Abstract
This paper presents an experimental investigation of the following questions: how does the average-case complexity of random 3-SAT, understood as a function of the order (number of variables) for fixed density (ratio of number of clauses to order) instances, depend on the density? Is there a phase transition in which the complexity shifts from polynomial to exponential? Is the transition dependent or independent of the solver? To study these questions, we gather median and mean running times for a large collection of random 3-SAT problems while systematically varying both densities and the order of the instances. We use three different complete SAT solvers, embodying very different underlying algorithms: GRASP, CPLEX, and CUDD. We observe new phase transitions for all three solvers, where the median running time shifts from polynomial in the order to exponential. The location of the phase transition appears to be solver-dependent. While GRASP and CUDD shift from polynomial to exponential complexity at a density of about 3.8, CUDD exhibits this transition between densities of 0.1 and 0.5. We believe these experimental observations are important for understanding the computational complexity of random 3-SAT, and can be used as a justification for developing density-aware solvers for 3-SAT.
Supported in part by NSF grant CCR-9700061, and by a grant from the Intel Corporation.
This work was done while the author was on sabbatical at Rice University, supported in part by CONACyT grant 145502.
Supported in part by NSF grant IRI-9796046.
Supported in part by NSF grant CCR-9700061, and by a grant from the Intel Corporation.
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References
D. Achlioptas. Setting two variables at a time yields a new lower bound for random 3-SAT. In Proc. 32th ACM Symp. on Theory of Computing, pages 28–37, 2000.
P. Beame, R. M. Karp, T. Pitassi, and M. E. Saks. On the complexity of unsatisfiability proofs for random k-CNF formulas. In Proc. 30th ACM Symp. on Theory of Computing, pages 561–571, 1998.
A. Biere, A. Cimatti, E. M. Clarke, M. Fujita, and Y. Zhu. Symbolic model checking using SAT procedures instead of BDDs. In Proc. 36th Conf. on Design Automation, pages 317–320, 1999.
R. E. Bixby. Implementing the Simplex method: The initial basis. ORSA J. on Computing, 4(3):267–284, 1992.
F. Bouquet. Gestion de la dynamicité et énumération d’implicants premiers: une approche fondée sur les Diagrammes de Décision Binaire. PhD thesis, Université de Provence, France, 1999.
A. Z. Broder, A. M. Frieze, and E. Upfal. On the satisfiability and maximum satisfiability of random 3-CNF formulas. In Proc. 4th Annual ACM-SIAM Symp. on Discrete Algorithms, pages 322–330, 1993.
R. E. Bryant. Graph-based algorithms for Boolean function manipulation. IEEE Trans. on Computers, 35(8):677–691, 1986.
M. Chao and J. V. Franco. Probabilistic analysis of a generalization of the unit-clause literal selection heuristics for the k satisfiability problem. Information Sciences, 51:289–314, 1990.
P. Cheeseman, B. Kanefsky, and W. M. Taylor. Where the really hard problems are. In Proc. 12th Int’l Joint Conf. on Artificial Intelligence (IJCAI’ 91), pages 331–337, 1991.
V. Chvátal and E. Szemerédi. Many hard examples for resolution. J. of the ACM, 35(4):759–768, 1988.
J. M. Crawford and L. D. Auton. Experimental results on the crossover point in satisfiability problems. AAAI, pages 21–27, 1993.
J. M. Crawford and L. D. Auton. Experimental results on the crossover point in random 3-SAT. Artificial Intelligence, 81(1–2):31–57, 1996.
M. Davis, G. Longemann, and D. Loveland. A machine program for theorem proving. Comm. of the ACM, 5:394–397, 1962.
O. Dubois, Y. Boufkhad, and J. Mandler. Typical random 3-SAT formulae and the satisfiability theshold. In Proc. 11th Annual ACM-SIAM Symp. on Discrete Algorithms, pages 126–127, 2000.
E. Friedgut. Necessary and sufficient conditions for sharp threshold of graph properties and the k-SAT problem. J. Amer. Math. Soc., 12:1917–1054, 1999.
A. Frieze and S. Suen. Analysis of two simple heuristics for random instances of k-SAT. J. of Algorithms, 20(2):312–355, 1996.
I. P. Gent and T. Walsh. The SAT phase transition. In Proc. European Conf. on Artificial Intelligence, pages 105–109, 1994.
J. F. Groote. Hiding propositional constants in BDDs. Formal Methods in System Design, 8:91–96, 1996.
J. F. Groote and H. Zantema. Resolution and binary decision diagrams cannot simulate each other polynomially. Technical report, Department of Computer Science, Utrecht University, 2000. Technical Report UU-CS-2000-14.
T. Hogg and C. P. Williams. The hardest constraint problems: A double phase transition. Artificial Intelligence, 69(1–2):359–377, 1994.
J. N. Hooker. Resolution vs. cutting plane solution of inference problems: Some computational experience. Operations Research Letters, 7:1–7, 1988.
S. Kirkpatrick and B. Selman. Critical behavior in the satisfiability of random formulas. Science, 264:1297–1301, 1994.
T. Larrabee and Y. Tsuji. Evidence for a satisfiability threshold for random 3CNF formulas. Technical report, University of California, Santa Cruz, 1992. Technical report USCS-CRL-92042.
J. P. Marques Silva and K. A. Sakallah. GRASP-A search algorithm for propositional satisfiability. IEEE Trans. on Computers, 48(5):506–521, 1999.
D. G. Mitchell and H. J. Levesque. Some pitfalls for experimenters with random SAT. Artificial Intelligence, 81(1–2):111–125, 1996.
M. Mitzenmacher. Tight thresholds for the pure literal rule. Technical report, Digital System Research Center, Palo Alto, California, 1997. SRC Technical Note 1997-011.
G. J. Nam, K. A. Sakallah, and R. A. Rutenbar. Satisfiability-based layout revisited: Detailed routing of complex fpgas via search-based boolean sat. In Proc. ACM Int’l Symp. on Field-Programmable Gate Arrays (FPGA’99), pages 167–175, 1999.
B. Selman and S. Kirkpatrick. Critical behavior in the computational cost of satisfiability testing. Artificial Intelligence, 81(1–2):273–295, 1996.
B. Selman, D. G. Mitchell, and H. J. Levesque. Generating hard satisfiability problems. Artificial Intelligence, 81(1–2):17–29, 1996.
B. M. Smith and M. E. Dyer. Locating the phase transition in binary constraint satisfaction problems. Artificial Intelligence Journal, 8(1–2):155–181, 1996.
F. Somenzi. CUDD: CU Decision Diagram package. release 2.3.0., 1998. Dept. of Electrical and Computer Engineering. University of Colorado at Boulder.
P. Svenson and M. G. Nordahl. Relaxation in graph coloring and satisfiability problems. Phys. Rev. E, 59(4):3983–3999, 1999.
The VIS Group. VIS: A system for verification and synthesis. In Proc. 8th Int’l Conf. on Computer Aided Verification (CAV’ 96), pages 428–432, 1996. LNCS 1102. Ed. by R. Alur and T. Henziger.
T. E. Uribe and M. E. Stickel. Ordered binary decision diagrams and the Davis-Putnam procedure. In First Int’l Conf. on Constraints in Computational Logics, volume 845 of Lecture Notes in Computer Science, pages 34–49, Munich, September 1994. Springer-Verlag.
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Coarfa, C., Demopoulos, D.D., Aguirre, A.S.M., Subramanian, D., Vardi, M.Y. (2000). Random 3-SAT: The Plot Thickens. In: Dechter, R. (eds) Principles and Practice of Constraint Programming – CP 2000. CP 2000. Lecture Notes in Computer Science, vol 1894. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-45349-0_12
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DOI: https://doi.org/10.1007/3-540-45349-0_12
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