Archive for ABC in Montréal

ABC in Montréal

Posted in pictures, R, Running, Statistics, Travel, University life with tags , , , , , , , on September 4, 2018 by xi'an

There will be a symposium on ABC in Montréal this coming December, the day before NIPS, in a continuation of past years NIPS workshops. While invited speakers and panelists have been selected by the committee, a call for papers is open. Note that in continuation with the best “ABC in…” tradition, registration is free! I will unfortunately be unable to make it to this symposium, as the date clashes with our Big Bayes conference at CIRM (free registration, with still some places available!).

Je reviendrai à Montréal [D-2]

Posted in pictures, Statistics, Travel, University life with tags , , , , , , , , , , , , , , on December 9, 2015 by xi'an

I have spent the day and more completing and compiling slides for my contrapuntal perspective on probabilistic numerics, back in Montréal, for the NIPS 2015 workshop of December 11 on this theme. As I presume the kind  invitation by the organisers was connected with my somewhat critical posts on the topic, I mostly  The day after, while I am flying back to London for the CFE (Computational and Financial Econometrics) workshop, somewhat reluctantly as there will be another NIPS workshop that day on scalable Monte Carlo.

Je veux revoir le long désert
Des rues qui n’en finissent pas
Qui vont jusqu’au bout de l’hiver
Sans qu’il y ait trace de pas

Je reviendrai à Montréal [NIPS 2015]

Posted in pictures, Statistics, Travel, University life with tags , , , , , , , , , , , , , , on September 30, 2015 by xi'an

I will be back in Montréal, as the song by Robert Charlebois goes, for the NIPS 2015 meeting there, more precisely for the workshops of December 11 and 12, 2015, on probabilistic numerics and ABC [à Montréal]. I was invited to give the first talk by the organisers of the NIPS workshop on probabilistic numerics, presumably to present a contrapuntal perspective on this mix of Bayesian inference with numerical issues, following my somewhat critical posts on the topic. And I also plan to attend some lectures in the (second) NIPS workshop on ABC methods. Which does not leave much free space for yet another workshop on Approximate Bayesian Inference! The day after, while I am flying back to London, there will be a workshop on scalable Monte Carlo. All workshops are calling for contributed papers to be presented during central poster sessions. To be submitted to abcinmontreal@gmail.com and to probnum@gmail.com and to aabi2015. Before October 16.

Funny enough, I got a joking email from Brad, bemoaning my traitorous participation to the workshop on probabilistic numerics because of its “anti-MCMC” agenda, reflected in the summary:

“Integration is the central numerical operation required for Bayesian machine learning (in the form of marginalization and conditioning). Sampling algorithms still abound in this area, although it has long been known that Monte Carlo methods are fundamentally sub-optimal. The challenges for the development of better performing integration methods are mostly algorithmic. Moreover, recent algorithms have begun to outperform MCMC and its siblings, in wall-clock time, on realistic problems from machine learning.

The workshop will review the existing, by now quite strong, theoretical case against the use of random numbers for integration, discuss recent algorithmic developments, relationships between conceptual approaches, and highlight central research challenges going forward.”

Position that I hope to water down in my talk! In any case,

Je veux revoir le long désert
Des rues qui n’en finissent pas
Qui vont jusqu’au bout de l’hiver
Sans qu’il y ait trace de pas

ABC à… Montréal

Posted in pictures, Statistics, Travel, University life with tags , , , , , , , , , on August 24, 2015 by xi'an

Montreal1Like last year, NIPS will be hosted in Montréal, Québec, Canada, and like last year there will be an ACB NIPS workshop. With a wide variety of speakers and poster presenters. There will also be a probabilistic integration NIPS workshop, to which I have been invited to give a talk, following my blog on the topic! Workshops are on December 11 and 12, and I hope those two won’t overlap so that I can enjoy both at length (before flying back to London for CFE 2015…)

Update: they do overlap, both being on December 11…

partly virtual meetings

Posted in Kids, pictures, Statistics, Travel, University life with tags , , , , , , , , , on December 29, 2014 by xi'an

flight to Montpelliers, Feb. 2012A few weeks ago, I read in the NYT an article about the American Academy of Religion cancelling its 2021 annual meeting as a sabbatical year, for environmental reasons.

“We could choose to not meet at a huge annual meeting in which we take over a city. Every year, each participant going to the meeting uses a quantum of carbon that is more than considerable. Air travel, staying in hotels, all of this creates a way of living on the Earth that is carbon intensive. It could be otherwise.”

While I am not in the least interested in the conference or in the topics covered by this society or yet in the benevolent religious activities suggested as a substitute, the notion of cancelling the behemoths that are our national and international academic meetings holds some appeal. I have posted several times on the topic, especially about JSM, and I have no clear and definitive answer to the question. Still, there lies a lack of efficiency on top of the environmental impact that we could and should try to address. Benidorm, June 5, 2010As I was thinking of those issues in the past week, I made another of my numerous “carbon footprints” by attending NIPS across the Atlantic for two workshops than ran in parallel with about twenty others. And hence could have taken place in twenty different places. Albeit without the same exciting feeling of constant intellectual simmering. And without the same mix of highly interactive scholars from all over the planet. (Although the ABC in Montréal workshop seemed predominantly European!) Since workshops are in my opinion the most profitable type of meeting, I would like to experiment with a large meeting made of those (focussed and intense) workshops in such a way that academics would benefit without travelling long distances across the World. One idea would be to have local nodes where a large enough group of researchers could gather to attend video-conferences given from any of the other nodes and to interact locally in terms of discussions and poster presentations. This should even increase the feedback on selected papers as small groups would more readily engage into discussing and criticising papers than a huge conference room. If we could build a World-wide web (!) of such nodes, we could then dream of a non-stop conference, with no central node, no gigantic conference centre, no terrifying beach-ressort…

ABC à Montréal

Posted in Kids, pictures, Running, Statistics, Travel, University life with tags , , , , , , , , , , , , , , , , on December 13, 2014 by xi'an

Montreal1So today was the NIPS 2014 workshop, “ABC in Montréal“, which started with a fantastic talk by Juliane Liepe on some exciting applications of ABC to the migration of immune cells, with the analysis of movies involving those cells acting to heal a damaged fly wing and a cut fish tail. Quite amazing videos, really. (With the great entry line of ‘We have all cut  a finger at some point in our lives’!) The statistical model behind those movies was a random walk on a grid, with different drift and bias features that served as model characteristics. Frank Wood managed to deliver his talk despite a severe case of food poisoning, with a great illustration of probabilistic programming that made me understand (at last!) the very idea of probabilistic programming. And  Vikash Mansinghka presented some applications in image analysis. Those two talks led me to realise why probabilistic programming was so close to ABC, with a programming touch! Hence why I was invited to talk today! Then Dennis Prangle exposed his latest version of lazy ABC, that I have already commented on the ‘Og, somewhat connected with our delayed acceptance algorithm, to the point that maybe something common can stem out of the two notions. Michael Blum ended the day with provocative answers to the provocative question of Ted Meeds as to whether or not machine learning needed ABC (Ans. No!) and whether or not machine learning could help ABC (Ans. ???). With an happily mix-up between mechanistic and phenomenological models that helped generating discussion from the floor.

The posters were also of much interest, with calibration as a distance measure by Michael Guttman, in continuation of the poster he gave at MCMski, Aaron Smith presenting his work with Luke Bornn, Natesh Pillai and Dawn Woodard, on why a single pseudo-sample is enough for ABC efficiency. This gave me the opportunity to discuss with him the apparent contradiction with the result of Kryz Łatunsziński and Anthony Lee about the geometric convergence of ABC-MCMC only attained with a random number of pseudo-samples… And to wonder if there is a geometric versus binomial dilemma in this setting, Namely, whether or not simulating pseudo-samples until one is accepted would be more efficient than just running one and discarding it in case it is too far. So, although the audience was not that large (when compared with the other “ABC in…” and when considering the 2500+ attendees at NIPS over the week!), it was a great day where I learned a lot, did not have a doze during talks (!), [and even had an epiphany of sorts at the treadmill when I realised I just had to take longer steps to reach 16km/h without hyperventilating!] So thanks to my fellow organisers, Neil D Lawrence, Ted Meeds, Max Welling, and Richard Wilkinson for setting the program of that day! And, by the way, where’s the next “ABC in…”?! (Finland, maybe?)

off to Montréal [NIPS workshops]

Posted in Statistics, Travel, University life with tags , , , , , , on December 9, 2014 by xi'an

On Thursday, I will travel to Montréal for the two days of NIPS workshop there. On Friday, there is the ABC in Montréal workshop that I cannot but attend! (First occurrence of an “ABC in…” in North America! Sponsored by ISBA as well.) And on Saturday, there is the 3rd NIPS Workshop on Probabilistic Programming where I am invited to give a talk on… ABC! And maybe will manage to get a sneak at the nearby workshop on Advances in variational inference… (0n a very personal side, I wonder if the weather will remain warm enough to go running in the early morning.)