphs.html. [Read more...]

Feature NumPy R contiguous (virtual) memory ✔ ✔ 'view' memory model ✔ ✘ subset-assignment ✔ ✔ vectorized operations ✔ ✔ memory-mapping ✔ ✘* broadcasting rules ✔ ✔ index arrays ✔ ✔ This comparison is current as of R 2.13.0, NumPy version 1.4.1, and other web resources to date. Because this post was motivated by a [...] [Read more...]

Below are some links to a patch against the R-2.12.2 source code that implements a tty connection for R. Since the release of R-2.13.0 is coming soon, I’ll have a patch for it soon also. What’s a tty connection? The tty connection is an R interface to computer ... [Read more...]

I recently uploaded some code to R-forge related to an R package I’ve been working on, titled yarr. The work was motivated by a desire to embed R code and output within my HTML blog posts! Months ago, I wrote about a potential solution to this using the brew ... [Read more...]

From the HRSA website: [The ARF 2009] is a database containing more than 6,000 variables for each of the nation’s counties. ARF contains information on health facilities, health professions, measures of resource scarcity, health status, economic activity, health training programs, and socioeconomic and environmental characteristics. The data file itself is formatted ... [Read more...]

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I connected the instrumentation amplifier described in an earlier post to a piezoelectric transducer (buzzer) and made recordings at 5000 gain. The plot below shows 1000 such measurements over 1.0 seconds. There is a 4.0 second (at 1000Hz) sample of the data here piezo.csv. There is a clear sinusoidal signal in these data ... [Read more...]

In an earlier post, I described some ECG signal processing. In fact, these recordings were from my own heart, and I had collected them using a homemade ECG. The following is a repost from my old site describing the device. I assembled an instrumentation amplifier to measure cardiac potentials (i.... [Read more...]

I picked up the AT&T Laboratories Cambridge database of faces for a clustering application. The database consists of images of 40 distinct subjects, each in 10 different facial positions and expressions. Typically, the goal of clustering in these data is to recover the ‘true’ partition, or that which isolates images of ... [Read more...]

In an earlier post, I discussed how to use Subversion to download, edit, and generate a patch against R‘s source code. Since most of us can’t commit our code changes back to R‘s repository, we can consider alternatives to store and maintain our patch, until it is ... [Read more...]

The development version of R is stored in a Subversion repository at the URL http://svn.r-project.org/R/trunk/. In fact, you can browse the source code by clicking the link. Subversion Hierarchy Subversion is software for source code revision control. That means it keeps track of changes, who ... [Read more...]

I recently decided to revisit some R code that implements a Gibbs sampler in an attempt to decrease the iteration time. My strategy was to implement the sampler state as an R environment rather than a list. The rationale was that passing an environment to and from functions would reduce ... [Read more...]

I’ve had enough of copy and pasting output from my R session into my email editor, blog, etc. I need something like Sweave for plain text files. In particular, I want the result of parsing = f [Read more...]

I completed (some time ago) an initial version of a patch for R, version 2.11.1, that adds a POSIX tty connection. The patch is confirmed to compile and works on Mac OS X (thanks to Ashwin Bhat of Georgia Tech) and Debian GNU Linux. However, it should be portable to other ... [Read more...]