Archive for Morgiou

CoRe in CiRM [end]

Posted in Books, Kids, Mountains, pictures, R, Running, Statistics, Travel, University life with tags , , , , , , , , , , , , , on July 18, 2010 by xi'an

Back home after those two weeks in CiRM for our “research in pair” invitation to work on the new edition of Bayesian Core, I am very grateful for the support we received from CiRM and through it from SMF and CNRS. Being “locked” away in such a remote place brought a considerable increase in concentration and decrease in stress levels. Although I was planning for more, we have made substantial advances on five chapters of the book (out of nine), including a completely new chapter (Chapter 8) on hierarchical models and a thorough rewriting of the normal chapter (Chapter 2), which along with Chapter 1 (largely inspired from  Chapter 1 of Introducing Monte Carlo Methods with R, itself inspired from the first edition of Bayesian Core,!). is nearly done. Chapter 9 on image processing is also quite close from completion, with just the result of a batch simulation running on the Linux server in Dauphine to include in the ABC section. As the only remaining major change is the elimination of reversible jump from the mixture chapter (to be replaced with Chib’s approximation) and from the time-series chapter (to be simplified into a birth-and-death process). Going back to the CiRM environment, I think we were lucky to come during the vacation season as there is hardly anyone on the campus, which means no car and no noise. The (good) feeling of remoteness is not as extreme as in Oberwolfach, but it is truly a quality environment. Besides, being able to work 24/7 in the math library is a major plus. as we could go and grab any reference we needed to check. (Presumably, CiRM is lacking in terms of statistics books, compared with Oberwolfach, still providing most of the references we were looking for.) At last, the freedom to walk right out of the Centre into the national park for a run, a climb or even a swim (in Morgiou, rather than Sugiton) makes working there very tantalising indeed! I thus dearly hope I can enjoy again this opportunity in a near future…

Ten stars for CiRM

Posted in Running, Travel, University life with tags , , , , , , on July 17, 2010 by xi'an

Along those two weeks in CiRM, among what I particularly appreciated there:

  1. the accessibility of the math library around the clock,
  2. the peace and seclusion of the CiRM buildings, far away from town, with hardly a car around, no driving for a week, students on vacations, and only the timbales of cicadas as a background noise,
  3. the availability of the helpful staff, whether for ordering books not in the library, arranging a special meal, or locating a climbing site,
  4. the [admittedly Spartan] studios provided by CiRM for long term visitors like us, with wireless connections and enough room for a small family,
  5. the background scenery of Mont Puget and of the Calanques national park,
  6. the multiple trails starting from the Centre, offering running opportunities for every [early] morning,
  7. the hundreds of fully equipped climbing routes in the Calanques, the nearest ones being 20 minutes from the Centre,
  8. an evening swim in Calanque de Morgiou, with hardly anyone around and incredibly warm water, followed by a fritura of small fish in the local and unique restaurant,
  9. a great bouillabaisse in CiRM, along with other good meals ([that I had to skip after a while!], and another one in the last fisherman district of Marseille, thanks to Michel’s hospitality (along with an incredible 1976 Monbazillac!),
  10. and, last but not least, the complete availability of my coauthor, Jean-Michel! (Which was the point in asking for a research in pair support in the first place!)

Back on Morgiou

Posted in Kids, Mountains with tags , , , , , on July 15, 2010 by xi'an

I went back climbing to Morgiou on Saturday night, achieving an easy 5c there but my son was in a hurry to get back to CiRM to watch the (football) game, so we did not try anything else. We started at 7pm, so the temperature was quite enjoyable. Too bad there is not another window of opportunity before I leave!

Climbing in Morgiou

Posted in Kids, Mountains with tags , , , , , on July 10, 2010 by xi'an

On Thursday evening, my son and I went climbing—along with Jean-Michel Marin who took those pictures—in the vale of Morgiou, on a spot called Royaume de dégun (dégun meaning nobody in the local provencal dialect, the name is apparently borrowed from a book by Gilles Del Pappas with the same name published in 2002). As we were in a hurry for the evening meal, we only tried the easiest route (5a). It took us a while to find the way into this small cirque, although it  is only 20mn from CiRM,  and it also took some pondering before going through the swarm of bees that elected the rock crack next to the path as home… But the nice thing was that, by 6pm, the rock was in blessed shade. The limestone rock is fairly characteristic of the area, with tiny “water droplet” holes for fingers and a very good grip for the feet. Most of the routes (including one called théorème de l’engambi, like most routes there a reference to a book by a local author, not to a climb by a visiting mathematician) in this spot are 6a/6b, because the cliff starts to lean forward at the top. I hope we can find some time to go back and try the 5c routes…

Core in CiRM [2]

Posted in Books, R, Statistics, University life with tags , , , , , , , on July 9, 2010 by xi'an

We are making slow progress on the normal and regression chapters as we decided to write the package at the same time we revise the chapters… Jean-Michel transformed the variable selection and model choice R codes of the regression chapter into generic functions that will fit within the package. I rewrote the section on testing, removing all connections to classical testing, 0-1 loss functions and 5% errors, towards a purely model-choice perspective. This does not modify the computational aspects but it makes the discourse more coherent and bypasses the debate about whether or not posterior probabilities are commensurable to p-values and all that. Last morning, I went running to the two creeks (locally called calanques) of Morgiou and Sugiton on a very nice costal trail.