Pushing Efficient Evaluation of HEX Programs by Modular Decomposition

摘要

The evaluation of logic programs with access to external knowledge sources requires to interleave external computation and model building. Decid ing where and how to stop with one task and proceed with the next is a diffi cult problem, and existing approaches have severe scalability limitations in many real-world application scenarios. We introduce a new approach for organizing the evaluation of logic programs with external knowledge sources and describe a configurable framework for dividing the non-ground program into overlapping possiblysmaller parts called evaluation units. These units will then be processed by interleaving external evaluations and model building according to an evalua tion and a model graph, and by combining intermediate results. Experiments with our prototype implementation show a significant improvement of this technique compared to existing approaches. Interestingly, even for ordinary logic programs (with no external access), our decomposition approach speeds up existing state of the art ASP solvers in some cases, showing its potential for wider usage.