H-PIPE: Facilitating Hierarchical Program Evolution through Skip Nodes
Rafał Sałustowicz, Jürgen Schmidhuber · 1998
To evolve structured programs we introduce H-PIPE, a hierarchical extension of Probabilistic Incremental Program Evolution (PIPE - Sa/lustowicz and Schmidhuber, 1997). 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 outperforms 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. Keywords: Probabilistic Incremental Program Evolution, Structured Programs, Hierarchical Programs, Introns, Non-Coding Segments. 1 Introduction and Previous Work Overview. Hierarchical Probabilistic Incremental Program Evolution (H-PIPE) is a novel method for synthesizing structured programs. It uses the PIPE paradigm (Sa/lustowicz and Schmidhuber, 1997) to iteratively generate succes...