A Quadratic Propagator for the Inter-Distance Constraint

We present a new propagator achieving bound consistency for the INTER-DISTANCE constraint. This constraint ensures that, among a set of variables X1, . . . , Xn, the difference between two variables is at least p. This restriction models, in particular, scheduling problems in which tasks require p contiguous units of a resource to be completed. Until now, the best known propagator for bound consistency had time complexity O(n3 ). In this work we propose a quadratic propagator for the same level of consistency. We then show that this theoretical gain gives savings of an order of magnitude in our benchmark of scheduling problems.

• Type: Conference
• Year: 2006
• Where: AAAI
• Authors: Claude-Guy Quimper, Alejandro López-Ortiz, Gilles Pesant
• Keywords: AAAI 2006, Bound Consistency, Intelligent Agents, Propagator, Scheduling Problems