diff -r f5320aba6750 -r 12d1be8ff862 src/Tools/random_word.ML
--- a/src/Tools/random_word.ML	Wed Sep 15 20:07:41 2010 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,78 +0,0 @@
-(*  Title:      Tools/random_word.ML
-    Author:     Makarius
-
-Simple generator for pseudo-random numbers, using unboxed word
-arithmetic only.  Unprotected concurrency introduces some true
-randomness.
-*)
-
-signature RANDOM_WORD =
-sig
-  val max_word: word
-  val step: word -> word
-  val next_word: unit -> word
-  val next_bool: unit -> bool
-  val next_int: int -> int -> int
-  val next_real: unit -> real
-  val pick_any: 'a list -> 'a
-  val pick_weighted: (int * 'a) list -> 'a
-end;
-
-structure Random_Word: RANDOM_WORD =
-struct
-
-(* random words: 0w0 <= result <= max_word *)
-
-(*minimum length of unboxed words on all supported ML platforms*)
-val _ = Word.wordSize >= 30
-  orelse raise Fail ("Bad platform word size");
-
-val max_word = 0wx3FFFFFFF;
-val top_bit = 0wx20000000;
-
-(*multiplier according to Borosh and Niederreiter (for modulus = 2^30),
-  see http://random.mat.sbg.ac.at/~charly/server/server.html*)
-val a = 0w777138309;
-fun step x = Word.andb (a * x + 0w1, max_word);
-
-local val rand = Unsynchronized.ref 0w1
-in fun next_word () = (Unsynchronized.change rand step; ! rand) end;
-
-(*NB: higher bits are more random than lower ones*)
-fun next_bool () = Word.andb (next_word (), top_bit) = 0w0;
-
-
-(* random integers: i <= result <= j *)
-
-val max_int = Word.toInt max_word;
-
-fun next_int i j =
-  let val k = j - i in
-    if k < 0 orelse k > max_int then raise Fail ("next_int: out of range")
-    else if k < max_int then i + Word.toInt (Word.mod (next_word (), Word.fromInt (k + 1)))
-    else i + Word.toInt (next_word ())
-  end;
-
-
-(* random reals: 0.0 <= result < 1.0 *)
-
-val scaling = real max_int + 1.0;
-fun next_real () = real (Word.toInt (next_word ())) / scaling;
-
-
-(* random list elements *)
-
-fun pick_any [] = raise Empty
-  | pick_any xs = nth xs (next_int 0 (length xs - 1));
-
-fun pick_weighted xs =
-  let
-    val total = fold (fn (k, _) => fn i =>
-      if k < 0 then raise Fail ("Bad weight: " ^ string_of_int k) else k + i) xs 0;
-    fun pick n ((k, x) :: xs) =
-        if n <= k then x else pick (n - k) xs
-      | pick _ [] = raise Empty;
-  in if total = 0 then raise Empty else pick (next_int 1 total) xs end;
-
-end;
-