I-DLV: The new intelligent grounder of DLV

DLV is a powerful system for knowledge representation and reasoning which supports Answer Set Programming (ASP) – a logic-based programming paradigm for solving problems in a fully declarative way. DLV is widely used in academy, and, importantly, it has been fruitfully employed in many relevant industrial applications. As for the other main-stream ASP systems, in the first phase of the computation DLV eliminates the variables, generating a ground program which is semantically equivalent to the original one but significantly smaller than the Herbrand Instantiation, in general. This phase, called ‘grounding’, plays a key role for the successful deployment in real-world contexts. In this work we present I-DLV, a brand new version of the intelligent grounder of DLV. While relying on the solid theoretical foundations of its predecessor, it has been completely redesigned and re-engineered, both in algorithms and data structures; it now features full support to ASP-Core2 standard language, increased flexibility and customizability, significantly improved performances, and an extensible design that eases the incorporation of language updates and optimization techniques. I-DLV results in a stable and efficient ASP instantiator that turns out to be a full-fledged deductive database system. We describe the main features of I-DLV and carry out experimental activities for assessing applicability and performances.