f64 - Rust
Description: API documentation for the Rust `f64` primitive in crate `std`.
Keywords: rust, rustlang, rust-lang, f64

# 1.0.0[−]Primitive Type f64

The 64-bit floating point type.

See also the `std::f64::consts` module.

## Implementations

### `impl f64`[src]

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn fract(self) -> f64`[src]

Returns the fractional part of a number.

# Examples

    let x = 3.6_f64;
    let y = -3.6_f64;
    let abs_difference_x = (x.fract() - 0.6).abs();
    let abs_difference_y = (y.fract() - (-0.6)).abs();

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

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#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn abs(self) -> f64`[src]

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

# Examples

    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());

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#### `#[must_use = "method returns a new number and does not mutate the original value"]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

    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());

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#### `#[must_use = "method returns a new number and does not mutate the original value"]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

    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

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]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 * 2.0

Run

#### `#[must_use = "method returns a new number and does not mutate the original value"]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!((-f64::EPSILON).rem_euclid(3.0) != 0.0);

Run

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn sqrt(self) -> f64`[src]

Returns 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());

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#### `#[must_use = "method returns a new number and does not mutate the original value"]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);

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#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]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 twenty_five = 25.0_f64;

    // log5(25) - 2 == 0
    let abs_difference = (twenty_five.log(5.0) - 2.0).abs();

    assert!(abs_difference < 1e-10);

Run

#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn log2(self) -> f64`[src]

Returns the base 2 logarithm of the number.

# Examples

    let four = 4.0_f64;

    // log2(4) - 2 == 0
    let abs_difference = (four.log2() - 2.0).abs();

    assert!(abs_difference < 1e-10);

Run

#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn log10(self) -> f64`[src]

Returns the base 10 logarithm of the number.

# Examples

    let hundred = 100.0_f64;

    // log10(100) - 2 == 0
    let abs_difference = (hundred.log10() - 2.0).abs();

    assert!(abs_difference < 1e-10);

Run

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn cbrt(self) -> f64`[src]

Returns 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

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn sin(self) -> f64`[src]

Computes the sine of a number (in radians).

# Examples

    let x = std::f64::consts::FRAC_PI_2;

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

    assert!(abs_difference < 1e-10);

Run

#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn cos(self) -> f64`[src]

Computes the cosine of a number (in radians).

# Examples

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

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

    assert!(abs_difference < 1e-10);

Run

#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn tan(self) -> f64`[src]

Computes the tangent of a number (in radians).

# Examples

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

    assert!(abs_difference < 1e-14);

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#### `#[must_use = "method returns a new number and does not mutate the original value"]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

    let f = std::f64::consts::FRAC_PI_2;

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

    assert!(abs_difference < 1e-10);

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#### `#[must_use = "method returns a new number and does not mutate the original value"]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

    let f = std::f64::consts::FRAC_PI_4;

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

    assert!(abs_difference < 1e-10);

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#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

    // 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) - (-std::f64::consts::FRAC_PI_4)).abs();
    let abs_difference_2 = (y2.atan2(x2) - (3.0 * std::f64::consts::FRAC_PI_4)).abs();

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

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

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

# Examples

    let x = std::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

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn ln_1p(self) -> f64`[src]

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

# Examples

    let x = std::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

#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn sinh(self) -> f64`[src]

Hyperbolic sine function.

# Examples

    let e = std::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

#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn cosh(self) -> f64`[src]

Hyperbolic cosine function.

# Examples

    let e = std::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

#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn tanh(self) -> f64`[src]

Hyperbolic tangent function.

# Examples

    let e = std::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

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]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

#### `#[must_use = "method returns a new number and does not mutate the original value"]pub fn atanh(self) -> f64`[src]

Inverse hyperbolic tangent function.

# Examples

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

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

    assert!(abs_difference < 1.0e-10);

Run

#### `#[must_use = "method returns a new number and does not mutate the original value"]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`.

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(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!((f64::NAN).clamp(-2.0, 1.0).is_nan());

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### `impl f64`[src]

#### `pub const RADIX: u32`1.43.0[src]

The radix or base of the internal representation of `f64`.

#### `pub const MANTISSA_DIGITS: u32`1.43.0[src]

Number of significant digits in base 2.

#### `pub const DIGITS: u32`1.43.0[src]

Approximate number of significant digits in base 10.

#### `pub const EPSILON: f64`1.43.0[src]

Machine epsilon value for `f64`.

This is the difference between `1.0` and the next larger representable number.

#### `pub const MIN: f64`1.43.0[src]

Smallest finite `f64` value.

#### `pub const MIN_POSITIVE: f64`1.43.0[src]

Smallest positive normal `f64` value.

#### `pub const MAX: f64`1.43.0[src]

Largest finite `f64` value.

#### `pub const MIN_EXP: i32`1.43.0[src]

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

#### `pub const MAX_EXP: i32`1.43.0[src]

Maximum possible power of 2 exponent.

#### `pub const MIN_10_EXP: i32`1.43.0[src]

Minimum possible normal power of 10 exponent.

#### `pub const MAX_10_EXP: i32`1.43.0[src]

Maximum possible power of 10 exponent.

#### `pub const NAN: f64`1.43.0[src]

Not a Number (NaN).

#### `pub const INFINITY: f64`1.43.0[src]

Infinity (∞).

#### `pub const NEG_INFINITY: f64`1.43.0[src]

Negative infinity (−∞).

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

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

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

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

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

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

    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());

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

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

    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());

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

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

    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());

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#### `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;

    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.

    let angle = std::f64::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.

    let angle = 180.0_f64;

    let abs_difference = (angle.to_radians() - std::f64::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 unsafe fn to_int_unchecked<Int>(self) -> Int where
f64: FloatToInt<Int>,` 1.44.0[src]

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

    let value = 4.6_f64;
    let rounded = unsafe { value.to_int_unchecked::<u16>() };
    assert_eq!(rounded, 4);

    let value = -128.9_f64;
    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

#### `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]`1.40.0[src]

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

# Examples

    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]`1.40.0[src]

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

# Examples

    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]`1.40.0[src]

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

    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`1.40.0[src]

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

# Examples

    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`1.40.0[src]

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

# Examples

    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`1.40.0[src]

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

    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

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

🔬 This is a nightly-only experimental API. (`total_cmp` #72599)

Returns an ordering between self and other values. Unlike the standard partial comparison between floating point numbers, this comparison always produces an ordering in accordance to the totalOrder predicate as defined in IEEE 754 (2008 revision) floating point standard. The values are ordered in following order:

- 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

# Example

    #![feature(total_cmp)]
    struct GoodBoy {
        name: String,
        weight: f64,
    }

    let mut bois = vec![
        GoodBoy { name: "Pucci".to_owned(), weight: 0.1 },
        GoodBoy { name: "Woofer".to_owned(), weight: 99.0 },
        GoodBoy { name: "Yapper".to_owned(), weight: 10.0 },
        GoodBoy { name: "Chonk".to_owned(), weight: f64::INFINITY },
        GoodBoy { name: "Abs. Unit".to_owned(), weight: f64::NAN },
        GoodBoy { name: "Floaty".to_owned(), weight: -5.0 },
    ];

    bois.sort_by(|a, b| a.weight.total_cmp(&b.weight));

Run

## Trait Implementations

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

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

The resulting type after applying the `+` operator.

#### `fn add(self, other: &f64) -> <f64 as Add<f64>>::Output`[src]

Performs the `+` operation.

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

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

The resulting type after applying the `+` operator.

#### `fn add(self, other: &f64) -> <f64 as Add<f64>>::Output`[src]

Performs the `+` operation.

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

#### `type Output = f64`

The resulting type after applying the `+` operator.

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

Performs the `+` operation.

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

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

The resulting type after applying the `+` operator.

#### `fn add(self, other: f64) -> <f64 as Add<f64>>::Output`[src]

Performs the `+` operation.

### `impl<'_> AddAssign<&'_ f64> for f64` 1.22.0[src]

#### `fn add_assign(&mut self, other: &f64)`[src]

Performs the `+=` operation.

### `impl AddAssign<f64> for f64` 1.8.0[src]

#### `fn add_assign(&mut self, other: f64)`[src]

Performs the `+=` operation.

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

#### `fn clone(&self) -> f64`[src]

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`[src]

Performs copy-assignment from `source`. Read more

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

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

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

Formats the value using the given formatter. Read more

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

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

Returns the default value of `0.0`

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

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

Formats the value using the given formatter. Read more

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

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

The resulting type after applying the `/` operator.

#### `fn div(self, other: &f64) -> <f64 as Div<f64>>::Output`[src]

Performs the `/` operation.

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

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

The resulting type after applying the `/` operator.

#### `fn div(self, other: &f64) -> <f64 as Div<f64>>::Output`[src]

Performs the `/` operation.

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

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

The resulting type after applying the `/` operator.

#### `fn div(self, other: f64) -> <f64 as Div<f64>>::Output`[src]

Performs the `/` operation.

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

#### `type Output = f64`

The resulting type after applying the `/` operator.

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

Performs the `/` operation.

### `impl<'_> DivAssign<&'_ f64> for f64` 1.22.0[src]

#### `fn div_assign(&mut self, other: &f64)`[src]

Performs the `/=` operation.

### `impl DivAssign<f64> for f64` 1.8.0[src]

#### `fn div_assign(&mut self, other: f64)`[src]

Performs the `/=` operation.

### `impl FloatToInt<i128> for f64`[src]

### `impl FloatToInt<i16> for f64`[src]

### `impl FloatToInt<i32> for f64`[src]

### `impl FloatToInt<i64> for f64`[src]

### `impl FloatToInt<i8> for f64`[src]

### `impl FloatToInt<isize> for f64`[src]

### `impl FloatToInt<u128> for f64`[src]

### `impl FloatToInt<u16> for f64`[src]

### `impl FloatToInt<u32> for f64`[src]

### `impl FloatToInt<u64> for f64`[src]

### `impl FloatToInt<u8> for f64`[src]

### `impl FloatToInt<usize> for f64`[src]

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

Converts `f32` to `f64` losslessly.

#### `fn from(small: f32) -> f64`[src]

Performs the conversion.

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

Converts `i16` to `f64` losslessly.

#### `fn from(small: i16) -> f64`[src]

Performs the conversion.

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

Converts `i32` to `f64` losslessly.

#### `fn from(small: i32) -> f64`[src]

Performs the conversion.

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

Converts `i8` to `f64` losslessly.

#### `fn from(small: i8) -> f64`[src]

Performs the conversion.

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

Converts `u16` to `f64` losslessly.

#### `fn from(small: u16) -> f64`[src]

Performs the conversion.

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

Converts `u32` to `f64` losslessly.

#### `fn from(small: u32) -> f64`[src]

Performs the conversion.

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

Converts `u8` to `f64` losslessly.

#### `fn from(small: u8) -> f64`[src]

Performs the conversion.

### `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 LowerExp for f64`[src]

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

Formats the value using the given formatter.

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

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

The resulting type after applying the `*` operator.

#### `fn mul(self, other: &f64) -> <f64 as Mul<f64>>::Output`[src]

Performs the `*` operation.

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

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

The resulting type after applying the `*` operator.

#### `fn mul(self, other: &f64) -> <f64 as Mul<f64>>::Output`[src]

Performs the `*` operation.

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

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

The resulting type after applying the `*` operator.

#### `fn mul(self, other: f64) -> <f64 as Mul<f64>>::Output`[src]

Performs the `*` operation.

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

#### `type Output = f64`

The resulting type after applying the `*` operator.

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

Performs the `*` operation.

### `impl<'_> MulAssign<&'_ f64> for f64` 1.22.0[src]

#### `fn mul_assign(&mut self, other: &f64)`[src]

Performs the `*=` operation.

### `impl MulAssign<f64> for f64` 1.8.0[src]

#### `fn mul_assign(&mut self, other: f64)`[src]

Performs the `*=` operation.

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

#### `type Output = f64`

The resulting type after applying the `-` operator.

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

Performs the unary `-` operation.

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

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

The resulting type after applying the `-` operator.

#### `fn neg(self) -> <f64 as Neg>::Output`[src]

Performs the unary `-` operation.

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

#### `fn eq(&self, other: &f64) -> bool`[src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `fn ne(&self, other: &f64) -> bool`[src]

This method tests for `!=`.

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

#### `fn partial_cmp(&self, other: &f64) -> Option<Ordering>`[src]

This method returns an ordering between `self` and `other` values if one exists. Read more

#### `fn lt(&self, other: &f64) -> bool`[src]

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

#### `fn le(&self, other: &f64) -> bool`[src]

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

#### `fn ge(&self, other: &f64) -> bool`[src]

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

#### `fn gt(&self, other: &f64) -> bool`[src]

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

### `impl<'a> Product<&'a f64> for f64` 1.12.0[src]

#### `fn product<I>(iter: I) -> f64 where
I: Iterator<Item = &'a f64>,` [src]

Method which takes an iterator and generates `Self` from the elements by multiplying the items. Read more

### `impl Product<f64> for f64` 1.12.0[src]

#### `fn product<I>(iter: I) -> f64 where
I: Iterator<Item = f64>,` [src]

Method which takes an iterator and generates `Self` from the elements by multiplying the items. Read more

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

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

The resulting type after applying the `%` operator.

#### `fn rem(self, other: &f64) -> <f64 as Rem<f64>>::Output`[src]

Performs the `%` operation.

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

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

The resulting type after applying the `%` operator.

#### `fn rem(self, other: &f64) -> <f64 as Rem<f64>>::Output`[src]

Performs the `%` operation.

### `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.

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

Performs the `%` operation.

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

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

The resulting type after applying the `%` operator.

#### `fn rem(self, other: f64) -> <f64 as Rem<f64>>::Output`[src]

Performs the `%` operation.

### `impl<'_> RemAssign<&'_ f64> for f64` 1.22.0[src]

#### `fn rem_assign(&mut self, other: &f64)`[src]

Performs the `%=` operation.

### `impl RemAssign<f64> for f64` 1.8.0[src]

#### `fn rem_assign(&mut self, other: f64)`[src]

Performs the `%=` operation.

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

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

The resulting type after applying the `-` operator.

#### `fn sub(self, other: &f64) -> <f64 as Sub<f64>>::Output`[src]

Performs the `-` operation.

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

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

The resulting type after applying the `-` operator.

#### `fn sub(self, other: &f64) -> <f64 as Sub<f64>>::Output`[src]

Performs the `-` operation.

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

#### `type Output = f64`

The resulting type after applying the `-` operator.

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

Performs the `-` operation.

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

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

The resulting type after applying the `-` operator.

#### `fn sub(self, other: f64) -> <f64 as Sub<f64>>::Output`[src]

Performs the `-` operation.

### `impl<'_> SubAssign<&'_ f64> for f64` 1.22.0[src]

#### `fn sub_assign(&mut self, other: &f64)`[src]

Performs the `-=` operation.

### `impl SubAssign<f64> for f64` 1.8.0[src]

#### `fn sub_assign(&mut self, other: f64)`[src]

Performs the `-=` operation.

### `impl<'a> Sum<&'a f64> for f64` 1.12.0[src]

#### `fn sum<I>(iter: I) -> f64 where
I: Iterator<Item = &'a f64>,` [src]

Method which takes an iterator and generates `Self` from the elements by "summing up" the items. Read more

### `impl Sum<f64> for f64` 1.12.0[src]

#### `fn sum<I>(iter: I) -> f64 where
I: Iterator<Item = f64>,` [src]

Method which takes an iterator and generates `Self` from the elements by "summing up" the items. Read more

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

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

Formats the value using the given formatter.

## Auto Trait Implementations

### `impl RefUnwindSafe for f64`

### `impl Send for f64`

### `impl Sync for f64`

### `impl Unpin for f64`

### `impl UnwindSafe for f64`

## Blanket Implementations

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `fn type_id(&self) -> TypeId`[src]

Gets the `TypeId` of `self`. Read more

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

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

Immutably borrows from an owned value. Read more

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

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

Mutably borrows from an owned value. Read more

### `impl<T> From<T> for T`[src]

#### `fn from(t: T) -> T`[src]

Performs the conversion.

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

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

Performs the conversion.

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

#### `type Owned = T`

The resulting type after obtaining ownership.

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

Creates owned data from borrowed data, usually by cloning. Read more

#### `fn clone_into(&self, target: &mut T)`[src]

🔬 This is a nightly-only experimental API. (`toowned_clone_into` #41263)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

### `impl<T> ToString for T where
T: Display + ?Sized,` [src]

#### `default fn to_string(&self) -> String`[src]

Converts the given value to a `String`. Read more

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

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>`[src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

#### `type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

#### `fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>`[src]

Performs the conversion.