Cosine Similarity with Elixir

main.exs

defmodule Script do
  def cosine_similarity(lhs, rhs) do
    {ab, aa, bb} = accumulate(lhs, rhs)
    ab / (:math.sqrt(aa) * :math.sqrt(bb))
  end
  
  defp accumulate(lhs, rhs) do
    accumulate(lhs, rhs, 0, 0, 0)
  end
  
  defp accumulate([], [], ab, aa, bb) do
    {ab, aa, bb}
  end
  
  defp accumulate([h1|t1], [h2|t2], ab, aa, bb) do
    accumulate(t1, t2,
      ab + h1 * h2,
      aa + h1 * h1,
      bb + h2 * h2)
  end
end

elixir_times = for (_ <- 1 .. 15) do
  lhs = for (_ <- 1 .. 300), do: :rand.uniform()
  rhs = for (_ <- 1 .. 300), do: :rand.uniform()
  {result, _} = :timer.tc fn ->
    Script.cosine_similarity(lhs, rhs)
  end
  result
end

elixir_average_time = elixir_times
  |> (fn x -> Enum.sum(x) / length(x) end).()

IO.puts "elixir #{elixir_average_time}µs"