Solving Intensional Weighted CSPs by Incremental Optimization with BDDs

  • Miquel Bofill
  • Miquel Palahí
  • Josep Suy
  • Mateu Villaret
Part of the Lecture Notes in Computer Science book series (LNCS, volume 8656)

Abstract

We present a method for solving weighted Constraint Satisfaction Problems, based on translation into a Constraint Optimization Problem and iterative calls to an SMT solver, with successively tighter bounds of the objective function. The novelty of the method herewith described lies in representing the bound constraint as a shared Binary Decision Diagram, which in turn is translated into SAT. This offers two benefits: first, BDDs built for previous bounds can be used to build the BDDs for new (tighter) bounds, considerably reducing the BDD construction time; second, as a by-product, many clauses asserted to the solver in previous iterations can be reused.

The reported experimentation on the WSimply system shows that this technique has better performance in general than other methods implemented in the system. Moreover, with the new technique WSimply outperforms some state-of-the-art solvers in most of the studied instances.

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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  • Miquel Bofill
    • 1
  • Miquel Palahí
    • 1
  • Josep Suy
    • 1
  • Mateu Villaret
    • 1
  1. 1.Departament d’Informàtica, Matemàtica Aplicada i EstadísticaUniversitat de GironaSpain

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