Sunday, June 07, 2009

SoCG 2009: Day 0

At least in my mind, things have been somewhat overshadowed by the sad news of yesterday, thus preventing me (thankfully) from writing the more frivolous posts that I might have penned.

Today was the 25th anniversary celebration for SoCG (1985-2009), and we had four speakers to do a retrospective on the field.

David Dobkin was first, talking about how some of the first geometric algorithms came to be. He interspersed many fun facts about the early days of SoCG:
  • One of the reasons CG is tied to the STOC/FOCS community is because when Michael Shamos first asked him where to publish a geometry paper, STOC was the first conference that came to mind.
  • The Preparata-Shamos book only came about because (after Shamos left for law school) Ron Graham brokered a deal for Franco Preparata to write a book based on Shamos' thesis.
  • SoCG was almost called the Symposium on Computer Geometry (ugh).

It was interesting to see that even way back then, there was serious intersection between numerical algorithms, the graphics and vision folks, and the nascent geometry area. Some things haven't really changed. It also explains (for me) why there is somewhere deep down a sense that CG doesn't wholly situate within the larger algorithms community, but has a core identity that's slightly different.

One point that David made was very interesting. He talked about how Michael Shamos essentially created a problem book from scratch, listing basic problems in the new area of computational geometry, and methodically solving them one by one. He then asserted that it was the creation of this problem book that played a major role in the unification of the area. I think that makes a lot of sense. It's not so much that a list of problems got created. It's not too hard to do that. What I think was the critical factor was the listing of problems within-reach, that encouraged more people to start thinking about them. Muthu is very good at doing this with any field he jumps into, and I think he's able to jumpstart a lot of research for this exact reason. It's not easy to do: the problems have to be core to the area, but still not that difficult to solve.

Micha Sharir went next with a talk on the evolution of work in arrangements. I've always felt that work on arrangements seems to have reached the point of diminishing returns after some point: that new results were mildly interesting, but didn't necessarily hook into algorithm design in a nontrivial way. I still have somewhat of the same opinion after the talk, but it was good to see the evolution of the problems into higher dimensional surface arrangement questions.

Emo Welzl gave a nice overview of the exciting years between 1987-1992 when randomization began to bloom into a powerful tool for doing geometry. Of course, the very first randomized algorithm was a geometric one (Rabin's closest pair algorithm), but the really powerful methods came into being really with Clarkson's work, and the eps-net work of Haussler and Welzl. It was amusing that almost every single paper mentioned in Emo's talk was written or co-written by Ken: just goes to show his profound influence on the field both for new techniques, as well as new results.
For me, another great influence was Raimund Seidel's amazingly lucid exposition of backwards analysis: there's something to be said for crystal-clear writing and the impact it can have.

The final talk was by Kurt Mehlhorn, on the history that led to the development of LEDA and CGAL. I must confess that I've always felt rather intimidated by CGAL and LEDA: there's something about the phrase "traits class" that strikes fear into my heart. But Kurt's talk was immensely enjoyable: he gave several simple examples of inputs where floating point implementations of geometric algorithms fail spectacularly, and really reinforced the importance of precise implementations, something (if I may add) the rest of the algorithms community often can avoid if they're dealing with graphs or numeric data. I REALLY need to weave CGAL into the next incarnation of my geometry class: must be less lazy, must be less lazy, .....

Notes from the conference: I was fervently hoping that the organizers would lower expectation for next year, but no such luck :(. Impeccable organization, food, and free beer. Sigh......

I'll be tweeting occasionally from the conference. If you're reading this at the conference and want to do the same, please the hashtag #socg so all tweets can be collected in one place.
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