selectparents {seao} | R Documentation |
Select the parents which are the basis for the next (child) generation. The individuals (set-ups) with highest fitness have the highest chance to be chosen, so some parents may be chosen a few times.
selectparents(struc.ea, gen=NULL, method=list(base="fit", rescale=0))
struc.ea |
An evolutionary algorithm structure |
gen |
The number of the generation (batch) for which the parents have to be chosen. The standard value is the last generation. |
method |
A list containing the base for selection, and possible selection. The base can be either "fit" (standard value) or "rank"; rescaling a number, standard value is 0, but 1.5 is a value which gives often nice results. |
The method is a list of base
and rescale
. base
gives which basis should be used for calculating the weights of the
different individuals:
In many cases, the difference between the lowest and highest
weights are very high. This would result in choosing the same
parent(s) every time. In order to decrease this extreme selection,
one can rescale the weights. Rescaling is done so that the highest
fitness is recale
times the average value of the fitnesses.
The function returns an evolutionary algorithm object, which is
actually the same as the input argument struc.ea
, but with new
individuals (experimental set-ups) and the selection method added in
the generation (batch) of selection:
genes |
a list containing the genome (parameter set)
stucture. This is the same as the genome (parameter set) structure
of in the input (struc.ea$genes ). |
generations |
a list of structures with information of each
generation:
|
As for all functions in this package, evolutionary terminology is used
as described in seao.terminology
.
Kurt Sys (kurt.sys@rug.ac.be)
genomestruc, newgen, chooseparents