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On Dec 29, 2005, at 2:43 PM, Sean Luke wrote:

> Liviu is our coevolution man, but I believe this will do the
> following:
>
> For each individual i in the population
>        If the individual has not yet had GROUPSIZE evaluations
>                Pick a random individual j from the population that
>                        has not yet had GROUPSIZE evaluations
>                evaluate i and j together once, assigning fitness to
> each
>
> Sometimes it happens that there's no one on left to evaluate against,
> in which case a random person j is chosen and his fitness is not
> assigned.

Okay, that would explain some things.  Is an individual ever matched
against itself?

> During breeding, except for a few GP modifiers which had a bug in
> them, individuals modified to the next generation should be marked as
> not evaluated.  Individuals which are direct copies will be marked as
> evaluated.  However CompetitiveEvaluator will evaluate individuals no
> matter how they're marked.

In other words, individuals will always be marked as not evaluated?

If so, how can I set the initial fitness of an unevaluated individual
just once?

> Your GoProblem example is odd though: it appears in
> postprocessPopulation you're just trimming fitnesses to between 0 and
> 100.  Why would you want to do that?

I set the minimum to zero in the belief that fitnesses have to be
nonnegative.  Is this true?

I set the maximum to 100 so that an individual could not build up a
huge fitness by winning many early games, then never be knocked down
by later losses.

Is this bad reasoning?

Peter Drake
Assistant Professor of Computer Science
Lewis & Clark College
http://www.lclark.edu/~drake/