Subthreshold-Seeking Behavior and Robust Local Search

Darrell Whitley¹, Keith Bush¹, and Jonathan Rowe²

¹Computer Science, Colorado State University, Fort Collins, CO 80523

²Computer Science, University of Birmingham, Birmingham B15 2TT, UK

Abstract. Subthreshold-seeking behavior occurs when the majority of the points that an algorithm samples have an evaluation less than some target threshold. We characterize sets of functions where subthreshold-seeking behavior is possible. Analysis shows that subthreshold-seeking behavior, when possible, can be increased when higher bit precision is used with a bit climber search algorithm and a Gray code representation. However, higher precision also can reduce exploration. A simple modification to a bit-climber can improve its subthreshold-seeking behavior. Experiments show that this modification results in both improved search efficiency and effectiveness on common benchmark problems.

LNCS 3103, p. 282 ff.

Full article in PDF

lncs@springer.de
© Springer-Verlag Berlin Heidelberg 2004