restrictNrows ::
       Int          -- ^ number of N rows to select
    -> RTable       -- ^ input RTable
    -> RTable       -- ^ output RTable
restrictNrows n r1 = V.take n r1
restrictNrows ::
       Int          -- ^ number of N rows to select
    -> RTable       -- ^ input RTable
    -> RTable
restrictNrows n r1 = V.take n r1
restrictNrows n r1 = V.take n r1