Cube and Conquer: Guiding CDCL SAT Solvers by Lookaheads

  • Marijn J. H. Heule
  • Oliver Kullmann
  • Siert Wieringa
  • Armin Biere
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 7261)


Satisfiability (SAT) is considered as one of the most important core technologies in formal verification and related areas. Even though there is steady progress in improving practical SAT solving, there are limits on scalability of SAT solvers. We address this issue and present a new approach, called cube-and-conquer, targeted at reducing solving time on hard instances. This two-phase approach partitions a problem into many thousands (or millions) of cubes using lookahead techniques. Afterwards, a conflict-driven solver tackles the problem, using the cubes to guide the search. On several hard competition benchmarks, our hybrid approach outperforms both lookahead and conflict-driven solvers. Moreover, because cube-and-conquer is natural to parallelize, it is a competitive alternative for solving SAT problems in parallel.


Partial Assignment Unit Clause Bound Model Check Hard Instance Decision Heuristic 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Marijn J. H. Heule
    • 1
    • 2
  • Oliver Kullmann
    • 3
  • Siert Wieringa
    • 4
  • Armin Biere
    • 2
  1. 1.Delft University of TechnologyThe Netherlands
  2. 2.Johannes Kepler University LinzAustria
  3. 3.Swansea UniversityUnited Kingdom
  4. 4.Aalto University HelsinkiFinland

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