User blog comment:KthulhuHimself/L-system functions, and why they might be fast growing./@comment-1605058-20151015161948

If you restrict yourself to m being a rational multiple of a degree, then I am pretty sure that your function is computable. If you let m be arbitrary real, then your function is not at all subject to recursion-theoretic considerations, so it sure isn't computable, but it's not really valid to call it "uncomputable" either (as this is usually restricted to functions with countable domain).