Module BatRandom

module BatRandom: sig .. end
Pseudo-random number generators (PRNG).

This module extends Stdlib's Random module, go there for documentation on the rest of the functions and types.
Author(s): Damien Doligez (base library), David Teller, Pierre Chambart



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 more-or-less random seed chosen in a system-dependent way.
val bits : unit -> int
Return 30 random bits in a nonnegative integer.
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 (inclusive) and bound (exclusive). 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.
val char : unit -> char
Return a random Latin-1 character.
val full_range_int : unit -> int
full_range_int () returns the maximum entropy possible in a single int: 31 bits on 32-bit platforms and 63 bits on 64-bit platforms. Intentionally gives different results on different platforms, so is not portable.

Enumerations of random values.

val enum_bits : unit -> int BatEnum.t
val enum_int : int -> int BatEnum.t
val enum_bool : unit -> bool BatEnum.t
val enum_float : float -> float BatEnum.t
val enum_int32 : Int32.t -> Int32.t BatEnum.t
val enum_int64 : Int64.t -> Int64.t BatEnum.t
val enum_nativeint : Nativeint.t -> Nativeint.t BatEnum.t
val enum_char : unit -> char BatEnum.t

Working with data structures.

val choice : 'a BatEnum.t -> 'a
choice e returns a randomly-chosen element of e.

This function only works on finite enumerations with less than 230 elements.

val multi_choice : int -> 'a BatEnum.t -> 'a BatEnum.t
multi_choice n e returns an enumeration of n randomly-chosen elements of e.
val shuffle : 'a BatEnum.t -> 'a array
shuffle e returns a new array, containing the same set of elements as e, but in a random order.

Shuffling is implemented using the Fisher-Yates algorithm and works in O(n), where n is the number of elements of e.

This function only works on finite enumerations with less than 230 elements.


Advanced functions

module State: sig .. end
Manipulate the current state of the random generator.
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.
module Incubator: sig .. end