Fitness proportionate selection
In this method, each solution is assigned a probability of selection based on its fitness. A solution with better fitness, for example, will have a larger proportion on a scale of 0 to 1, resulting in a higher probability of being selected. The whole method is illustrated through the following diagram in which the fitness of each solution is divided by the sum of the fitness of all solutions. Then the accumulative probability distribution on the scale of 0 to 1 is calculated by summing the fitness of each solution into the sum of fitness of all previous solutions.
A random number in the range 0 to 1 will be generated and if it lies in 0 – 0.251 then chromosome 1 will be selected for crossover, if it lies in 0.252 – 0.2761 then chromosome 2 will be selected, and so on.