# Random.3o man page

Random — Pseudo-random number generators (PRNG).

## Module

Module Random

## Documentation

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**

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 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.**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** (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.