An operator that calls a user-defined function when it is applied to a population (pre- or post-mating) or offsprings (during- mating). The function can have have parameters pop when the operator is applied pre- or post-mating, pop, off, dad, mom when the operator is applied during-mating. An optional parameter can be passed if parameter param is given. In the during-mating case, parameters pop, dad and mom can be ignored if offspringOnly is set to True.
Create a pure-Python operator that calls a user-defined function when it is applied. If this operator is applied before or after mating, your function should have form func(pop) or func(pop, param) where pop is the population to which the operator is applied, param is the value specified in parameter param. param will be ignored if your function only accepts one parameter. Althernatively, the function should have form func(ind) with optional parameters pop and param. In this case, the function will be called for all individuals, or individuals in subpopulations subPops. Individuals for which the function returns False will be removed from the population. This operator can therefore perform similar functions as operator DiscardIf.
If this operator is applied during mating, your function should accept parameters pop, off (or ind), dad, mom and param where pop is the parental population, and off or ind, dad, and mom are offspring and their parents for each mating event, and param is an optional parameter. If subPops are provided, only offspring in specified (virtual) subpopulations are acceptable.
This operator does not support parameters output, and infoFields. If certain output is needed, it should be handled in the user defined function func. Because the status of files used by other operators through parameter output is undetermined during evolution, they should not be open or closed in this Python operator.