Abstract
One lesson learned from practical constraint solving applications is that constraints are often heterogeneous. Solving such constraints requires a collaboration of constraint solvers. In this paper, we introduce a methodology for the tight integration of CHR constraint programs into one such program. CHR is a high-level rule-based language for writing constraint solvers and reasoning systems. A constraint solver is well-behaved if it is terminating and confluent. When merging constraint solvers, this property may be lost. Based on previous results on CHR program analysis and transformation we show how to utilize completion to regain well-behavedness. We identify a class of solvers whose union is always confluent and we show that for preserving termination such a class is hard to find. The merged and completed constraint solvers may contain redundant rules. Utilizing the notion of operational equivalence, which is decidable for well-behaved CHR programs, we present a method to detect redundant rules in a CHR program.
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.
References
Abdennadher, S.: Operational semantics and confluence of constraint propagation rules. In: Smolka, G. (ed.) CP 1997. LNCS, vol. 1330, Springer, Heidelberg (1997)
Abdennadher, S., Frühwirth, T.: On completion of constraint handling rules. In: Maher, M.J., Puget, J.-F. (eds.) CP 1998. LNCS, vol. 1520, p. 25. Springer, Heidelberg (1998)
Abdennadher, S., Frühwirth, T.: Operational equivalence of constraint handling rules. In: Jaffar, J. (ed.) CP 1999. LNCS, vol. 1713, pp. 43–57. Springer, Heidelberg (1999)
Abdennadher, S., Frühwirth, T.: Using program analysis for integration and optimization of rule-based constraint solvers. In: Onziemes Journees Francophones de Programmation Logique et Programmation par Contraintes (JFPLC 2002) (2002)
Abdennadher, S., Frühwirth, T., Meuss, H.: Confluence and semantics of constraint simplification rules. Constraints Journal 4(2) (May 1999)
Arts, T., Giesl, J., Ohlebusch, E.: Modular termination proofs for rewriting using dependency pairs. Journal of Symbolic Computation 34(1), 21–58 (2002)
Baader, F., Schulz, K.U.: Combining constraint solving. In: Comon, H., Marché, C., Treinen, R. (eds.) CCL 1999. LNCS, vol. 2002, pp. 104–158. Springer, Heidelberg (2001)
Castro, C., Monfroy, E.: Basic operators for solving constraints via collaboration of solvers. In: Campbell, J., Roanes-Lozano, E. (eds.) AISC 2000. LNCS (LNAI), vol. 1930, p. 142. Springer, Heidelberg (2001)
Frühwirth, T.: Theory and practice of constraint handling rules. Journal of Logic Programming 37(1-3), 95–138 (1998)
Frühwirth, T.: Proving termination of constraint solver programs. In: Apt, K.R., Kakas, A.C., Monfroy, E., Rossi, F. (eds.) Compulog Net WS 1999. LNCS (LNAI), vol. 1865, p. 298. Springer, Heidelberg (2000)
Frühwirth, T.: Constraint handling rules web pages (2004), www.informatik.uniulm.de/pm/mitarbeiter/fruehwirth/chr-intro.html
Frühwirth, T., Abdennadher, S.: Essentials of Constraint Programming. Springer, Heidelberg (2003)
Gramlich, B.: On termination and confluence properties of disjoint and constructorsharing conditional rewrite systems. Theoretical Computer Science 165(1), 97–131 (1996)
Granvilliers, L., Monfroy, E., Benhamou, F.: Cooperative solvers in constraint programming: A short introduction. In: Workshop on Cooperative Solvers in Constraint Programming (CoSolv) at CP 2001 (2001)
Hofstedt, P.: Better communication for tighter cooperation. In: Palamidessi, C., Moniz Pereira, L., Lloyd, J.W., Dahl, V., Furbach, U., Kerber, M., Lau, K.-K., Sagiv, Y., Stuckey, P.J. (eds.) CL 2000. LNCS (LNAI), vol. 1861, p. 342. Springer, Heidelberg (2000)
Monfroy, E.: The constraint solver collaboration language of BALI. In: Frontiers of Combining Systems 2. Studies in Logic and Computation, vol. 7, Research Studies Press/Wiley (2000)
Ohlebusch, E.: Modular properties of composable term rewriting systems. Journal of Symbolic Computation 20(1) (1995)
Tinelli, C., Ringeissen, C.: Unions of non-disjoint theories and combinations of satisfiability procedures. Theoretical Computer Science 290(1), 291–353 (2003)
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2004 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Abdennadher, S., Frühwirth, T. (2004). Integration and Optimization of Rule-Based Constraint Solvers. In: Bruynooghe, M. (eds) Logic Based Program Synthesis and Transformation. LOPSTR 2003. Lecture Notes in Computer Science, vol 3018. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-25938-1_17
Download citation
DOI: https://doi.org/10.1007/978-3-540-25938-1_17
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-22174-6
Online ISBN: 978-3-540-25938-1
eBook Packages: Springer Book Archive