Monthly Archives: October 2009

Dense-Subset Break-the-Bank Challenge

I’m preparing for my first global travel for global health, but the net is paying attention to a paper that I think I’ll like, and I want to mention it briefly before I fly.

Computational Complexity and Information Asymmetry in Financial Products is 27 pages of serious TCS, but it is so obviously applicable that people outside of our particular ivory tower, and even outside of academia entirely are blogging and twittering about it, and even reading it!

Freedom to Tinker has a nice summary of this paper, if you want to know what it’s about in a hurry.

Mike Trick makes the salient observation that NP-hard doesn’t mean computers can’t do it. But the assumption that this paper is based on is not about worst-case complexity; it is, as it should be, based on an assumption about the average-case complexity of a particular optimization problem over a particular distribution.

As it turns out, this is an average-case combinatorial optimization problem that I know and love, the densest subgraph problem. My plan is to repeat the problem here, and share some Python code for generating instances of it. Then, you, me, and everyone, can have a handy instance to try optimizing. I think that this problem is pretty hard, on average, but there is a lot more chance of making progress on an algorithm for it than for cracking the P versus NP nut. Continue reading


Filed under combinatorial optimization, cryptography, TCS

The Two Rules of Program Optimization

Wow, where does the day go? I spent all my non-meeting time debugging something. At least I fixed it before 5 PM.

The details of the problem are boring, but the whole ordeal could have been avoided if I had just followed the two rules of optimizing software in my Generic Disease Modeling System. What are they?

      First Rule of Program Optimization: Don’t do it
      Second Rule of Program Optimization (for experts only!): Don’t do it yet

Maybe next week I’ll get a second to write about the good kind of optimization; my statistical physics friends have posted an article on the arxiv which I am a co-author on, about an application of bounded-depth minimum spanning trees, Clustering with Shallow Trees.

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Filed under software engineering

Conference you should know about

This weekend marks the submission of my first “Global Health” paper. Congratulations to me! And many, many thanks to all the people who have worked with me to make it happen. I’ll go into details sometime in the future, first let me see how things go in the refereeing process.

While I was over-working on that business, I got an interesting Call-for-Papers forwarded from global health/AI researcher Emma Brunskill. The AAAI Spring Symposium on Artificial Intelligence for Development (AI-D) is an effort to build a community of people applying computer science and artificial intelligence in less-developed settings.

TCS people, don’t let the “AI” in their title turn you off. Eric Horvitz says that this is for all of us. Continue reading

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Filed under global health, TCS