Publications by xi'an
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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FFT / Power Spectrum Box-and-Whisker Plot with Gggplot2
I have a bunch of time series whose power spectra (FFT via R‘s spectrum() function) I’ve been trying to visualize in an intuitive, aesthetically appealing way. At first, I just used lattice’s bwplot, but the spacing of the X-axis here really matters. The spectra’s frequencies aren’t regularly-spaced categories, which is th...
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understanding computational Bayesian statistics
I have just finished reading this book by Bill Bolstad (University of Waikato, New Zealand) which a previous ‘Og post pointed out when it appeared, shortly after our Introducing Monte Carlo Methods with R. My family commented that the cover was nicer than those of my own books, which is true. Before I launch into a review, let me warn the ‘Og...
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Le Monde puzzle [#743]
As Le Monde weekend has yet again changed its format (with so much more advertisements for luxurious items that I sometimes wonder whether or not this is the weekend edition of Le Monde!], it took me a while to locate the mathematical puzzle. The good news is there now is a science&techno leaflet with, at the end, the math puzzle! (Sorry, this is...
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Typos in Introduction to Monte Carlo Methods with R
The two translators of our book in Japanese, Kazue & Motohiro Ishida, contacted me about some R code mistakes in the book. The translation is nearly done and they checked every piece of code in the book, an endeavour for which I am very grateful! Here are the two issues they have noticed (after incorporating the typos signaled in the overall up-t...
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principles of uncertainty
“Bayes Theorem is a simple consequence of the axioms of probability, and is therefore accepted by all as valid. However, some who challenge the use of personal probability reject certain applications of Bayes Theorem.“ J. Kadane, p.44 Principles of uncertainty by Joseph (“Jay”) Kadane (Carnegie Mellon University, Pittsburgh) is a profou...
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National Gallery of Ireland
During a short if profitable visit to Dublin for a SFI meeting on Tuesday/Friday, I had the opportunity to visit the National Gallery of Ireland in my sole hour of free time (as my classy hotel was very close). The building itself is quite nice, being well-inserted between brick houses from the outside, while providing impressive height, space, a...
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the Wang-Landau algorithm reaches the flat histogram in finite time
Pierre Jacob and Robin Ryder (from Paris-Dauphine, CREST, and Statisfaction) have just arXived (and submitted to the Annals of Applied Probability) a neat result on the Wang-Landau algorithm. (This algorithm, which modifies the target in a sort of reweighted partioned sampling to achieve faster convergence, has always been perplexing to me.) Th...
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postdoctoral positions in Paris
There is a call for postdoctoral positions supported by the Paris Mathematical Sciences Foundation. The deadline is December 13 and the on-line application is available. If you are interested in working with me on Bayesian statistics (model choice, time series model) or computational methods (SMC, MCMC, ABC, &c.) thru this call, please contact ...
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