Conference Proceedings
Encodings of the SEQUENCE constraint
S Brand, N Narodytska, CG Quimper, P Stuckey, T Walsh
Lecture Notes in Computer Science Including Subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics | SPRINGER-VERLAG BERLIN | Published : 2007
Abstract
The SEQUENCE constraint is useful in modelling car sequencing, rostering, scheduling and related problems, We introduce half a dozen new encodings of the SEQUENCE constraint, some of which do not hinder propagation. We prove that, down a branch of a search tree, domain consistency can be enforced on the SEQUENCE constraint in just O(n2 log n) time. This improves upon the previous bound of O(n3) for each call down the tree. We also consider a generalization of the SEQUENCE constraint - the Multiple SEQUENCE constraint. Our experiments suggest that, on very large and tight problems, domain consistency algorithms are best. However, on smaller or looser problems, much simpler encodings are bette..
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