We discuss the use of normal distribution theory as a tool to model the convergence characteristics of di erent GA selection schemes. The models predict the proportion of optimal alleles in function of the number of generations when optimizing the bit-counting function. The selection schemes analyzed are proportionate selection, tournament selection, truncation selection and elitist recombination. Simple yet accurate models are derived that have only a slight deviation from the experimental results. It is argued that this small di erence is due to the build-up of covariances between the alleles { a phenomenon called linkage disequilibrium in quantitative genetics. We conclude with a brief discussion of this linkage disequilibrium.
Dirk Thierens, David E. Goldberg