# RANDOM - reference manual online

Pseudo-random number generators (PRNG).

Chapter

source:

Random(3o) OCamldoc Random(3o)NAMERandom - Pseudo-random number generators (PRNG).ModuleModule RandomDocumentationModule 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 Same as Random.init but takes more data as seed. 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 ini‐ tial 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. Before3.12.0 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 2^{30. 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 (exclu‐ sive). 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 === === 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.2016-02-07 source: Random(3o)