module Random: sig .. end
Pseudo-random number generators (PRNG).
Basic functions
val init : int -> unit
Initialize the generator, using the argument as a seed.
The same seed will always yield the same sequence of numbers.
val full_init : int array -> unit
val self_init : unit -> unit
Initialize the generator with a random seed chosen
in a system-dependent way. If /dev/urandom is available on
the host machine, it is used to provide a highly random initial
seed. Otherwise, a less random seed is computed from system
parameters (current time, process IDs).
val bits : unit -> int
Return 30 random bits in a nonnegative integer.
- Before 3.12.0 used a different algorithm (affects all the following
functions)
val int : int -> int
Random.int bound returns a random integer between 0 (inclusive)
and bound (exclusive). bound must be greater than 0 and less
than 230.
val int32 : Int32.t -> Int32.t
Random.int32 bound returns a random integer between 0 (inclusive)
and bound (exclusive). bound must be greater than 0.
val nativeint : Nativeint.t -> Nativeint.t
Random.nativeint bound returns a random integer between 0 (inclusive)
and bound (exclusive). bound must be greater than 0.
val int64 : Int64.t -> Int64.t
Random.int64 bound returns a random integer between 0 (inclusive)
and bound (exclusive). bound must be greater than 0.
val float : float -> float
Random.float bound returns a random floating-point number
between 0 and bound (inclusive). If bound is
negative, the result is negative or zero. If bound is 0,
the result is 0.
val bool : unit -> bool
Random.bool () returns true or false with probability 0.5 each.
Advanced functions
The functions from module State manipulate the current state
of the random generator explicitly.
This allows using one or several deterministic PRNGs,
even in a multi-threaded program, without interference from
other parts of the program.
module State: sig .. end
val get_state : unit -> State.t
Return the current state of the generator used by the basic functions.
val set_state : State.t -> unit
Set the state of the generator used by the basic functions.