Decomposition of the NVALUE constraint
Abstract
We study decompositions of NVALUE, a global constraint that can be used to model a wide range of problems where values need to be counted. Whilst decomposition typically hinders propagation, we identify one decomposition that maintains a global view as enforcing bound consistency on the decomposition achieves bound consistency on the original global NVALUE constraint. Such decompositions offer the prospect for advanced solving techniques like nogood learning and impact based branching heuristics. They may also help SAT and IP solvers take advantage of the propagation of global constraints.
Cite
@article{arxiv.0909.3273,
title = {Decomposition of the NVALUE constraint},
author = {Christian Bessiere and George Katsirelos and Nina Narodytska and Claude-Guy Quimper and Toby Walsh},
journal= {arXiv preprint arXiv:0909.3273},
year = {2009}
}
Comments
To appear in Proceedings of the Eighth International Workshop on Constraint Modelling and Reformulation, held alongside the 15th International Conference on Principles and Practice of Constraint Programming (CP 2009), Lisbon, Portugal