estimator.rb

  def compress!
    r_i = 0.0
    c = Cursor.new(self.samples)
    while ~c != nil && ~c.next != nil
      r_i = (~c).rank + (~c.next).value + (~c.next).delta
      if r_i <= @invariant.upper_bound(r_i, n)
        removed = ~c.next
        (~c).value = removed.value
        (~c).delta = removed.delta
        c.remove!
      end
      r_i += (~c).rank
      c = c.next
    end
  end