Par Top Down_

top-down-par.scala

trait PTopDownUpdater extends FrontierUpdater {
 
  def update(frontier: Seq[Int], parents: Array[Int]): Seq[Int] = {
    val next = ArrayBuffer[Int]()
 
    frontier.par.foreach { node =>
      graph.getNeighbors(node).filter(parents(_) == -1).foreach { neighbor =>
        next += neighbor
        parents(neighbor) = node
      }
    }
    next
  }