sigmoid_weight: Weight based sigmoidal selectivity function
Description
A sigmoidal selectivity function with 50% selectivity at
weight sigmoidal_weight and width sigmoidal_sigma.
Usage
sigmoid_weight(w, sigmoidal_weight, sigmoidal_sigma, ...)
Arguments
w
The size of the individual.
sigmoidal_weight
The weight at which the knife-edge operates.
sigmoidal_sigma
The width of the selection function