Blog Archives

Introducing R on video

March 9, 2010
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Introducing R on video

Darren Wraith pointed out to me this site proposing a whole series of videos introducing to R. (Unfortunately in a Windows environment.) This can be handy when facing students with no R background… Filed under: R, Statistics, University life Tagged: course, video

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Chinese versus Japanese editions

March 8, 2010
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Chinese versus Japanese editions

Last week, I got news from Springer Verlag about possibly two new editions of my books, one in Chinese and one in Japanese. These were bad news and good news: the bad news was that the Chinese edition was actually a reprint of our original book,  Monte Carlo Statistical Method, by a Chinese publishing company.

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schoolmath

March 6, 2010
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schoolmath

In connection with the Le Monde puzzle of last week, I was looking for an R function that would give me the prime factor decomposition of any integer. Such a function exists within the package schoolmath, developped by Joerg Schlarmann and Josef Wienand. It is called prime.factor and it returns the prime factors of any

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Posterior likelihood

March 6, 2010
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Posterior likelihood

At the Edinburgh mixture estimation workshop, Murray Aitkin presented his proposal to compare models via the posterior distribution of the likelihood ratio. As already commented in a post last July, the positive aspect of looking at this quantity rather than at the Bayes factor is that the priors are then allowed to be improper if

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An email about mixtures

March 4, 2010
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An email about mixtures

As a coincidence, or not, I received the following email just before starting our mixture estimation workshop (the above is Ben Nevis on Monday, whose skyline really looks like a three component mixture!) and giving a discussion on label switching: I am implementing a Markov-Chain Monte Carlo method for Gibbs sampling from a simple mixture

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New Le Monde puzzle

March 3, 2010
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New Le Monde puzzle

When I first read Le Monde puzzle this weekend, I though it was even less exciting than the previous one: find and , such that is a multiple of . The solution is obtained by brute-force checking through an R program: and then the a next solution is (with several values for N). However, while

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How to use mcsm

February 27, 2010
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How to use mcsm

Within the past two days, I received this email Dear Prof.Robert I have just bought your recent book on Introducing Monte Carlo Methods with R.  Although I have checked your web page for the R programs (bits of the code in the book, codes for generating the figures and tec – not the package available

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Welcome, Robin!

February 25, 2010
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Welcome, Robin!

Robin Ryder started his new blog with his different solutions to Le Monde puzzle of last Saturday (about the algebraic sum of products…), solutions that are much more elegant than my pedestrian rendering. I particularly like the one based on the Jacobian of a matrix! (Robin is doing a postdoc in Dauphine and CREST—under my

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Sudoku via simulated annealing

February 22, 2010
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Sudoku via simulated annealing

The Sudoku puzzle in this Sunday edition of Le Monde was horrendously difficult, so after spending one hour with only 4 entries filled, I decided to feed it to the simulated annealing R program I wrote while visiting SAMSI last year. The R program reached the exact (and only) solution in about 6000 iterations, as

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R exam postprocessing

February 19, 2010
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R exam postprocessing

Following my three-fold R exam of last month, I had a depressing afternoon meeting (with other faculty members) some students who had submitted R codes that were suspiciously close to other submitted R codes… In other words, it looked very  likely they had cheated. (A long-term issue with my R course, alas!) During this meeting,

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