Archive for Vienna

Nature snapshots [and snide shots]

Posted in Books, pictures, Statistics, Travel, University life with tags , , , , , , , , , , , on October 12, 2017 by xi'an

A very rich issue of Nature I received [late] just before leaving for Warwick with a series of reviews on quantum computing, presenting machine learning as the most like immediate application of this new type of computing. Also including irate letters and an embarassed correction of an editorial published the week before reflecting on the need (or lack thereof) to remove or augment statues of scientists whose methods were unethical, even when eventually producing long lasting advances. (Like the 19th Century gynecologist J. Marion Sims experimenting on female slaves.) And a review of a book on the fascinating topic of Chinese typewriters. And this picture above of a flooded playground that looks like a piece of abstract art thanks to the muddy background.

“Quantum mechanics is well known to produce atypical patterns in data. Classical machine learning methods such as deep neural networks frequently have the feature that they can both recognize statistical patterns in data and produce data that possess the same statistical patterns: they recognize the patterns that they produce. This observation suggests the following hope. If small quantum information processors can produce statistical patterns that are computationally difficult for a classical computer to produce, then perhaps they can also recognize patterns that are equally difficult to recognize classically.” Jacob Biamonte et al., Nature, 14 Sept 2017

One of the review papers on quantum computing is about quantum machine learning. Although like Jon Snow I know nothing about this, I find it rather dull as it spends most of its space on explaining existing methods like PCA and support vector machines. Rather than exploring potential paradigm shifts offered by the exotic nature of quantum computing. Like moving to Bayesian logic that mimics a whole posterior rather than produces estimates or model probabilities. And away from linear representations. (The paper mentions a O(√N) speedup for Bayesian inference in a table, but does not tell more, which may thus be only about MAP estimators for all I know.) I also disagree with the brave new World tone of the above quote or misunderstand its meaning. Since atypical and statistical cannot but clash, “universal deep quantum learners may recognize and classify patterns that classical computers cannot” does not have a proper meaning. The paper contains a vignette about quantum Boltzman machines that finds a minimum entropy approximation to a four state distribution, with comments that seem to indicate an ability to simulate from this system.

Die Zauberflöte

Posted in Statistics with tags , , , , , , , , on October 1, 2017 by xi'an

Attending Mozart’s Zauberflöte last week at the Volksoper Wien was a great reward for taking part in this (somewhat gruesome) grant evaluation! The atmosphere was relaxed, with loads of families and (very well-behaved!) young children [all siding for Papageno!] And the opera was given from a 2005 production, with a fast-paced orchestration and a great female singer cast (as opposed to the last time I saw the opera in Sceaux, when the Queen of the Night had botched her major arias!), if less so on the male singer side, Papageno excepted. (Sarastro barely audible in the lowest notes…) The three boys were fantastic as well. (As usual, I find the plot  incomprehensible, with Sarastro and his cult (and the kidnapping of his daughter) as despicable as the Queen’s moral pressure on Pamina…)

When running towards the Donauinsel in the early morning the next day, I saw this poster and realised the same Zauberflöte was played in another Viennese theatre, which is amazing, given that the Staatoper will also give it next December. Or not if considering that a part of Vienna’s attraction is this rich music scene.

für die menschen Rechte! [Volkshilfe].

Posted in pictures, Running, Travel with tags , , , , , on September 28, 2017 by xi'an

Kürbissuppe trilogy

Posted in pictures, Running, Travel with tags , , , , , , , , on September 24, 2017 by xi'an

Gaußplatz [jatp]

Posted in pictures, Running, Travel with tags , , , , , , on September 22, 2017 by xi'an

snapshot from Vienna [jatp]

Posted in Statistics with tags , , , , , on September 21, 2017 by xi'an

LaTeX issues from Vienna

Posted in Books, Statistics, University life with tags , , , , , , , , , , , on September 21, 2017 by xi'an

When working on the final stage of our edited handbook on mixtures, in Vienna, I came across unexpected practical difficulties! One was that by working on Dropbox with Windows users, files and directories names suddenly switched from upper case to lower cases letters !, making hard-wired paths to figures and subsections void in the numerous LaTeX files used for the book. And forcing us to change to lower cases everywhere. Having not worked under Windows since George Casella gave me my first laptop in the mid 90’s!, I am amazed that this inability to handle both upper and lower names is still an issue. And that Dropbox replicates it. (And that some people see that as a plus.)

The other LaTeX issue that took a while to solve was that we opted for one chapter one bibliography, rather than having a single bibliography at the end of the book, mainly because CRC Press asked for this feature in order to sell chapters individually… This was my first encounter with this issue and I found the solutions to produce individual bibliographies incredibly heavy handed, whether through chapterbib or bibunits, since one has to bibtex one .aux file for each chapter. Even with a one line bash command, this is annoying to the extreme!