1.0.0[]Primitive Type f64

The 64-bit floating point type.

See also the std::f64 module.

Methods

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

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

#[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

use std::f64;

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

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

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

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

#[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

use std::f64;

let f = 3.5_f64;

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

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

#[must_use = "method returns a new number and does not mutate the original value"] pub fn copysign(self, sign: f64) -> f641.35.0[src]

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

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

Examples

use std::f64;

let f = 3.5_f64;

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

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

#[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) -> f641.38.0[src]

Calculates Euclidean division, the matching method for rem_euclid.

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

Examples

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

#[must_use = "method returns a new number and does not mutate the original value"] pub fn rem_euclid(self, rhs: f64) -> f641.38.0[src]

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

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

Examples

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

#[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]

Takes the square root of a number.

Returns NaN if self is a negative number.

Examples

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

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

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

#[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]

Takes the cubic root of a number.

Examples

let x = 8.0_f64;

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

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

#[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

use std::f64;

let x = 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

use std::f64;

let x = 2.0 * 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

use std::f64;

let x = 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

use std::f64;

let f = f64::consts::FRAC_PI_2;

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

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

#[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

use std::f64;

let f = f64::consts::FRAC_PI_4;

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

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

#[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

use std::f64;

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

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

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

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

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

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

Examples

use std::f64;

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

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

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

#[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

use std::f64;

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

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

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

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

Hyperbolic sine function.

Examples

use std::f64;

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

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

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

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

Hyperbolic cosine function.

Examples

use std::f64;

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

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

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

Hyperbolic tangent function.

Examples

use std::f64;

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

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

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

#[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

use std::f64;

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

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

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

#[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.

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

Panics

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

Examples

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

impl f64[src]

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

Returns true if this value is NaN.

use std::f64;

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

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

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

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

use std::f64;

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

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

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

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

Returns true if this number is neither infinite nor NaN.

use std::f64;

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

assert!(f.is_finite());

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

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

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

use std::f64;

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

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

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

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

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

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

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

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

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

Returns true if self has a positive sign, including +0.0, 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 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.

use std::f64::consts;

let angle = consts::PI;

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

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

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

Converts degrees to radians.

use std::f64::consts;

let angle = 180.0_f64;

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

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

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

Returns the maximum of the two numbers.

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

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

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

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

Returns the minimum of the two numbers.

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

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

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

pub fn to_bits(self) -> 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 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 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]) -> 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 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 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

Trait Implementations

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

Converts f32 to f64 losslessly.

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

Converts u16 to f64 losslessly.

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

Converts i32 to f64 losslessly.

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

Converts i16 to f64 losslessly.

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

Converts u8 to f64 losslessly.

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

Converts i8 to f64 losslessly.

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

Converts u32 to f64 losslessly.

impl PartialEq<f64> for f64[src]

impl Default for f64[src]

fn default() -> f64[src]

Returns the default value of 0.0

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

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

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

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

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

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

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

type Output = <f64 as Neg>::Output

The resulting type after applying the - operator.

impl Neg for f64[src]

type Output = f64

The resulting type after applying the - operator.

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

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

The resulting type after applying the / operator.

impl Div<f64> for f64[src]

type Output = f64

The resulting type after applying the / operator.

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

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

The resulting type after applying the / operator.

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

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

The resulting type after applying the / operator.

impl FromStr for f64[src]

type Err = ParseFloatError

The associated error which can be returned from parsing.

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

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

This function accepts strings such as

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

Leading and trailing whitespace represent an error.

Grammar

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

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

Known bugs

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

Arguments

  • src - A string

Return value

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

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

impl Product<f64> for f641.12.0[src]

impl Mul<f64> for f64[src]

type Output = f64

The resulting type after applying the * operator.

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

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

The resulting type after applying the * operator.

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

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

The resulting type after applying the * operator.

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

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

The resulting type after applying the * operator.

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

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

impl Clone for f64[src]

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

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

The resulting type after applying the - operator.

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

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

The resulting type after applying the - operator.

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

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

The resulting type after applying the - operator.

impl Sub<f64> for f64[src]

type Output = f64

The resulting type after applying the - operator.

impl PartialOrd<f64> for f64[src]

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

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

The resulting type after applying the + operator.

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

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

The resulting type after applying the + operator.

impl Add<f64> for f64[src]

type Output = f64

The resulting type after applying the + operator.

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

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

The resulting type after applying the + operator.

impl LowerExp for f64[src]

impl Display for f64[src]

impl Copy for f64[src]

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

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

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

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

impl Debug for f64[src]

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

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

The resulting type after applying the % operator.

impl Rem<f64> for f64[src]

The remainder from the division of two floats.

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

Examples

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

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

type Output = f64

The resulting type after applying the % operator.

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

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

The resulting type after applying the % operator.

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

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

The resulting type after applying the % operator.

impl UpperExp for f64[src]

Auto Trait Implementations

impl UnwindSafe for f64

impl RefUnwindSafe for f64

impl Unpin for f64

impl Send for f64

impl Sync for f64

Blanket Implementations

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

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

type Error = Infallible

The type returned in the event of a conversion error.

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

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

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

The type returned in the event of a conversion error.

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

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

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

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

type Owned = T

The resulting type after obtaining ownership.

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