speed of R, C, &tc.

February 2, 2012 | xi'an

My Paris colleague (and fellow-runner) Aurélien Garivier has produced an interesting comparison of 4 (or 6 if you consider scilab and octave as different from matlab) computer languages in terms of speed for producing the MLE in a hidden Markov model, using EM and the Baum-Welch algorithms. His conclusions are that ... [Read more...]

A misleading title…

September 4, 2011 | xi'an

When I received this book, Handbook of fitting statistical distributions with R, by Z. Karian and E.J. Dudewicz,  from/for the Short Book Reviews section of the International Statistical Review, I was obviously impressed by its size (around 1700 pages and 3 kilos…). From briefly glancing at the table of contents, ... [Read more...]

Nomograms everywhere!

August 30, 2011 | richierocks

At useR!, Jonty Rougier talked about nomograms, a once popular visualisation that has fallen by the wayside with the rise of computers. I’d seen a few before, but hadn’t understood how they worked or why you’d want to use them. Anyway, since that talk I’ve been ... [Read more...]

Friday Function: nclass

May 6, 2011 | richierocks

When you draw a histogram, an important question is “how many bar should I draw?”. This should inspire an indignant response. You didn’t become a programmer to answer questions, did you? No. The whole point of programming is to let your computer do your thinking for you, giving you ... [Read more...]

supercalifragilisticexpialidocious = 1

April 21, 2011 | richierocks

I notice that the latest version of R has upped the maximum length of variable names from 256 characters to a whopping 10 000! (See ?name.) It makes the 63 character limit in MATLAB look rather pitiful by comparison. Come on MathWorks! Let’s have the ability to be stupidly verbose in our variable ... [Read more...]

Converting MATLAB and R date and time values

February 20, 2011 | Luke Miller

For some unknown reason, MATLAB codes its date/time values as the number of elapsed days starting from January 1 in the year 0000. R uses the equally arbitrary, but much more widespread POSIX/Unix epoch as a reference for time keeping, so that R’... [Read more...]

Software tools for data analysis – an overview

February 19, 2011 | Szilard

by Szilard Pafka Discussions on various software tools (C, C++, Perl, Python, Unix shell, R, Matlab, SAS, SPSS, Excel, databases, Hadoop etc.) used in data analysis. Szilard Pafka (founder and co-organizer of the Los Angeles R users group) presents an … Continue reading →
[Read more...]

When 1 * x != x

January 16, 2011 | richierocks

Trying to dimly recall things from my maths degree, it seems that in most contexts the whole point of the number one is that it is a multiplicative identity. That is, for any x in your set, 1 * x is equal to x. It turns out that when you move to ... [Read more...]

Julien on R shortcomings

September 8, 2010 | xi'an

Julien Cornebise posted a rather detailed set of comments (from Jasper!) that I thought was interesting and thought-provoking enough (!) to promote to a guest post. Here it is , then, to keep the debate rolling (with my only censoring being the removal of smileys!). (Please keep in mind that I do ... [Read more...]

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