typed vs fields

gistfile1.scala

import com.twitter.scalding._
import TDsl._

class mult(args:Args) extends Job(args) {
  def mkRow(columns:Int, dominant:Int):Seq[Double] = Seq.tabulate[Double](columns)(i=> if (i==dominant) 5+math.random*10 else math.random)
  val n:Int = args("rows").toInt

  /* Typed - FAILS :( OOM for n as small as 10,000
  TypedPipe.from(0 to n)
  .map{
    i=> (i, mkRow(n, i))
  }
  .write(TypedTsv[(Int, Seq[Double])]("typed"))
  */

  // Fields To Typed - WORKS
  IterableSource((0 until n), 'a)
  .read
  .toTypedPipe[Int]('a)
  .map {
    i=> (i, mkRow(n, i))
  }
  .write(TypedTsv[(Int, Seq[Double])]("typed"))

  /* Fields API - WORKS !!!
  IterableSource((0 until n), 'a)
  .read
  .map('a -> 'b){
    i:Int =>
      mkRow(n, i)
  }
  .write(Tsv("fields"))
  */
}