Different Populations in Genetic Algorithms

Growing and shrinking populations

Genetic algorithms can operate on either fixed or variable population sizes. All of the genetic algorithms we’ve implemented so far have had fixed size populations. The distinction between replacement and reinsertion lies in how the population size is affected. Replacement strategies focus specifically on maintaining a fixed population size where they replace old chromosomes with new ones. Reinsertion strategies focus mainly on inserting new chromosomes into a population where they integrate new chromosomes with old ones. Although the terms are often used interchangeably, their meanings are slightly different.

If we opt for populations of variable size, we need to consider how fast the size of the population changes. For example, if we have a selection rate of 80% and choose to keep the top 30% of chromosomes every generation, our population will grow by 10% every generation. If we start with a population of 100 chromosomes, our population will have 1.37 million chromosomes by the hundredth ...