Bump Polars to v0.41.3

lib/explorer/data_frame.ex

@@ -2778,7 +2778,7 @@ defmodule Explorer.DataFrame do
       #Explorer.DataFrame<
         Polars[3 x 2]
         a string ["a", "b", "c"]
-        b f64 [1.0, 4.0, 9.0]
+        b s64 [1, 4, 9]
       >
 
   It's possible to "reuse" a variable for different computations:

lib/explorer/polars_backend/data_frame.ex

@@ -195,6 +195,11 @@ defmodule Explorer.PolarsBackend.DataFrame do
 
     {columns, with_projection} = column_names_or_projection(columns)
 
+    dtypes_list =
+      if not Enum.empty?(dtypes) do
+        Map.to_list(dtypes)
+      end
+
     df =
       Native.df_load_csv(
         contents,
@@ -207,7 +212,7 @@ defmodule Explorer.PolarsBackend.DataFrame do
         delimiter,
         true,
         columns,
-        Map.to_list(dtypes),
+        dtypes_list,
         encoding,
         nil_values,
         parse_dates,

lib/explorer/series.ex

@@ -3616,7 +3616,7 @@ defmodule Explorer.Series do
       iex> Explorer.Series.pow(s, 3)
       #Explorer.Series<
         Polars[3]
-        f64 [8.0, 64.0, 216.0]
+        s64 [8, 64, 216]
       >
 
       iex> s = [2, 4, 6] |> Explorer.Series.from_list()
@@ -3657,7 +3657,7 @@ defmodule Explorer.Series do
   defp cast_to_pow({:f, l}, {:f, r}), do: {:f, max(l, r)}
   defp cast_to_pow({:f, l}, {n, _}) when K.in(n, [:u, :s]), do: {:f, l}
   defp cast_to_pow({n, _}, {:f, r}) when K.in(n, [:u, :s]), do: {:f, r}
-  defp cast_to_pow({n, _}, {:s, _}) when K.in(n, [:u, :s]), do: {:f, 64}
+  defp cast_to_pow({n, _}, {:s, _}) when K.in(n, [:u, :s]), do: {:s, 64}
   defp cast_to_pow(_, _), do: nil
 
   @doc """