[−][src]Struct rand_isaac::isaac64::Isaac64Rng
A random number generator that uses ISAAC-64, the 64-bit variant of the ISAAC algorithm.
ISAAC stands for "Indirection, Shift, Accumulate, Add, and Count" which are the principal bitwise operations employed. It is the most advanced of a series of array based random number generator designed by Robert Jenkins in 19961.
ISAAC-64 is mostly similar to ISAAC. Because it operates on 64-bit integers instead of 32-bit, it uses twice as much memory to hold its state and results. Also it uses different constants for shifts and indirect indexing, optimized to give good results for 64bit arithmetic.
ISAAC-64 is notably fast and produces excellent quality random numbers for non-cryptographic applications.
In spite of being designed with cryptographic security in mind, ISAAC hasn't
been stringently cryptanalyzed and thus cryptographers do not not
consensually trust it to be secure. When looking for a secure RNG, prefer
Hc128Rng
instead, which, like ISAAC, is an array-based RNG and one of
the stream-ciphers selected the by eSTREAM contest.
Overview of the ISAAC-64 algorithm:
(in pseudo-code)
Input: a, b, c, s[256] // state
Output: r[256] // results
mix(a,i) = !(a ^ a << 21) if i = 0 mod 4
a ^ a >> 5 if i = 1 mod 4
a ^ a << 12 if i = 2 mod 4
a ^ a >> 33 if i = 3 mod 4
c = c + 1
b = b + c
for i in 0..256 {
x = s_[i]
a = mix(a,i) + s[i+128 mod 256]
y = a + b + s[x>>3 mod 256]
s[i] = y
b = x + s[y>>11 mod 256]
r[i] = b
}
This implementation uses BlockRng64
to implement the RngCore
methods.
See for more information the documentation of IsaacRng
.
-
Bob Jenkins, ISAAC and RC4 ↩
Methods
impl Isaac64Rng
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impl Isaac64Rng
pub fn new_from_u64(seed: u64) -> Self
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pub fn new_from_u64(seed: u64) -> Self
: use SeedableRng::seed_from_u64 instead
Create an ISAAC-64 random number generator using an u64
as seed.
If seed == 0
this will produce the same stream of random numbers as
the reference implementation when used unseeded.
Trait Implementations
impl Debug for Isaac64Rng
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impl Debug for Isaac64Rng
fn fmt(&self, f: &mut Formatter) -> Result
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fn fmt(&self, f: &mut Formatter) -> Result
Formats the value using the given formatter. Read more
impl Clone for Isaac64Rng
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impl Clone for Isaac64Rng
fn clone(&self) -> Isaac64Rng
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fn clone(&self) -> Isaac64Rng
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
1.0.0[src]
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source
. Read more
impl SeedableRng for Isaac64Rng
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impl SeedableRng for Isaac64Rng
type Seed = <Isaac64Core as SeedableRng>::Seed
Seed type, which is restricted to types mutably-dereferencable as u8
arrays (we recommend [u8; N]
for some N
). Read more
fn from_seed(seed: Self::Seed) -> Self
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fn from_seed(seed: Self::Seed) -> Self
Create a new PRNG using the given seed. Read more
fn seed_from_u64(seed: u64) -> Self
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fn seed_from_u64(seed: u64) -> Self
Create an ISAAC random number generator using an u64
as seed.
If seed == 0
this will produce the same stream of random numbers as
the reference implementation when used unseeded.
fn from_rng<S: RngCore>(rng: S) -> Result<Self, Error>
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fn from_rng<S: RngCore>(rng: S) -> Result<Self, Error>
Create a new PRNG seeded from another Rng
. Read more
impl RngCore for Isaac64Rng
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impl RngCore for Isaac64Rng
fn next_u32(&mut self) -> u32
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fn next_u32(&mut self) -> u32
Return the next random u32
. Read more
fn next_u64(&mut self) -> u64
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fn next_u64(&mut self) -> u64
Return the next random u64
. Read more
fn fill_bytes(&mut self, dest: &mut [u8])
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fn fill_bytes(&mut self, dest: &mut [u8])
Fill dest
with random data. Read more
fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error>
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fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error>
Fill dest
entirely with random data. Read more
Auto Trait Implementations
impl Send for Isaac64Rng
impl Send for Isaac64Rng
impl Sync for Isaac64Rng
impl Sync for Isaac64Rng
Blanket Implementations
impl<T, U> TryFrom for T where
T: From<U>,
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impl<T, U> TryFrom for T where
T: From<U>,
type Error = !
try_from
)The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
try_from
)Performs the conversion.
impl<T> From for T
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impl<T> From for T
impl<T, U> TryInto for T where
U: TryFrom<T>,
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impl<T, U> TryInto for T where
U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
try_from
)The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
try_from
)Performs the conversion.
impl<T, U> Into for T where
U: From<T>,
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impl<T, U> Into for T where
U: From<T>,
impl<T> Borrow for T where
T: ?Sized,
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impl<T> Borrow for T where
T: ?Sized,
impl<T> BorrowMut for T where
T: ?Sized,
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impl<T> BorrowMut for T where
T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
impl<T> Any for T where
T: 'static + ?Sized,
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impl<T> Any for T where
T: 'static + ?Sized,
fn get_type_id(&self) -> TypeId
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fn get_type_id(&self) -> TypeId
🔬 This is a nightly-only experimental API. (get_type_id
)
this method will likely be replaced by an associated static
Gets the TypeId
of self
. Read more
impl<T> ToOwned for T where
T: Clone,
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impl<T> ToOwned for T where
T: Clone,
type Owned = T
fn to_owned(&self) -> T
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fn to_owned(&self) -> T
Creates owned data from borrowed data, usually by cloning. Read more
fn clone_into(&self, target: &mut T)
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fn clone_into(&self, target: &mut T)
🔬 This is a nightly-only experimental API. (toowned_clone_into
)
recently added
Uses borrowed data to replace owned data, usually by cloning. Read more