Patent ID: 7363281

Claim:
An evolutionary optimization method for optimizing a hydrodynamic or aerodynamic design, a set of parameters for the hydrodynamic or aerodynamic design represented by individuals, the method comprising the steps of: (a) setting up an initial population of the individuals representing the set of parameters for the hydrodynamic or aerodynamic design and applying an original fitness function; (b) selecting offspring individuals having a high evaluated quality value as parents; (c) reproducing the parents to create a plurality of offspring individuals; (d) evaluating the quality of the plurality of offspring individuals by selectively using the original fitness function or an approximate fitness function for each offspring individual, the approximation function comprising a neural network ensemble including a plurality of neural networks, evaluating the quality of the plurality of offspring individuals including the steps of: grouping all of the plurality of offspring individuals into clusters; selecting for each cluster one or more offspring individuals, resulting in altogether selected offspring individuals; evaluating the selected offspring individuals by means of the original fitness function to generate original fitness values; evaluating the remaining offspring individuals by means of the approximate fitness function to generate approximate fitness values; determining a variance of the approximate fitness values for the remaining offspring individuals; and replacing the approximate fitness values of the remaining offspring individuals in a cluster with the original fitness value of the selected offspring individual closest to a center of the cluster responsive to the variance of the approximate fitness value being larger than a threshold; (e) repeating steps (b) through (d) until a termination condition is met; and (f) storing the offspring individuals representing the set of parameters for the hydrodynamic or aerodynamic design in a computer storage.