Lately, I have been working a lot with CryptoMiniSat, to get it up and running for the 2010 SAT Race, held by Carsten Sinz. Getting CryptoMiniSat fast and bug-free has been a long and winding road. I can now understand the difficulty of choosing magic parameters that these SAT solvers make use of regularly. As I have added ~6000 lines of code to a codebase of ~1500, you can probably imagine the number of magic constants that I had to come up with. Worst of all, these constants interact in non-intuitive and sometimes in a fully “magical” manner.
To test my choice of magic constants, I have been running experiments on the Gird5000 project of French universities. It is quite easy to get access to Grid5000 if you work in a French university, and it is surprisingly easy to run experiments. On the other hand, interpreting the results of such experiments is not so easy :) However, CryptoMiniSat is coming along. On crypto examples I think we are unbeatable. When it comes to other examples, we are good, but we will see how the new MiniSat (yes, it’s coming!) and precosat will do. Apparently, the GLUCOSE people are also planning to enter the competition, so the race will be very interesting. Fingers are crossed that CryptoMiniSat will finish somewhere in the top 3 :)
There are some “secret” improvements that I have made the past couple of months, and there are some open secrets. I tried to incorporate the GLUCOSE restart heuristic, and XORs are automatically detected (XOR clauses are no longer neccessary, but they are of course supported!). This means that CryptoMiniSat is now a plug-and-play experience for all the crypto-folks. I have tested the solver with a good number of crypto problems, and the speedup relative to MiniSat is on the order of 2-50x, depending on the problem.
The new CryptoMiniSat will be released when the SAT Race starts and everyone’s executables have been freezed. I will then detail all the new features. Until then, let me just run a couple of more experiments on that cluster :)