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An interesting suduko-like puzzle for this week puzzle in Le Monde thi A 10×10 grid is filled by a random permutation of {0,…,99}. The 4 largest figures in each row are coloured in yellow and the 4 largest values in each column are coloured in red. What is the range of the number of ... [Read more...]

Michael Blum and Olivier François, along with Katalin Csillery, just released an R package entitled abc. (I am surprised the name was not already registered!) Its aim is obviously to implement ABC approximations for Bayesian inference: Description The ’abc’ package provides various functions for parameter estimation and model selection ... [Read more...]

Last weekend, my friend and coauthor Jean-Michel Marin was interviewed (as Jean-Claude Marin, sic!) by a national radio about the probability of the replication of a draw on the Israeli Lottery. Twice the same series of numbers appeared within a month. This lotery operates on a principle of 6/37 + 1/8: 6 numbers are ... [Read more...]

We have just posted the (mostly definitive) program for Adap’skii, January 3-4, The Canyons, Utah. This is taking place just before and as a satellite of the larger MCMSki III conference, January 4-7, same location. The registration for the conference and for lodging is available through the  MCMCSki III ... [Read more...]

The current puzzle in Le Monde this week is again about prime numbers: The control key on a credit card is an integer η(a) associated with the card number a such that, if the card number is c=ab, its key η(c) satisfies η(c)=η(a)+η(b)-1. There is only ... [Read more...]

Here is an announcement I received that should interest potential postdocs (willing to come to Paris). The location is on the Orsay campus, south of Paris. In the framework of the ANR-funded Metacoli project which aims at identifying the metabolic underpinnings of the lifestyle diversity in the E. coli species, ... [Read more...]

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The puzzle in Le Monde this week[end] is called the “square five” (sic!): Two players each have twenty-five cards with five times each of the digits 1,2,3,4,5. They alternate putting one card on top of the pile, except that they can instead take an arbitrary number of consecutive cards from ... [Read more...]

Those are the slides for the (basic) introduction of the paper by Mark Girolami and Ben Calderhead at the RSS next week. Not to be confused with my comments on the paper. Filed under: R, Statistics, Travel, University life Tagged: Hamiltonian, Langevi... [Read more...]

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Since the puzzle in this week (-end) edition of Le Monde is not (easily) solvable via an R program, I chose to go back to an older puzzle that my students can solve. Eleven [distinguishable] token are [arbitrarily] distributed around a 200 meter perimeter-long ring. They all start moving at the ... [Read more...]

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Since I have resumed my R class, I will restart my resolution of Le Monde mathematical puzzles…as they make good exercises for the class. The puzzle this week is not that exciting: Find the four non-zero different digits a,b,c,d such that abcd is equal to the ... [Read more...]

Stephen Stigler has written a paper in the Journal of the Royal Statistical Society Series A on Francis Galton’s analysis of (his cousin) Charles Darwin’ Origin of Species, leading to nothing less than Bayesian analysis and accept-reject algorithms! “On September 10th, 1885, Francis Galton ushered in a new era of ... [Read more...]

Here is a (prompt!) reply from Mark Girolami corresponding to the earlier post: In preparation for the Read Paper session next month at the RSS, our research group at CREST has collectively read the Girolami and Calderhead paper on Riemann manifold Langevin and Hamiltonian Monte Carlo methods and I hope ... [Read more...]

In the previous days I have received several emails asking for clarification of the effective sample size derivation in “Introducing Monte Carlo Methods with R” (Section 4.4, pp. 98-100). Formula (4.3) gives the Monte Carlo estimate of the variance of a self-normalised importance sampling estimator (note the change from the original version ... [Read more...]

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Edward Kao pointed out the following difficulty about Example 3.6 in Chapter 3 of “Introducing Monte Carlo Methods with R”: I have two questions that have puzzled me for a while. I hope you can shed some lights. They are all about Example 3.6 of your book. 1. On page 74, there is a term [...] [Read more...]