launch :: Word32 
          -> Word32 
          -> (Array (Exp a) -> Kernel (Array (Exp b)))
          -> GPUArray a 
          -> GPUArray b
          -> Coord ()
launch = undefined
launch :: Word32 
          -> Word32 
          -> (Array (Exp a) -> Kernel (Array (Exp b)))
          -> GPUArray a 
          -> GPUArray b
          -> Coord ()
launch = undefined
launch = undefined