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Le Monde puzzle [#737 re-read]

August 27, 2011
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Le Monde puzzle [#737 re-read]

As a coincidence, while I was waiting for the solution to puzzle #737 published this Friday in Le Monde, the delivery (wo)man forgot to include the weekend magazine and I had to buy it this morning with my baguette (as if anyone cares!). The solution is (y0,z0,w0)=(38,40,46) and…it does not work! The value of (x1,y1,z1,w1) is

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How Much of R is Written in R?

August 26, 2011
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How Much of R is Written in R?

My boss sent me an email (on my day off!) asking me just how much of R is written in the R language.  This is very simple if you use R and a Unix-like system.  It also gives me a good excuse to defend the title of this blog.  It’s librestats, not projecteulerstats, afterall. So

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25+ more ways to bring data into R

August 26, 2011
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25+ more ways to bring data into R

The rdatamarket post on the Revolutions blog and this post on Decision Stats reminded me about my list of Data APIs/feeds available as packages in R on Cross-Validated (which is a great site that you all should use).  Many of these packa...

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Quick labels within figures

August 26, 2011
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Quick labels within figures

One of the coolest R packages I heard about at the useR! Conference: Toby Dylan Hocking‘s directlabels package for putting labels directly next to the relevant curves or point clouds in a figure. I think I first learned about this idea from Andrew Gelman: that a separate legend requires a lot of back-and-forth glances, so

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Le Monde puzzle [#737]

August 26, 2011
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Le Monde puzzle [#737]

The puzzle in the weekend edition of Le Monde this week can be expressed as follows: Consider four integer sequences (xn), (yn), (zn), and (wn), such that and, if u=(xn,yn,zn,wn), for i=1,…,4, if ui is not the maximum of u and otherwise. Find the first return time n (if any) such that xn=0. Find the value

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Examples on Clustering with R

August 25, 2011
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Examples on Clustering with R

R code examples on various clustering techniques are available as “Clustering in R” in Chapter 4 of R & Bioconductor Manual by Thomas Girke, UC Riverside. It provides R examples on - Hierarchical Clustering, including tree cutting/coloring and heatmaps, - … Continue reading →

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Numerical analysis for statisticians

August 25, 2011
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Numerical analysis for statisticians

“In the end, it really is just a matter of choosing the relevant parts of mathematics and ignoring the rest. Of course, the hard part is deciding what is irrelevant.” Somehow, I had missed the first edition of this book and thus I started reading it this afternoon with a newcomer’s eyes (obviously, I will

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computational difficulties [with notations]

August 25, 2011
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computational difficulties [with notations]

Here is an email I received from Umberto: I have a doubt regarding the tempered transitions method you considered in your JASA article with Celeux and Hurn. On page 961 you detail the several steps for building a proposal for a given distribution by simulating through l tempered power densities. I am slightly confused regarding

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le logiciel R

August 24, 2011
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le logiciel R

For once, here is a book review I wrote in French about the book Le logiciel R, written by Pierre Lafaye de Micheaux (Université de Montréal), Rémy Drouilhet (Université de Grenoble 2) and Benoît Liquet (Université de Bordeaux 2): Ce livre édité par Springer (dans la même collection que Le Choix Bayesien) propose une couverture

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expectation-propagation and ABC

August 23, 2011
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expectation-propagation and ABC

“It seems quite absurd to reject an EP-based approach, if the only alternative is an ABC approach based on summary statistics, which introduces a bias which seems both larger (according to our numerical examples) and more arbitrary, in the sense that in real-world applications one has little intuition and even less mathematical guidance on to

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