gapt.provers.sat.Sat4j.scala Maven / Gradle / Ivy

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General Architecture for Proof Theory

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package gapt.provers.sat

import gapt.formats.dimacs.DIMACS
import gapt.proofs.rup.RupProof
import org.sat4j.core.{LiteralsUtils, Vec, VecInt}
import org.sat4j.minisat.SolverFactory
import org.sat4j.specs._

class Sat4j extends DrupSolver {
  import Sat4j._

  override def solve(cnf: DIMACS.CNF): Option[DIMACS.Model] = {
    val solver = SolverFactory.newDefault()
    solver.newVar(DIMACS maxAtom cnf)

    try {
      solver.addAllClauses(cnf)

      if (solver.isSatisfiable) {
        Some(solver.model().toIndexedSeq)
      } else {
        None
      }
    } catch {
      case _: ContradictionException => None
    }
  }

  class RupListener extends SearchListenerAdapter[ISolverService] {
    val drup = Seq.newBuilder[RupProof.Line]

    override def learnUnit(p: Int) = drup += RupProof.Rup(Set(p))
    override def learn(c: IConstr) = drup += RupProof.Rup(c)

    override def end(result: Lbool) =
      if (result == Lbool.FALSE) drup += RupProof.Rup(Set())

    def result() = RupProof(drup.result())
  }

  override def getDrupProof(cnf: DIMACS.CNF): Option[RupProof] = {
    val solver = SolverFactory.newDefault()
    val listener = new RupListener
    listener.drup ++= cnf.view.map(RupProof.Input(_))
    solver.setSearchListener(listener)
    solver.newVar(DIMACS maxAtom cnf)

    try {
      solver.addAllClauses(cnf)

      if (solver.isSatisfiable) {
        None
      } else {
        Some(listener.result())
      }
    } catch {
      case _: ContradictionException =>
        listener.end(Lbool.FALSE)
        Some(listener.result())
    }
  }
}

object Sat4j extends Sat4j {
  implicit def clause2sat4j(clause: DIMACS.Clause): IVecInt =
    new VecInt(clause toArray)

  implicit def cnf2sat4j(cnf: DIMACS.CNF): IVec[IVecInt] =
    new Vec(cnf.map { implicitly[IVecInt](_) }.toArray)

  implicit def sat4j2clause(constr: IConstr): DIMACS.Clause =
    for (i <- 0 until constr.size()) yield LiteralsUtils.toDimacs(constr get i)
}