Missing persist on predictionAndLabels in MulticlassClassificationEvaluator

  override def evaluate(dataset: Dataset[_]): Double = {
    val schema = dataset.schema
    SchemaUtils.checkColumnType(schema, $(predictionCol), DoubleType)
    SchemaUtils.checkNumericType(schema, $(labelCol))
    // Needs to be persisted
    val predictionAndLabels =
      dataset.select(col($(predictionCol)), col($(labelCol)).cast(DoubleType)).rdd.map {
        case Row(prediction: Double, label: Double) => (prediction, label)
      }
    // The initialization will use predictionAndLabels multi times in different actions.
    val metrics = new MulticlassMetrics(predictionAndLabels)
    val metric = $(metricName) match {
      case "f1" => metrics.weightedFMeasure
      case "weightedPrecision" => metrics.weightedPrecision
      case "weightedRecall" => metrics.weightedRecall
      case "accuracy" => metrics.accuracy
    }
    metric
  }