Struct OrderedFloat

#[repr(transparent)]
pub struct OrderedFloat<T>(pub T);

Expand description

A wrapper around floats providing implementations of Eq, Ord, and Hash.

NaN is sorted as greater than all other values and equal to itself, in contradiction with the IEEE standard.

use ordered_float::OrderedFloat;
use std::f32::NAN;

let mut v = [OrderedFloat(NAN), OrderedFloat(2.0), OrderedFloat(1.0)];
v.sort();
assert_eq!(v, [OrderedFloat(1.0), OrderedFloat(2.0), OrderedFloat(NAN)]);

Because OrderedFloat implements Ord and Eq, it can be used as a key in a HashSet, HashMap, BTreeMap, or BTreeSet (unlike the primitive f32 or f64 types):

let mut s: HashSet<OrderedFloat<f32>> = HashSet::new();
s.insert(OrderedFloat(NAN));
assert!(s.contains(&OrderedFloat(NAN)));

Some non-identical values are still considered equal by the PartialEq implementation, and will therefore also be considered equal by maps, sets, and the == operator:

-0.0 and +0.0 are considered equal. This different sign may show up in printing, or when dividing by zero (the sign of the zero becomes the sign of the resulting infinity).
All NaN values are considered equal, even though they may have different bits, and therefore different sign, signaling/quiet status, and NaN payload bits.

Therefore, OrderedFloat may be unsuitable for use as a key in interning and memoization applications which require equal results from equal inputs, unless these cases make no difference or are canonicalized before insertion.

§Representation

OrderedFloat has #[repr(transparent)] and permits any value, so it is sound to use transmute or pointer casts to convert between any type T and OrderedFloat<T>. However, consider using bytemuck as a safe alternative if possible.

Tuple Fields§

§0: T

Implementations§

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impl<T> OrderedFloat<T>
where T: FloatCore,

pub fn into_inner(self) -> T

Get the value out.

Trait Implementations§

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impl<'a, T> Add<&'a OrderedFloat<T>> for OrderedFloat<T>
where T: Add<&'a T>,

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type Output = OrderedFloat<<T as Add<&'a T>>::Output>

The resulting type after applying the + operator.

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fn add( self, other: &'a OrderedFloat<T>, ) -> <OrderedFloat<T> as Add<&'a OrderedFloat<T>>>::Output

Performs the + operation. Read more

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impl<'a, T> Add<&'a T> for &'a OrderedFloat<T>
where &'a T: Add,

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type Output = OrderedFloat<<&'a T as Add>::Output>

The resulting type after applying the + operator.

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fn add(self, other: &'a T) -> <&'a OrderedFloat<T> as Add<&'a T>>::Output

Performs the + operation. Read more

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impl<'a, T> Add<&'a T> for OrderedFloat<T>
where T: Add<&'a T>,

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type Output = OrderedFloat<<T as Add<&'a T>>::Output>

The resulting type after applying the + operator.

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fn add(self, other: &'a T) -> <OrderedFloat<T> as Add<&'a T>>::Output

Performs the + operation. Read more

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impl<'a, T> Add<OrderedFloat<T>> for &'a OrderedFloat<T>
where &'a T: Add<T>,

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type Output = OrderedFloat<<&'a T as Add<T>>::Output>

The resulting type after applying the + operator.

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fn add( self, other: OrderedFloat<T>, ) -> <&'a OrderedFloat<T> as Add<OrderedFloat<T>>>::Output

Performs the + operation. Read more

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impl<'a, T> Add<T> for &'a OrderedFloat<T>
where &'a T: Add<T>,

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type Output = OrderedFloat<<&'a T as Add<T>>::Output>

The resulting type after applying the + operator.

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fn add(self, other: T) -> <&'a OrderedFloat<T> as Add<T>>::Output

Performs the + operation. Read more

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impl<T> Add<T> for OrderedFloat<T>
where T: Add,

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type Output = OrderedFloat<<T as Add>::Output>

The resulting type after applying the + operator.

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fn add(self, other: T) -> <OrderedFloat<T> as Add<T>>::Output

Performs the + operation. Read more

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impl<'a, T> Add for &'a OrderedFloat<T>
where T: Add + Copy,

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type Output = OrderedFloat<<T as Add>::Output>

The resulting type after applying the + operator.

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fn add(self, other: &'a OrderedFloat<T>) -> <&'a OrderedFloat<T> as Add>::Output

Performs the + operation. Read more

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impl<T> Add for OrderedFloat<T>
where T: Add,

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type Output = OrderedFloat<<T as Add>::Output>

The resulting type after applying the + operator.

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fn add(self, other: OrderedFloat<T>) -> <OrderedFloat<T> as Add>::Output

Performs the + operation. Read more

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impl<'a, T> AddAssign<&'a OrderedFloat<T>> for OrderedFloat<T>
where T: AddAssign<&'a T>,

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fn add_assign(&mut self, other: &'a OrderedFloat<T>)

Performs the += operation. Read more

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impl<'a, T> AddAssign<&'a T> for OrderedFloat<T>
where T: AddAssign<&'a T>,

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fn add_assign(&mut self, other: &'a T)

Performs the += operation. Read more

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impl<T> AddAssign<T> for OrderedFloat<T>
where T: AddAssign,

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fn add_assign(&mut self, other: T)

Performs the += operation. Read more

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impl<T> AddAssign for OrderedFloat<T>
where T: AddAssign,

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fn add_assign(&mut self, other: OrderedFloat<T>)

Performs the += operation. Read more

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impl<T> AsMut<T> for OrderedFloat<T>
where T: FloatCore,

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fn as_mut(&mut self) -> &mut T

Converts this type into a mutable reference of the (usually inferred) input type.

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