Abstract
We introduce a new generic scheme to guide backtrack search, called Conflict Ordering Search (COS), that reorders variables on the basis of conflicts that happen during search. Similarly to generalized Last Conflict (LC), our approach remembers the last variables on which search decisions failed. Importantly, the initial ordering behind COS is given by a specified variable ordering heuristic, but contrary to LC, once consumed, this first ordering is forgotten, which makes COS conflict-driven. Our preliminary experiments show that COS – although simple to implement and parameter-free – is competitive with specialized searches on scheduling problems. We also show that our approach fits well within a restart framework, and can be enhanced with a value ordering heuristic that selects in priority the last assigned values.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Similar content being viewed by others
References
Boussemart, F., Hemery, F., Lecoutre, C., Sais, L.: Boosting systematic search by weighting constraints. In: Proceedings of ECAI 2004, pp. 146–150 (2004)
Gay, S., Hartert, R., Schaus, P.: Simple and scalable time-table filtering for the cumulative constraint. In: Pesant, G. (ed.) Proceedings of CP 2015. LNCS, vol. 9255, pp. 149–157. Springer, Heidelberg (2015)
Gay, S., Hartert, R., Schaus, P.: Time-table disjunctive reasoning for the cumulative constraint. In: Michel, L. (ed.) CPAIOR 2015. LNCS, vol. 9075, pp. 157–172. Springer, Heidelberg (2015)
Gomes, C., Selman, B., Crato, N., Kautz, H.: Heavy-tailed phenomena in satisfiability and constraint satisfaction problems. Journal of Automated Reasoning 24, 67–100 (2000)
Haralick, R.M., Elliott, G.L.: Increasing tree search efficiency for constraint satisfaction problems. Artificial Intelligence 14, 263–313 (1980)
Kolisch, R., Schwindt, C., Sprecher, A.: Benchmark instances for project scheduling problems. In: Project Scheduling, pp. 197–212. Springer (1999)
Le Pape, C., Couronné, P., Vergamini, D., Gosselin, V.: Time-versus-capacity compromises in project scheduling (1994)
Lecoutre, C., Sais, L., Tabary, S., Vidal, V.: Nogood recording from restarts. In: Proceedings of IJCAI 2007, pp. 131–136 (2007)
Lecoutre, C., Sais, L., Tabary, S., Vidal, V.: Reasonning from last conflict(s) in constraint programming. Artificial Intelligence 173(18), 1592–1614 (2009)
Lecoutre, C., Sais, L., Tabary, S., Vidal, V.: Recording and minimizing nogoods from restarts. Journal on Satisfiability, Boolean Modeling and Computation 1, 147–167 (2007)
Michel, L., Van Hentenryck, P.: Activity-based search for black-box constraint programming solvers. In: Beldiceanu, N., Jussien, N., Pinson, É. (eds.) CPAIOR 2012. LNCS, vol. 7298, pp. 228–243. Springer, Heidelberg (2012)
Moskewicz, M.W., Madigan, C.F., Zhao, Y., Zhang, L., Malik, S. Chaff: engineering an efficient SAT solver. In: Proceedings of DAC 2001, pp. 530–535 (2001)
OscaR Team. OscaR: Scala in OR (2012). bitbucket.org/oscarlib/oscar
Pesant, G., Quimper, C.-G., Zanarini, A.: Counting-based search: Branching heuristics for constraint satisfaction problems. Journal of Artificial Intelligence Research 43, 173–210 (2012)
Pipatsrisawat, K., Darwiche, A.: A lightweight component caching scheme for satisfiability solvers. In: Marques-Silva, J., Sakallah, K.A. (eds.) SAT 2007. LNCS, vol. 4501, pp. 294–299. Springer, Heidelberg (2007)
Refalo, P.: Impact-based search strategies for constraint programming. In: Wallace, M. (ed.) CP 2004. LNCS, vol. 3258, pp. 557–571. Springer, Heidelberg (2004)
Vilím, P.: Timetable edge finding filtering algorithm for discrete cumulative resources. In: Achterberg, T., Beck, J.C. (eds.) CPAIOR 2011. LNCS, vol. 6697, pp. 230–245. Springer, Heidelberg (2011)
Vilím, P., Laborie, P., Shaw, P.: Failure-directed search for constraint-based scheduling. In: Michel, L. (ed.) CPAIOR 2015. LNCS, vol. 9075, pp. 437–453. Springer, Heidelberg (2015)
Wolf, A., Schrader, G.: \({\cal O}(n \log n)\) overload checking for the cumulative constraint and its application. In: Umeda, M., Wolf, A., Bartenstein, O., Geske, U., Seipel, D., Takata, O. (eds.) INAP 2005. LNCS (LNAI), vol. 4369, pp. 88–101. Springer, Heidelberg (2006)
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2015 Springer International Publishing Switzerland
About this paper
Cite this paper
Gay, S., Hartert, R., Lecoutre, C., Schaus, P. (2015). Conflict Ordering Search for Scheduling Problems. In: Pesant, G. (eds) Principles and Practice of Constraint Programming. CP 2015. Lecture Notes in Computer Science(), vol 9255. Springer, Cham. https://doi.org/10.1007/978-3-319-23219-5_10
Download citation
DOI: https://doi.org/10.1007/978-3-319-23219-5_10
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-23218-8
Online ISBN: 978-3-319-23219-5
eBook Packages: Computer ScienceComputer Science (R0)