Fisher–Yates Shuffle Elixir Implemetation

fisher_yates.ex

defmodule FisherYates do
	@moduledoc """

		Fisher–Yates Shuffle explained and implemented in javascripy with animated demo - http://bost.ocks.org/mike/shuffle/
		Reference implementation: http://stackoverflow.com/a/12646864/44080

		Usage:
			iex(2)> FisherYates.shuffle [1, 2, 3, 4, 5, 6, 7, 8, 9]
			[5, 7, 8, 9, 4, 3, 6, 1, 2]
	"""

	def shuffle(list), do: _shuffle(list, length(list), [])

	defp _shuffle([h|_t],1,result), do: [h|result]	# when n = 1

	defp _shuffle(list,n,[]) do 	# when n = list.length
		r=:rand.uniform(n)
		_shuffle(List.replace_at(list, r-1, List.last(list)),n-1,[r])
	end

	defp _shuffle(list,n,result) do
		r=:rand.uniform(n)		# a random number from 0 to n-1 inclusive
		vR=Enum.at(list,r-1)	# list value at r
		vE=Enum.at(list,n-1)	# list value at n-1
		_shuffle(List.replace_at(list, r-1, vE),n-1,[vR|result])
	end
end

#Question: How to make this efficient for much larger lists? (Length 100_000 above)

Question: How to make this efficient for much larger lists? (Length 100_000 above)