Sexual reproduction (aka string crossover)
Sexual reproduction is not string crossover. Normal reproduction in a typical GA picks two individuals from the population independently with probability related to their fitness. In sexual reproduction, the pairs are constrained such that selection is not independent e.g., 'males' mate with 'females'. Sexual reproduction is one factor that dampens premature dominance of the population by a few 'great' individuals, so that search can continue on other hills, i.e. encourages diversity and thus IS good, as was previously stated, in choppier solution spaces. Also consider the dominance mechanism supported by the diploid chromosome. One reason why double-strand species like ourselves can more rapidly adapt than haploid species. Dominance protects solutions that were good once (and might be again) from being sampled to death, by holding them in abeyance (a 'recessive' trait) in a temporarily unfavorable environment. Again, this encourages diversity by dampening premature destruction of hard won solutions. Scott Collins | "Few people realize what tremendous power there | is in one of these things." -- Willy Wonka ......................|................................................ BUSINESS. voice:408.862.0540 fax:974.6094 collins@newton.apple.com Apple Computer, Inc. 1 Infinite Loop, MS 301-2C Cupertino, CA 95014 ....................................................................... PERSONAL. voice/fax:408.257.1746 1024/669687 catalyst@netcom.com