Evolutionery Strategy

Evolutionary Strategy is a powerful and common class of Evolutionary Algorithms that directly evolves the phenotypes by representing them as real-valued vectors, which is typically applied to numerical optimization through a stochastic search method.
In the algorithm, the parents are mutated to create offspring so that the more fit among the two survives to the next generation, where new parents are selected from one or both of generations. The parents contributing to the offspring pool are usually selected uniformly at random, while survival is accomplished by truncation, where the new parent population consists of only the best of the competing individuals.