Primitive Type f641.0.0[]

A 64-bit floating point type (specifically, the “binary64” type defined in IEEE 754-2008).

This type is very similar to f32, but has increased precision by using twice as many bits. Please see the documentation for f32 or Wikipedia on double precision values for more information.

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);
Run

#[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());
Run

#[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());
Run

#[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 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.

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());
Run

#[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);
Run

#[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 cube 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);
Run

#[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);
Run

#[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);
Run

#[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);
Run

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

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

Examples

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 = 1e-16_f64;

// 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-20);
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 = 1e-16_f64;

// 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-20);
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

impl f64[src]

pub const RADIX: u321.43.0[src]

The radix or base of the internal representation of f64.

pub const MANTISSA_DIGITS: u321.43.0[src]

Number of significant digits in base 2.

pub const DIGITS: u321.43.0[src]

Approximate number of significant digits in base 10.

pub const EPSILON: f641.43.0[src]

Machine epsilon value for f64.

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

pub const MIN: f641.43.0[src]

Smallest finite f64 value.

pub const MIN_POSITIVE: f641.43.0[src]

Smallest positive normal f64 value.

pub const MAX: f641.43.0[src]

Largest finite f64 value.

pub const MIN_EXP: i321.43.0[src]

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

pub const MAX_EXP: i321.43.0[src]

Maximum possible power of 2 exponent.

pub const MIN_10_EXP: i321.43.0[src]

Minimum possible normal power of 10 exponent.

pub const MAX_10_EXP: i321.43.0[src]

Maximum possible power of 10 exponent.

pub const NAN: f641.43.0[src]

Not a Number (NaN).

pub const INFINITY: f641.43.0[src]

Infinity (∞).

pub const NEG_INFINITY: f641.43.0[src]

Negative infinity (−∞).

pub const 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());
Run

pub const 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());
Run

pub const 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());
Run

pub const fn is_subnormal(self) -> bool1.53.0[src]

Returns true if the number is subnormal.

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

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

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

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

Returns true if self has a positive sign, including +0.0, NaNs 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 const fn is_sign_negative(self) -> bool[src]

Returns true if self has a negative sign, including -0.0, NaNs 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 const fn to_bits(self) -> u641.20.0[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 const fn from_bits(v: u64) -> f641.20.0[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 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 signaling-ness (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 const 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 const 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 const 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 as_ne_bytes(&self) -> &[u8; 8][src]

🔬 This is a nightly-only experimental API. (num_as_ne_bytes #76976)

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

to_ne_bytes should be preferred over this whenever possible.

Examples

#![feature(num_as_ne_bytes)]
let num = 12.5f64;
let bytes = num.as_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 const fn from_be_bytes(bytes: [u8; 8]) -> f641.40.0[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 const fn from_le_bytes(bytes: [u8; 8]) -> f641.40.0[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 const fn from_ne_bytes(bytes: [u8; 8]) -> f641.40.0[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

Note that this function does not always agree with the PartialOrd and PartialEq implementations of f64. In particular, they regard negative and positive zero as equal, while total_cmp doesn’t.

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

#[must_use = "method returns a new number and does not mutate the original value"]
pub fn clamp(self, min: f64, max: f64) -> f64
1.50.0[src]

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

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());
Run

Trait Implementations

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

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

The resulting type after applying the + operator.

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

Performs the + operation. Read more

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

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

The resulting type after applying the + operator.

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

Performs the + operation. Read more

impl Add<f64> for f64[src]

type Output = f64

The resulting type after applying the + operator.

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

Performs the + operation. Read more

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

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

The resulting type after applying the + operator.

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

Performs the + operation. Read more

impl<'_> AddAssign<&'_ f64> for f641.22.0[src]

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

Performs the += operation. Read more

impl AddAssign<f64> for f641.8.0[src]

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

Performs the += operation. Read more

impl Clone for f64[src]

pub 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 Debug for f64[src]

pub fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>[src]

Formats the value using the given formatter. Read more

impl Default for f64[src]

pub fn default() -> f64[src]

Returns the default value of 0.0

impl Display for f64[src]

pub 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.

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

Performs the / operation. Read more

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

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

The resulting type after applying the / operator.

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

Performs the / operation. Read more

impl Div<f64> for f64[src]

type Output = f64

The resulting type after applying the / operator.

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

Performs the / operation. Read more

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

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

The resulting type after applying the / operator.

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

Performs the / operation. Read more

impl<'_> DivAssign<&'_ f64> for f641.22.0[src]

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

Performs the /= operation. Read more

impl DivAssign<f64> for f641.8.0[src]

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

Performs the /= operation. Read more

impl From<f32> for f641.6.0[src]

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

Converts f32 to f64 losslessly.

impl From<i16> for f641.6.0[src]

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

Converts i16 to f64 losslessly.

impl From<i32> for f641.6.0[src]

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

Converts i32 to f64 losslessly.

impl From<i8> for f641.6.0[src]

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

Converts i8 to f64 losslessly.

impl From<u16> for f641.6.0[src]

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

Converts u16 to f64 losslessly.

impl From<u32> for f641.6.0[src]

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

Converts u32 to f64 losslessly.

impl From<u8> for f641.6.0[src]

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

Converts u8 to f64 losslessly.

impl FromStr for f64[src]

pub 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.

type Err = ParseFloatError

The associated error which can be returned from parsing.

impl LowerExp for f64[src]

pub 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.

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

Performs the * operation. Read more

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

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

The resulting type after applying the * operator.

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

Performs the * operation. Read more

impl Mul<f64> for f64[src]

type Output = f64

The resulting type after applying the * operator.

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

Performs the * operation. Read more

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

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

The resulting type after applying the * operator.

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

Performs the * operation. Read more

impl<'_> MulAssign<&'_ f64> for f641.22.0[src]

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

Performs the *= operation. Read more

impl MulAssign<f64> for f641.8.0[src]

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

Performs the *= operation. Read more

impl Neg for f64[src]

type Output = f64

The resulting type after applying the - operator.

pub fn neg(self) -> f64[src]

Performs the unary - operation. Read more

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

type Output = <f64 as Neg>::Output

The resulting type after applying the - operator.

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

Performs the unary - operation. Read more

impl PartialEq<f64> for f64[src]

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

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

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

This method tests for !=.

impl PartialOrd<f64> for f64[src]

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

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

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

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

pub 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

pub 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

pub 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 f641.12.0[src]

pub 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 f641.12.0[src]

pub 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.

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

Performs the % operation. Read more

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

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

The resulting type after applying the % operator.

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

Performs the % operation. Read more

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.

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

Performs the % operation. Read more

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

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

The resulting type after applying the % operator.

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

Performs the % operation. Read more

impl<'_> RemAssign<&'_ f64> for f641.22.0[src]

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

Performs the %= operation. Read more

impl RemAssign<f64> for f641.8.0[src]

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

Performs the %= operation. Read more

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

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

The resulting type after applying the - operator.

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

Performs the - operation. Read more

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

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

The resulting type after applying the - operator.

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

Performs the - operation. Read more

impl Sub<f64> for f64[src]

type Output = f64

The resulting type after applying the - operator.

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

Performs the - operation. Read more

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

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

The resulting type after applying the - operator.

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

Performs the - operation. Read more

impl<'_> SubAssign<&'_ f64> for f641.22.0[src]

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

Performs the -= operation. Read more

impl SubAssign<f64> for f641.8.0[src]

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

Performs the -= operation. Read more

impl<'a> Sum<&'a f64> for f641.12.0[src]

pub 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 f641.12.0[src]

pub 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]

pub fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>[src]

Formats the value using the given formatter.

impl Copy for f64[src]

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]

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]

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

Gets the TypeId of self. Read more

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

pub fn borrow(&self) -> &T

Notable traits for &'_ mut I

impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized
type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
    F: Future + Unpin + ?Sized
type Output = <F as Future>::Output;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
[src]

Immutably borrows from an owned value. Read more

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

pub fn borrow_mut(&mut self) -> &mut T

Notable traits for &'_ mut I

impl<'_, I> Iterator for &'_ mut I where
    I: Iterator + ?Sized
type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
    F: Future + Unpin + ?Sized
type Output = <F as Future>::Output;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
[src]

Mutably borrows from an owned value. Read more

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

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

Performs the conversion.

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

pub 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.

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

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

pub 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]

pub 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.

pub 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.

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

Performs the conversion.