Tailoring Solver-Independent Constraint Models: A Case Study with Essence' and Minion

In order to apply constraint programming to a particular domain, the problem must first be modelled as a constraint satisfaction problem. There are typically many alternative models of a given problem, and formulating an effective model requires a great deal of expertise. To reduce this bottleneck, the Essence language allows the specification of a problem abstractly, i.e. without making modelling decisions. This specification is refined automatically by the Conjure system to a solverindependent constraint modelling language Essence′. However, there is still significant work involved in translating an Essence′ model for use with a particular constraint solver. This paper discusses this ‘tailoring’ process with reference to the constraint solver Minion.