Study of Immune Genetic Algorithm Based on "Stretching" Technique

In order to enhance the global optimal search ability of AIA in solving multi-modal function optimization problem, based on mechanism of immune theory and genetic algorithm, a function "stretching" technique is introduced to obtain stretching immune genetic algorithm (SIGA). The algorithm equipped with the technique can narrow the range of extreme value of the objective function, so it reduces searching difficulty and improves the global convergence performance effectively. Using mathematical methods of Markov chains theory, it is proved theoretically that the SIGA is global convergent with probability 1. Simulation results indicate that the SIGA equipped with the "stretching" technique exhibits better convergent performance compared with traditional immune genetic algorithm.