Struct rand_pcg::Mcg128Xsl64

pub struct Mcg128Xsl64 { /* private fields */ }

A PCG random number generator (XSL 128/64 (MCG) variant).

Permuted Congruential Generator with 128-bit state, internal Multiplicative Congruential Generator, and 64-bit output via “xorshift low (bits), random rotation” output function.

This is a 128-bit MCG with the PCG-XSL-RR output function, also known as pcg64_fast. Note that compared to the standard pcg64 (128-bit LCG with PCG-XSL-RR output function), this RNG is faster, also has a long cycle, and still has good performance on statistical tests.

Implementations

impl Mcg128Xsl64

pub fn advance(&mut self, delta: u128)

Multi-step advance functions (jump-ahead, jump-back)

The method used here is based on Brown, “Random Number Generation with Arbitrary Stride,”, Transactions of the American Nuclear Society (Nov. 1994). The algorithm is very similar to fast exponentiation.

Even though delta is an unsigned integer, we can pass a signed integer to go backwards, it just goes “the long way round”.

Using this function is equivalent to calling next_64() delta number of times.

pub fn new(state: u128) -> Self

Construct an instance compatible with PCG seed.

Note that PCG specifies a default value for the parameter:

• state = 0xcafef00dd15ea5e5

Trait Implementations

impl Clone for Mcg128Xsl64

fn clone(&self) -> Mcg128Xsl64

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Mcg128Xsl64

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq<Mcg128Xsl64> for Mcg128Xsl64

fn eq(&self, other: &Mcg128Xsl64) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl RngCore for Mcg128Xsl64

fn next_u32(&mut self) -> u32

Return the next random u32.

fn next_u64(&mut self) -> u64

Return the next random u64.

fn fill_bytes(&mut self, dest: &mut [u8])

Fill dest with random data.

fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error>

Fill dest entirely with random data.

impl SeedableRng for Mcg128Xsl64

We use a single 126-bit seed to initialise the state and select a stream. Two seed bits (lowest order of last byte) are ignored.

type Seed = [u8; 16]

Seed type, which is restricted to types mutably-dereferenceable as u8 arrays (we recommend [u8; N] for some N).

fn from_seed(seed: Self::Seed) -> Self

Create a new PRNG using the given seed.

fn seed_from_u64(state: u64) -> Self

Create a new PRNG using a u64 seed.

fn from_rng<R>(rng: R) -> Result<Self, Error>where
    R: RngCore,

Create a new PRNG seeded from another Rng.

fn from_entropy() -> Self

Creates a new instance of the RNG seeded via getrandom.

impl Eq for Mcg128Xsl64

impl StructuralEq for Mcg128Xsl64

impl StructuralPartialEq for Mcg128Xsl64