(*kitmandelbrot.sml*)

fun digit n = chr(ord #"0" + n)
fun digits(n,acc) =
      if n >=0 andalso n<=9 then digit n:: acc
      else digits (n div 10, digit(n mod 10) :: acc)

fun int_to_string(n) = implode(digits(n,[]))

(* mandelbrot.sml *)

(*
structure Main : BMARK =
  struct
*)
    val x_base = ~2.0
    val y_base = 1.25
    val side = 2.5

    val sz = 2048
    val maxCount = 1024

    val delta = side / (real sz)

    val sum_iterations = ref 0

    fun loop1 i = if (i >= sz)
          then ()
          else let
            val c_im : real = y_base - (delta * real i)
            fun loop2 j = if (j >= sz)
                  then ()
                  else let
                    val c_re = x_base * (delta + real j)
                    fun loop3 (count, z_re : real, z_im : real) = if (count < maxCount)
                          then let
                            val z_re_sq = z_re * z_re
                            val z_im_sq = z_im * z_im
                            in
                              if ((z_re_sq + z_im_sq) > 4.0)
                                then count
                                else let
                                  val z_re_im = (z_re * z_im)
                                  in
                                    loop3 (count+1,
                                      (z_re_sq - z_im_sq) + c_re,
                                       z_re_im + z_re_im + c_im)
                                  end
                            end (* loop3 *)
                          else count
                    val count = loop3 (0, c_re, c_im)
                    in
                      sum_iterations := !sum_iterations + 1(*count*);
                      loop2 (j+1)
                    end
            in
              loop2 0;
              loop1 (i+1)
            end

    fun doit () = (sum_iterations := 0; loop1 0)

    fun testit () = (
          sum_iterations := 0;
          loop1 0;
          print(int_to_string(!sum_iterations) ^ " iterations\n"))
(*
  end (* Mandelbrot *)
*)

(*val _ = (doit (); doit(); doit());*)

val _  = (testit (); testit (); testit ());   (* this should give ``1084512 iterations'' *)