A model building framework for Answer Set Programming with external computations

Abstract

As software systems are getting increasingly connected, there is a need for equipping nonmonotonic logic programs with access to external sources that are possibly remote and may contain information in heterogeneous formats. To cater for this need, HEX programs were designed as a generalization of answer set programs with an API style interface that allows to access arbitrary external sources, providing great flexibility. Efficient evaluation of such programs however is challenging, and it requires to interleave external computation and model building; to decide when to switch between these tasks is difficult, and existing approaches have limited scalability in many real-world application scenarios. We present a new approach for the evaluation of logic programs with external source access, which is based on a configurable framework for dividing the non-ground program into possibly overlapping smaller parts called evaluation units. The latter will be processed by interleaving external evaluation and model building using an evaluation graph and a model graph, respectively, and by combining intermediate results. Experiments with our prototype implementation show a significant improvement compared to previous approaches. While designed for HEX-programs, the new evaluation approach may be deployed to related rule-based formalisms as well.

57 pages, 9 figures, 3 tables, 6 algorithms, to appear in Theory and Practice of Logic Programming (accepted in June 2015)

References in corpus (4)

• Modularity Aspects of Disjunctive Stable Models
• Conflict-driven ASP Solving with External Sources
• Achieving compositionality of the stable model semantics for Smodels programs
• Hybrid Automated Reasoning Tools: from Black-box to Clear-box Integration

Cited by in corpus (10)

• Modeling Variations of First-Order Horn Abduction in Answer Set Programming
• Constraints, Lazy Constraints, or Propagators in ASP Solving: An Empirical Analysis
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• Exploiting Answer Set Programming with External Sources for Meta-Interpretive Learning
• Inlining External Sources in Answer Set Programs
• Explainable Answer-set Programming
• Efficient OWL2QL Meta-reasoning Using ASP-based Hybrid Knowledge Bases
• Technical Report: Inconsistency in Answer Set Programs and Extensions
• A Formal Framework for Robot Construction Problems: A Hybrid Planning Approach
• Integrated Algorithms for HEX-Programs and Applications in Machine Learning