next up previous
Next: Introduction

Why ``Building Blocks'' Don't Work on Parity Problems

W. B. Langdon and R. Poli
School of Computer Science
The University of Birmingham,
Birmingham B15 2TT, UK
{W.B.Langdon,R.Poli}, 126 rmp
Tel: +44 (0) 121 414 4791 Fax: +44 (0) 121 414 4281

Technical Report: CSRP-98-17
13 July 1998


We investigate the distribution of performance of the parity and always-on Boolean functions given only the appropriate building block. These problems have ``needle in a haystack'' fitness landscape and so are unsuitable for genetic programming or other progressive search techniques. Theoretical analysis shows in the limit as program size grows the density of solutions is independent of size but falls exponentially with number of inputs.

William B Langdon
Mon Jul 13 15:53:27 BST 1998