There will be not one but two consecutive events in Edinburgh next May²⁴ on sequential Monte Carlo methods! Both hosted by the fantastic International Centre for Mathematical Sciences (ICMS) in Edinburgh Olde Town. Within the Bayes Centre. And running distance to Arthur’s Seat. (Reminding me of my first ICMS workshop in 2001 run with Mike Titterington. May have been my first week long visit to Edinburgh as well…)
First, a Summer School on Bayesian filtering: fundamental theory and numerical methods (SSBF 2024), Edinburgh (UK), May 6-10, 2024. This summer (in the Scottish sense!) school will cover topics related to fundamental theory, state-of-the-art methodologies, and real-world applications.
Second, a Sequential Monte Carlo workshop (SMC 2024), the week later, on May 13-17, 2024. The workshop will cover topics related to sequential Monte Carlo and nearby fields, from theory to applications, following earlier workshops in the series. Including the one at CREST in 2015.
Thanks to Víctor Elvira, Jana de Wiljes, and Dan Crisan for this double deal (and the opportunity to return to Scotland for the first time since the pandemic).
![\mathbb E[y|X=x] = \mathbb E\left[y\frac{f_{XY}(x,y)}{f_X(x)f_Y(y)}|X=x\right] = \frac{\mathbb E\left[y\frac{f_{XY}(x,y)}{f_Y(y)}|X=x\right]}{f_X(x)}](https://s0.wp.com/latex.php?latex=%5Cmathbb+E%5By%7CX%3Dx%5D+%3D+%5Cmathbb+E%5Cleft%5By%5Cfrac%7Bf_%7BXY%7D%28x%2Cy%29%7D%7Bf_X%28x%29f_Y%28y%29%7D%7CX%3Dx%5Cright%5D+%3D+%5Cfrac%7B%5Cmathbb+E%5Cleft%5By%5Cfrac%7Bf_%7BXY%7D%28x%2Cy%29%7D%7Bf_Y%28y%29%7D%7CX%3Dx%5Cright%5D%7D%7Bf_X%28x%29%7D&bg=000000&fg=B0B0B0&s=0&c=20201002)
The main BayesComp meeting started right after the ABC workshop and went on at a grueling pace, and offered a constant conundrum as to which of the four sessions to attend, the more when trying to enjoy some outdoor activity during the lunch breaks. My overall feeling is that it went on too fast, too quickly! Here are some quick and haphazard notes from some of the talks I attended, as for instance the practical parallelisation of an SMC algorithm by Adrien Corenflos, the advances made by Giacommo Zanella on using Bayesian asymptotics to assess robustness of Gibbs samplers to the dimension of the data (although with no assessment of the ensuing time requirements), a nice session on simulated annealing, from black holes to Alps (if the wrong mountain chain for Levi), and the central role of contrastive learning à la Geyer (1994) in the GAN talks of Veronika Rockova and Éric Moulines. Victor Elvira delivered an enthusiastic talk on our massively recycled importance on-going project that we need to complete asap!
In a not-solely-ABC session, I appreciated Sirio Legramanti speaking on comparing different distance measures via Rademacher complexity, highlighting that some distances are not robust, incl. for instance some (all?) Wasserstein distances that are not defined for heavy tailed distributions like the Cauchy distribution. And using the mean as a summary statistic in such heavy tail settings comes as an issue, since the distance between simulated and observed means does not decrease in variance with the sample size, with the practical difficulty that the problem is hard to detect on real (misspecified) data since the true distribution behing (if any) is unknown. Would that imply that only intrinsic distances like maximum mean discrepancy or Kolmogorov-Smirnov are the only reasonable choices in misspecified settings?! While, in the ABC session, Jeremiah went back to this role of distances for generalised Bayesian inference, replacing likelihood by scoring rule, and requirement for Monte Carlo approximation (but is approximating an approximation that a terrible thing?!). I also discussed briefly with Alejandra Avalos on her use of pseudo-likelihoods in Ising models, which, while not the original model, is nonetheless a model and therefore to taken as such rather than as approximation.
I had missed the séminaire parisien de statistique for most of the Fall semester, hence was determined to attend the first session of the year 2023, the more because the talks were close to my interest. To wit, 
Last but not least!, my friend Randal talked about his 
