Data commit

Task/Roots-of-a-function/Elixir/roots-of-a-function.elixir

@@ -0,0 +1,27 @@
+defmodule RC do
+  def find_roots(f, range, step \\ 0.001) do
+    first .. last = range
+    max = last + step / 2
+    Stream.iterate(first, &(&1 + step))
+    |> Stream.take_while(&(&1 < max))
+    |> Enum.reduce(sign(first), fn x,sn ->
+         value = f.(x)
+         cond do
+           abs(value) < step / 100 ->
+             IO.puts "Root found at #{x}"
+             0
+           sign(value) == -sn ->
+             IO.puts "Root found between #{x-step} and #{x}"
+             -sn
+           true -> sign(value)
+         end
+       end)
+  end
+
+  defp sign(x) when x>0, do: 1
+  defp sign(x) when x<0, do: -1
+  defp sign(0)         , do: 0
+end
+
+f = fn x -> x*x*x - 3*x*x + 2*x end
+RC.find_roots(f, -1..3)