Archive for Apple II

future of computational statistics

Posted in Books, pictures, R, Statistics, University life with tags , , , , , , , , , , , , , , on September 29, 2014 by xi'an

I am currently preparing a survey paper on the present state of computational statistics, reflecting on the massive evolution of the field since my early Monte Carlo simulations on an Apple //e, which would take a few days to return a curve of approximate expected squared error losses… It seems to me that MCMC is attracting more attention nowadays than in the past decade, both because of methodological advances linked with better theoretical tools, as for instance in the handling of stochastic processes, and because of new forays in accelerated computing via parallel and cloud computing, The breadth and quality of talks at MCMski IV is testimony to this. A second trend that is not unrelated to the first one is the development of new and the rehabilitation of older techniques to handle complex models by approximations, witness ABC, Expectation-Propagation, variational Bayes, &tc. With a corollary being an healthy questioning of the models themselves. As illustrated for instance in Chris Holmes’ talk last week. While those simplifications are inevitable when faced with hardly imaginable levels of complexity, I still remain confident about the “inevitability” of turning statistics into an “optimize+penalize” tunnel vision…  A third characteristic is the emergence of new languages and meta-languages intended to handle complexity both of problems and of solutions towards a wider audience of users. STAN obviously comes to mind. And JAGS. But it may be that another scale of language is now required…

If you have any suggestion of novel directions in computational statistics or instead of dead ends, I would be most interested in hearing them! So please do comment or send emails to my gmail address bayesianstatistics

Steve Jobs: 1955-2011

Posted in Travel, University life with tags , , on October 7, 2011 by xi'an

I bought my first Apple in May 1983, it was an Apple IIe computer, just out from the factory, and I spent most of my savings on the [approximately 13,000 francs] 8K machine. Then most of my summer programming in Pascal games and algorithms. (I even had a special suitcase built by my brother-in-law to carry the thing back and forth between Paris and Normandy, on the train! An early version of the portable computer.) This Apple computer did run most of the simulations for my thesis on the James-Stein phenomenon, running for days and days, the top lid often removed to let the heat out.

In 1991, I brought an Apple Macintosh IIc back from Purdue. I remember that the custom officer in the airport was so clueless about computers that he asked me whether the RAM was under 64K or not. I used this second Apple computer at home for writing my first books and for logging to the Paris 6 mainframe by shaky modem connections, but not for computing apart from some Mathematica formal calculus. (At that time, CREST still did not have Internet and I had to rely on the rudimentary Minitel…) Then in 1996 we bought a PowerMac that was so pleasantly efficient (a NeXT would have been even better but the cost was just too high without a research grant!) that we kept using it till 2000 or 2001 (when my then young son ruined the CD reader by stuffing all his color pen into the slot). At that point, I had moved to exclusively using Linux and laptops, so there was little point (and even less money) in buying Macs, and it is only three years ago that I tried using them in conjunction with an Ubuntu system, not a perfect combination but smooth enough for my own purpose and idiosyncrasies… (Plus the guaranty of reliable material and hardware.) Thus, a long and still going relation with Apple computers. Hence a sincere salute to Steve Jobs for his vision and charisma in keeping the technology and innovation ahead of the crowd over these 35 years.

(Counterpoint #1: I am always wary of the easy trend to turn individuals into geniuses without accounting for their environment: Mr Jobs was head of a huge company with an army of engineers, designers, publicists, &tc. and they contributed to the success of Apple, the more as the years went on, I presume. So I have more trust in the law of large numbers than in black, gray, or white swans. Nonetheless, it can be argued Apple would not have impacted our daily life the way it did without Steve Jobs. An exception to my rule above.)

(Counterpoint #2: Apple is a commercial company. That it delivers fairly good products and keeps an innovative research policy does not absolve it from corporate flaws. Nor does it exclude other high tech companies from delivering other types of innovation.)

Randomness through computation

Posted in Books, Statistics, University life with tags , , , , , , , , , , , , , , on June 22, 2011 by xi'an

A few months ago, I received a puzzling advertising for this book, Randomness through Computation, and I eventually ordered it, despite getting a rather negative impression from reading the chapter written by Tomasso Toffoli… The book as a whole is definitely perplexing (even when correcting for this initial bias) and I would not recommend it to readers interested in simulation, in computational statistics or even in the philosophy of randomness. My overall feeling is indeed that, while there are genuinely informative and innovative chapters in this book, some chapters read more like newspeak than scientific material (mixing the Second Law of Thermodynamics, Gödel’s incompleteness theorem, quantum physics, and NP completeness within the same sentence) and do not provide a useful entry on the issue of randomness. Hence, the book is not contributing in a significant manner to my understanding of the notion. (This post also appeared on the Statistics Forum.) Continue reading