Publications by xi'an
Le Monde puzzle [#738]
The Friday puzzle in Le Monde this week is about “friendly perfect squares”, namely perfect squares x2>10 and y2>10 with the same number of digits and such that, when drifting all digits of x2 by the same value a (modulo 10), one recovers y2. For instance, 121 is “friend” with 676. Here is my R code: xtrct=function(x){ x=as.integer(x) ...
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A misleading title…
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, and the list of standard distr...
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Bayes-250, Edinburgh [day 2]
After a terrific run this morning to the top of Arthur’s Seat, and then around (the ribs are feeling fine, now!), the Bayes-250 talks were exhilarating and challenging. Jim Smith gave an introduction to the challenges of getting different experts to collaborate on a complex risk assessment, much in the spirit of his book, that got me wondering ...
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Le Monde puzzle [#739]
The weekend puzzle in Le Monde this week is again about a clock. Now, the clock has one hand and x ticks where a lamp is either on or off. The hand moves from tick to tick and each time the lights go on or off depending on whether or not both neighbours were in the same state the previous time. Here is my R code that describes the evolution o...
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Testing and significance
Julien Cornebise pointed me to this Guardian article that itself summarises the findings of a Nature Neuroscience article I cannot access. The core of the paper is that a large portion of comparative studies conclude to a significant difference between protocols when one protocol result is significantly different from zero and the other one(s) is...
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About commercial publishers
Julien Cornebise has [once again!] pointed out a recent Guardian article. It is about commercial publishers of academic journals, mainly Elsevier, Springer, and Wiley, with a clear stand from its title: “Academic publishers make Murdoch look like a socialist“! The valuable argument therein is that academic publishers make hefty profits (a 40%...
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Handbook of Markov chain Monte Carlo
At JSM, John Kimmel gave me a copy of the Handbook of Markov chain Monte Carlo, as I had not (yet?!) received it. This handbook is edited by Steve Brooks, Andrew Gelman, Galin Jones, and Xiao-Li Meng, all first-class jedis of the MCMC galaxy. I had not had a chance to get a look at the book until now as Jean-Michel Marin took it home for me from ...
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workshop in Columbia [day 3]
Although this was only a half-day of talks, the third day of the workshop was equally thought-challenging and diverse. (I managed to miss the ten first minutes by taking a Line 3 train to 125th street, having overlooked the earlier split from Line 1… Crossing south Harlem on a Sunday morning is a fairly mild experience though.) Jean-Marc Aza�...
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Bessel integral
Pierre Pudlo and I worked this morning on a distribution related to philogenic trees and got stuck on the following Bessel integral Related To leave a comment for the author, please follow the link and comment on their blog: Xi'an's Og » R. R-bloggers.com offers daily e-mail updates about R news and tutorials about learning R and many other ...
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Bat Country
I’ve spent a lot of time thinking about and using R’s spectrum() function and the Fast Fourier Transform (FFT) in the last 5+ years. Lately, they’ve begun to remind me a little of a Theremin: simple to use, difficult to master. While prepping a figure for the R Graph Gallery (which is awesome, by the way), I ran across this cu...
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