Publications by Matt Shotwell
Plans for a Real tty Connection
I reverted the name of the tty connection that I described previously, to “serial” connection and updated the patch to R 2.11.1. This name is more appropriate to its function and also makes way for another patch I am working on which implements the full POSIX terminal interface (essentially all of termios.h). The connection provided in the ne...
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static symbols too?
Continuing in the context of this previous post… 1. Select a static symbol from the R sources, like Connections $ grep "static Rconnection Connections" src/main/connections.c static Rconnection Connections[NCONNECTIONS]; 2. Get its address $ objdump -t `R RHOME`/bin/exec/R | awk '/ Connections/ {print $1}' 000000000093b700 3. Use the symbol > l...
753 sym R (498 sym/3 pcs)
R-help follow-up: truncated exponential
I recently posted the message below with regard to sampling from the truncated exponential distribution. I left out the derivation of the CDF (mostly because text math is ugly), so I’ve included it here. There is also a short JSS article about truncated distributions in R. This problem in particular may likely be found in an introductory text o...
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Mary, Chloe, and Miriam at breakfast
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More powerful iconv in R
The R function iconv converts between character string encodings, for example, from the locale dependent encoding to UTF-8: > iconv("foo", to="UTF-8") [1] "foo" However, R has long-running trouble with embedded null characters ('\0') in strings. Hence, if we try to convert to an encoding that permits embedded null characters, iconv will fail: > i...
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ASCII Scatterplots in R
I really like R‘s stem function, it creates a stem-and-leaf plot right in the R console, no fancy graphics devices required! In a recent R-help post, Ralf Bierig presented a very nice ASCII scatterplot representing two densities. Unfortunately, I don’t know of any R function that will generate this type of plot, but I will argue that they are...
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Funny Math in Governor Approval Ratings
Andrew Gelman wrote today about some erroneous U.S. Governor approval ratings, noting that the ratings for Janet Napolitano sum to 108%. In fact most of these ratings do not sum to 100%. I prepared a clean CSV file of the ratings, making use of R‘s XML library and the readHTMLTable function. The ratings data file is here approval.csv. > approva...
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Short Open Source Q&A with Revolution Analytics
I recently e-mailed David Smith of Revolution Analytics with a few questions about their relationship with the R-project, and how they handle R‘s source code. David mentioned, and I’m flattered that my email motivated an additional page on the Revolution website. Beyond this, I have no other relationship with the company. I’d like to thank ...
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Documenting R‘s Connections Internals
In studying R‘s connections source code, I’ve put together a series of notes about their workings. Rather than let the notes go where most of my notes go (I have no idea ), I decided to do some proofreading and make the notes available to others who might be interested. These notes should make the task of extending or maintaining the connect...
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A tty Connection for R
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 POSIX compliant operating systems. The tty patch allows for a variety of in...
1739 sym R (388 sym/1 pcs)