Adaptive Constraint Satisfaction: The Quickest First Principle

The choice of a particular algorithm for solving a given class of constraint satisfaction problems is often confused by exceptional behaviour of algorithms. One method of reducing the impact of this exceptional behaviour is to adopt an adaptive philosophy to constraint satisfaction problem solving. In this paper we describe one such adaptive algorithm based on the principle of chaining and designed to avoid the phenomenon of exceptionally hard problems. Our algorithm shows how the speed of more naïve algorithms can be utilised safe in the knowledge that the exceptional behaviour is being bounded, clearly demonstrating the potential benefits of the adaptive approach.