Roulette Selection

Learn about the implementation of roulette selection along with various other types of selection.

Introducing roulette selection

Roulette selection, also known as the fitness-proportionate selection, chooses parents with a probability proportional to their fitness. Roulette selection puts every chromosome on a roulette wheel based on their fitness. Individuals with higher fitness occupy a larger space on the roulette wheel, meaning they have a higher chance of getting chosen. We then spin the wheel to select parents. Like tournament selection, roulette selection can be implemented with or without duplicates.

Roulette selection attempts to balance genetic diversity and fitness based on probability. Individuals that are more fit have a higher chance of being selected; however, it’s still possible that individuals that are less fit will get selected as well. Think of it like this: in the wheel of fortune, the more valuable spaces have a smaller area, meaning the probability of landing on them is lower. The relationship is the same in roulette selection, albeit in reverse.

The following image might help to visualize roulette selection:

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