pub struct Lcg64Xsh32 { /* private fields */ }
Expand description
A PCG random number generator (XSH RR 64/32 (LCG) variant).
Permuted Congruential Generator with 64-bit state, internal Linear Congruential Generator, and 32-bit output via “xorshift high (bits), random rotation” output function.
This is a 64-bit LCG with explicitly chosen stream with the PCG-XSH-RR
output function. This combination is the standard pcg32
.
Despite the name, this implementation uses 16 bytes (128 bit) space
comprising 64 bits of state and 64 bits stream selector. These are both set
by SeedableRng
, using a 128-bit seed.
Note that two generators with different stream parameter may be closely correlated.
Implementations§
Source§impl Lcg64Xsh32
impl Lcg64Xsh32
Sourcepub fn advance(&mut self, delta: u64)
pub fn advance(&mut self, delta: u64)
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_32()
delta
number of times.
Sourcepub fn new(state: u64, stream: u64) -> Self
pub fn new(state: u64, stream: u64) -> Self
Construct an instance compatible with PCG seed and stream.
Note that the highest bit of the stream
parameter is discarded
to simplify upholding internal invariants.
Note that two generators with different stream parameters may be closely correlated.
PCG specifies the following default values for both parameters:
state = 0xcafef00dd15ea5e5
stream = 0xa02bdbf7bb3c0a7
Trait Implementations§
Source§impl Clone for Lcg64Xsh32
impl Clone for Lcg64Xsh32
Source§fn clone(&self) -> Lcg64Xsh32
fn clone(&self) -> Lcg64Xsh32
1.0.0 · Source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moreSource§impl Debug for Lcg64Xsh32
impl Debug for Lcg64Xsh32
Source§impl<'de> Deserialize<'de> for Lcg64Xsh32
impl<'de> Deserialize<'de> for Lcg64Xsh32
Source§fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>where
__D: Deserializer<'de>,
fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>where
__D: Deserializer<'de>,
Source§impl PartialEq for Lcg64Xsh32
impl PartialEq for Lcg64Xsh32
Source§impl RngCore for Lcg64Xsh32
impl RngCore for Lcg64Xsh32
Source§impl SeedableRng for Lcg64Xsh32
impl SeedableRng for Lcg64Xsh32
Source§fn from_seed(seed: Self::Seed) -> Self
fn from_seed(seed: Self::Seed) -> Self
We use a single 127-bit seed to initialise the state and select a stream.
One seed
bit (lowest bit of seed[8]
) is ignored.
Source§type Seed = [u8; 16]
type Seed = [u8; 16]
u8
arrays (we recommend [u8; N]
for some N
). Read moreSource§fn seed_from_u64(state: u64) -> Self
fn seed_from_u64(state: u64) -> Self
u64
seed. Read moreSource§fn from_rng(rng: &mut impl RngCore) -> Self
fn from_rng(rng: &mut impl RngCore) -> Self
Rng
. Read moreSource§fn try_from_rng<R>(rng: &mut R) -> Result<Self, <R as TryRngCore>::Error>where
R: TryRngCore,
fn try_from_rng<R>(rng: &mut R) -> Result<Self, <R as TryRngCore>::Error>where
R: TryRngCore,
Rng
. Read moreSource§fn from_os_rng() -> Self
fn from_os_rng() -> Self
Source§impl Serialize for Lcg64Xsh32
impl Serialize for Lcg64Xsh32
impl Eq for Lcg64Xsh32
impl StructuralPartialEq for Lcg64Xsh32
Auto Trait Implementations§
impl Freeze for Lcg64Xsh32
impl RefUnwindSafe for Lcg64Xsh32
impl Send for Lcg64Xsh32
impl Sync for Lcg64Xsh32
impl Unpin for Lcg64Xsh32
impl UnwindSafe for Lcg64Xsh32
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
Source§unsafe fn clone_to_uninit(&self, dst: *mut T)
unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)Source§impl<R> TryRngCore for Rwhere
R: RngCore,
impl<R> TryRngCore for Rwhere
R: RngCore,
Source§type Error = Infallible
type Error = Infallible
Source§fn try_next_u32(&mut self) -> Result<u32, <R as TryRngCore>::Error>
fn try_next_u32(&mut self) -> Result<u32, <R as TryRngCore>::Error>
u32
.Source§fn try_next_u64(&mut self) -> Result<u64, <R as TryRngCore>::Error>
fn try_next_u64(&mut self) -> Result<u64, <R as TryRngCore>::Error>
u64
.Source§fn try_fill_bytes(
&mut self,
dst: &mut [u8],
) -> Result<(), <R as TryRngCore>::Error>
fn try_fill_bytes( &mut self, dst: &mut [u8], ) -> Result<(), <R as TryRngCore>::Error>
dest
entirely with random data.Source§fn read_adapter(&mut self) -> RngReadAdapter<'_, Self>where
Self: Sized,
fn read_adapter(&mut self) -> RngReadAdapter<'_, Self>where
Self: Sized,
RngCore
to a RngReadAdapter
.