pub struct Lcg128CmDxsm64 { /* private fields */ }
Expand description
A PCG random number generator (CM DXSM 128/64 (LCG) variant).
Permuted Congruential Generator with 128-bit state, internal Linear Congruential Generator, and 64-bit output via “double xorshift multiply” output function.
This is a 128-bit LCG with explicitly chosen stream with the PCG-DXSM
output function. This corresponds to pcg_engines::cm_setseq_dxsm_128_64
from pcg_cpp and PCG64DXSM
from NumPy.
Despite the name, this implementation uses 32 bytes (256 bit) space
comprising 128 bits of state and 128 bits stream selector. These are both
set by SeedableRng
, using a 256-bit seed.
Note that while two generators with different stream parameter may be closely correlated, this is mitigated by the DXSM output function.
Implementations§
Source§impl Lcg128CmDxsm64
impl Lcg128CmDxsm64
Sourcepub fn advance(&mut self, delta: u128)
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.
Sourcepub fn new(state: u128, stream: u128) -> Self
pub fn new(state: u128, stream: u128) -> 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 while two generators with different stream parameter may be closely correlated, this is mitigated by the DXSM output function.
PCG specifies the following default values for both parameters:
state = 0xcafef00dd15ea5e5
stream = 0xa02bdbf7bb3c0a7ac28fa16a64abf96
Trait Implementations§
Source§impl Clone for Lcg128CmDxsm64
impl Clone for Lcg128CmDxsm64
Source§fn clone(&self) -> Lcg128CmDxsm64
fn clone(&self) -> Lcg128CmDxsm64
1.0.0 · Source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moreSource§impl Debug for Lcg128CmDxsm64
impl Debug for Lcg128CmDxsm64
Source§impl<'de> Deserialize<'de> for Lcg128CmDxsm64
impl<'de> Deserialize<'de> for Lcg128CmDxsm64
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 Lcg128CmDxsm64
impl PartialEq for Lcg128CmDxsm64
Source§impl RngCore for Lcg128CmDxsm64
impl RngCore for Lcg128CmDxsm64
Source§impl SeedableRng for Lcg128CmDxsm64
impl SeedableRng for Lcg128CmDxsm64
Source§fn from_seed(seed: Self::Seed) -> Self
fn from_seed(seed: Self::Seed) -> Self
We use a single 255-bit seed to initialise the state and select a stream.
One seed
bit (lowest bit of seed[8]
) is ignored.
Source§type Seed = [u8; 32]
type Seed = [u8; 32]
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 Lcg128CmDxsm64
impl Serialize for Lcg128CmDxsm64
impl Eq for Lcg128CmDxsm64
impl StructuralPartialEq for Lcg128CmDxsm64
Auto Trait Implementations§
impl Freeze for Lcg128CmDxsm64
impl RefUnwindSafe for Lcg128CmDxsm64
impl Send for Lcg128CmDxsm64
impl Sync for Lcg128CmDxsm64
impl Unpin for Lcg128CmDxsm64
impl UnwindSafe for Lcg128CmDxsm64
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
.