Archive for quarantine

squash invasion

Posted in pictures, Wines with tags , , , , , , on August 1, 2020 by xi'an


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a journal of the plague year [more deconfined reviews]

Posted in Books, Kids, pictures with tags , , , , , , , , , , , , , , , , , , on July 18, 2020 by xi'an

Took a copy of Room 10 by Åke Edwardson yet again on the book sharing shelves at Dauphine. And read it within a few days, with limited enthusiasm as the story proceeds quite sluggishly, every single clue is driven to its very end, e.g. detailing the examination of security recordings for pages!, the Swedish background is mostly missing, the personal stories of the policemen prove frankly boring, and the final explanations stand way beyond a mere suspension of belief. The book is back on the shelves.

Watched the beginning of the Salvation series and quickly gave up. Because I soon realised it had nothing to do with the Peter Hamilton’s trilogy. And because the story did not seem to get anywhere, despite the impending destruction of Earth by a massive asteroid, turning into an East versus West spy story. And because the scientific aspects and characters were plain ridiculous. And also because the secondary plot about whom should be saved in case of a destruction was quite distasteful in its primitive eugenism.

Read an Indriðason I had not yet read, Sons of dust [Synir duftsins], the first book he wrote, but ironically rather repetitive on the themes of missing fathers, child abuse, social consequences of the second World War allied occupation, found in the subsequent volumes. And a rather unconvincing plot, especially from a genetic engineering perspective. (The book is not currently available in English. I read it in French.)

Eventually came to watch There will be blood, the 2007 masterpiece by Paul Anderson, with Daniel Day-Lewis rendering so impressively the descent into madness of the oil tycoon and his thirst for absolute control, loosing his adopted son in the process. And unable to stop at exposing the duplicity of the preacher whom he fought the entire film. The ending is somewhat less impressive than the rest, maybe because all is finished, but it does not diminish the raw power of this tale. And the music track is perfect, with Brahms’ Violin Concerto as a leitmotiv. A journey into oily darkness…

a journal of the plague year [deconfited reviews]

Posted in Books, Kids, pictures, Running, Wines with tags , , , , , , , , , , , , , , , , , , , , , , , , on July 4, 2020 by xi'an

Found a copy of Humans by Donald Westlake on the book sharing shelves at Dauphine. And read it within a few hours, as it is very light reading but quite funny nonetheless. If hardly ranking as a mystery novel. Or crime novel, unless the crime is Gaiacide and the criminal God. Reminded me of the equally light Bobby Dollar series by Tad Williams. As the main character is an angel, falling for humans as he tries to steer them towards the Armageddon. The setting is the early 1990s, with the main scares being atomic disaster (Chernobyl) and the AIDS pandemic. Plus the rise of environmental worries and of Chinese autocracy. I put it back on the shelves on my next visit to Dauphine, hopefully for someone else to enjoy!

Baked radish stems with basil for making pesto, with a bit more bitterness than usual. Cooked plenty of fennel since this is fennel season. Continued making my weekly rhubarb preserve. Keeping the garden active, now watching squash vines invading new territory, hopefully with an eatable reward in the Fall. Tomatoes are growing incredibly fast as well..! Saw another fox in the Parc before official opening times, quite close if speeding away from me and barely avoiding bumping in a pair of greyhounds which fortunately sounded completely unconcerned.

Watched Children of Men after an exhausting week online for a grant panel. While a parabola for the coming collapse of civilisation under political, biological and environmental apocalypses [is there any meaning to use apocalyse in the plural tense!?] and a premonitory tale on Brexit and the buttressing of Britain [or Trump and his Big Wall mania] induced by anti-immigrant rethorics, the film is over the top in terms of plot and action, with symbolism taking over realism, even on the slightest degree, every shot being filled with references to religions and arts (like the Pink Floyd flying pig), to previous environmental disasters (with long shots of burning cows reminiscent of the mad cow crisis) and geo-political upheavals (including a Hamas type protest in the refugee camp, with a short appearance of a jeep with a French flag more reminiscent of the liberation of Paris in August 1944). Characters are charicaturesque, with a very Manichean division between very few good ones and mostly bad ones. The most ridiculous part of the scenario may well be the battle scene in the refugee camp [tanks versus pistols!]… Once again stunned by all the awards and praise piled upon that film.

Read two more volumes of the Witcher [bought during BayesComp for my son!]. One being Sword of Destiny and a series of short stories, like the first volume. The second Blood of Elves and the beginning of the novels. The first season on TV borrows mostly from the first two collections of short stories. Which are somewhat better than the novel, as the latter is very slow paced and overly sentimental. Not terrible, mind.

Completed with uttermost reluctance the Horde du Contrevent [translating as the windwalkers] by Alain Damasio (no English translation available, but an Italian version, l’Orda del Vento,  is). Book that I again picked for figuring in Le Monde 100 bes&tc list! And felt like constantly fronting a strong, icy wind when going through the pages of that unusual book. The style is unpleasant and rather pretentious, with numerous puns in French.. The story is one of a (religious? mystical?) group walking against the wind(s) for decades to reach the source of these winds and to find the last types of wind no one has ever met. Their dreary pilgrimage is described by the 23 membres of the group, called the Horde, with a heavy-handed typographical symbol at the start of each paragraph identifying who’s speaking (and a convenient page marker with all these symbols). A bit heavy handed as a polyphonic novel (appropriately composed in a Corsican retreat!) and even more in the crypt-Nietschean philosophy it carries… The background universe there is somehow eco-steam-punk, with the wind producing most of the energy. The most exciting part involves rather realistic ice climbing. However, I clearly stand in the small minority of those less than impressed by the book as it is highly popular among French readers, one of the highest printings in the Folio collection, with side products a BD (above) and a movie (in the making?). (And enough votes from fans to almost reach the 10 most favourite novels in Le Monde list. )

a cartoon that could have been made for lockdown

Posted in Books, pictures with tags , , , , , , , on June 27, 2020 by xi'an

scalable Langevin exact algorithm [armchair Read Paper]

Posted in Books, pictures, Statistics, Travel, University life with tags , , , , , , , , , , , on June 26, 2020 by xi'an

So, Murray Pollock, Paul Fearnhead, Adam M. Johansen and Gareth O. Roberts presented their Read Paper with discussions on the Wednesday aft! With a well-sized if virtual audience of nearly a hundred people. Here are a few notes scribbled during the Readings. And attempts at keeping the traditional structure of the meeting alive.

In their introduction, they gave the intuition of a quasi-stationary chain as the probability to be in A at time t while still alice as π(A) x exp(-λt) for a fixed killing rate λ. The concept is quite fascinating if less straightforward than stationarity! The presentation put the stress on the available recourse to an unbiased estimator of the κ rate whose initialisation scaled as O(n) but allowed a subsampling cost reduction afterwards. With a subsampling rat connected with Bayesian asymptotics, namely on how quickly the posterior concentrates. Unfortunately, this makes the practical construction harder, since n is finite and the concentration rate is unknown (although a default guess should be √n). I wondered if the link with self-avoiding random walks was more than historical.

The initialisation of the method remains a challenge in complex environments. And hence one may wonder if and how better it does when compared with SMC. Furthermore, while the motivation for using a Brownian motion stems from the practical side, this simulation does not account for the target π. This completely blind excursion sounds worse than simulating from the prior in other settings.

One early illustration for quasi stationarity was based on an hypothetical distribution of lions and wandering (Brownian) antelopes. I found that the associated concept of soft killing was not necessarily well received by …. the antelopes!

As it happens, my friend and coauthor Natesh Pillai was the first discussant! I did no not get the details of his first bimodal example. But he addressed my earlier question about how large the running time T should be. Since the computational cost should be exploding with T. He also drew a analogy with improper posteriors as to wonder about the availability of convergence assessment.

And my friend and coauthor Nicolas Chopin was the second discussant! Starting with a request to… leave the Pima Indians (model)  alone!! But also getting into a deeper assessment of the alternative use of SMCs.