def getCombinedMean()

in algebird-core/src/main/scala/com/twitter/algebird/MomentsGroup.scala [324:335]

• 11 lines of code
• 7 McCabe index (conditional complexity)

  def getCombinedMean(n: Long, an: Double, k: Long, ak: Double): Double =
    if (n < k) getCombinedMean(k, ak, n, an)
    else
      (n + k) match {
        case 0L                        => 0.0
        case newCount if newCount == n => an
        case newCount =>
          val scaling = k.toDouble / newCount
          // a_n + (a_k - a_n)*(k/(n+k)) is only stable if n is not approximately k
          if (scaling < STABILITY_CONSTANT) an + (ak - an) * scaling
          else (n * an + k * ak) / newCount
      }