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.
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
orINFINITY
-1.0
if the number is negative,-0.0
orNEG_INFINITY
NAN
if the number isNAN
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 * 2.0Run
#[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]
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]
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());Run
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());Run
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());Run
pub fn is_subnormal(self) -> bool
[src]
Returns true
if the number is subnormal.
#![feature(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 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());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; 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]
f64: FloatToInt<Int>,
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 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 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 as_ne_bytes(&self) -> &[u8; 8]
[src]
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 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]
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]
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]
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]
impl Add<f64> for f64
[src]
type Output = f64
The resulting type after applying the +
operator.
pub fn add(self, other: f64) -> f64
[src]
impl<'_> AddAssign<&'_ f64> for f64
1.22.0[src]
pub fn add_assign(&mut self, other: &f64)
[src]
impl AddAssign<f64> for f64
1.8.0[src]
pub fn add_assign(&mut self, other: f64)
[src]
impl Clone for f64
[src]
impl Copy for f64
[src]
impl Debug for f64
[src]
impl Default for f64
[src]
impl Display for f64
[src]
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]
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]
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]
impl Div<f64> for f64
[src]
type Output = f64
The resulting type after applying the /
operator.
pub fn div(self, other: f64) -> f64
[src]
impl<'_> DivAssign<&'_ f64> for f64
1.22.0[src]
pub fn div_assign(&mut self, other: &f64)
[src]
impl DivAssign<f64> for f64
1.8.0[src]
pub fn div_assign(&mut self, other: 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]
impl From<f32> for f64
1.6.0[src]
Converts f32
to f64
losslessly.
impl From<i16> for f64
1.6.0[src]
Converts i16
to f64
losslessly.
impl From<i32> for f64
1.6.0[src]
Converts i32
to f64
losslessly.
impl From<i8> for f64
1.6.0[src]
Converts i8
to f64
losslessly.
impl From<u16> for f64
1.6.0[src]
Converts u16
to f64
losslessly.
impl From<u32> for f64
1.6.0[src]
Converts u32
to f64
losslessly.
impl From<u8> for f64
1.6.0[src]
Converts u8
to f64
losslessly.
impl FromStr for f64
[src]
type Err = ParseFloatError
The associated error which can be returned from parsing.
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
.
impl LowerExp for f64
[src]
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]
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]
impl Mul<f64> for f64
[src]
type Output = f64
The resulting type after applying the *
operator.
pub fn mul(self, other: f64) -> f64
[src]
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]
impl<'_> MulAssign<&'_ f64> for f64
1.22.0[src]
pub fn mul_assign(&mut self, other: &f64)
[src]
impl MulAssign<f64> for f64
1.8.0[src]
pub fn mul_assign(&mut self, other: f64)
[src]
impl Neg for f64
[src]
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]
impl PartialEq<f64> for f64
[src]
impl PartialOrd<f64> for f64
[src]
pub fn partial_cmp(&self, other: &f64) -> Option<Ordering>
[src]
pub fn lt(&self, other: &f64) -> bool
[src]
pub fn le(&self, other: &f64) -> bool
[src]
pub fn ge(&self, other: &f64) -> bool
[src]
pub fn gt(&self, other: &f64) -> bool
[src]
impl<'a> Product<&'a f64> for f64
1.12.0[src]
impl Product<f64> for f64
1.12.0[src]
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]
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]
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]
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]
impl<'_> RemAssign<&'_ f64> for f64
1.22.0[src]
pub fn rem_assign(&mut self, other: &f64)
[src]
impl RemAssign<f64> for f64
1.8.0[src]
pub fn rem_assign(&mut self, other: f64)
[src]
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]
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]
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]
impl Sub<f64> for f64
[src]
type Output = f64
The resulting type after applying the -
operator.
pub fn sub(self, other: f64) -> f64
[src]
impl<'_> SubAssign<&'_ f64> for f64
1.22.0[src]
pub fn sub_assign(&mut self, other: &f64)
[src]
impl SubAssign<f64> for f64
1.8.0[src]
pub fn sub_assign(&mut self, other: f64)
[src]
impl<'a> Sum<&'a f64> for f64
1.12.0[src]
impl Sum<f64> for f64
1.12.0[src]
impl UpperExp 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]
T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
T: ?Sized,
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]
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
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
T: ?Sized,
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]
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
impl<T> From<T> for T
[src]
impl<T, U> Into<U> for T where
U: From<T>,
[src]
U: From<T>,
impl<T> ToOwned for T where
T: Clone,
[src]
T: Clone,
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
[src]
pub fn clone_into(&self, target: &mut T)
[src]
impl<T> ToString for T where
T: Display + ?Sized,
[src]
T: Display + ?Sized,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
[src]
U: Into<T>,
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]
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
[src]
U: TryFrom<T>,