On Oct 10, 2007, at 7:10 AM, David Robert White wrote:

> Firstly - thanks to all those who have contributed to ECJ.  I've  
> been using it for a while and have found it to be a great toolkit  
> to work with.
> I've recently started using the SPEA2 classes with ECJ.  I have two  
> queries that I need help with:
> 1.  Which one of the following correctly describes the fitness  
> values held in multifitness within the SPEA2MultiObjectiveFitness  
> class, inherited from the MultiObjectiveFitness class:
> 0 (best) to infinity (worst)
> 0 (worst) to infinity (best)
> 0 (worst) to 1 (best)
> I know this is a basic question, but it seems to depend on where  
> you look as to which answer you receive.

I think this is a documentation casualty of minor changes made to  
ECJ's fitness model.  I *believe* the proper answer should be 0  
(worst) to infinity (better than the best).  But as SPEA2 uses a  
tournament selection mechanism, your fitness values can *probably* be  
anything >= 0 so long as x>y if x is better than y in that objective.

> 2.  Does anyone have an example that uses SPEA2, including their  
> parameter files, that they could possibly share?

Rob Hubley wrote the package and can speak best here.  Here's his URL: