On Dec 29, 2005, at 2:58 PM, Liviu Panait wrote: >> I set the minimum to zero in the belief that fitnesses have to be >> nonnegative. Is this true? > > SimpleFitness may have arbitrary values as of the previous version (I > believe, or if not the current version does not complain about that > anymore). Yes, I guess there would be no need to "normalize" the values if we use tournament selection. > I am not sure I follow the reasoning. Even if an individual won > against early competitors in initial generations, that says little > about how good he is against better opponents found at later > generations. I would treat this on a per-generation basis and ignore > information about wins or loses from previous generations. I had thoughts about accumulating fitness information so I didn't have to play a lot of games each round, but in retrospect I see that this is already taken into account by the GA. > Again, I encourage you to look into the single-elimination > tournament, which we found to work nicely. There is also a version > of double-elimination-tournament somewhere, though we have not tested > it that much. I read your GECCO paper, and I'm convinced by your argument. Back to the bit mines with me! Thanks, Peter Drake Assistant Professor of Computer Science Lewis & Clark College http://www.lclark.edu/~drake/