Last week I received in my mailbox a copy of the Princeton University Press book "Machine Learning for Physics and Astronomy" by Viviana Acquaviva. They sent me a copy because I had reviewed its contents for Princeton Press.


I am happy with the book. When I accepted to review it, I was a bit hesitant because I am not a computer scientist. I might pass as an expert in machine learning because after all I have been developing such tools for 20 years now (or maybe I should say over 30, as my first attempt was in 1992, with a bootstrap-powered classification method), but I feel I still lack knowledge in some of the theoretical underpinnings, and there are holes in my knowledge base. 

Having spent the past 12 months coding up an end-to-end model of an astrophysics experiment, with the sole aim of searching for an optimal solution for its design by use of stochastic gradient descent, I am the least qualified person to judge the aesthetic value of the results I am finally getting from it. 
Therefore it makes sense to ask you, dear reader, what you think of the eerily arcane geometries that the system is proposing. I do not think that to be a good judge you need to know the details of how the model is put together, but I will nevertheless make an attempt at briefing you on it, just in case it makes a difference in your judgment.

These days I am in Paris, for a short vacation - for once, I am following my wife in a work trip; she performs at the grand Halle at la Villette (she is a soprano singer), and I exploit the occasion to have some pleasant time in one of the cities I like the most.


This morning I took the metro to go downtown, and found myself standing up in a wagon full of people. When my eyes wandered to the pavement, I saw that the plastic sheet had circular bumps, presumably reducing the chance of slips. And the pattern immediately reminded me of the Monte Carlo method, as it betrayed the effect of physical sampling of the ground by the passengers' feet:

The Indian Center for Theoretical Sciences is located in a rural area a few kilometers north of Bangalore, in southern India. Bangalore is a mid-sized city that saw a very big expansion in the past few years due to having become a center for the information technology in the country - with most of the big multinationals opening sections there. The rapid expansion increased the wealth of the middle class there (but remember, the middle class is the top 5% in India), but it also created stress to the traffic in the city, which is notoriously a plague there.
The campus of ICTS is very nice from an architectonic point of view, embedding nature in its buildings and trying to integrate the two realities. Below is a picture.

I recently read a book by Martin Rees, "On the future". I found it an agile small book packed full with wisdom and interesting considerations on what's in the plate for humanity in the coming decades, centuries, millennia, billions of years. And I agree with much of what he wrote in it, finding also coincidental views on topics I had built my own judgement independently in the past.

What is multithreading? It is the use of multiple processors to perform tasks in parallel by a single computer program. I have known this simple fact for over thirty years, but funnily enough I never explored it in practice. The reason is fundamentally that I am a physicist, not a computer scientist, and as a physicist I tend to stick with a known skillset to solve my problems, and to invest time in more physics knowledge than software wizardry. You might well say I am not a good programmer altogether, although that would secretly cause me pain. I would answer that while it is certainly true that my programs are ugly and hard to read, they do what they are supposed to do, as proven by a certain record of scientific publications.