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doc/batteries.unthreaded/BatRandom/index.html
Module BatRandom
Pseudo-random number generators (PRNG).
This module extends Stdlib's Random module, go there for documentation on the rest of the functions and types.
@documents Random
Basic functions
Initialize the generator, using the argument as a seed. The same seed will always yield the same sequence of numbers.
Same as Random.init
but takes more data as seed.
Initialize the generator with a more-or-less random seed chosen in a system-dependent way.
Random.int bound
returns a random integer between 0 (inclusive) and bound
(exclusive). bound
must be greater than 0 and less than 230.
Random.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, Random.full_int bound
is equal to Random.int
bound
. If bound
is greater than 230 (on 64-bit systems or non-standard environments, such as JavaScript), Random.full_int
returns a value, where Random.int
raises Invalid_argument
.
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.
Random.int64 bound
returns a random integer between 0 (inclusive) and bound
(exclusive). bound
must be greater than 0.
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.
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_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
.
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.
val bits32 : unit -> Int32.t
Random.bits32 ()
returns 32 random bits as an integer between Int32.min_int
and Int32.max_int
.
val bits64 : unit -> Int64.t
Random.bits64 ()
returns 64 random bits as an integer between Int64.min_int
and Int64.max_int
.
val nativebits : unit -> Nativeint.t
Random.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
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.
val split : unit -> State.t
Draw a fresh PRNG state from the current state of the domain-local generator used by the default functions. (The state of the domain-local generator is modified.) See Random.State.split
.
module Incubator : sig ... end