Split scheduling with uniform setup times

Frans Schalekamp (1) , René Sitters (2) , Suzanne van Der Ster (2) , Leen Stougie (3, 4, 2) , Víctor Verdugo (5) , Anke van Zuylen (1)

1 WM - College of William and Mary [Williamsburg]
2 VU - Vrije Universiteit Amsterdam [Amsterdam]
3 ERABLE - Equipe de recherche européenne en algorithmique et biologie formelle et expérimentale
4 CWI - Centrum Wiskunde & Informatica
5 UCHILE - Universidad de Chile = University of Chile [Santiago]

We study a scheduling problem in which jobs may be split into parts, where the parts of a split job may be processed simultaneously on more than one machine. Each part of a job requires a setup time, however, on the machine where the job part is processed. During setup, a machine cannot process or set up any other job. We concentrate on the basic case in which setup times are job-, machine- and sequence-independent. Problems of this kind were encountered when modelling practical problems in planning disaster relief operations. Our main algorithmic result is a polynomial-time algorithm for minimising total completion time on two parallel identical machines. We argue, why the same problem with three machines is not an easy extension of the two-machine case, leaving the complexity of this case as a tantalising open problem. We give a constant-factor approximation algorithm for the general case with any number of machines and a polynomial-time approximation scheme for a fixed number of machines. For the version with the objective to minimise total weighted completion time, we prove NP-hardness. Finally, we conclude with an overview of the state of the art for other split scheduling problems with job-, machine- and sequence-independent setup times.

Domaines: Algorithme et structure de données [cs.DS]

Frans Schalekamp, René Sitters, Suzanne van Der Ster, Leen Stougie, Víctor Verdugo, et al.. Split scheduling with uniform setup times. Journal of Scheduling, 2015, 18 (2), pp.119-129 ⟨10.1007/s10951-014-0370-4⟩. ⟨hal-01249095⟩