Читать книгу Power Magnetic Devices - Scott D. Sudhoff - Страница 32

In the canonical GA, the entire population is replaced by children. Those individuals who are selected in the mating pool but do not undergo any crossover, segregation, or mutation “survive” to the next generation unchanged. However, in some GAs, rather than forming a mating pool of the same size as the population, a mating pool that is a fraction of the size of the population is formed, thereby generating a population of children a fraction of the size of the population. The children replace members of the existing population, so that a new population is formed which has the children, plus some members of the previous population. In order to make room for the children (to hold the population size constant), it becomes necessary to decide which members of the current population will “die” to make room for the introduction of children. The selection of those individuals to be replaced can be made on criteria other than those used for selection—for example, based on diversity (or more particularly lack thereof) or some other attribute. In some sense, these approaches are reminiscent of biological populations, where the boundaries between generations are gradual.