Scala Parallel Collection with parallelism level

package.scala

/** Parallel Collection with parallelism level
*
* Changes the task support of a parallel collection to use a fork-join pool
* with desired parallelism level
*
* Usage:
* {{{
* Seq(1, 2, 3, 4).par.withCores(Runtime.getRuntime.availableProcessors * 2).map(_ * 2).sum
* }}}
*
* @see [[scala.collection.parallel.TaskSupport]]
*/
implicit class ParExtensions[T](iter: ParIterable[T]) {
  def withCores(n: Int): ParIterable[T] = {
    iter.tasksupport = new ForkJoinTaskSupport(new ForkJoinPool(n))
    iter
  }
}