Describe (μ, λ) and (μ + λ) algorithms in manual

[jenetics]

Add description of (μ, λ) and (μ + λ) evolution strategies in the user's manual and how to configure Jenetics for performing this ES.

(μ, λ) ES (Essentials of Metaheuristic by Sean Luke, page 33)

Among the simplest ES algorithms is the (μ, λ) algorithm. We begin with a population of (typically) λ number of individuals, generated randomly. We then iterate as follows. First we assess the fitness of all the individuals. Then we delete from the population all but the μ fittest ones (this is all there’s to Truncation Selection). Each of the μ fittest individuals gets to produce λ/μ childre through an ordinary Mutation. All told we’ve created λ new children. Our Join operation is simple: the children just replace the parents, who are discarded. The iteration continues anew.

(μ + λ) ES (Essentials of Metaheuristic by Sean Luke, page 34)

(μ + λ) differs from (μ, λ) in only one respect: the Join operation. Recall that in (μ, λ) the parents are simply replaced with the children in the next generation. But in (μ + λ), the next generation consists of the μ parents plus the λ new children. That is, the parents compete with the kids next time around. Thus the next and all successive generations are μ + λ in size.

[jenetics]

Merged into r3.8.0 branch.