Evolution Strategy - ES
An ES works on a population of real valued solutions
by repeated use of evolutionary operators like reproduction,
recombination and mutation.
λ offspring individuals are generated from μ parents
by recombination and mutation (with μ < λ).
After evaluating the fitness of the λ
offspring individuals, the comma-strategy selects the μ individuals
with the best fitness as parent population for the next generation.
On the other hand, a plus-strategy selects the best μ individuals
from the aggregation of parents and offspring individuals, so in this
case the best individual is guaranteed to survive.
In general, however, the comma-strategy is more robust and can easier
escape from local optima, which is why it is usually the standard selection.