# [−][src]Struct rand_isaac::isaac64::Isaac64Rng

    pub struct 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`.

1. Bob Jenkins, ISAAC and RC4 ↩

## Methods

### `impl Isaac64Rng`[src]

#### `pub fn new_from_u64(seed: u64) -> Self`[src]

Deprecated since 0.6.0:

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`[src]

#### `fn fmt(&self, f: &mut Formatter) -> Result`[src]

Formats the value using the given formatter. Read more

### `impl Clone for Isaac64Rng`[src]

#### `fn clone(&self) -> Isaac64Rng`[src]

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`1.0.0[src]

Performs copy-assignment from `source`. Read more

### `impl SeedableRng for Isaac64Rng`[src]

#### `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`[src]

Create a new PRNG using the given seed. Read more

#### `fn seed_from_u64(seed: u64) -> Self`[src]

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>`[src]

Create a new PRNG seeded from another `Rng`. Read more

### `impl RngCore for Isaac64Rng`[src]

#### `fn next_u32(&mut self) -> u32`[src]

Return the next random `u32`. Read more

#### `fn next_u64(&mut self) -> u64`[src]

Return the next random `u64`. Read more

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

Fill `dest` with random data. Read more

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

Fill `dest` entirely with random data. Read more

## Auto Trait Implementations

### `impl Unpin for Isaac64Rng`

### `impl Send for Isaac64Rng`

### `impl Sync for Isaac64Rng`

### `impl UnwindSafe for Isaac64Rng`

### `impl RefUnwindSafe for Isaac64Rng`

## Blanket Implementations

### `impl<T> From<T> for T`[src]

#### `fn from(t: T) -> T`[src]

Performs the conversion.

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>`[src]

Performs the conversion.

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `fn into(self) -> U`[src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

#### `type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

#### `fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>`[src]

Performs the conversion.

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `fn borrow(&self) -> &T`[src]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `fn borrow_mut(&mut self) -> &mut T`[src]

Mutably borrows from an owned value. Read more

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `fn type_id(&self) -> TypeId`[src]

Gets the `TypeId` of `self`. Read more

### `impl<T> ToOwned for T where
T: Clone,` [src]

#### `type Owned = T`

The resulting type after obtaining ownership.

#### `fn to_owned(&self) -> T`[src]

Creates owned data from borrowed data, usually by cloning. Read more

#### `fn clone_into(&self, target: &mut T)`[src]

🔬 This is a nightly-only experimental API. (`toowned_clone_into`)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

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