Wednesday, July 08, 2009

NSF Workshop: Electronic Design Automation

I'm currently at an NSF Worshop on Electronic Design Automation (the thing that used to be called VLSI design). I'm here as part of the 'theory audience' along with Vijaya Ramachandran and Dick Lipton (blogger power!).

Thankfully, Dick has posted an extensive summary of the day of talks, so I don't have to. Our mandate here is to listen in on the discussions and come up with a response that suggests avenues where theory folk might have something useful to contribute.

From a purely biased algorithms perspective, one thing that strikes me about the EDA community (at least in the formal methods/verification realm) is their unwillingness to give up in the face of beyond-NP-completeness. What I mean is this: most of my training in algorithms (and this is likely true for you as well) is in the polynomial-time regime: all the algorithic paradigms we learn are effective at reducing the complexity of an algorithm from one polynomial to another.

When we engage with NP-hardness, we switch modes to approximations, and focus on the issue of quality: even the approximation algorithms themselves run in poly time. There are very few people (David Eppstein comes to mind) who work on algorithms in the exponential/subexponential realm and will worry about (say) reducing the base of the exponent for SAT or graph coloring or other hard problems.

The verification folks don't necessarily solve their (very hard) problems exactly, but they do design all kinds of tricks (and heuristics) to deal with these problems, because they actually need to solve them ! In my view, it wouldn't be a bad idea for students learning algorithms to learn at least a few tricks for designing algorithms that might run in exponential time, but are efficient. Remember that exponential might be better than n^100 for many values of n.

One thing that came to mind as I listened to talks. With the exception of a talk by Rupak Mazumdar on faulty computations, and a talk by Ed Clarke (yes, that Ed Clarke) on statistical model checking (based on the Neyman-Pearson hypothesis testing framework), there was little talk of the role that randomization might have to play in the problems of EDA.

A second thought was how the lessons of massive data analysis might be useful in the realm of DA. One speakr described one critical problem as being the degree of complexity associated with current DA tools: there are over 4000 "knobs" to turn in one such tool ! It's believed that these knobs are not independent, and might even be contradictory. If we think of each "run" of the DA tool, outputing some kind of chip layout, as a point in this 4000+ dimensional space, I wonder whether techniques for dimensionality reduction and manifold analysis might be useful to find a set of "core knobs" that control the process.

I have to say that it's nice to attend a workshop with a community that throws out terms like NP-Complete, \Sigma_2, and PSPACE so freely :).

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