class

Alea::XSR256

Inherits Alea::XSR / Alea::PRNG / Reference / Object

Alea::XSR256 is the alternative PRNG loaded with 256 bits of state. As a result of this, double steps are needed and therefore performance is affected.

 - period:     2^256 -1
 - state type: UInt64

Constants

JUMP_64B_128 = StaticArray[1733541517147835066_u64, 15395012609548302636_u64, 12202545078643706282_u64, 4155657270789760540_u64]
JUMP_64B_192 = StaticArray[8566230491382795199_u64, 14195432079911694259_u64, 8606660816089834049_u64, 4111957640723818037_u64]
STATE_STORAGE_64 = 4

Constructors

new(seed32 : Int, seed64 : Int)

Initializes the PRNG with initial seeds.

@parameters:

  • seed32: value as input to init. the state of 32-bit generators.
  • seed64: value as input to init. the state of 64-bit generators.

@note: both 32-bit and 64-bit states are internally processed as arrays of UInt64, and so is the type of seeds.

@references:

  • Alea::Core::SplitMix64(4)#init_state.

@exceptions:

  • Alea::UndefinedError if any of seed32 or seed64 is negative.
Source
new(state32 : StaticArray(UInt64, STATE_STORAGE_64), state64 : StaticArray(UInt64, STATE_STORAGE_64))

Initializes the PRNG with initial states.

@parameters:

  • state32: array of values for state of 32-bit generators.
  • state64: array of values for state of 64-bit generators.
Source
new(seed : Int)

Initializes the PRNG with initial seed.

@parameters:

  • seed: value as input to init. the state of both 32-bit and 64-bit generators.

@references:

  • Alea::Core::SplitMix64(4)#init_state.

@exceptions:

  • Alea::UndefinedError if seed is negative.
Source
new

Initializes the PRNG with initial seeds readed from system resources.

Source

Instance methods

jump_32(long : Bool = false) : self

Performs an advance over the 32-bit state. This is the equivalent of 2^128 calls to #next_u32.

@parameters:

  • long: flag to advance the state by 2^192 calls.
Source
jump_64(long : Bool = false) : self

Performs an advance over the 32-bit state. This is the equivalent of 2^128 calls to #next_u32.

@parameters:

  • long: flag to advance the state by 2^192 calls.
Source
next_u32

Generate a uniform-distributed random UInt32.

@examples:

rng = Alea::XSR128.new
rng.next_u32 # => 1767702788
Source
next_u64

Generate a uniform-distributed random UInt64.

@examples:

rng = Alea::XSR256.new
rng.next_u # => 9136120204379184874
Source