Hierarchical Probabilistic Incremental Program Evolution

[Rafal Salustowicz]

      H-PIPE: FACILITATING HIERARCHICAL PROGRAM EVOLUTION
  		      THROUGH SKIP NODES

        Rafal Salustowicz           Juergen Schmidhuber

        Technical Report IDSIA-8-98, IDSIA, Switzerland

To evolve structured programs we introduce H-PIPE,  a hierarchical
extension of Probabilistic Incremental Program Evolution   (PIPE).
Structure is induced by "hierarchical instructions" (HIs) limited
to top-level, structuring program parts.       "Skip nodes"  (SNs)
inspired by biology's introns   (non-coding segments)   allow  for
switching program parts on and off. In our experiments H-PIPE out-
performs PIPE,  and SNs facilitate synthesis of certain structured
programs but not unstructured ones.   We conclude that introns can
be particularly useful in the presence of structural bias.

      ftp://ftp.idsia.ch/pub/rafal/TR-8-98-H-PIPE.ps.gz
      http://www.idsia.ch/~rafal/research.html

Short version: Evolving Structured Programs with Hierarchical
Instructions and Skip Nodes. In J. Shavlik, ed., Machine Learning:
Proceedings of the Fifteenth International Conference   (ICML'98),
pages 488-496,  Morgan Kaufmann Publishers,  San Francisco,  1998.
ftp://ftp.idsia.ch/pub/rafal/ICML98_H-PIPE.ps.gz

Rafal & Juergen, IDSIA                                www.idsia.ch