SetExtinction(Population As Integer, ExtinctionPeriod As Integer, ExtinctionRate As Single)

Purpose: This function sets the new parameters of the additional genetic algorithm operator called Extinction. Extinction refreshes the whole population when the population gets “stuck” and cannot further improve.  By default, the extinction operator is turned off in the DLL until you execute the SetExtinction function, so ExtinctionPeriod is set to 32,767, and ExtinctionRate is set to zero.  To activate the operator you will need to set the ExtinctionPeriod to some reasonable value (10-50), and set the ExtinctionRate to a non-zero value. Extinction does not kill the most fit individual.

Arguments:

Population is the number of the population for which you are going to set the parameters of the operators.

ExtinctionPeriod is a number of generations which you set.  If the best fitness does not change during the ExtinctionPeriod (i.e., during any consecutive period of that many generations), the extinction operator is applied to refresh the population.  Reasonable values for the ExtinctionPeriod are in the range 10-30.

ExtinctionRate Extinction mutates the best individual many times to form the new population. ExtinctionRate is the mutation rate at which the individual is mutated (the rate of mutation per bit in a continuous chromosome, or the rate of mutation per element of an enumerated chromosome).  Allowed values are in the range [0,1], and recommended values are 0.1-0.5.  The default value is 0.

Example: i = SetExtinction(PopNum, 15, 0.1)

This example sets parameters of the extinction operator for the population PopNum.  The extinction period will be 15, and the extinction rate will be 0.1.

Related Functions: none