pi.scala

  def pi1(lsz: Int): Double = {
    var a = 3.0
    var off = 1
    var lcnt = lsz
    def p_elem(t: Int): Double = 4.0 / ((2 * t) * (2 * t + 1) * (2 * t + 2))
    while (lcnt > 0) {
      if (off % 2 == 0) {
        a -= p_elem(off)
      } else {
        a += p_elem(off)
      }
      off += 1
      lcnt -= 1
    }
    a
  }
  
  def pi2(lsz: Int): Double = {
    var a = 3.0
    def p_elem(t: Int): Double = 4.0 / ((2 * t) * (2 * t + 1) * (2 * t + 2))
    (1 to lsz).toArray.par.foreach(b => {
      if (b == 0) {
        a
      } else if (b % 2 == 0) {
        a -= p_elem(b)
      } else {
        a += p_elem(b)
      }
    })
    a
  }