A SAT-based CSP Solver sCOP and its Results on 2018 XCSP3 Competition

Abstract

Constraint Satisfaction Problem (CSP) is the combinatorial problem of finding a variable assignment which satisfies all given constraints over finite domains. CSP has a wide range of applications in the research domains of Artificial Intelligence and Operations Research. XCSP3 is one of the major constraint languages that can describe CSPs. More than 23,000 instances over 105 series are available in the XCSP3 database. In 2018, the international XCSP3 competition was held and 18 solvers participated. This paper describes the under development CSP solver sCOP and its results on the 2018 XCSP3 competition. sCOP is a SAT-based solver which encodes CSPs into SAT problems and finds a solution using SAT solvers. Currently, sCOP equips the order and log encodings, and uses off-the-shelves backend SAT solvers. We registered sCOP to two competition tracks CSP-Standard-Sequential and CSP-Standard-Parallel of the 2018 XCSP3 competition and won both tracks.