Structure Random

(* Random -- random number generator *)

type generator

val newgenseed : real -> generator
val newgen     : unit -> generator
val random     : generator -> real
val randomlist : int * generator -> real list
val range      : int * int -> generator -> int
val rangelist  : int * int -> int * generator -> int list

(* 
   [generator] is the type of random number generators, here the
   linear congruential generators from Paulson 1991, 1996.

   [newgenseed seed] returns a random number generator with the given
   seed.  Throws exception Fail on seed 0.0 (which would give rise to
   a degenerate sequence of random numbers).

   [newgen ()] returns a random number generator, taking the seed from
   the system clock.

   [random gen] returns a random number in the interval [0..1).

   [randomlist (n, gen)] returns a list of n random numbers in the
   interval [0,1).

   [range (min, max) gen] returns an integral random number in the
   range [min, max).  Raises Fail if min >= max.

   [rangelist (min, max) (n, gen)] returns a list of n integral random
   numbers in the range [min, max).  Raises Fail if min >= max.  
*)