benchmark/tests/mandelbrot.sml

   1 (* From the SML/NJ benchmark suite. *)
   2
   3 signature BMARK =
   4   sig
   5     val doit : int -> unit
   6     val testit : TextIO.outstream -> unit
   7   end;
   8 (* mandelbrot.sml *)
   9
  10 structure Main : BMARK =
  11   struct
  12     val x_base = ~2.0
  13     val y_base = 1.25
  14     val side = 2.5
  15
  16     val sz = 32768
  17     val maxCount = 2048
  18
  19     val delta = side / (real sz)
  20
  21     val sum_iterations = ref 0
  22
  23     fun loop1 i = if (i >= sz)
  24           then ()
  25           else let
  26             val c_im : real = y_base - (delta * real i)
  27             fun loop2 j = if (j >= sz)
  28                   then ()
  29                   else let
  30                     val c_re = x_base * (delta + real j)
  31                     fun loop3 (count, z_re : real, z_im : real) = if (count < maxCount)
  32                           then let
  33                             val z_re_sq = z_re * z_re
  34                             val z_im_sq = z_im * z_im
  35                             in
  36                               if ((z_re_sq + z_im_sq) > 4.0)
  37                                 then count
  38                                 else let
  39                                   val z_re_im = (z_re * z_im)
  40                                   in
  41                                     loop3 (count+1,
  42                                       (z_re_sq - z_im_sq) + c_re,
  43                                        z_re_im + z_re_im + c_im)
  44                                   end
  45                             end (* loop3 *)
  46                           else count
  47                     val count = loop3 (0, c_re, c_im)
  48                     in
  49                       sum_iterations := !sum_iterations + count;
  50                       loop2 (j+1)
  51                     end
  52             in
  53               loop2 0;
  54               loop1 (i+1)
  55             end
  56
  57     fun doit () = (sum_iterations := 0; loop1 0)
  58
  59     val doit =
  60        fn size =>
  61        let
  62           fun loop n =
  63              if n = 0
  64                 then ()
  65              else (doit();
  66                    loop(n-1))
  67        in loop size
  68        end
  69     fun testit outstrm = (
  70           sum_iterations := 0;
  71           loop1 0;
  72           TextIO.output (outstrm, Int.toString(!sum_iterations) ^ " iterations\n"))
  73
  74   end (* Mandelbrot *)