package stdlib-random

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package stdlib-random
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Module Random4Source

Pseudo-random number generators (PRNG).

Basic functions

Sourceval init : int -> unit

Initialize the generator, using the argument as a seed. The same seed will always yield the same sequence of numbers.

Sourceval full_init : int array -> unit

Same as Random4.init but takes more data as seed.

Sourceval 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).

Sourceval bits : unit -> int

Return 30 random bits in a nonnegative integer.

Sourceval int : int -> int

Random4.int bound returns a random integer between 0 (inclusive) and bound (exclusive). bound must be greater than 0 and less than 230.

Sourceval full_int : int -> int

Random4.full_int bound returns a random integer between 0 (inclusive) and bound (exclusive). bound may be any positive integer.

If bound is less than 230, Random4.full_int bound is equal to Random4.int bound. If bound is greater than 230 (on 64-bit systems or non-standard environments, such as JavaScript), Random4.full_int returns a value, where Random4.int raises Invalid_argument.

Sourceval int32 : Int32.t -> Int32.t

Random4.int32 bound returns a random integer between 0 (inclusive) and bound (exclusive). bound must be greater than 0.

Sourceval nativeint : Nativeint.t -> Nativeint.t

Random4.nativeint bound returns a random integer between 0 (inclusive) and bound (exclusive). bound must be greater than 0.

Sourceval int64 : Int64.t -> Int64.t

Random4.int64 bound returns a random integer between 0 (inclusive) and bound (exclusive). bound must be greater than 0.

Sourceval float : float -> float

Random4.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.

Sourceval bool : unit -> bool

Random4.bool () returns true or false with probability 0.5 each.

Sourceval bits32 : unit -> Int32.t

Random4.bits32 () returns 32 random bits as an integer between Int32.min_int and Int32.max_int.

Sourceval bits64 : unit -> Int64.t

Random4.bits64 () returns 64 random bits as an integer between Int64.min_int and Int64.max_int.

Sourceval nativebits : unit -> Nativeint.t

Random4.nativebits () returns 32 or 64 random bits (depending on the bit width of the platform) as an integer between Nativeint.min_int and Nativeint.max_int.

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.

Sourcemodule State : sig ... end
Sourceval get_state : unit -> State.t

Return the current state of the generator used by the basic functions.

Sourceval set_state : State.t -> unit

Set the state of the generator used by the basic functions.