Michael Skinner's tutorial for the AI Article Writing Contest has just been published.

Starting by an introduction of the terminology, the article quickly progresses into biological inspiration and example manifestations of evolution. A computational description is then given, along with potential applications of the technology.

http://geneticalgorithms.ai-depot.com/Tutorial/Overview.html

Hi.
In the overview section of the tutorial, it is mentioned: "In roulette wheel selection, individuals are given a probability of being selected that is directly proportionate to their fitness". However, the pseudocode of the roulette wheel selection assigns fitness values to the individuals which are not directly proportional. This may be due to the following:

for all members of population
probability = sum of probabilities + (fitness / sum)
sum of probabilities += probability
end for

I think that this should be changed to:

for all members of population
probability = previous probability + (fitness / sum)
previous probability = probability
end for

Once again, please do correct me if I am wrong. Might have misunderstood something somewhere.

- Neophy