# Primitive Type f128

`f128`

#116909)## Expand description

A 128-bit floating point type (specifically, the “binary128” type defined in IEEE 754-2008).

This type is very similar to `f32`

and `f64`

, but has increased precision by using twice
as many bits as `f64`

. Please see [the documentation for `f32`

or Wikipedia on
quad-precision values for more information.

Note that no platforms have hardware support for `f128`

without enabling target specific features,
as for all instruction set architectures `f128`

is considered an optional feature.
Only Power ISA (“PowerPC”) and RISCV specify it, and only certain microarchitectures
actually implement it. For x86-64 and AArch64, ISA support is not even specified,
so it will always be a software implementation significantly slower than `f64`

.

*Note: f128 support is incomplete. Many platforms will not be able to link math functions. On
x86 in particular, these functions do link but their results are always incorrect.*

## Implementations§

source§### impl f128

### impl f128

source#### pub fn round(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn round(self) -> f128

`f128`

#116909)Returns the nearest integer to `self`

. If a value is half-way between two
integers, round away from `0.0`

.

This function always returns the precise result.

##### §Examples

```
#![feature(f128)]
let f = 3.3_f128;
let g = -3.3_f128;
let h = -3.7_f128;
let i = 3.5_f128;
let j = 4.5_f128;
assert_eq!(f.round(), 3.0);
assert_eq!(g.round(), -3.0);
assert_eq!(h.round(), -4.0);
assert_eq!(i.round(), 4.0);
assert_eq!(j.round(), 5.0);
```

Runsource#### pub fn round_ties_even(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn round_ties_even(self) -> f128

`f128`

#116909)Returns the nearest integer to a number. Rounds half-way cases to the number with an even least significant digit.

This function always returns the precise result.

##### §Examples

```
#![feature(f128)]
let f = 3.3_f128;
let g = -3.3_f128;
let h = 3.5_f128;
let i = 4.5_f128;
assert_eq!(f.round_ties_even(), 3.0);
assert_eq!(g.round_ties_even(), -3.0);
assert_eq!(h.round_ties_even(), 4.0);
assert_eq!(i.round_ties_even(), 4.0);
```

Runsource#### pub fn trunc(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn trunc(self) -> f128

`f128`

#116909)Returns the integer part of `self`

.
This means that non-integer numbers are always truncated towards zero.

This function always returns the precise result.

##### §Examples

```
#![feature(f128)]
let f = 3.7_f128;
let g = 3.0_f128;
let h = -3.7_f128;
assert_eq!(f.trunc(), 3.0);
assert_eq!(g.trunc(), 3.0);
assert_eq!(h.trunc(), -3.0);
```

Runsource#### pub fn fract(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn fract(self) -> f128

`f128`

#116909)Returns the fractional part of `self`

.

This function always returns the precise result.

##### §Examples

```
#![feature(f128)]
let x = 3.6_f128;
let y = -3.6_f128;
let abs_difference_x = (x.fract() - 0.6).abs();
let abs_difference_y = (y.fract() - (-0.6)).abs();
assert!(abs_difference_x <= f128::EPSILON);
assert!(abs_difference_y <= f128::EPSILON);
```

Runsource#### pub fn signum(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn signum(self) -> f128

`f128`

#116909)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

```
#![feature(f128)]
let f = 3.5_f128;
assert_eq!(f.signum(), 1.0);
assert_eq!(f128::NEG_INFINITY.signum(), -1.0);
assert!(f128::NAN.signum().is_nan());
```

Runsource#### pub fn copysign(self, sign: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn copysign(self, sign: f128) -> f128

`f128`

#116909)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 bit of
`sign`

is returned. Note, however, that conserving the sign bit on NaN
across arithmetical operations is not generally guaranteed.
See explanation of NaN as a special value for more info.

##### §Examples

```
#![feature(f128)]
let f = 3.5_f128;
assert_eq!(f.copysign(0.42), 3.5_f128);
assert_eq!(f.copysign(-0.42), -3.5_f128);
assert_eq!((-f).copysign(0.42), 3.5_f128);
assert_eq!((-f).copysign(-0.42), -3.5_f128);
assert!(f128::NAN.copysign(1.0).is_nan());
```

Runsource#### pub fn mul_add(self, a: f128, b: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn mul_add(self, a: f128, b: f128) -> f128

`f128`

#116909)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`

*may* be more performant than an unfused multiply-add if
the target architecture has a dedicated `fma`

CPU instruction. However,
this is not always true, and will be heavily dependant on designing
algorithms with specific target hardware in mind.

##### §Precision

The result of this operation is guaranteed to be the rounded
infinite-precision result. It is specified by IEEE 754 as
`fusedMultiplyAdd`

and guaranteed not to change.

##### §Examples

```
#![feature(f128)]
let m = 10.0_f128;
let x = 4.0_f128;
let b = 60.0_f128;
assert_eq!(m.mul_add(x, b), 100.0);
assert_eq!(m * x + b, 100.0);
let one_plus_eps = 1.0_f128 + f128::EPSILON;
let one_minus_eps = 1.0_f128 - f128::EPSILON;
let minus_one = -1.0_f128;
// The exact result (1 + eps) * (1 - eps) = 1 - eps * eps.
assert_eq!(one_plus_eps.mul_add(one_minus_eps, minus_one), -f128::EPSILON * f128::EPSILON);
// Different rounding with the non-fused multiply and add.
assert_eq!(one_plus_eps * one_minus_eps + minus_one, 0.0);
```

Runsource#### pub fn div_euclid(self, rhs: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn div_euclid(self, rhs: f128) -> f128

`f128`

#116909)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`

.

##### §Precision

The result of this operation is guaranteed to be the rounded infinite-precision result.

##### §Examples

```
#![feature(f128)]
let a: f128 = 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 * 2.0
```

Runsource#### pub fn rem_euclid(self, rhs: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn rem_euclid(self, rhs: f128) -> f128

`f128`

#116909)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)`

approximately.

##### §Precision

The result of this operation is guaranteed to be the rounded infinite-precision result.

##### §Examples

```
#![feature(f128)]
let a: f128 = 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!((-f128::EPSILON).rem_euclid(3.0) != 0.0);
```

Runsource#### pub fn powi(self, n: i32) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn powi(self, n: i32) -> f128

`f128`

#116909)Raises a number to an integer power.

Using this function is generally faster than using `powf`

.
It might have a different sequence of rounding operations than `powf`

,
so the results are not guaranteed to agree.

##### §Unspecified precision

The precision of this function is non-deterministic. This means it varies by platform, Rust version, and can even differ within the same execution from one invocation to the next.

source#### pub fn powf(self, n: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn powf(self, n: f128) -> f128

`f128`

#116909)Raises a number to a floating point power.

##### §Unspecified precision

The precision of this function is non-deterministic. This means it varies by platform, Rust version, and can even differ within the same execution from one invocation to the next.

##### §Examples

```
#![feature(f128)]
let x = 2.0_f128;
let abs_difference = (x.powf(2.0) - (x * x)).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn sqrt(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn sqrt(self) -> f128

`f128`

#116909)Returns the square root of a number.

Returns NaN if `self`

is a negative number other than `-0.0`

.

##### §Precision

The result of this operation is guaranteed to be the rounded
infinite-precision result. It is specified by IEEE 754 as `squareRoot`

and guaranteed not to change.

##### §Examples

```
#![feature(f128)]
let positive = 4.0_f128;
let negative = -4.0_f128;
let negative_zero = -0.0_f128;
assert_eq!(positive.sqrt(), 2.0);
assert!(negative.sqrt().is_nan());
assert!(negative_zero.sqrt() == negative_zero);
```

Runsource#### pub fn exp(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn exp(self) -> f128

`f128`

#116909)Returns `e^(self)`

, (the exponential function).

##### §Unspecified precision

The precision of this function is non-deterministic. This means it varies by platform, Rust version, and can even differ within the same execution from one invocation to the next.

##### §Examples

```
#![feature(f128)]
let one = 1.0f128;
// e^1
let e = one.exp();
// ln(e) - 1 == 0
let abs_difference = (e.ln() - 1.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn exp2(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn exp2(self) -> f128

`f128`

#116909)Returns `2^(self)`

.

##### §Unspecified precision

##### §Examples

```
#![feature(f128)]
let f = 2.0f128;
// 2^2 - 4 == 0
let abs_difference = (f.exp2() - 4.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn ln(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn ln(self) -> f128

`f128`

#116909)Returns the natural logarithm of the number.

##### §Unspecified precision

##### §Examples

```
#![feature(f128)]
let one = 1.0f128;
// e^1
let e = one.exp();
// ln(e) - 1 == 0
let abs_difference = (e.ln() - 1.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn log(self, base: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn log(self, base: f128) -> f128

`f128`

#116909)Returns the logarithm of the number with respect to an arbitrary base.

The result might 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.

##### §Unspecified precision

##### §Examples

```
#![feature(f128)]
let five = 5.0f128;
// log5(5) - 1 == 0
let abs_difference = (five.log(5.0) - 1.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn log2(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn log2(self) -> f128

`f128`

#116909)Returns the base 2 logarithm of the number.

##### §Unspecified precision

##### §Examples

```
#![feature(f128)]
let two = 2.0f128;
// log2(2) - 1 == 0
let abs_difference = (two.log2() - 1.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn log10(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn log10(self) -> f128

`f128`

#116909)Returns the base 10 logarithm of the number.

##### §Unspecified precision

##### §Examples

```
#![feature(f128)]
let ten = 10.0f128;
// log10(10) - 1 == 0
let abs_difference = (ten.log10() - 1.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn cbrt(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn cbrt(self) -> f128

`f128`

#116909)Returns the cube root of a number.

##### §Unspecified precision

This function currently corresponds to the `cbrtf128`

from libc on Unix
and Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
let x = 8.0f128;
// x^(1/3) - 2 == 0
let abs_difference = (x.cbrt() - 2.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn hypot(self, other: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn hypot(self, other: f128) -> f128

`f128`

#116909)Compute the distance between the origin and a point (`x`

, `y`

) on the
Euclidean plane. Equivalently, compute the length of the hypotenuse of a
right-angle triangle with other sides having length `x.abs()`

and
`y.abs()`

.

##### §Unspecified precision

This function currently corresponds to the `hypotf128`

from libc on Unix
and Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
let x = 2.0f128;
let y = 3.0f128;
// sqrt(x^2 + y^2)
let abs_difference = (x.hypot(y) - (x.powi(2) + y.powi(2)).sqrt()).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn sin(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn sin(self) -> f128

`f128`

#116909)Computes the sine of a number (in radians).

##### §Unspecified precision

##### §Examples

```
#![feature(f128)]
let x = std::f128::consts::FRAC_PI_2;
let abs_difference = (x.sin() - 1.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn cos(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn cos(self) -> f128

`f128`

#116909)Computes the cosine of a number (in radians).

##### §Unspecified precision

##### §Examples

```
#![feature(f128)]
let x = 2.0 * std::f128::consts::PI;
let abs_difference = (x.cos() - 1.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn tan(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn tan(self) -> f128

`f128`

#116909)Computes the tangent of a number (in radians).

##### §Unspecified precision

This function currently corresponds to the `tanf128`

from libc on Unix and
Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
let x = std::f128::consts::FRAC_PI_4;
let abs_difference = (x.tan() - 1.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn asin(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn asin(self) -> f128

`f128`

#116909)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].

##### §Unspecified precision

This function currently corresponds to the `asinf128`

from libc on Unix
and Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
let f = std::f128::consts::FRAC_PI_2;
// asin(sin(pi/2))
let abs_difference = (f.sin().asin() - std::f128::consts::FRAC_PI_2).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn acos(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn acos(self) -> f128

`f128`

#116909)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].

##### §Unspecified precision

This function currently corresponds to the `acosf128`

from libc on Unix
and Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
let f = std::f128::consts::FRAC_PI_4;
// acos(cos(pi/4))
let abs_difference = (f.cos().acos() - std::f128::consts::FRAC_PI_4).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn atan(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn atan(self) -> f128

`f128`

#116909)Computes the arctangent of a number. Return value is in radians in the range [-pi/2, pi/2];

##### §Unspecified precision

This function currently corresponds to the `atanf128`

from libc on Unix
and Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
let f = 1.0f128;
// atan(tan(1))
let abs_difference = (f.tan().atan() - 1.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn atan2(self, other: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn atan2(self, other: f128) -> f128

`f128`

#116909)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)`

##### §Unspecified precision

This function currently corresponds to the `atan2f128`

from libc on Unix
and Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
// Positive angles measured counter-clockwise
// from positive x axis
// -pi/4 radians (45 deg clockwise)
let x1 = 3.0f128;
let y1 = -3.0f128;
// 3pi/4 radians (135 deg counter-clockwise)
let x2 = -3.0f128;
let y2 = 3.0f128;
let abs_difference_1 = (y1.atan2(x1) - (-std::f128::consts::FRAC_PI_4)).abs();
let abs_difference_2 = (y2.atan2(x2) - (3.0 * std::f128::consts::FRAC_PI_4)).abs();
assert!(abs_difference_1 <= f128::EPSILON);
assert!(abs_difference_2 <= f128::EPSILON);
```

Runsource#### pub fn sin_cos(self) -> (f128, f128)

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn sin_cos(self) -> (f128, f128)

`f128`

#116909)Simultaneously computes the sine and cosine of the number, `x`

. Returns
`(sin(x), cos(x))`

.

##### §Unspecified precision

This function currently corresponds to the `(f128::sin(x), f128::cos(x))`

. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
let x = std::f128::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 <= f128::EPSILON);
assert!(abs_difference_1 <= f128::EPSILON);
```

Runsource#### pub fn exp_m1(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn exp_m1(self) -> f128

`f128`

#116909)Returns `e^(self) - 1`

in a way that is accurate even if the
number is close to zero.

##### §Unspecified precision

This function currently corresponds to the `expm1f128`

from libc on Unix
and Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
let x = 1e-8_f128;
// for very small x, e^x is approximately 1 + x + x^2 / 2
let approx = x + x * x / 2.0;
let abs_difference = (x.exp_m1() - approx).abs();
assert!(abs_difference < 1e-10);
```

Runsource#### pub fn ln_1p(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn ln_1p(self) -> f128

`f128`

#116909)Returns `ln(1+n)`

(natural logarithm) more accurately than if
the operations were performed separately.

##### §Unspecified precision

This function currently corresponds to the `log1pf128`

from libc on Unix
and Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
let x = 1e-8_f128;
// for very small x, ln(1 + x) is approximately x - x^2 / 2
let approx = x - x * x / 2.0;
let abs_difference = (x.ln_1p() - approx).abs();
assert!(abs_difference < 1e-10);
```

Runsource#### pub fn sinh(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn sinh(self) -> f128

`f128`

#116909)Hyperbolic sine function.

##### §Unspecified precision

This function currently corresponds to the `sinhf128`

from libc on Unix
and Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
let e = std::f128::consts::E;
let x = 1.0f128;
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 <= f128::EPSILON);
```

Runsource#### pub fn cosh(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn cosh(self) -> f128

`f128`

#116909)Hyperbolic cosine function.

##### §Unspecified precision

This function currently corresponds to the `coshf128`

from libc on Unix
and Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
let e = std::f128::consts::E;
let x = 1.0f128;
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 <= f128::EPSILON);
```

Runsource#### pub fn tanh(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn tanh(self) -> f128

`f128`

#116909)Hyperbolic tangent function.

##### §Unspecified precision

This function currently corresponds to the `tanhf128`

from libc on Unix
and Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
let e = std::f128::consts::E;
let x = 1.0f128;
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 <= f128::EPSILON);
```

Runsource#### pub fn asinh(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn asinh(self) -> f128

`f128`

#116909)Inverse hyperbolic sine function.

##### §Unspecified precision

##### §Examples

```
#![feature(f128)]
let x = 1.0f128;
let f = x.sinh().asinh();
let abs_difference = (f - x).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn acosh(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn acosh(self) -> f128

`f128`

#116909)Inverse hyperbolic cosine function.

##### §Unspecified precision

##### §Examples

```
#![feature(f128)]
let x = 1.0f128;
let f = x.cosh().acosh();
let abs_difference = (f - x).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn atanh(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn atanh(self) -> f128

`f128`

#116909)Inverse hyperbolic tangent function.

##### §Unspecified precision

##### §Examples

```
#![feature(f128)]
let e = std::f128::consts::E;
let f = e.tanh().atanh();
let abs_difference = (f - e).abs();
assert!(abs_difference <= 1e-5);
```

Runsource#### pub fn gamma(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn gamma(self) -> f128

`f128`

#116909)Gamma function.

##### §Unspecified precision

This function currently corresponds to the `tgammaf128`

from libc on Unix
and Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
#![feature(float_gamma)]
let x = 5.0f128;
let abs_difference = (x.gamma() - 24.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn ln_gamma(self) -> (f128, i32)

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn ln_gamma(self) -> (f128, i32)

`f128`

#116909)Natural logarithm of the absolute value of the gamma function

The integer part of the tuple indicates the sign of the gamma function.

##### §Unspecified precision

This function currently corresponds to the `lgammaf128_r`

from libc on Unix
and Windows. Note that this might change in the future.

##### §Examples

```
#![feature(f128)]
#![feature(float_gamma)]
let x = 2.0f128;
let abs_difference = (x.ln_gamma().0 - 0.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource§### impl f128

### impl f128

source#### pub const RADIX: u32 = 2u32

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const RADIX: u32 = 2u32

`f128`

#116909)The radix or base of the internal representation of `f128`

.

source#### pub const MANTISSA_DIGITS: u32 = 113u32

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const MANTISSA_DIGITS: u32 = 113u32

`f128`

#116909)Number of significant digits in base 2.

source#### pub const DIGITS: u32 = 33u32

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const DIGITS: u32 = 33u32

`f128`

#116909)Approximate number of significant digits in base 10.

This is the maximum *x* such that any decimal number with *x*
significant digits can be converted to `f128`

and back without loss.

Equal to floor(log_{10} 2^{MANTISSA_DIGITS − 1}).

source#### pub const EPSILON: f128 = 1.92592994438723585305597794258492732E-34f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const EPSILON: f128 = 1.92592994438723585305597794258492732E-34f128

`f128`

#116909)Machine epsilon value for `f128`

.

This is the difference between `1.0`

and the next larger representable number.

Equal to 2^{1 − MANTISSA_DIGITS}.

source#### pub const MIN: f128 = -1.18973149535723176508575932662800702E+4932f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const MIN: f128 = -1.18973149535723176508575932662800702E+4932f128

`f128`

#116909)Smallest finite `f128`

value.

Equal to −`MAX`

.

source#### pub const MIN_POSITIVE: f128 = 3.3621031431120935062626778173217526E-4932f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const MIN_POSITIVE: f128 = 3.3621031431120935062626778173217526E-4932f128

`f128`

#116909)Smallest positive normal `f128`

value.

Equal to 2^{MIN_EXP − 1}.

source#### pub const MAX: f128 = 1.18973149535723176508575932662800702E+4932f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const MAX: f128 = 1.18973149535723176508575932662800702E+4932f128

`f128`

#116909)Largest finite `f128`

value.

Equal to
(1 − 2^{−MANTISSA_DIGITS}) 2^{MAX_EXP}.

source#### pub const MIN_EXP: i32 = -16_381i32

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const MIN_EXP: i32 = -16_381i32

`f128`

#116909)One greater than the minimum possible normal power of 2 exponent.

If *x* = `MIN_EXP`

, then normal numbers
≥ 0.5 × 2^{x}.

source#### pub const MAX_EXP: i32 = 16_384i32

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const MAX_EXP: i32 = 16_384i32

`f128`

#116909)Maximum possible power of 2 exponent.

If *x* = `MAX_EXP`

, then normal numbers
< 1 × 2^{x}.

source#### pub const MIN_10_EXP: i32 = -4_931i32

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const MIN_10_EXP: i32 = -4_931i32

`f128`

#116909)Minimum *x* for which 10^{x} is normal.

Equal to ceil(log_{10} `MIN_POSITIVE`

).

source#### pub const MAX_10_EXP: i32 = 4_932i32

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const MAX_10_EXP: i32 = 4_932i32

`f128`

#116909)Maximum *x* for which 10^{x} is normal.

Equal to floor(log_{10} `MAX`

).

source#### pub const NAN: f128 = NaN_f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const NAN: f128 = NaN_f128

`f128`

#116909)Not a Number (NaN).

Note that IEEE 754 doesn’t define just a single NaN value; a plethora of bit patterns are considered to be NaN. Furthermore, the standard makes a difference between a “signaling” and a “quiet” NaN, and allows inspecting its “payload” (the unspecified bits in the bit pattern). This constant isn’t guaranteed to equal to any specific NaN bitpattern, and the stability of its representation over Rust versions and target platforms isn’t guaranteed.

source#### pub const INFINITY: f128 = +Inf_f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const INFINITY: f128 = +Inf_f128

`f128`

#116909)Infinity (∞).

source#### pub const NEG_INFINITY: f128 = -Inf_f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const NEG_INFINITY: f128 = -Inf_f128

`f128`

#116909)Negative infinity (−∞).

source#### pub const fn is_nan(self) -> bool

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn is_nan(self) -> bool

`f128`

#116909)Returns `true`

if this value is NaN.

```
#![feature(f128)]
let nan = f128::NAN;
let f = 7.0_f128;
assert!(nan.is_nan());
assert!(!f.is_nan());
```

Runsource#### pub const fn is_infinite(self) -> bool

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn is_infinite(self) -> bool

`f128`

#116909)Returns `true`

if this value is positive infinity or negative infinity, and
`false`

otherwise.

```
#![feature(f128)]
let f = 7.0f128;
let inf = f128::INFINITY;
let neg_inf = f128::NEG_INFINITY;
let nan = f128::NAN;
assert!(!f.is_infinite());
assert!(!nan.is_infinite());
assert!(inf.is_infinite());
assert!(neg_inf.is_infinite());
```

Runsource#### pub const fn is_finite(self) -> bool

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn is_finite(self) -> bool

`f128`

#116909)Returns `true`

if this number is neither infinite nor NaN.

```
#![feature(f128)]
let f = 7.0f128;
let inf: f128 = f128::INFINITY;
let neg_inf: f128 = f128::NEG_INFINITY;
let nan: f128 = f128::NAN;
assert!(f.is_finite());
assert!(!nan.is_finite());
assert!(!inf.is_finite());
assert!(!neg_inf.is_finite());
```

Runsource#### pub const fn is_subnormal(self) -> bool

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn is_subnormal(self) -> bool

`f128`

#116909)Returns `true`

if the number is subnormal.

```
#![feature(f128)]
let min = f128::MIN_POSITIVE; // 3.362103143e-4932f128
let max = f128::MAX;
let lower_than_min = 1.0e-4960_f128;
let zero = 0.0_f128;
assert!(!min.is_subnormal());
assert!(!max.is_subnormal());
assert!(!zero.is_subnormal());
assert!(!f128::NAN.is_subnormal());
assert!(!f128::INFINITY.is_subnormal());
// Values between `0` and `min` are Subnormal.
assert!(lower_than_min.is_subnormal());
```

Runsource#### pub const fn is_normal(self) -> bool

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn is_normal(self) -> bool

`f128`

#116909)Returns `true`

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

```
#![feature(f128)]
let min = f128::MIN_POSITIVE; // 3.362103143e-4932f128
let max = f128::MAX;
let lower_than_min = 1.0e-4960_f128;
let zero = 0.0_f128;
assert!(min.is_normal());
assert!(max.is_normal());
assert!(!zero.is_normal());
assert!(!f128::NAN.is_normal());
assert!(!f128::INFINITY.is_normal());
// Values between `0` and `min` are Subnormal.
assert!(!lower_than_min.is_normal());
```

Runsource#### pub const fn classify(self) -> FpCategory

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn classify(self) -> FpCategory

`f128`

#116909)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.

```
#![feature(f128)]
use std::num::FpCategory;
let num = 12.4_f128;
let inf = f128::INFINITY;
assert_eq!(num.classify(), FpCategory::Normal);
assert_eq!(inf.classify(), FpCategory::Infinite);
```

Runsource#### pub fn is_sign_positive(self) -> bool

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn is_sign_positive(self) -> bool

`f128`

#116909)Returns `true`

if `self`

has a positive sign, including `+0.0`

, NaNs with
positive sign bit and positive infinity. Note that IEEE 754 doesn’t assign any
meaning to the sign bit in case of a NaN, and as Rust doesn’t guarantee that
the bit pattern of NaNs are conserved over arithmetic operations, the result of
`is_sign_positive`

on a NaN might produce an unexpected result in some cases.
See explanation of NaN as a special value for more info.

```
#![feature(f128)]
let f = 7.0_f128;
let g = -7.0_f128;
assert!(f.is_sign_positive());
assert!(!g.is_sign_positive());
```

Runsource#### pub fn is_sign_negative(self) -> bool

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn is_sign_negative(self) -> bool

`f128`

#116909)Returns `true`

if `self`

has a negative sign, including `-0.0`

, NaNs with
negative sign bit and negative infinity. Note that IEEE 754 doesn’t assign any
meaning to the sign bit in case of a NaN, and as Rust doesn’t guarantee that
the bit pattern of NaNs are conserved over arithmetic operations, the result of
`is_sign_negative`

on a NaN might produce an unexpected result in some cases.
See explanation of NaN as a special value for more info.

```
#![feature(f128)]
let f = 7.0_f128;
let g = -7.0_f128;
assert!(!f.is_sign_negative());
assert!(g.is_sign_negative());
```

Runsource#### pub fn next_up(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn next_up(self) -> f128

`f128`

#116909)Returns the least number greater than `self`

.

Let `TINY`

be the smallest representable positive `f128`

. Then,

- if
`self.is_nan()`

, this returns`self`

; - if
`self`

is`NEG_INFINITY`

, this returns`MIN`

; - if
`self`

is`-TINY`

, this returns -0.0; - if
`self`

is -0.0 or +0.0, this returns`TINY`

; - if
`self`

is`MAX`

or`INFINITY`

, this returns`INFINITY`

; - otherwise the unique least value greater than
`self`

is returned.

The identity `x.next_up() == -(-x).next_down()`

holds for all non-NaN `x`

. When `x`

is finite `x == x.next_up().next_down()`

also holds.

```
#![feature(f128)]
#![feature(float_next_up_down)]
// f128::EPSILON is the difference between 1.0 and the next number up.
assert_eq!(1.0f128.next_up(), 1.0 + f128::EPSILON);
// But not for most numbers.
assert!(0.1f128.next_up() < 0.1 + f128::EPSILON);
assert_eq!(4611686018427387904f128.next_up(), 4611686018427387904.000000000000001);
```

Runsource#### pub fn next_down(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn next_down(self) -> f128

`f128`

#116909)Returns the greatest number less than `self`

.

Let `TINY`

be the smallest representable positive `f128`

. Then,

- if
`self.is_nan()`

, this returns`self`

; - if
`self`

is`INFINITY`

, this returns`MAX`

; - if
`self`

is`TINY`

, this returns 0.0; - if
`self`

is -0.0 or +0.0, this returns`-TINY`

; - if
`self`

is`MIN`

or`NEG_INFINITY`

, this returns`NEG_INFINITY`

; - otherwise the unique greatest value less than
`self`

is returned.

The identity `x.next_down() == -(-x).next_up()`

holds for all non-NaN `x`

. When `x`

is finite `x == x.next_down().next_up()`

also holds.

```
#![feature(f128)]
#![feature(float_next_up_down)]
let x = 1.0f128;
// Clamp value into range [0, 1).
let clamped = x.clamp(0.0, 1.0f128.next_down());
assert!(clamped < 1.0);
assert_eq!(clamped.next_up(), 1.0);
```

Runsource#### pub fn recip(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn recip(self) -> f128

`f128`

#116909)Takes the reciprocal (inverse) of a number, `1/x`

.

```
#![feature(f128)]
let x = 2.0_f128;
let abs_difference = (x.recip() - (1.0 / x)).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn to_degrees(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn to_degrees(self) -> f128

`f128`

#116909)Converts radians to degrees.

```
#![feature(f128)]
let angle = std::f128::consts::PI;
let abs_difference = (angle.to_degrees() - 180.0).abs();
assert!(abs_difference <= f128::EPSILON);
```

Runsource#### pub fn to_radians(self) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn to_radians(self) -> f128

`f128`

#116909)Converts degrees to radians.

```
#![feature(f128)]
let angle = 180.0f128;
let abs_difference = (angle.to_radians() - std::f128::consts::PI).abs();
assert!(abs_difference <= 1e-30);
```

Runsource#### pub fn max(self, other: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn max(self, other: f128) -> f128

`f128`

#116909)Returns the maximum of the two numbers, ignoring NaN.

If one of the arguments is NaN, then the other argument is returned. This follows the IEEE 754-2008 semantics for maxNum, except for handling of signaling NaNs; this function handles all NaNs the same way and avoids maxNum’s problems with associativity. This also matches the behavior of libm’s fmax.

```
#![feature(f128)]
let x = 1.0f128;
let y = 2.0f128;
assert_eq!(x.max(y), y);
```

Runsource#### pub fn min(self, other: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn min(self, other: f128) -> f128

`f128`

#116909)Returns the minimum of the two numbers, ignoring NaN.

If one of the arguments is NaN, then the other argument is returned. This follows the IEEE 754-2008 semantics for minNum, except for handling of signaling NaNs; this function handles all NaNs the same way and avoids minNum’s problems with associativity. This also matches the behavior of libm’s fmin.

```
#![feature(f128)]
let x = 1.0f128;
let y = 2.0f128;
assert_eq!(x.min(y), x);
```

Runsource#### pub fn maximum(self, other: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn maximum(self, other: f128) -> f128

`f128`

#116909)Returns the maximum of the two numbers, propagating NaN.

This returns NaN when *either* argument is NaN, as opposed to
`f128::max`

which only returns NaN when *both* arguments are NaN.

```
#![feature(f128)]
#![feature(float_minimum_maximum)]
let x = 1.0f128;
let y = 2.0f128;
assert_eq!(x.maximum(y), y);
assert!(x.maximum(f128::NAN).is_nan());
```

RunIf one of the arguments is NaN, then NaN is returned. Otherwise this returns the greater of the two numbers. For this operation, -0.0 is considered to be less than +0.0. Note that this follows the semantics specified in IEEE 754-2019.

Also note that “propagation” of NaNs here doesn’t necessarily mean that the bitpattern of a NaN operand is conserved; see explanation of NaN as a special value for more info.

source#### pub fn minimum(self, other: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn minimum(self, other: f128) -> f128

`f128`

#116909)Returns the minimum of the two numbers, propagating NaN.

This returns NaN when *either* argument is NaN, as opposed to
`f128::min`

which only returns NaN when *both* arguments are NaN.

```
#![feature(f128)]
#![feature(float_minimum_maximum)]
let x = 1.0f128;
let y = 2.0f128;
assert_eq!(x.minimum(y), x);
assert!(x.minimum(f128::NAN).is_nan());
```

RunIf one of the arguments is NaN, then NaN is returned. Otherwise this returns the lesser of the two numbers. For this operation, -0.0 is considered to be less than +0.0. Note that this follows the semantics specified in IEEE 754-2019.

Also note that “propagation” of NaNs here doesn’t necessarily mean that the bitpattern of a NaN operand is conserved; see explanation of NaN as a special value for more info.

source#### pub fn midpoint(self, other: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn midpoint(self, other: f128) -> f128

`f128`

#116909)source#### pub unsafe fn to_int_unchecked<Int>(self) -> Intwhere
f128: FloatToInt<Int>,

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub unsafe fn to_int_unchecked<Int>(self) -> Intwhere
f128: FloatToInt<Int>,

`f128`

#116909)Rounds toward zero and converts to any primitive integer type, assuming that the value is finite and fits in that type.

```
#![feature(f128)]
let value = 4.6_f128;
let rounded = unsafe { value.to_int_unchecked::<u16>() };
assert_eq!(rounded, 4);
let value = -128.9_f128;
let rounded = unsafe { value.to_int_unchecked::<i8>() };
assert_eq!(rounded, i8::MIN);
```

Run##### §Safety

The value must:

- Not be
`NaN`

- Not be infinite
- Be representable in the return type
`Int`

, after truncating off its fractional part

source#### pub const fn to_bits(self) -> u128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn to_bits(self) -> u128

`f128`

#116909)Raw transmutation to `u128`

.

This is currently identical to `transmute::<f128, u128>(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.

```
#![feature(f128)]
assert_eq!((12.5f128).to_bits(), 0x40029000000000000000000000000000);
```

Runsource#### pub const fn from_bits(v: u128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn from_bits(v: u128) -> f128

`f128`

#116909)Raw transmutation from `u128`

.

This is currently identical to `transmute::<u128, f128>(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 favors 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.

```
#![feature(f128)]
let v = f128::from_bits(0x40029000000000000000000000000000);
assert_eq!(v, 12.5);
```

Runsource#### pub const fn to_be_bytes(self) -> [u8; 16]

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn to_be_bytes(self) -> [u8; 16]

`f128`

#116909)Returns the memory representation of this floating point number as a byte array in big-endian (network) byte order.

See `from_bits`

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

##### §Examples

```
#![feature(f128)]
let bytes = 12.5f128.to_be_bytes();
assert_eq!(
bytes,
[0x40, 0x02, 0x90, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
);
```

Runsource#### pub const fn to_le_bytes(self) -> [u8; 16]

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn to_le_bytes(self) -> [u8; 16]

`f128`

#116909)Returns the memory representation of this floating point number as a byte array in little-endian byte order.

See `from_bits`

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

##### §Examples

```
#![feature(f128)]
let bytes = 12.5f128.to_le_bytes();
assert_eq!(
bytes,
[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x90, 0x02, 0x40]
);
```

Runsource#### pub const fn to_ne_bytes(self) -> [u8; 16]

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn to_ne_bytes(self) -> [u8; 16]

`f128`

#116909)Returns 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.

See `from_bits`

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

##### §Examples

```
#![feature(f128)]
let bytes = 12.5f128.to_ne_bytes();
assert_eq!(
bytes,
if cfg!(target_endian = "big") {
[0x40, 0x02, 0x90, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
} else {
[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x90, 0x02, 0x40]
}
);
```

Runsource#### pub const fn from_be_bytes(bytes: [u8; 16]) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn from_be_bytes(bytes: [u8; 16]) -> f128

`f128`

#116909)Creates a floating point value from its representation as a byte array in big endian.

See `from_bits`

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

##### §Examples

```
#![feature(f128)]
let value = f128::from_be_bytes(
[0x40, 0x02, 0x90, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
);
assert_eq!(value, 12.5);
```

Runsource#### pub const fn from_le_bytes(bytes: [u8; 16]) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn from_le_bytes(bytes: [u8; 16]) -> f128

`f128`

#116909)Creates a floating point value from its representation as a byte array in little endian.

See `from_bits`

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

##### §Examples

```
#![feature(f128)]
let value = f128::from_le_bytes(
[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x90, 0x02, 0x40]
);
assert_eq!(value, 12.5);
```

Runsource#### pub const fn from_ne_bytes(bytes: [u8; 16]) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub const fn from_ne_bytes(bytes: [u8; 16]) -> f128

`f128`

#116909)Creates 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.

See `from_bits`

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

##### §Examples

```
#![feature(f128)]
let value = f128::from_ne_bytes(if cfg!(target_endian = "big") {
[0x40, 0x02, 0x90, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
} else {
[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x90, 0x02, 0x40]
});
assert_eq!(value, 12.5);
```

Runsource#### pub fn total_cmp(&self, other: &f128) -> Ordering

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn total_cmp(&self, other: &f128) -> Ordering

`f128`

#116909)Returns the ordering between `self`

and `other`

.

Unlike the standard partial comparison between floating point numbers,
this comparison always produces an ordering in accordance to
the `totalOrder`

predicate as defined in the IEEE 754 (2008 revision)
floating point standard. The values are ordered in the following sequence:

- negative quiet NaN
- negative signaling NaN
- negative infinity
- negative numbers
- negative subnormal numbers
- negative zero
- positive zero
- positive subnormal numbers
- positive numbers
- positive infinity
- positive signaling NaN
- positive quiet NaN.

The ordering established by this function does not always agree with the
`PartialOrd`

and `PartialEq`

implementations of `f128`

. For example,
they consider negative and positive zero equal, while `total_cmp`

doesn’t.

The interpretation of the signaling NaN bit follows the definition in the IEEE 754 standard, which may not match the interpretation by some of the older, non-conformant (e.g. MIPS) hardware implementations.

##### §Example

```
#![feature(f128)]
struct GoodBoy {
name: &'static str,
weight: f128,
}
let mut bois = vec![
GoodBoy { name: "Pucci", weight: 0.1 },
GoodBoy { name: "Woofer", weight: 99.0 },
GoodBoy { name: "Yapper", weight: 10.0 },
GoodBoy { name: "Chonk", weight: f128::INFINITY },
GoodBoy { name: "Abs. Unit", weight: f128::NAN },
GoodBoy { name: "Floaty", weight: -5.0 },
];
bois.sort_by(|a, b| a.weight.total_cmp(&b.weight));
// `f128::NAN` could be positive or negative, which will affect the sort order.
if f128::NAN.is_sign_negative() {
bois.into_iter().map(|b| b.weight)
.zip([f128::NAN, -5.0, 0.1, 10.0, 99.0, f128::INFINITY].iter())
.for_each(|(a, b)| assert_eq!(a.to_bits(), b.to_bits()))
} else {
bois.into_iter().map(|b| b.weight)
.zip([-5.0, 0.1, 10.0, 99.0, f128::INFINITY, f128::NAN].iter())
.for_each(|(a, b)| assert_eq!(a.to_bits(), b.to_bits()))
}
```

Runsource#### pub fn clamp(self, min: f128, max: f128) -> f128

🔬This is a nightly-only experimental API. (`f128`

#116909)

#### pub fn clamp(self, min: f128, max: f128) -> f128

`f128`

#116909)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`

.

Note 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(f128)]
assert!((-3.0f128).clamp(-2.0, 1.0) == -2.0);
assert!((0.0f128).clamp(-2.0, 1.0) == 0.0);
assert!((2.0f128).clamp(-2.0, 1.0) == 1.0);
assert!((f128::NAN).clamp(-2.0, 1.0).is_nan());
```

Run## Trait Implementations§

1.22.0 · source§### impl AddAssign<&f128> for f128

### impl AddAssign<&f128> for f128

source§#### fn add_assign(&mut self, other: &f128)

#### fn add_assign(&mut self, other: &f128)

`+=`

operation. Read more1.8.0 · source§### impl AddAssign for f128

### impl AddAssign for f128

source§#### fn add_assign(&mut self, other: f128)

#### fn add_assign(&mut self, other: f128)

`+=`

operation. Read more1.22.0 · source§### impl DivAssign<&f128> for f128

### impl DivAssign<&f128> for f128

source§#### fn div_assign(&mut self, other: &f128)

#### fn div_assign(&mut self, other: &f128)

`/=`

operation. Read more1.8.0 · source§### impl DivAssign for f128

### impl DivAssign for f128

source§#### fn div_assign(&mut self, other: f128)

#### fn div_assign(&mut self, other: f128)

`/=`

operation. Read more1.22.0 · source§### impl MulAssign<&f128> for f128

### impl MulAssign<&f128> for f128

source§#### fn mul_assign(&mut self, other: &f128)

#### fn mul_assign(&mut self, other: &f128)

`*=`

operation. Read more1.8.0 · source§### impl MulAssign for f128

### impl MulAssign for f128

source§#### fn mul_assign(&mut self, other: f128)

#### fn mul_assign(&mut self, other: f128)

`*=`

operation. Read more1.0.0 · source§### impl PartialOrd for f128

### impl PartialOrd for f128

1.0.0 · source§### impl Rem for f128

### impl Rem for f128

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);
```

Run1.22.0 · source§### impl RemAssign<&f128> for f128

### impl RemAssign<&f128> for f128

source§#### fn rem_assign(&mut self, other: &f128)

#### fn rem_assign(&mut self, other: &f128)

`%=`

operation. Read more1.8.0 · source§### impl RemAssign for f128

### impl RemAssign for f128

source§#### fn rem_assign(&mut self, other: f128)

#### fn rem_assign(&mut self, other: f128)

`%=`

operation. Read more1.22.0 · source§### impl SubAssign<&f128> for f128

### impl SubAssign<&f128> for f128

source§#### fn sub_assign(&mut self, other: &f128)

#### fn sub_assign(&mut self, other: &f128)

`-=`

operation. Read more1.8.0 · source§### impl SubAssign for f128

### impl SubAssign for f128

source§#### fn sub_assign(&mut self, other: f128)

#### fn sub_assign(&mut self, other: f128)

`-=`

operation. Read more