Struct SFC64 

pub struct SFC64 { /* private fields */ }

The “Small Fast Chaotic” PRNG, originally designed by Chris Doty-Humphrey.

This PRNG holds 256 bits of state (including a 64-bit counter) and generates 64 bits of output with each step. The minimum cycle length is $2^{64}$, and the expected period is $~2^{255}$. Independent seeds are guaranteed to not collide within the first $2^{64}$ steps, although the actual time to collision may be much longer.

This specific implementation passes PractRand with >2TB of output for each of several low-entropy seeds, and >1TB for sets of 8 and 64 parallel streams whose seed differs by only a single bit.

Seeding (construction)

This generator implements the [SeedableRng] trait. Any method may be used, and the results are guaranteed to be portable.

Seeding the generator with seed_from_u64 is often the most convenient and guarantees good pseudorandom statistics.

use hoomd_rand::SFC64;
use rand::SeedableRng;
let rng = SFC64::seed_from_u64(42);

See also Seeding RNGs in the Rust Rand book.

Generation

The generators implements [TryRng] and thus also Rng. See also the Random Values chapter in the Rust Rand book.

Trait Implementations

impl Clone for SFC64

fn clone(&self) -> SFC64

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SFC64

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for SFC64

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for SFC64

fn eq(&self, other: &SFC64) -> bool

Tests for self and other values to be equal, and is used by ==.

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

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

impl SeedableRng for SFC64

type Seed = [u8; 24]

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: &mut R) -> Self

where R: Rng + ?Sized,

Create a new PRNG seeded from an infallible Rng.

fn try_from_rng<R>(rng: &mut R) -> Result<Self, <R as TryRng>::Error>

where R: TryRng + ?Sized,

Create a new PRNG seeded from a potentially fallible Rng.

fn fork(&mut self) -> Self

where Self: Rng,

Fork this PRNG

fn try_fork(&mut self) -> Result<Self, Self::Error>

where Self: TryRng,

Fork this PRNG

impl Serialize for SFC64

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl TryRng for SFC64

type Error = Infallible

The type returned in the event of a RNG error.

fn try_next_u64(&mut self) -> Result<u64, Self::Error>

Return the next random u64.

fn try_next_u32(&mut self) -> Result<u32, Self::Error>

Return the next random u32.

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

Fill dst entirely with random data.

impl Eq for SFC64

impl StructuralPartialEq for SFC64