Table 5 Average error rate obtained by IMPSO using ring topology with Ry», As mention above, the tow other basic and important parameters of island models are migration rate a1 migration frequency, that indicate how frequently migrations occur, here we used the iterations number and ho many particles migrate. The value of iterations number p =500. T the impact of the migration rate on convergence and diversity be values of R,, are studied (R,, = 10%, 20% and 30%), using three he last set of experiments is designed to measu haviours of IMPSO algorithm. Three alternati topologies migration (chain, ring and torus) wi islands number equals to 4. The value of R,,;= 20% means the number of migrants are I, X 20% = IMPSO/I, 20% = 40/4 * 20% = 2. The table 5 shows t cases of migration rate that the smaller value migration, which suggest that a single particle i of R,, tends to have an effect on diversity simp he results produced of R,, indicates an According to the comparison between the d s able to impact as a for the 25 IEEE-CEC2005 functions for the thr increase in diversity in generations following seed for changes in a stagnated island. Big val y due to replacing a ifferent kind of topologies and the use of many cases of the islan lager number of particles.