Trait sp_std::ops::Add

1.0.0 · source · []
pub trait Add<Rhs = Self> {
    type Output;
    fn add(self, rhs: Rhs) -> Self::Output;
}
Expand description

The addition operator +.

Note that Rhs is Self by default, but this is not mandatory. For example, std::time::SystemTime implements Add<Duration>, which permits operations of the form SystemTime = SystemTime + Duration.

Examples

Addable points

use std::ops::Add;

#[derive(Debug, Copy, Clone, PartialEq)]
struct Point {
    x: i32,
    y: i32,
}

impl Add for Point {
    type Output = Self;

    fn add(self, other: Self) -> Self {
        Self {
            x: self.x + other.x,
            y: self.y + other.y,
        }
    }
}

assert_eq!(Point { x: 1, y: 0 } + Point { x: 2, y: 3 },
           Point { x: 3, y: 3 });

Implementing Add with generics

Here is an example of the same Point struct implementing the Add trait using generics.

use std::ops::Add;

#[derive(Debug, Copy, Clone, PartialEq)]
struct Point<T> {
    x: T,
    y: T,
}

// Notice that the implementation uses the associated type `Output`.
impl<T: Add<Output = T>> Add for Point<T> {
    type Output = Self;

    fn add(self, other: Self) -> Self::Output {
        Self {
            x: self.x + other.x,
            y: self.y + other.y,
        }
    }
}

assert_eq!(Point { x: 1, y: 0 } + Point { x: 2, y: 3 },
           Point { x: 3, y: 3 });

Associated Types

The resulting type after applying the + operator.

Required methods

Performs the + operation.

Example
assert_eq!(12 + 1, 13);

Implementations on Foreign Types

Panics

This function may panic if the resulting point in time cannot be represented by the underlying data structure. See SystemTime::checked_add for a version without panic.

Panics

This function may panic if the resulting point in time cannot be represented by the underlying data structure. See Instant::checked_add for a version without panic.

Implements the + operator for concatenating two strings.

This consumes the String on the left-hand side and re-uses its buffer (growing it if necessary). This is done to avoid allocating a new String and copying the entire contents on every operation, which would lead to O(n^2) running time when building an n-byte string by repeated concatenation.

The string on the right-hand side is only borrowed; its contents are copied into the returned String.

Examples

Concatenating two Strings takes the first by value and borrows the second:

let a = String::from("hello");
let b = String::from(" world");
let c = a + &b;
// `a` is moved and can no longer be used here.

If you want to keep using the first String, you can clone it and append to the clone instead:

let a = String::from("hello");
let b = String::from(" world");
let c = a.clone() + &b;
// `a` is still valid here.

Concatenating &str slices can be done by converting the first to a String:

let a = "hello";
let b = " world";
let c = a.to_string() + b;

Implementors

impl<Tz: TimeZone> Add<FixedOffset> for DateTime<Tz>

impl<Tz: TimeZone> Add<Duration> for Date<Tz>

impl<Tz: TimeZone> Add<Duration> for DateTime<Tz>

impl<'a, 'b> Add<&'b Scalar> for &'a Scalar

impl<'b> Add<&'b Scalar> for Scalar

impl<'a> Add<Scalar> for &'a Scalar

impl Add<Scalar> for Scalar

impl<'a, 'b> Add<&'b EdwardsPoint> for &'a EdwardsPoint

impl<'b> Add<&'b EdwardsPoint> for EdwardsPoint

impl<'a> Add<EdwardsPoint> for &'a EdwardsPoint

impl<'a, 'b> Add<&'b RistrettoPoint> for &'a RistrettoPoint

impl<T: Into<Self>> Add<T> for Bytes

impl<T: Into<Self>> Add<T> for Words

impl<T: Into<Self>> Add<T> for Pages

impl<T: Into<Self>> Add<T> for Words

impl<T: Into<Self>> Add<T> for Pages

impl Add<usize> for Dynamic

impl<'b, T, R1, C1, R2, C2, SA, SB> Add<&'b Matrix<T, R2, C2, SB>> for Matrix<T, R1, C1, SA> where
    R1: Dim,
    C1: Dim,
    R2: Dim,
    C2: Dim,
    T: Scalar + ClosedAdd,
    SA: Storage<T, R1, C1>,
    SB: Storage<T, R2, C2>,
    DefaultAllocator: SameShapeAllocator<T, R1, C1, R2, C2>,
    ShapeConstraint: SameNumberOfRows<R1, R2> + SameNumberOfColumns<C1, C2>, 

impl<'a, T, R1, C1, R2, C2, SA, SB> Add<Matrix<T, R2, C2, SB>> for &'a Matrix<T, R1, C1, SA> where
    R1: Dim,
    C1: Dim,
    R2: Dim,
    C2: Dim,
    T: Scalar + ClosedAdd,
    SA: Storage<T, R1, C1>,
    SB: Storage<T, R2, C2>,
    DefaultAllocator: SameShapeAllocator<T, R2, C2, R1, C1>,
    ShapeConstraint: SameNumberOfRows<R2, R1> + SameNumberOfColumns<C2, C1>, 

impl<T, R1, C1, R2, C2, SA, SB> Add<Matrix<T, R2, C2, SB>> for Matrix<T, R1, C1, SA> where
    R1: Dim,
    C1: Dim,
    R2: Dim,
    C2: Dim,
    T: Scalar + ClosedAdd,
    SA: Storage<T, R1, C1>,
    SB: Storage<T, R2, C2>,
    DefaultAllocator: SameShapeAllocator<T, R1, C1, R2, C2>,
    ShapeConstraint: SameNumberOfRows<R1, R2> + SameNumberOfColumns<C1, C2>, 

impl<'a, 'b, T, R1, C1, R2, C2, SA, SB> Add<&'b Matrix<T, R2, C2, SB>> for &'a Matrix<T, R1, C1, SA> where
    R1: Dim,
    C1: Dim,
    R2: Dim,
    C2: Dim,
    T: Scalar + ClosedAdd,
    SA: Storage<T, R1, C1>,
    SB: Storage<T, R2, C2>,
    DefaultAllocator: SameShapeAllocator<T, R1, C1, R2, C2>,
    ShapeConstraint: SameNumberOfRows<R1, R2> + SameNumberOfColumns<C1, C2>, 

impl<'a, 'b, T, D2, SB, const D1: usize> Add<&'b Matrix<T, D2, Const<1_usize>, SB>> for &'a Point<T, D1> where
    T: Scalar + ClosedAdd,
    ShapeConstraint: SameNumberOfRows<Const<D1>, D2, Representative = Const<D1>> + SameNumberOfColumns<U1, U1, Representative = U1>,
    D2: Dim,
    SB: Storage<T, D2>, 

impl<'a, T, D2, SB, const D1: usize> Add<Matrix<T, D2, Const<1_usize>, SB>> for &'a Point<T, D1> where
    T: Scalar + ClosedAdd,
    ShapeConstraint: SameNumberOfRows<Const<D1>, D2, Representative = Const<D1>> + SameNumberOfColumns<U1, U1, Representative = U1>,
    D2: Dim,
    SB: Storage<T, D2>, 

impl<'b, T, D2, SB, const D1: usize> Add<&'b Matrix<T, D2, Const<1_usize>, SB>> for Point<T, D1> where
    T: Scalar + ClosedAdd,
    ShapeConstraint: SameNumberOfRows<Const<D1>, D2, Representative = Const<D1>> + SameNumberOfColumns<U1, U1, Representative = U1>,
    D2: Dim,
    SB: Storage<T, D2>, 

impl<T, D2, SB, const D1: usize> Add<Matrix<T, D2, Const<1_usize>, SB>> for Point<T, D1> where
    T: Scalar + ClosedAdd,
    ShapeConstraint: SameNumberOfRows<Const<D1>, D2, Representative = Const<D1>> + SameNumberOfColumns<U1, U1, Representative = U1>,
    D2: Dim,
    SB: Storage<T, D2>, 

impl<'a, 'b, T: SimdRealField> Add<&'b Quaternion<T>> for &'a Quaternion<T> where
    T::Element: SimdRealField

impl<'a, T: SimdRealField> Add<Quaternion<T>> for &'a Quaternion<T> where
    T::Element: SimdRealField

impl<'b, T: SimdRealField> Add<&'b Quaternion<T>> for Quaternion<T> where
    T::Element: SimdRealField

impl<T: SimdRealField> Add<Quaternion<T>> for Quaternion<T> where
    T::Element: SimdRealField

impl<'a, 'b, T: SimdRealField> Add<&'b DualQuaternion<T>> for &'a DualQuaternion<T> where
    T::Element: SimdRealField

impl<'a, T: SimdRealField> Add<DualQuaternion<T>> for &'a DualQuaternion<T> where
    T::Element: SimdRealField

impl<'b, T: SimdRealField> Add<&'b DualQuaternion<T>> for DualQuaternion<T> where
    T::Element: SimdRealField

impl<T: SimdRealField> Add<DualQuaternion<T>> for DualQuaternion<T> where
    T::Element: SimdRealField

impl<'a, 'b> Add<&'b BigInt> for &'a BigInt

impl<'a> Add<BigInt> for &'a BigInt

impl<'a> Add<&'a BigInt> for BigInt

impl Add<BigInt> for BigInt

impl<'a> Add<&'a u8> for BigInt

impl<'a> Add<BigInt> for &'a u8

impl<'a> Add<u8> for &'a BigInt

impl<'a> Add<&'a BigInt> for u8

impl<'a, 'b> Add<&'b u8> for &'a BigInt

impl<'a, 'b> Add<&'a BigInt> for &'b u8

impl Add<u8> for BigInt

impl Add<BigInt> for u8

impl<'a> Add<&'a u16> for BigInt

impl<'a> Add<BigInt> for &'a u16

impl<'a> Add<u16> for &'a BigInt

impl<'a> Add<&'a BigInt> for u16

impl<'a, 'b> Add<&'b u16> for &'a BigInt

impl<'a, 'b> Add<&'a BigInt> for &'b u16

impl Add<u16> for BigInt

impl Add<BigInt> for u16

impl<'a> Add<&'a usize> for BigInt

impl<'a> Add<BigInt> for &'a usize

impl<'a> Add<usize> for &'a BigInt

impl<'a> Add<&'a BigInt> for usize

impl<'a, 'b> Add<&'b usize> for &'a BigInt

impl<'a, 'b> Add<&'a BigInt> for &'b usize

impl Add<usize> for BigInt

impl Add<BigInt> for usize

impl<'a> Add<&'a i8> for BigInt

impl<'a> Add<BigInt> for &'a i8

impl<'a> Add<i8> for &'a BigInt

impl<'a> Add<&'a BigInt> for i8

impl<'a, 'b> Add<&'b i8> for &'a BigInt

impl<'a, 'b> Add<&'a BigInt> for &'b i8

impl Add<i8> for BigInt

impl Add<BigInt> for i8

impl<'a> Add<&'a i16> for BigInt

impl<'a> Add<BigInt> for &'a i16

impl<'a> Add<i16> for &'a BigInt

impl<'a> Add<&'a BigInt> for i16

impl<'a, 'b> Add<&'b i16> for &'a BigInt

impl<'a, 'b> Add<&'a BigInt> for &'b i16

impl Add<i16> for BigInt

impl Add<BigInt> for i16

impl<'a> Add<&'a isize> for BigInt

impl<'a> Add<BigInt> for &'a isize

impl<'a> Add<isize> for &'a BigInt

impl<'a> Add<&'a BigInt> for isize

impl<'a, 'b> Add<&'b isize> for &'a BigInt

impl<'a, 'b> Add<&'a BigInt> for &'b isize

impl Add<isize> for BigInt

impl Add<BigInt> for isize

impl Add<BigInt> for u32

impl<'a> Add<&'a u32> for BigInt

impl<'a> Add<BigInt> for &'a u32

impl<'a> Add<u32> for &'a BigInt

impl<'a> Add<&'a BigInt> for u32

impl<'a, 'b> Add<&'b u32> for &'a BigInt

impl<'a, 'b> Add<&'a BigInt> for &'b u32

impl Add<BigInt> for u64

impl<'a> Add<&'a u64> for BigInt

impl<'a> Add<BigInt> for &'a u64

impl<'a> Add<u64> for &'a BigInt

impl<'a> Add<&'a BigInt> for u64

impl<'a, 'b> Add<&'b u64> for &'a BigInt

impl<'a, 'b> Add<&'a BigInt> for &'b u64

impl Add<BigInt> for u128

impl<'a> Add<&'a u128> for BigInt

impl<'a> Add<BigInt> for &'a u128

impl<'a> Add<u128> for &'a BigInt

impl<'a> Add<&'a BigInt> for u128

impl<'a, 'b> Add<&'b u128> for &'a BigInt

impl<'a, 'b> Add<&'a BigInt> for &'b u128

impl Add<u32> for BigInt

impl Add<u64> for BigInt

impl Add<u128> for BigInt

impl Add<BigInt> for i32

impl<'a> Add<&'a i32> for BigInt

impl<'a> Add<BigInt> for &'a i32

impl<'a> Add<i32> for &'a BigInt

impl<'a> Add<&'a BigInt> for i32

impl<'a, 'b> Add<&'b i32> for &'a BigInt

impl<'a, 'b> Add<&'a BigInt> for &'b i32

impl Add<BigInt> for i64

impl<'a> Add<&'a i64> for BigInt

impl<'a> Add<BigInt> for &'a i64

impl<'a> Add<i64> for &'a BigInt

impl<'a> Add<&'a BigInt> for i64

impl<'a, 'b> Add<&'b i64> for &'a BigInt

impl<'a, 'b> Add<&'a BigInt> for &'b i64

impl Add<BigInt> for i128

impl<'a> Add<&'a i128> for BigInt

impl<'a> Add<BigInt> for &'a i128

impl<'a> Add<i128> for &'a BigInt

impl<'a> Add<&'a BigInt> for i128

impl<'a, 'b> Add<&'b i128> for &'a BigInt

impl<'a, 'b> Add<&'a BigInt> for &'b i128

impl Add<i32> for BigInt

impl Add<i64> for BigInt

impl Add<i128> for BigInt

impl Add<BigUint> for BigUint

impl<'a> Add<BigUint> for &'a BigUint

impl<'a, 'b> Add<&'b BigUint> for &'a BigUint

impl<'a> Add<&'a BigUint> for BigUint

impl<'a> Add<&'a u8> for BigUint

impl<'a> Add<BigUint> for &'a u8

impl<'a> Add<u8> for &'a BigUint

impl<'a> Add<&'a BigUint> for u8

impl<'a, 'b> Add<&'b u8> for &'a BigUint

impl<'a, 'b> Add<&'a BigUint> for &'b u8

impl Add<u8> for BigUint

impl Add<BigUint> for u8

impl<'a> Add<&'a u16> for BigUint

impl<'a> Add<BigUint> for &'a u16

impl<'a> Add<u16> for &'a BigUint

impl<'a> Add<&'a BigUint> for u16

impl<'a, 'b> Add<&'b u16> for &'a BigUint

impl<'a, 'b> Add<&'a BigUint> for &'b u16

impl Add<u16> for BigUint

impl Add<BigUint> for u16

impl<'a> Add<&'a usize> for BigUint

impl<'a> Add<BigUint> for &'a usize

impl<'a> Add<usize> for &'a BigUint

impl<'a> Add<&'a BigUint> for usize

impl<'a, 'b> Add<&'b usize> for &'a BigUint

impl<'a, 'b> Add<&'a BigUint> for &'b usize

impl Add<usize> for BigUint

impl Add<BigUint> for usize

impl Add<BigUint> for u32

impl<'a> Add<&'a u32> for BigUint

impl<'a> Add<BigUint> for &'a u32

impl<'a> Add<u32> for &'a BigUint

impl<'a> Add<&'a BigUint> for u32

impl<'a, 'b> Add<&'b u32> for &'a BigUint

impl<'a, 'b> Add<&'a BigUint> for &'b u32

impl Add<BigUint> for u64

impl<'a> Add<&'a u64> for BigUint

impl<'a> Add<BigUint> for &'a u64

impl<'a> Add<u64> for &'a BigUint

impl<'a> Add<&'a BigUint> for u64

impl<'a, 'b> Add<&'b u64> for &'a BigUint

impl<'a, 'b> Add<&'a BigUint> for &'b u64

impl Add<BigUint> for u128

impl<'a> Add<&'a u128> for BigUint

impl<'a> Add<BigUint> for &'a u128

impl<'a> Add<u128> for &'a BigUint

impl<'a> Add<&'a BigUint> for u128

impl<'a, 'b> Add<&'b u128> for &'a BigUint

impl<'a, 'b> Add<&'a BigUint> for &'b u128

impl Add<u32> for BigUint

impl Add<u64> for BigUint

impl Add<u128> for BigUint

impl<'a, 'b, T: Clone + Num> Add<&'b Complex<T>> for &'a Complex<T>

impl<'a, T: Clone + Num> Add<Complex<T>> for &'a Complex<T>

impl<'a, T: Clone + Num> Add<&'a Complex<T>> for Complex<T>

impl<T: Clone + Num> Add<Complex<T>> for Complex<T>

impl<T: Clone + Num> Add<T> for Complex<T>

impl<'a, T: Clone + Num> Add<&'a T> for Complex<T>

impl<'a, T: Clone + Num> Add<T> for &'a Complex<T>

impl<'a, 'b, T: Clone + Num> Add<&'a T> for &'b Complex<T>

impl<'a> Add<&'a Complex<usize>> for usize

impl<'a> Add<Complex<usize>> for &'a usize

impl<'a, 'b> Add<&'a Complex<usize>> for &'b usize

impl<'a> Add<&'a Complex<u8>> for u8

impl<'a> Add<Complex<u8>> for &'a u8

impl<'a, 'b> Add<&'a Complex<u8>> for &'b u8

impl<'a> Add<&'a Complex<u16>> for u16

impl<'a> Add<Complex<u16>> for &'a u16

impl<'a, 'b> Add<&'a Complex<u16>> for &'b u16

impl<'a> Add<&'a Complex<u32>> for u32

impl<'a> Add<Complex<u32>> for &'a u32

impl<'a, 'b> Add<&'a Complex<u32>> for &'b u32

impl<'a> Add<&'a Complex<u64>> for u64

impl<'a> Add<Complex<u64>> for &'a u64

impl<'a, 'b> Add<&'a Complex<u64>> for &'b u64

impl<'a> Add<&'a Complex<u128>> for u128

impl<'a> Add<Complex<u128>> for &'a u128

impl<'a, 'b> Add<&'a Complex<u128>> for &'b u128

impl<'a> Add<&'a Complex<isize>> for isize

impl<'a> Add<Complex<isize>> for &'a isize

impl<'a, 'b> Add<&'a Complex<isize>> for &'b isize

impl<'a> Add<&'a Complex<i8>> for i8

impl<'a> Add<Complex<i8>> for &'a i8

impl<'a, 'b> Add<&'a Complex<i8>> for &'b i8

impl<'a> Add<&'a Complex<i16>> for i16

impl<'a> Add<Complex<i16>> for &'a i16

impl<'a, 'b> Add<&'a Complex<i16>> for &'b i16

impl<'a> Add<&'a Complex<i32>> for i32

impl<'a> Add<Complex<i32>> for &'a i32

impl<'a, 'b> Add<&'a Complex<i32>> for &'b i32

impl<'a> Add<&'a Complex<i64>> for i64

impl<'a> Add<Complex<i64>> for &'a i64

impl<'a, 'b> Add<&'a Complex<i64>> for &'b i64

impl<'a> Add<&'a Complex<i128>> for i128

impl<'a> Add<Complex<i128>> for &'a i128

impl<'a, 'b> Add<&'a Complex<i128>> for &'b i128

impl<'a> Add<&'a Complex<f32>> for f32

impl<'a> Add<Complex<f32>> for &'a f32

impl<'a, 'b> Add<&'a Complex<f32>> for &'b f32

impl<'a> Add<&'a Complex<f64>> for f64

impl<'a> Add<Complex<f64>> for &'a f64

impl<'a, 'b> Add<&'a Complex<f64>> for &'b f64

impl Add<Complex<usize>> for usize

impl Add<Complex<u8>> for u8

impl Add<Complex<u16>> for u16

impl Add<Complex<u32>> for u32

impl Add<Complex<u64>> for u64

impl Add<Complex<u128>> for u128

impl Add<Complex<isize>> for isize

impl Add<Complex<i8>> for i8

impl Add<Complex<i16>> for i16

impl Add<Complex<i32>> for i32

impl Add<Complex<i64>> for i64

impl Add<Complex<i128>> for i128

impl Add<Complex<f32>> for f32

impl Add<Complex<f64>> for f64

impl<'a, 'b, T: Clone + Integer> Add<&'b Ratio<T>> for &'a Ratio<T>

impl<'a, 'b, T: Clone + Integer> Add<&'b T> for &'a Ratio<T>

impl<'a, T> Add<Ratio<T>> for &'a Ratio<T> where
    T: Clone + Integer

impl<'a, T> Add<T> for &'a Ratio<T> where
    T: Clone + Integer

impl<'a, T> Add<&'a Ratio<T>> for Ratio<T> where
    T: Clone + Integer

impl<'a, T> Add<&'a T> for Ratio<T> where
    T: Clone + Integer

impl<T: Clone + Integer> Add<Ratio<T>> for Ratio<T>

impl<T: Clone + Integer> Add<T> for Ratio<T>

impl<T> Add<T> for U128 where
    T: Into<U128>, 

impl<'a, T> Add<T> for &'a U128 where
    T: Into<U128>, 

impl<T> Add<T> for U256 where
    T: Into<U256>, 

impl<'a, T> Add<T> for &'a U256 where
    T: Into<U256>, 

impl<T> Add<T> for U512 where
    T: Into<U512>, 

impl<'a, T> Add<T> for &'a U512 where
    T: Into<U512>, 

impl Add<Field> for Field

impl<'a, 'b> Add<&'a Field> for &'b Field

impl Add<Scalar> for Scalar

impl<'a, 'b> Add<&'a Scalar> for &'b Scalar

impl Add<BigUint> for BigUint

impl Add<Slot> for Slot

impl Add<u64> for Slot

impl Add<Duration> for Tm

impl Add<Duration> for Instant

impl<I: Integer> Add<I> for Z0

impl<U: Unsigned + NonZero> Add<Z0> for PInt<U>

impl<U: Unsigned + NonZero> Add<Z0> for NInt<U>

impl<Ul: Unsigned + NonZero, Ur: Unsigned + NonZero> Add<PInt<Ur>> for PInt<Ul> where
    Ul: Add<Ur>,
    <Ul as Add<Ur>>::Output: Unsigned + NonZero

impl<Ul: Unsigned + NonZero, Ur: Unsigned + NonZero> Add<NInt<Ur>> for NInt<Ul> where
    Ul: Add<Ur>,
    <Ul as Add<Ur>>::Output: Unsigned + NonZero

impl<Ul: Unsigned + NonZero, Ur: Unsigned + NonZero> Add<NInt<Ur>> for PInt<Ul> where
    Ul: Cmp<Ur> + PrivateIntegerAdd<<Ul as Cmp<Ur>>::Output, Ur>, 

impl<Ul: Unsigned + NonZero, Ur: Unsigned + NonZero> Add<PInt<Ur>> for NInt<Ul> where
    Ur: Cmp<Ul> + PrivateIntegerAdd<<Ur as Cmp<Ul>>::Output, Ul>, 

impl Add<B0> for UTerm

impl<U: Unsigned, B: Bit> Add<B0> for UInt<U, B>

impl Add<B1> for UTerm

impl<U: Unsigned> Add<B1> for UInt<U, B0>

impl<U: Unsigned> Add<B1> for UInt<U, B1> where
    U: Add<B1>,
    Add1<U>: Unsigned

impl<U: Unsigned> Add<U> for UTerm

impl<U: Unsigned, B: Bit> Add<UTerm> for UInt<U, B>

impl<Ul: Unsigned, Ur: Unsigned> Add<UInt<Ur, B0>> for UInt<Ul, B0> where
    Ul: Add<Ur>, 

impl<Ul: Unsigned, Ur: Unsigned> Add<UInt<Ur, B1>> for UInt<Ul, B0> where
    Ul: Add<Ur>, 

impl<Ul: Unsigned, Ur: Unsigned> Add<UInt<Ur, B0>> for UInt<Ul, B1> where
    Ul: Add<Ur>, 

impl<Ul: Unsigned, Ur: Unsigned> Add<UInt<Ur, B1>> for UInt<Ul, B1> where
    Ul: Add<Ur>,
    Sum<Ul, Ur>: Add<B1>, 

impl Add<ATerm> for ATerm

impl<Al, Vl, Ar, Vr> Add<TArr<Vr, Ar>> for TArr<Vl, Al> where
    Al: Add<Ar>,
    Vl: Add<Vr>, 

impl<T: Into<F32>> Add<T> for F32

impl<T: Into<F64>> Add<T> for F64