Elitist Steady-state replacement strategy

[Jeannief]

Hi,

If possible I would like to clarify how the steady-state algorithm works with elitism in OB:

If I specify a value in ec.elite.keepsize parameter in the configuration file,

is this number / proportion of individuals protected until the next iteration or are they available for crossover/mutation and thus replacement until such time as the 

current iteration population is completely filled? In other words, given that steady-state is "in place" and overlapping can it happen that elite individuals do not actually survive until the next iteration if they are available for selection immediately?

If I understand it correctly, crossover and mutation etc work the same way in steady-state as they do in generational: i.e. for crossover - two parents produce two children and these replace the parents, regardless of fitness?

all the best,

jeannie

[Christian Gagné]

Hi Jeannie,

The way it is implemented, the steady-state replacement strategy proceeds by processing n individuals, where n is equal to the population size, to simulate a generation of the generational model. It first selects the m best individuals of the population (where n is equal to the value in ec.elite.keepsize) and set them apart in the population -- no variation operation is applied on them. Then, for the remaining (n-m) individuals it proceeds as usual, producing new individuals by crossover, mutation, and possibly reproduction (copy individual as is) if the breeder tree implements this.

Be sure to implement your steady-state algorithm using the SteadyStateOp as replacement strategy.

The crossovers and mutation operators work otherwize the same way than with in the generational model.

Best,

Christian

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Christian Gagné
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[Jeannie.Fitzgerald]

Hi again Christian,

Many thanks for the clarification. Enjoy the holidays.

jeannie