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Extending Operator Equalisation: Fitness Based Self Adaptive Length Distribution for Bloat Free GP

  • Sara Silva
  • Stephen Dignum
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 5481)

Abstract

Operator equalisation is a recent bloat control technique that allows accurate control of the program length distribution during a GP run. By filtering which individuals are allowed in the population, it can easily bias the search towards smaller or larger programs. This technique achieved promising results with different predetermined target length distributions, using a conservative program length limit. Here we improve operator equalisation by giving it the ability to automatically determine and follow the ideal length distribution for each stage of the run, unconstrained by a fixed maximum limit. Results show that in most cases the new technique performs a more efficient search and effectively reduces bloat, by achieving better fitness and/or using smaller programs. The dynamics of the self adaptive length distributions are briefly analysed, and the overhead involved in following the target distribution is discussed, advancing simple ideas for improving the efficiency of this new technique.

Keywords

Genetic Programming Bloat Operator Equalisation 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Sara Silva
    • 1
  • Stephen Dignum
    • 2
  1. 1.CISUC, Department of Informatics EngineeringUniversity of CoimbraCoimbraPortugal
  2. 2.School of Computer Science and Electronic EngineeringUniversity of EssexWivenhoe ParkUK

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