ts5.scala

  implicit class DMatrixConverter(seq: Seq[FeaturesRecord]) {
    def toDMatrix: DMatrix = {
      val labeledPoints = seq.map { case FeaturesRecord(_, _, features, label) =>
        LabeledPoint(label, features.size, null, features.toArray)
      }
      new DMatrix(labeledPoints.iterator)
    }
  }