# [−][src]Struct rand::distributions::uniform::UniformInt

    pub struct UniformInt<X> { /* fields omitted */ }

The back-end implementing [`UniformSampler`] for integer types.

Unless you are implementing [`UniformSampler`] for your own type, this type should not be used directly, use [`Uniform`] instead.

# Implementation notes

For a closed range, the number of possible numbers we should generate is `range = (high - low + 1)`. It is not possible to end up with a uniform distribution if we map all the random integers that can be generated to this range. We have to map integers from a `zone` that is a multiple of the range. The rest of the integers, that cause a bias, are rejected.

The problem with `range` is that to cover the full range of the type, it has to store `unsigned_max + 1`, which can't be represented. But if the range covers the full range of the type, no modulus is needed. A range of size 0 can't exist, so we use that to represent this special case. Wrapping arithmetic even makes representing `unsigned_max + 1` as 0 simple.

We don't calculate `zone` directly, but first calculate the number of integers to reject. To handle `unsigned_max + 1` not fitting in the type, we use: `ints_to_reject = (unsigned_max + 1) % range;` `ints_to_reject = (unsigned_max - range + 1) % range;`

The smallest integer PRNGs generate is `u32`. That is why for small integer sizes (`i8`/`u8` and `i16`/`u16`) there is an optimization: don't pick the largest zone that can fit in the small type, but pick the largest zone that can fit in an `u32`. `ints_to_reject` is always less than half the size of the small integer. This means the first bit of `zone` is always 1, and so are all the other preceding bits of a larger integer. The easiest way to grow the `zone` for the larger type is to simply sign extend it.

An alternative to using a modulus is widening multiply: After a widening multiply by `range`, the result is in the high word. Then comparing the low word against `zone` makes sure our distribution is uniform.

## Trait Implementations

### `impl UniformSampler for UniformInt<i8>`[src]

#### `type X = i8`

The type sampled by this implementation.

#### `fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

#### `fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive bounds `[low, high]`. Read more

#### `fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X`[src]

Sample a value.

#### `fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

### `impl UniformSampler for UniformInt<i16>`[src]

#### `type X = i16`

The type sampled by this implementation.

#### `fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

#### `fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive bounds `[low, high]`. Read more

#### `fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X`[src]

Sample a value.

#### `fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

### `impl UniformSampler for UniformInt<i32>`[src]

#### `type X = i32`

The type sampled by this implementation.

#### `fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

#### `fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive bounds `[low, high]`. Read more

#### `fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X`[src]

Sample a value.

#### `fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

### `impl UniformSampler for UniformInt<i64>`[src]

#### `type X = i64`

The type sampled by this implementation.

#### `fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

#### `fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive bounds `[low, high]`. Read more

#### `fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X`[src]

Sample a value.

#### `fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

### `impl UniformSampler for UniformInt<i128>`[src]

#### `type X = i128`

The type sampled by this implementation.

#### `fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

#### `fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive bounds `[low, high]`. Read more

#### `fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X`[src]

Sample a value.

#### `fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

### `impl UniformSampler for UniformInt<isize>`[src]

#### `type X = isize`

The type sampled by this implementation.

#### `fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

#### `fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive bounds `[low, high]`. Read more

#### `fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X`[src]

Sample a value.

#### `fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

### `impl UniformSampler for UniformInt<u8>`[src]

#### `type X = u8`

The type sampled by this implementation.

#### `fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

#### `fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive bounds `[low, high]`. Read more

#### `fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X`[src]

Sample a value.

#### `fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

### `impl UniformSampler for UniformInt<u16>`[src]

#### `type X = u16`

The type sampled by this implementation.

#### `fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

#### `fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive bounds `[low, high]`. Read more

#### `fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X`[src]

Sample a value.

#### `fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

### `impl UniformSampler for UniformInt<u32>`[src]

#### `type X = u32`

The type sampled by this implementation.

#### `fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

#### `fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive bounds `[low, high]`. Read more

#### `fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X`[src]

Sample a value.

#### `fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

### `impl UniformSampler for UniformInt<u64>`[src]

#### `type X = u64`

The type sampled by this implementation.

#### `fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

#### `fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive bounds `[low, high]`. Read more

#### `fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X`[src]

Sample a value.

#### `fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

### `impl UniformSampler for UniformInt<usize>`[src]

#### `type X = usize`

The type sampled by this implementation.

#### `fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

#### `fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive bounds `[low, high]`. Read more

#### `fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X`[src]

Sample a value.

#### `fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

### `impl UniformSampler for UniformInt<u128>`[src]

#### `type X = u128`

The type sampled by this implementation.

#### `fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

#### `fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Construct self, with inclusive bounds `[low, high]`. Read more

#### `fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X`[src]

Sample a value.

#### `fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,` [src]

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

### `impl<X: Clone> Clone for UniformInt<X>`[src]

#### `fn clone(&self) -> UniformInt<X>`[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<X: Copy> Copy for UniformInt<X>`[src]

### `impl<X: Debug> Debug for UniformInt<X>`[src]

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

Formats the value using the given formatter. Read more

## Auto Trait Implementations

### `impl<X> Send for UniformInt<X> where
X: Send,`

### `impl<X> Unpin for UniformInt<X> where
X: Unpin,`

### `impl<X> Sync for UniformInt<X> where
X: Sync,`

### `impl<X> UnwindSafe for UniformInt<X> where
X: UnwindSafe,`

### `impl<X> RefUnwindSafe for UniformInt<X> where
X: RefUnwindSafe,`

## Blanket Implementations

### `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

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

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

Performs the conversion.

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

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

Immutably 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

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