Hi,
Here is an implementation of the mandelbrot test for OCaml.
ChriS
(*
http://shootout.alioth.debian.org/benchmark.php?test=mandelbrot&lang=all *)
(* Plot the Mandelbrot set [-1.5-i,0.5+i] on an N-by-N bitmap
(
http://www-info2.informatik.uni-wuerzburg.de/mitarbeiter/wolfram/lehre/bildformate.html#pbm). *)
let niter = 50
let limit = 2.
let limit2 = limit *. limit
let add_bit0 cr ci byte =
let rec loop i zr zi =
if i > niter then (byte lsl 1) lor 0x01
else if zr *. zr +. zi *. zi > limit2 then (byte lsl 1) lor 0x00
else loop (succ i) (zr *. zr -. zi *. zi +. cr) (2. *. zr *. zi +. ci) in
loop 1 0. 0.
let () =
let w = int_of_string Sys.argv.(1) in
let h = w in
let invw = 2. /. float w
and invh = 2. /. float h
and cplmt8 = let w8 = w mod 8 in if w8 = 0 then 0 else 8 - w8 in
Printf.printf "P4\n%i %i\n" w h;
let byte = ref 0
and bit = ref 0 in
for y = 0 to h - 1 do
let ci = float y *. invh -. 1. in
for x = 0 to w - 2 do
byte := add_bit0 (float x *. invw -. 1.5) ci !byte;
incr bit;
if !bit = 8 then (
output_byte stdout !byte;
byte := 0;
bit := 0;
)
done;
output_byte stdout (!byte lsl cplmt8);
byte := 0;
bit := 0;
done
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