They uses three operator. selection (choose solution), reproduction (use choosen solutions to construct other ones), replacement (replace solution if better).
- Fitness proportionate selection. Also known as roulette-wheel selection, is a function used for selecting solutions.
- Truncation selection. Another method for selecting solutions, ordered by fitness.
- Tournament selection. Select the best solution by a kind of tournament.
- Stochastic universal sampling. The individuals are mapped to contiguous segments of a line, such that each individual's segment is equal in size to its fitness exactly as in roulette-wheel selection.