Solving Functional Constraints by Variable Substitution
Abstract
Functional constraints and bi-functional constraints are an important constraint class in Constraint Programming (CP) systems, in particular for Constraint Logic Programming (CLP) systems. CP systems with finite domain constraints usually employ CSP-based solvers which use local consistency, for example, arc consistency. We introduce a new approach which is based instead on variable substitution. We obtain efficient algorithms for reducing systems involving functional and bi-functional constraints together with other non-functional constraints. It also solves globally any CSP where there exists a variable such that any other variable is reachable from it through a sequence of functional constraints. Our experiments on random problems show that variable elimination can significantly improve the efficiency of solving problems with functional constraints.
Cite
@article{arxiv.1006.3215,
title = {Solving Functional Constraints by Variable Substitution},
author = {Yuanlin Zhang and Roland H. C. Yap},
journal= {arXiv preprint arXiv:1006.3215},
year = {2010}
}