# 1.0.0[−]Primitive Type f64

The 64-bit floating point type.

See also the `std::f64` module.

## Methods

### `impl f64`[src]

#### `pub fn floor(self) -> f64`[src]

Returns the largest integer less than or equal to a number.

# Examples

```let f = 3.7_f64;
let g = 3.0_f64;
let h = -3.7_f64;

assert_eq!(f.floor(), 3.0);
assert_eq!(g.floor(), 3.0);
assert_eq!(h.floor(), -4.0);Run```

#### `pub fn ceil(self) -> f64`[src]

Returns the smallest integer greater than or equal to a number.

# Examples

```let f = 3.01_f64;
let g = 4.0_f64;

assert_eq!(f.ceil(), 4.0);
assert_eq!(g.ceil(), 4.0);Run```

#### `pub fn round(self) -> f64`[src]

Returns the nearest integer to a number. Round half-way cases away from `0.0`.

# Examples

```let f = 3.3_f64;
let g = -3.3_f64;

assert_eq!(f.round(), 3.0);
assert_eq!(g.round(), -3.0);Run```

#### `pub fn trunc(self) -> f64`[src]

Returns the integer part of a number.

# Examples

```let f = 3.7_f64;
let g = 3.0_f64;
let h = -3.7_f64;

assert_eq!(f.trunc(), 3.0);
assert_eq!(g.trunc(), 3.0);
assert_eq!(h.trunc(), -3.0);Run```

#### `pub fn fract(self) -> f64`[src]

Returns the fractional part of a number.

# Examples

```let x = 3.5_f64;
let y = -3.5_f64;
let abs_difference_x = (x.fract() - 0.5).abs();
let abs_difference_y = (y.fract() - (-0.5)).abs();

assert!(abs_difference_x < 1e-10);
assert!(abs_difference_y < 1e-10);Run```

#### `pub fn abs(self) -> f64`[src]

Computes the absolute value of `self`. Returns `NAN` if the number is `NAN`.

# Examples

```use std::f64;

let x = 3.5_f64;
let y = -3.5_f64;

let abs_difference_x = (x.abs() - x).abs();
let abs_difference_y = (y.abs() - (-y)).abs();

assert!(abs_difference_x < 1e-10);
assert!(abs_difference_y < 1e-10);

assert!(f64::NAN.abs().is_nan());Run```

#### `pub fn signum(self) -> f64`[src]

Returns a number that represents the sign of `self`.

• `1.0` if the number is positive, `+0.0` or `INFINITY`
• `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY`
• `NAN` if the number is `NAN`

# Examples

```use std::f64;

let f = 3.5_f64;

assert_eq!(f.signum(), 1.0);
assert_eq!(f64::NEG_INFINITY.signum(), -1.0);

assert!(f64::NAN.signum().is_nan());Run```

#### ```#[must_use] pub fn copysign(self, sign: f64) -> f64```1.35.0[src]

Returns a number composed of the magnitude of `self` and the sign of `sign`.

Equal to `self` if the sign of `self` and `sign` are the same, otherwise equal to `-self`. If `self` is a `NAN`, then a `NAN` with the sign of `sign` is returned.

# Examples

```use std::f64;

let f = 3.5_f64;

assert_eq!(f.copysign(0.42), 3.5_f64);
assert_eq!(f.copysign(-0.42), -3.5_f64);
assert_eq!((-f).copysign(0.42), 3.5_f64);
assert_eq!((-f).copysign(-0.42), -3.5_f64);

assert!(f64::NAN.copysign(1.0).is_nan());Run```

#### `pub fn mul_add(self, a: f64, b: f64) -> f64`[src]

Fused multiply-add. Computes `(self * a) + b` with only one rounding error, yielding a more accurate result than an unfused multiply-add.

Using `mul_add` can be more performant than an unfused multiply-add if the target architecture has a dedicated `fma` CPU instruction.

# Examples

```let m = 10.0_f64;
let x = 4.0_f64;
let b = 60.0_f64;

// 100.0
let abs_difference = (m.mul_add(x, b) - ((m * x) + b)).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn div_euclid(self, rhs: f64) -> f64`1.38.0[src]

Calculates Euclidean division, the matching method for `rem_euclid`.

This computes the integer `n` such that `self = n * rhs + self.rem_euclid(rhs)`. In other words, the result is `self / rhs` rounded to the integer `n` such that `self >= n * rhs`.

# Examples

```let a: f64 = 7.0;
let b = 4.0;
assert_eq!(a.div_euclid(b), 1.0); // 7.0 > 4.0 * 1.0
assert_eq!((-a).div_euclid(b), -2.0); // -7.0 >= 4.0 * -2.0
assert_eq!(a.div_euclid(-b), -1.0); // 7.0 >= -4.0 * -1.0
assert_eq!((-a).div_euclid(-b), 2.0); // -7.0 >= -4.0 * 2.0Run```

#### `pub fn rem_euclid(self, rhs: f64) -> f64`1.38.0[src]

Calculates the least nonnegative remainder of `self (mod rhs)`.

In particular, the return value `r` satisfies `0.0 <= r < rhs.abs()` in most cases. However, due to a floating point round-off error it can result in `r == rhs.abs()`, violating the mathematical definition, if `self` is much smaller than `rhs.abs()` in magnitude and `self < 0.0`. This result is not an element of the function's codomain, but it is the closest floating point number in the real numbers and thus fulfills the property `self == self.div_euclid(rhs) * rhs + self.rem_euclid(rhs)` approximatively.

# Examples

```let a: f64 = 7.0;
let b = 4.0;
assert_eq!(a.rem_euclid(b), 3.0);
assert_eq!((-a).rem_euclid(b), 1.0);
assert_eq!(a.rem_euclid(-b), 3.0);
assert_eq!((-a).rem_euclid(-b), 1.0);
// limitation due to round-off error
assert!((-std::f64::EPSILON).rem_euclid(3.0) != 0.0);Run```

#### `pub fn powi(self, n: i32) -> f64`[src]

Raises a number to an integer power.

Using this function is generally faster than using `powf`

# Examples

```let x = 2.0_f64;
let abs_difference = (x.powi(2) - (x * x)).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn powf(self, n: f64) -> f64`[src]

Raises a number to a floating point power.

# Examples

```let x = 2.0_f64;
let abs_difference = (x.powf(2.0) - (x * x)).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn sqrt(self) -> f64`[src]

Takes the square root of a number.

Returns NaN if `self` is a negative number.

# Examples

```let positive = 4.0_f64;
let negative = -4.0_f64;

let abs_difference = (positive.sqrt() - 2.0).abs();

assert!(abs_difference < 1e-10);
assert!(negative.sqrt().is_nan());Run```

#### `pub fn exp(self) -> f64`[src]

Returns `e^(self)`, (the exponential function).

# Examples

```let one = 1.0_f64;
// e^1
let e = one.exp();

// ln(e) - 1 == 0
let abs_difference = (e.ln() - 1.0).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn exp2(self) -> f64`[src]

Returns `2^(self)`.

# Examples

```let f = 2.0_f64;

// 2^2 - 4 == 0
let abs_difference = (f.exp2() - 4.0).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn ln(self) -> f64`[src]

Returns the natural logarithm of the number.

# Examples

```let one = 1.0_f64;
// e^1
let e = one.exp();

// ln(e) - 1 == 0
let abs_difference = (e.ln() - 1.0).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn log(self, base: f64) -> f64`[src]

Returns the logarithm of the number with respect to an arbitrary base.

The result may not be correctly rounded owing to implementation details; `self.log2()` can produce more accurate results for base 2, and `self.log10()` can produce more accurate results for base 10.

# Examples

```let five = 5.0_f64;

// log5(5) - 1 == 0
let abs_difference = (five.log(5.0) - 1.0).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn log2(self) -> f64`[src]

Returns the base 2 logarithm of the number.

# Examples

```let two = 2.0_f64;

// log2(2) - 1 == 0
let abs_difference = (two.log2() - 1.0).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn log10(self) -> f64`[src]

Returns the base 10 logarithm of the number.

# Examples

```let ten = 10.0_f64;

// log10(10) - 1 == 0
let abs_difference = (ten.log10() - 1.0).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn abs_sub(self, other: f64) -> f64`[src]

Deprecated since 1.10.0:

you probably meant `(self - other).abs()`: this operation is `(self - other).max(0.0)` except that `abs_sub` also propagates NaNs (also known as `fdim` in C). If you truly need the positive difference, consider using that expression or the C function `fdim`, depending on how you wish to handle NaN (please consider filing an issue describing your use-case too).

The positive difference of two numbers.

• If `self <= other`: `0:0`
• Else: `self - other`

# Examples

```let x = 3.0_f64;
let y = -3.0_f64;

let abs_difference_x = (x.abs_sub(1.0) - 2.0).abs();
let abs_difference_y = (y.abs_sub(1.0) - 0.0).abs();

assert!(abs_difference_x < 1e-10);
assert!(abs_difference_y < 1e-10);Run```

#### `pub fn cbrt(self) -> f64`[src]

Takes the cubic root of a number.

# Examples

```let x = 8.0_f64;

// x^(1/3) - 2 == 0
let abs_difference = (x.cbrt() - 2.0).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn hypot(self, other: f64) -> f64`[src]

Calculates the length of the hypotenuse of a right-angle triangle given legs of length `x` and `y`.

# Examples

```let x = 2.0_f64;
let y = 3.0_f64;

// sqrt(x^2 + y^2)
let abs_difference = (x.hypot(y) - (x.powi(2) + y.powi(2)).sqrt()).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn sin(self) -> f64`[src]

Computes the sine of a number (in radians).

# Examples

```use std::f64;

let x = f64::consts::FRAC_PI_2;

let abs_difference = (x.sin() - 1.0).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn cos(self) -> f64`[src]

Computes the cosine of a number (in radians).

# Examples

```use std::f64;

let x = 2.0 * f64::consts::PI;

let abs_difference = (x.cos() - 1.0).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn tan(self) -> f64`[src]

Computes the tangent of a number (in radians).

# Examples

```use std::f64;

let x = f64::consts::FRAC_PI_4;
let abs_difference = (x.tan() - 1.0).abs();

assert!(abs_difference < 1e-14);Run```

#### `pub fn asin(self) -> f64`[src]

Computes the arcsine of a number. Return value is in radians in the range [-pi/2, pi/2] or NaN if the number is outside the range [-1, 1].

# Examples

```use std::f64;

let f = f64::consts::FRAC_PI_2;

// asin(sin(pi/2))
let abs_difference = (f.sin().asin() - f64::consts::FRAC_PI_2).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn acos(self) -> f64`[src]

Computes the arccosine of a number. Return value is in radians in the range [0, pi] or NaN if the number is outside the range [-1, 1].

# Examples

```use std::f64;

let f = f64::consts::FRAC_PI_4;

// acos(cos(pi/4))
let abs_difference = (f.cos().acos() - f64::consts::FRAC_PI_4).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn atan(self) -> f64`[src]

Computes the arctangent of a number. Return value is in radians in the range [-pi/2, pi/2];

# Examples

```let f = 1.0_f64;

// atan(tan(1))
let abs_difference = (f.tan().atan() - 1.0).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn atan2(self, other: f64) -> f64`[src]

Computes the four quadrant arctangent of `self` (`y`) and `other` (`x`) in radians.

• `x = 0`, `y = 0`: `0`
• `x >= 0`: `arctan(y/x)` -> `[-pi/2, pi/2]`
• `y >= 0`: `arctan(y/x) + pi` -> `(pi/2, pi]`
• `y < 0`: `arctan(y/x) - pi` -> `(-pi, -pi/2)`

# Examples

```use std::f64;

// Positive angles measured counter-clockwise
// from positive x axis
// -pi/4 radians (45 deg clockwise)
let x1 = 3.0_f64;
let y1 = -3.0_f64;

// 3pi/4 radians (135 deg counter-clockwise)
let x2 = -3.0_f64;
let y2 = 3.0_f64;

let abs_difference_1 = (y1.atan2(x1) - (-f64::consts::FRAC_PI_4)).abs();
let abs_difference_2 = (y2.atan2(x2) - (3.0 * f64::consts::FRAC_PI_4)).abs();

assert!(abs_difference_1 < 1e-10);
assert!(abs_difference_2 < 1e-10);Run```

#### `pub fn sin_cos(self) -> (f64, f64)`[src]

Simultaneously computes the sine and cosine of the number, `x`. Returns `(sin(x), cos(x))`.

# Examples

```use std::f64;

let x = f64::consts::FRAC_PI_4;
let f = x.sin_cos();

let abs_difference_0 = (f.0 - x.sin()).abs();
let abs_difference_1 = (f.1 - x.cos()).abs();

assert!(abs_difference_0 < 1e-10);
assert!(abs_difference_1 < 1e-10);Run```

#### `pub fn exp_m1(self) -> f64`[src]

Returns `e^(self) - 1` in a way that is accurate even if the number is close to zero.

# Examples

```let x = 7.0_f64;

// e^(ln(7)) - 1
let abs_difference = (x.ln().exp_m1() - 6.0).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn ln_1p(self) -> f64`[src]

Returns `ln(1+n)` (natural logarithm) more accurately than if the operations were performed separately.

# Examples

```use std::f64;

let x = f64::consts::E - 1.0;

// ln(1 + (e - 1)) == ln(e) == 1
let abs_difference = (x.ln_1p() - 1.0).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn sinh(self) -> f64`[src]

Hyperbolic sine function.

# Examples

```use std::f64;

let e = f64::consts::E;
let x = 1.0_f64;

let f = x.sinh();
// Solving sinh() at 1 gives `(e^2-1)/(2e)`
let g = ((e * e) - 1.0) / (2.0 * e);
let abs_difference = (f - g).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn cosh(self) -> f64`[src]

Hyperbolic cosine function.

# Examples

```use std::f64;

let e = f64::consts::E;
let x = 1.0_f64;
let f = x.cosh();
// Solving cosh() at 1 gives this result
let g = ((e * e) + 1.0) / (2.0 * e);
let abs_difference = (f - g).abs();

// Same result
assert!(abs_difference < 1.0e-10);Run```

#### `pub fn tanh(self) -> f64`[src]

Hyperbolic tangent function.

# Examples

```use std::f64;

let e = f64::consts::E;
let x = 1.0_f64;

let f = x.tanh();
// Solving tanh() at 1 gives `(1 - e^(-2))/(1 + e^(-2))`
let g = (1.0 - e.powi(-2)) / (1.0 + e.powi(-2));
let abs_difference = (f - g).abs();

assert!(abs_difference < 1.0e-10);Run```

#### `pub fn asinh(self) -> f64`[src]

Inverse hyperbolic sine function.

# Examples

```let x = 1.0_f64;
let f = x.sinh().asinh();

let abs_difference = (f - x).abs();

assert!(abs_difference < 1.0e-10);Run```

#### `pub fn acosh(self) -> f64`[src]

Inverse hyperbolic cosine function.

# Examples

```let x = 1.0_f64;
let f = x.cosh().acosh();

let abs_difference = (f - x).abs();

assert!(abs_difference < 1.0e-10);Run```

#### `pub fn atanh(self) -> f64`[src]

Inverse hyperbolic tangent function.

# Examples

```use std::f64;

let e = f64::consts::E;
let f = e.tanh().atanh();

let abs_difference = (f - e).abs();

assert!(abs_difference < 1.0e-10);Run```

#### `pub fn clamp(self, min: f64, max: f64) -> f64`[src]

🔬 This is a nightly-only experimental API. (`clamp` #44095)

Restrict a value to a certain interval unless it is NaN.

Returns `max` if `self` is greater than `max`, and `min` if `self` is less than `min`. Otherwise this returns `self`.

Not that this function returns NaN if the initial value was NaN as well.

# Panics

Panics if `min > max`, `min` is NaN, or `max` is NaN.

# Examples

```#![feature(clamp)]
assert!((-3.0f64).clamp(-2.0, 1.0) == -2.0);
assert!((0.0f64).clamp(-2.0, 1.0) == 0.0);
assert!((2.0f64).clamp(-2.0, 1.0) == 1.0);
assert!((std::f64::NAN).clamp(-2.0, 1.0).is_nan());Run```

### `impl f64`[src]

#### `pub fn is_nan(self) -> bool`[src]

Returns `true` if this value is `NaN`.

```use std::f64;

let nan = f64::NAN;
let f = 7.0_f64;

assert!(nan.is_nan());
assert!(!f.is_nan());Run```

#### `pub fn is_infinite(self) -> bool`[src]

Returns `true` if this value is positive infinity or negative infinity, and `false` otherwise.

```use std::f64;

let f = 7.0f64;
let inf = f64::INFINITY;
let neg_inf = f64::NEG_INFINITY;
let nan = f64::NAN;

assert!(!f.is_infinite());
assert!(!nan.is_infinite());

assert!(inf.is_infinite());
assert!(neg_inf.is_infinite());Run```

#### `pub fn is_finite(self) -> bool`[src]

Returns `true` if this number is neither infinite nor `NaN`.

```use std::f64;

let f = 7.0f64;
let inf: f64 = f64::INFINITY;
let neg_inf: f64 = f64::NEG_INFINITY;
let nan: f64 = f64::NAN;

assert!(f.is_finite());

assert!(!nan.is_finite());
assert!(!inf.is_finite());
assert!(!neg_inf.is_finite());Run```

#### `pub fn is_normal(self) -> bool`[src]

Returns `true` if the number is neither zero, infinite, subnormal, or `NaN`.

```use std::f64;

let min = f64::MIN_POSITIVE; // 2.2250738585072014e-308f64
let max = f64::MAX;
let lower_than_min = 1.0e-308_f64;
let zero = 0.0f64;

assert!(min.is_normal());
assert!(max.is_normal());

assert!(!zero.is_normal());
assert!(!f64::NAN.is_normal());
assert!(!f64::INFINITY.is_normal());
// Values between `0` and `min` are Subnormal.
assert!(!lower_than_min.is_normal());Run```

#### `pub fn classify(self) -> FpCategory`[src]

Returns the floating point category of the number. If only one property is going to be tested, it is generally faster to use the specific predicate instead.

```use std::num::FpCategory;
use std::f64;

let num = 12.4_f64;
let inf = f64::INFINITY;

assert_eq!(num.classify(), FpCategory::Normal);
assert_eq!(inf.classify(), FpCategory::Infinite);Run```

#### `pub fn is_sign_positive(self) -> bool`[src]

Returns `true` if `self` has a positive sign, including `+0.0`, `NaN`s with positive sign bit and positive infinity.

```let f = 7.0_f64;
let g = -7.0_f64;

assert!(f.is_sign_positive());
assert!(!g.is_sign_positive());Run```

#### `pub fn is_sign_negative(self) -> bool`[src]

Returns `true` if `self` has a negative sign, including `-0.0`, `NaN`s with negative sign bit and negative infinity.

```let f = 7.0_f64;
let g = -7.0_f64;

assert!(!f.is_sign_negative());
assert!(g.is_sign_negative());Run```

#### `pub fn recip(self) -> f64`[src]

Takes the reciprocal (inverse) of a number, `1/x`.

```let x = 2.0_f64;
let abs_difference = (x.recip() - (1.0 / x)).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn to_degrees(self) -> f64`[src]

Converts radians to degrees.

```use std::f64::consts;

let angle = consts::PI;

let abs_difference = (angle.to_degrees() - 180.0).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn to_radians(self) -> f64`[src]

Converts degrees to radians.

```use std::f64::consts;

let angle = 180.0_f64;

let abs_difference = (angle.to_radians() - consts::PI).abs();

assert!(abs_difference < 1e-10);Run```

#### `pub fn max(self, other: f64) -> f64`[src]

Returns the maximum of the two numbers.

```let x = 1.0_f64;
let y = 2.0_f64;

assert_eq!(x.max(y), y);Run```

If one of the arguments is NaN, then the other argument is returned.

#### `pub fn min(self, other: f64) -> f64`[src]

Returns the minimum of the two numbers.

```let x = 1.0_f64;
let y = 2.0_f64;

assert_eq!(x.min(y), x);Run```

If one of the arguments is NaN, then the other argument is returned.

#### `pub fn to_bits(self) -> u64`1.20.0[src]

Raw transmutation to `u64`.

This is currently identical to `transmute::<f64, u64>(self)` on all platforms.

See `from_bits` for some discussion of the portability of this operation (there are almost no issues).

Note that this function is distinct from `as` casting, which attempts to preserve the numeric value, and not the bitwise value.

# Examples

```assert!((1f64).to_bits() != 1f64 as u64); // to_bits() is not casting!
assert_eq!((12.5f64).to_bits(), 0x4029000000000000);
Run```

#### `pub fn from_bits(v: u64) -> f64`1.20.0[src]

Raw transmutation from `u64`.

This is currently identical to `transmute::<u64, f64>(v)` on all platforms. It turns out this is incredibly portable, for two reasons:

• Floats and Ints have the same endianness on all supported platforms.
• IEEE-754 very precisely specifies the bit layout of floats.

However there is one caveat: prior to the 2008 version of IEEE-754, how to interpret the NaN signaling bit wasn't actually specified. Most platforms (notably x86 and ARM) picked the interpretation that was ultimately standardized in 2008, but some didn't (notably MIPS). As a result, all signaling NaNs on MIPS are quiet NaNs on x86, and vice-versa.

Rather than trying to preserve signaling-ness cross-platform, this implementation favours preserving the exact bits. This means that any payloads encoded in NaNs will be preserved even if the result of this method is sent over the network from an x86 machine to a MIPS one.

If the results of this method are only manipulated by the same architecture that produced them, then there is no portability concern.

If the input isn't NaN, then there is no portability concern.

If you don't care about signalingness (very likely), then there is no portability concern.

Note that this function is distinct from `as` casting, which attempts to preserve the numeric value, and not the bitwise value.

# Examples

```let v = f64::from_bits(0x4029000000000000);
assert_eq!(v, 12.5);Run```

#### `pub fn to_be_bytes(self) -> [u8; 8]`[src]

🔬 This is a nightly-only experimental API. (`float_to_from_bytes` #60446)

Return the memory representation of this floating point number as a byte array in big-endian (network) byte order.

# Examples

```#![feature(float_to_from_bytes)]
let bytes = 12.5f64.to_be_bytes();
assert_eq!(bytes, [0x40, 0x29, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]);Run```

#### `pub fn to_le_bytes(self) -> [u8; 8]`[src]

🔬 This is a nightly-only experimental API. (`float_to_from_bytes` #60446)

Return the memory representation of this floating point number as a byte array in little-endian byte order.

# Examples

```#![feature(float_to_from_bytes)]
let bytes = 12.5f64.to_le_bytes();
assert_eq!(bytes, [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x29, 0x40]);Run```

#### `pub fn to_ne_bytes(self) -> [u8; 8]`[src]

🔬 This is a nightly-only experimental API. (`float_to_from_bytes` #60446)

Return the memory representation of this floating point number as a byte array in native byte order.

As the target platform's native endianness is used, portable code should use `to_be_bytes` or `to_le_bytes`, as appropriate, instead.

# Examples

```#![feature(float_to_from_bytes)]
let bytes = 12.5f64.to_ne_bytes();
assert_eq!(
bytes,
if cfg!(target_endian = "big") {
[0x40, 0x29, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
} else {
[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x29, 0x40]
}
);Run```

#### `pub fn from_be_bytes(bytes: [u8; 8]) -> f64`[src]

🔬 This is a nightly-only experimental API. (`float_to_from_bytes` #60446)

Create a floating point value from its representation as a byte array in big endian.

# Examples

```#![feature(float_to_from_bytes)]
let value = f64::from_be_bytes([0x40, 0x29, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]);
assert_eq!(value, 12.5);Run```

#### `pub fn from_le_bytes(bytes: [u8; 8]) -> f64`[src]

🔬 This is a nightly-only experimental API. (`float_to_from_bytes` #60446)

Create a floating point value from its representation as a byte array in little endian.

# Examples

```#![feature(float_to_from_bytes)]
let value = f64::from_le_bytes([0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x29, 0x40]);
assert_eq!(value, 12.5);Run```

#### `pub fn from_ne_bytes(bytes: [u8; 8]) -> f64`[src]

🔬 This is a nightly-only experimental API. (`float_to_from_bytes` #60446)

Create a floating point value from its representation as a byte array in native endian.

As the target platform's native endianness is used, portable code likely wants to use `from_be_bytes` or `from_le_bytes`, as appropriate instead.

# Examples

```#![feature(float_to_from_bytes)]
let value = f64::from_ne_bytes(if cfg!(target_endian = "big") {
[0x40, 0x29, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
} else {
[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x29, 0x40]
});
assert_eq!(value, 12.5);Run```

## Trait Implementations

### `impl Neg for f64`[src]

#### `type Output = f64`

The resulting type after applying the `-` operator.

### `impl<'_> Neg for &'_ f64`[src]

#### `type Output = <f64 as Neg>::Output`

The resulting type after applying the `-` operator.

### `impl Rem<f64> for f64`[src]

The remainder from the division of two floats.

The remainder has the same sign as the dividend and is computed as: `x - (x / y).trunc() * y`.

# Examples

```let x: f32 = 50.50;
let y: f32 = 8.125;
let remainder = x - (x / y).trunc() * y;

// The answer to both operations is 1.75
assert_eq!(x % y, remainder);Run```

#### `type Output = f64`

The resulting type after applying the `%` operator.

### `impl<'_, '_> Rem<&'_ f64> for &'_ f64`[src]

#### `type Output = <f64 as Rem<f64>>::Output`

The resulting type after applying the `%` operator.

### `impl<'a> Rem<f64> for &'a f64`[src]

#### `type Output = <f64 as Rem<f64>>::Output`

The resulting type after applying the `%` operator.

### `impl<'_> Rem<&'_ f64> for f64`[src]

#### `type Output = <f64 as Rem<f64>>::Output`

The resulting type after applying the `%` operator.

### `impl Div<f64> for f64`[src]

#### `type Output = f64`

The resulting type after applying the `/` operator.

### `impl<'_> Div<&'_ f64> for f64`[src]

#### `type Output = <f64 as Div<f64>>::Output`

The resulting type after applying the `/` operator.

### `impl<'a> Div<f64> for &'a f64`[src]

#### `type Output = <f64 as Div<f64>>::Output`

The resulting type after applying the `/` operator.

### `impl<'_, '_> Div<&'_ f64> for &'_ f64`[src]

#### `type Output = <f64 as Div<f64>>::Output`

The resulting type after applying the `/` operator.

### `impl FromStr for f64`[src]

#### `type Err = ParseFloatError`

The associated error which can be returned from parsing.

#### `fn from_str(src: &str) -> Result<f64, ParseFloatError>`[src]

Converts a string in base 10 to a float. Accepts an optional decimal exponent.

This function accepts strings such as

• '3.14'
• '-3.14'
• '2.5E10', or equivalently, '2.5e10'
• '2.5E-10'
• '5.'
• '.5', or, equivalently, '0.5'
• 'inf', '-inf', 'NaN'

Leading and trailing whitespace represent an error.

# Grammar

All strings that adhere to the following EBNF grammar will result in an `Ok` being returned:

``````Float  ::= Sign? ( 'inf' | 'NaN' | Number )
Number ::= ( Digit+ |
Digit+ '.' Digit* |
Digit* '.' Digit+ ) Exp?
Exp    ::= [eE] Sign? Digit+
Sign   ::= [+-]
Digit  ::= [0-9]
``````

# Known bugs

In some situations, some strings that should create a valid float instead return an error. See issue #31407 for details.

# Arguments

• src - A string

# Return value

`Err(ParseFloatError)` if the string did not represent a valid number. Otherwise, `Ok(n)` where `n` is the floating-point number represented by `src`.

### `impl<'_> Mul<&'_ f64> for f64`[src]

#### `type Output = <f64 as Mul<f64>>::Output`

The resulting type after applying the `*` operator.

### `impl<'a> Mul<f64> for &'a f64`[src]

#### `type Output = <f64 as Mul<f64>>::Output`

The resulting type after applying the `*` operator.

### `impl Mul<f64> for f64`[src]

#### `type Output = f64`

The resulting type after applying the `*` operator.

### `impl<'_, '_> Mul<&'_ f64> for &'_ f64`[src]

#### `type Output = <f64 as Mul<f64>>::Output`

The resulting type after applying the `*` operator.

### `impl<'a> Sub<f64> for &'a f64`[src]

#### `type Output = <f64 as Sub<f64>>::Output`

The resulting type after applying the `-` operator.

### `impl<'_> Sub<&'_ f64> for f64`[src]

#### `type Output = <f64 as Sub<f64>>::Output`

The resulting type after applying the `-` operator.

### `impl Sub<f64> for f64`[src]

#### `type Output = f64`

The resulting type after applying the `-` operator.

### `impl<'_, '_> Sub<&'_ f64> for &'_ f64`[src]

#### `type Output = <f64 as Sub<f64>>::Output`

The resulting type after applying the `-` operator.

### `impl<'_> Add<&'_ f64> for f64`[src]

#### `type Output = <f64 as Add<f64>>::Output`

The resulting type after applying the `+` operator.

### `impl<'_, '_> Add<&'_ f64> for &'_ f64`[src]

#### `type Output = <f64 as Add<f64>>::Output`

The resulting type after applying the `+` operator.

### `impl<'a> Add<f64> for &'a f64`[src]

#### `type Output = <f64 as Add<f64>>::Output`

The resulting type after applying the `+` operator.

### `impl Add<f64> for f64`[src]

#### `type Output = f64`

The resulting type after applying the `+` operator.

### `impl From<f32> for f64`1.6.0[src]

Converts `f32` to `f64` losslessly.

### `impl From<i16> for f64`1.6.0[src]

Converts `i16` to `f64` losslessly.

### `impl From<u8> for f64`1.6.0[src]

Converts `u8` to `f64` losslessly.

### `impl From<u16> for f64`1.6.0[src]

Converts `u16` to `f64` losslessly.

### `impl From<i8> for f64`1.6.0[src]

Converts `i8` to `f64` losslessly.

### `impl From<i32> for f64`1.6.0[src]

Converts `i32` to `f64` losslessly.

### `impl From<u32> for f64`1.6.0[src]

Converts `u32` to `f64` losslessly.

### `impl Default for f64`[src]

#### `fn default() -> f64`[src]

Returns the default value of `0.0`

## Blanket Implementations

### `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.

### `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.

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

#### `type Owned = T`

The resulting type after obtaining ownership.