Fitness Function Comparison for GA-Based Feature Construction

When primitive data representation yields attribute interactions, learning requires feature construction. MFE2/GA, a GA-based feature construction has been shown to learn more accurately than others when there exist several complex attribute interactions. A new fitness function, based on the principle of Minimum Description Length (MDL), is proposed and implemented as part of the MFE3/GA system. Since the individuals of the GA population are collections of new features constructed to change the representation of data, an MDL-based fitness considers not only the part of data left unexplained by the constructed features (errors), but also the complexity of the constructed features as a new representation (theory). An empirical study shows the advantage of the new fitness over other fitness not based on MDL, and both are compared to the performance baselines provided by relevant systems.