Abstract
The Smodels system is a C++ implementation of the well-founded and stable model semantics for range-restricted function-free normal programs. The system includes two modules: (i) smodels which implements the two semantics for ground programs and (ii) parse which computes a grounded version of a range-restricted function-free normal program. The latter module does not produce the whole set of ground instances of the program but a subset that is sufficient in the sense that no stable models are lost. The implementation of the stable model semantics for ground programs is based on bottom-up backtracking search where a powerful pruning method is employed. The pruning method exploits an approximation technique for stable models which is closely related to the well-founded semantics. One of the advantages of this novel technique is that it can be implemented to work in linear space. This makes it possible to apply the stable model semantics also in areas where resulting programs are highly non-stratified and can possess a large number of stable models. The implementation has been tested extensively and compared with a state of the art implementation of the stable model semantics, the SLG system. In tests involving ground programs it clearly outperforms SLG.
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C. Baral and M. Gelfond. Logic programming and knowledge representation. Journal of Logic Programming, 19&20(73–148), 1994.
C. Bell, A. Nerode, R.T. Ng, and V.S. Subrahmanian, Mixed integer programming methods for computing nonmonotonic deductive databases. Journal of the ACM, 41(6):1178–1215, November 1994.
W. Chen and D.S. Warren. The SLG system, 1993. Available at ftp://seas.smu.edu/pub/or ftp://sbcs.sunysv.edu/pub/XSB/.
W. Chen and D.S. Warren. Computation of stable models and its integration with logical query processing. IEEE Transactions on Knowledge and Data Engineering, 8(5):742–757, 1996.
P. Cholewiński, V.W. Marek, A. Mikitiuk, and M. Truszczyński. Experimenting with nonmonotonic reasoning. In Proceedings of the 12th International Conference on Logic Programming, pages 267–281, Tokyo, June 1995.
P. Cholewiński, V.W. Marek, and M. Truszczyński. Default reasoning system DeReS. In Proceedings of the 5th International Conference on Principles of Knowledge Representation and Reasoning, pages 518–528, Cambridge, MA, USA, November 1996. Morgan Kaufmann Publishers.
J.M. Crawford and L.D. Auton. Experimental results on the crossover point in random 3-SAT. Artificial Intelligence, 81(1):31–57, 1996.
M. Gelfond and V. Lifschitz. The stable model semantics for logic programming. In Proceedings of the 5th International Conference on Logic Programming, pages 1070–1080, Seattle, USA, August 1988. The MIT Press.
D.E. Knuth. The Stanford GraphBase, 1993. Available at ftp://labrea.stanford.edu/.
I. Niemelä. Towards efficient default reasoning. In Proceedings of the 14th International Joint Conference on Artificial Intelligence, pages 312–318, Montreal, Canada, August 1995. Morgan Kaufmann Publishers.
Ilkka Niemelä and Patrik Simons. Efficient implementation of the well-founded and stable model semantics. In M. Maher, editor, Proceedings of the Joint International Conference and Symposium on Logic Programming, pages 289–303, Bonn, Germany, September 1996. The MIT Press.
Ilkka Niemelä and Patrik Simons. Efficient implementation of the well-founded and stable model semantics. Fachbericht Informatik 7–96, Universität Koblenz-Landau, 1996. Available at http://www.uni-koblenz.de/universitaet/fb4/publications/GelbeReihe/.
K. Sagonas, T. Swift, and D.S. Warren. An abstract machine for computing the well-founded semantics. In M. Maher, editor, Proceedings of the Joint International Conference and Symposium on Logic Programming, pages 274–288, Bonn, Germany, September 1996. The MIT Press.
V.S. Subrahmanian, D. Nau, and C. Vago. WFS+branch bound=stable models. IEEE Transactions on Knowledge and Data Engineering, 7(3):362–377, 1995.
A. Van Gelder, K.A. Ross, and J.S. Schlipf. The well-founded semantics for general logic programs. Journal of the ACM, 38(3):620–650, July 1991.
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© 1997 Springer-Verlag Berlin Heidelberg
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Niemelä, I., Simons, P. (1997). Smodels — an implementation of the stable model and well-founded semantics for normal logic programs. In: Dix, J., Furbach, U., Nerode, A. (eds) Logic Programming And Nonmonotonic Reasoning. LPNMR 1997. Lecture Notes in Computer Science, vol 1265. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-63255-7_32
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DOI: https://doi.org/10.1007/3-540-63255-7_32
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