eclingo: A solver for Epistemic Logic Programs

TL;DR

eclingo is a new solver for epistemic logic programs that extends clingo, employing a guess and check approach with optimizations, and it outperforms existing solvers on benchmark tests.

Contribution

The paper introduces eclingo, a novel epistemic logic program solver built on clingo, with a guess and check strategy and performance optimizations.

Findings

eclingo outperforms two state-of-the-art solvers on benchmark scenarios.

The solver uses multi-shot functionalities of clingo for efficient checking.

Optimizations reduce search space and improve efficiency in certain cases.

Abstract

We describe eclingo, a solver for epistemic logic programs under Gelfond 1991 semantics built upon the Answer Set Programming system clingo. The input language of eclingo uses the syntax extension capabilities of clingo to define subjective literals that, as usual in epistemic logic programs, allow for checking the truth of a regular literal in all or in some of the answer sets of a program. The eclingo solving process follows a guess and check strategy. It first generates potential truth values for subjective literals and, in a second step, it checks the obtained result with respect to the cautious and brave consequences of the program. This process is implemented using the multi-shot functionalities of clingo. We have also implemented some optimisations, aiming at reducing the search space and, therefore, increasing eclingo's efficiency in some scenarios. Finally, we compare the efficiency of eclingo with two state-of-the-art solvers for epistemic logic programs on a pair of benchmark scenarios and show that eclingo generally outperforms their obtained results. Under consideration for acceptance in TPLP.