controlled propagation in continuous numerical constraint networks
Local consistency is usually enforced on continuous constraints by decomposing them beforehand into so-called primitive constraints. It has long been observed that such a decomposition drastically slows down the computation of solutions. Five years ago, Benhamou et al. introduced an algorithm that avoids formally decomposing constraints, and whose efficiency is often on a par with state-of-the-art methods. It is shown here that this algorithm implements a strategy to enforce on a continuous constraint a consistency akin to directional bounds consistency as introduced by Dechter and Pearl for discrete problems. The actual impact of decomposition is also thoroughly analyzed by means of new experimental results.
local consistency constraint propagation directional consistency