Trait num::Float
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pub trait Float: Copy + NumCast + Num + Neg<Output=Self> + PartialOrd<Self> { fn nan() -> Self; fn infinity() -> Self; fn neg_infinity() -> Self; fn neg_zero() -> Self; fn min_value() -> Self; fn min_positive_value() -> Self; fn max_value() -> Self; fn is_nan(self) -> bool; fn is_infinite(self) -> bool; fn is_finite(self) -> bool; fn is_normal(self) -> bool; fn classify(self) -> FpCategory; fn floor(self) -> Self; fn ceil(self) -> Self; fn round(self) -> Self; fn trunc(self) -> Self; fn fract(self) -> Self; fn abs(self) -> Self; fn signum(self) -> Self; fn is_sign_positive(self) -> bool; fn is_sign_negative(self) -> bool; fn mul_add(self, a: Self, b: Self) -> Self; fn recip(self) -> Self; fn powi(self, n: i32) -> Self; fn powf(self, n: Self) -> Self; fn sqrt(self) -> Self; fn exp(self) -> Self; fn exp2(self) -> Self; fn ln(self) -> Self; fn log(self, base: Self) -> Self; fn log2(self) -> Self; fn log10(self) -> Self; fn max(self, other: Self) -> Self; fn min(self, other: Self) -> Self; fn abs_sub(self, other: Self) -> Self; fn cbrt(self) -> Self; fn hypot(self, other: Self) -> Self; fn sin(self) -> Self; fn cos(self) -> Self; fn tan(self) -> Self; fn asin(self) -> Self; fn acos(self) -> Self; fn atan(self) -> Self; fn atan2(self, other: Self) -> Self; fn sin_cos(self) -> (Self, Self); fn exp_m1(self) -> Self; fn ln_1p(self) -> Self; fn sinh(self) -> Self; fn cosh(self) -> Self; fn tanh(self) -> Self; fn asinh(self) -> Self; fn acosh(self) -> Self; fn atanh(self) -> Self; fn integer_decode(self) -> (u64, i16, i8); fn epsilon() -> Self { ... } fn to_degrees(self) -> Self { ... } fn to_radians(self) -> Self { ... } }
Required Methods
fn nan() -> Self
Returns the NaN value.
use num_traits::Float; let nan: f32 = Float::nan(); assert!(nan.is_nan());Run
fn infinity() -> Self
Returns the infinite value.
extern crate num; fn main() { use num_traits::Float; use std::f32; let infinity: f32 = Float::infinity(); assert!(infinity.is_infinite()); assert!(!infinity.is_finite()); assert!(infinity > f32::MAX); }use num_traits::Float; use std::f32; let infinity: f32 = Float::infinity(); assert!(infinity.is_infinite()); assert!(!infinity.is_finite()); assert!(infinity > f32::MAX);Run
fn neg_infinity() -> Self
Returns the negative infinite value.
extern crate num; fn main() { use num_traits::Float; use std::f32; let neg_infinity: f32 = Float::neg_infinity(); assert!(neg_infinity.is_infinite()); assert!(!neg_infinity.is_finite()); assert!(neg_infinity < f32::MIN); }use num_traits::Float; use std::f32; let neg_infinity: f32 = Float::neg_infinity(); assert!(neg_infinity.is_infinite()); assert!(!neg_infinity.is_finite()); assert!(neg_infinity < f32::MIN);Run
fn neg_zero() -> Self
Returns -0.0.
use num_traits::{Zero, Float}; let inf: f32 = Float::infinity(); let zero: f32 = Zero::zero(); let neg_zero: f32 = Float::neg_zero(); assert_eq!(zero, neg_zero); assert_eq!(7.0f32/inf, zero); assert_eq!(zero * 10.0, zero);Run
fn min_value() -> Self
Returns the smallest finite value that this type can represent.
extern crate num; fn main() { use num_traits::Float; use std::f64; let x: f64 = Float::min_value(); assert_eq!(x, f64::MIN); }use num_traits::Float; use std::f64; let x: f64 = Float::min_value(); assert_eq!(x, f64::MIN);Run
fn min_positive_value() -> Self
Returns the smallest positive, normalized value that this type can represent.
extern crate num; fn main() { use num_traits::Float; use std::f64; let x: f64 = Float::min_positive_value(); assert_eq!(x, f64::MIN_POSITIVE); }use num_traits::Float; use std::f64; let x: f64 = Float::min_positive_value(); assert_eq!(x, f64::MIN_POSITIVE);Run
fn max_value() -> Self
Returns the largest finite value that this type can represent.
extern crate num; fn main() { use num_traits::Float; use std::f64; let x: f64 = Float::max_value(); assert_eq!(x, f64::MAX); }use num_traits::Float; use std::f64; let x: f64 = Float::max_value(); assert_eq!(x, f64::MAX);Run
fn is_nan(self) -> bool
Returns true if this value is NaN and false otherwise.
use num_traits::Float; use std::f64; let nan = f64::NAN; let f = 7.0; assert!(nan.is_nan()); assert!(!f.is_nan());Run
fn is_infinite(self) -> bool
Returns true if this value is positive infinity or negative infinity and
false otherwise.
use num_traits::Float; use std::f32; let f = 7.0f32; let inf: f32 = Float::infinity(); let neg_inf: f32 = Float::neg_infinity(); let nan: f32 = f32::NAN; assert!(!f.is_infinite()); assert!(!nan.is_infinite()); assert!(inf.is_infinite()); assert!(neg_inf.is_infinite());Run
fn is_finite(self) -> bool
Returns true if this number is neither infinite nor NaN.
use num_traits::Float; use std::f32; let f = 7.0f32; let inf: f32 = Float::infinity(); let neg_inf: f32 = Float::neg_infinity(); let nan: f32 = f32::NAN; assert!(f.is_finite()); assert!(!nan.is_finite()); assert!(!inf.is_finite()); assert!(!neg_inf.is_finite());Run
fn is_normal(self) -> bool
Returns true if the number is neither zero, infinite,
subnormal, or NaN.
use num_traits::Float; use std::f32; let min = f32::MIN_POSITIVE; // 1.17549435e-38f32 let max = f32::MAX; let lower_than_min = 1.0e-40_f32; let zero = 0.0f32; assert!(min.is_normal()); assert!(max.is_normal()); assert!(!zero.is_normal()); assert!(!f32::NAN.is_normal()); assert!(!f32::INFINITY.is_normal()); // Values between `0` and `min` are Subnormal. assert!(!lower_than_min.is_normal());Run
fn classify(self) -> FpCategory
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.
extern crate num; fn main() { use num_traits::Float; use std::num::FpCategory; use std::f32; let num = 12.4f32; let inf = f32::INFINITY; assert_eq!(num.classify(), FpCategory::Normal); assert_eq!(inf.classify(), FpCategory::Infinite); }use num_traits::Float; use std::num::FpCategory; use std::f32; let num = 12.4f32; let inf = f32::INFINITY; assert_eq!(num.classify(), FpCategory::Normal); assert_eq!(inf.classify(), FpCategory::Infinite);Run
fn floor(self) -> Self
Returns the largest integer less than or equal to a number.
extern crate num; fn main() { use num_traits::Float; let f = 3.99; let g = 3.0; assert_eq!(f.floor(), 3.0); assert_eq!(g.floor(), 3.0); }use num_traits::Float; let f = 3.99; let g = 3.0; assert_eq!(f.floor(), 3.0); assert_eq!(g.floor(), 3.0);Run
fn ceil(self) -> Self
Returns the smallest integer greater than or equal to a number.
extern crate num; fn main() { use num_traits::Float; let f = 3.01; let g = 4.0; assert_eq!(f.ceil(), 4.0); assert_eq!(g.ceil(), 4.0); }use num_traits::Float; let f = 3.01; let g = 4.0; assert_eq!(f.ceil(), 4.0); assert_eq!(g.ceil(), 4.0);Run
fn round(self) -> Self
Returns the nearest integer to a number. Round half-way cases away from
0.0.
use num_traits::Float; let f = 3.3; let g = -3.3; assert_eq!(f.round(), 3.0); assert_eq!(g.round(), -3.0);Run
fn trunc(self) -> Self
Return the integer part of a number.
extern crate num; fn main() { use num_traits::Float; let f = 3.3; let g = -3.7; assert_eq!(f.trunc(), 3.0); assert_eq!(g.trunc(), -3.0); }use num_traits::Float; let f = 3.3; let g = -3.7; assert_eq!(f.trunc(), 3.0); assert_eq!(g.trunc(), -3.0);Run
fn fract(self) -> Self
Returns the fractional part of a number.
extern crate num; fn main() { use num_traits::Float; let x = 3.5; let y = -3.5; 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); }use num_traits::Float; let x = 3.5; let y = -3.5; 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
fn abs(self) -> Self
Computes the absolute value of self. Returns Float::nan() if the
number is Float::nan().
use num_traits::Float; use std::f64; let x = 3.5; let y = -3.5; 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
fn signum(self) -> Self
Returns a number that represents the sign of self.
1.0if the number is positive,+0.0orFloat::infinity()-1.0if the number is negative,-0.0orFloat::neg_infinity()Float::nan()if the number isFloat::nan()
use num_traits::Float; use std::f64; let f = 3.5; assert_eq!(f.signum(), 1.0); assert_eq!(f64::NEG_INFINITY.signum(), -1.0); assert!(f64::NAN.signum().is_nan());Run
fn is_sign_positive(self) -> bool
Returns true if self is positive, including +0.0 and
Float::infinity().
use num_traits::Float; use std::f64; let nan: f64 = f64::NAN; let f = 7.0; let g = -7.0; assert!(f.is_sign_positive()); assert!(!g.is_sign_positive()); // Requires both tests to determine if is `NaN` assert!(!nan.is_sign_positive() && !nan.is_sign_negative());Run
fn is_sign_negative(self) -> bool
Returns true if self is negative, including -0.0 and
Float::neg_infinity().
use num_traits::Float; use std::f64; let nan = f64::NAN; let f = 7.0; let g = -7.0; assert!(!f.is_sign_negative()); assert!(g.is_sign_negative()); // Requires both tests to determine if is `NaN`. assert!(!nan.is_sign_positive() && !nan.is_sign_negative());Run
fn mul_add(self, a: Self, b: Self) -> Self
Fused multiply-add. Computes (self * a) + b with only one rounding
error. This produces a more accurate result with better performance than
a separate multiplication operation followed by an add.
use num_traits::Float; let m = 10.0; let x = 4.0; let b = 60.0; // 100.0 let abs_difference = (m.mul_add(x, b) - (m*x + b)).abs(); assert!(abs_difference < 1e-10);Run
fn recip(self) -> Self
Take the reciprocal (inverse) of a number, 1/x.
use num_traits::Float; let x = 2.0; let abs_difference = (x.recip() - (1.0/x)).abs(); assert!(abs_difference < 1e-10);Run
fn powi(self, n: i32) -> Self
Raise a number to an integer power.
Using this function is generally faster than using powf
use num_traits::Float; let x = 2.0; let abs_difference = (x.powi(2) - x*x).abs(); assert!(abs_difference < 1e-10);Run
fn powf(self, n: Self) -> Self
Raise a number to a floating point power.
extern crate num; fn main() { use num_traits::Float; let x = 2.0; let abs_difference = (x.powf(2.0) - x*x).abs(); assert!(abs_difference < 1e-10); }use num_traits::Float; let x = 2.0; let abs_difference = (x.powf(2.0) - x*x).abs(); assert!(abs_difference < 1e-10);Run
fn sqrt(self) -> Self
Take the square root of a number.
Returns NaN if self is a negative number.
use num_traits::Float; let positive = 4.0; let negative = -4.0; let abs_difference = (positive.sqrt() - 2.0).abs(); assert!(abs_difference < 1e-10); assert!(negative.sqrt().is_nan());Run
fn exp(self) -> Self
Returns e^(self), (the exponential function).
use num_traits::Float; let one = 1.0; // e^1 let e = one.exp(); // ln(e) - 1 == 0 let abs_difference = (e.ln() - 1.0).abs(); assert!(abs_difference < 1e-10);Run
fn exp2(self) -> Self
Returns 2^(self).
use num_traits::Float; let f = 2.0; // 2^2 - 4 == 0 let abs_difference = (f.exp2() - 4.0).abs(); assert!(abs_difference < 1e-10);Run
fn ln(self) -> Self
Returns the natural logarithm of the number.
extern crate num; fn main() { use num_traits::Float; let one = 1.0; // e^1 let e = one.exp(); // ln(e) - 1 == 0 let abs_difference = (e.ln() - 1.0).abs(); assert!(abs_difference < 1e-10); }use num_traits::Float; let one = 1.0; // e^1 let e = one.exp(); // ln(e) - 1 == 0 let abs_difference = (e.ln() - 1.0).abs(); assert!(abs_difference < 1e-10);Run
fn log(self, base: Self) -> Self
Returns the logarithm of the number with respect to an arbitrary base.
extern crate num; fn main() { use num_traits::Float; let ten = 10.0; let two = 2.0; // log10(10) - 1 == 0 let abs_difference_10 = (ten.log(10.0) - 1.0).abs(); // log2(2) - 1 == 0 let abs_difference_2 = (two.log(2.0) - 1.0).abs(); assert!(abs_difference_10 < 1e-10); assert!(abs_difference_2 < 1e-10); }use num_traits::Float; let ten = 10.0; let two = 2.0; // log10(10) - 1 == 0 let abs_difference_10 = (ten.log(10.0) - 1.0).abs(); // log2(2) - 1 == 0 let abs_difference_2 = (two.log(2.0) - 1.0).abs(); assert!(abs_difference_10 < 1e-10); assert!(abs_difference_2 < 1e-10);Run
fn log2(self) -> Self
Returns the base 2 logarithm of the number.
extern crate num; fn main() { use num_traits::Float; let two = 2.0; // log2(2) - 1 == 0 let abs_difference = (two.log2() - 1.0).abs(); assert!(abs_difference < 1e-10); }use num_traits::Float; let two = 2.0; // log2(2) - 1 == 0 let abs_difference = (two.log2() - 1.0).abs(); assert!(abs_difference < 1e-10);Run
fn log10(self) -> Self
Returns the base 10 logarithm of the number.
extern crate num; fn main() { use num_traits::Float; let ten = 10.0; // log10(10) - 1 == 0 let abs_difference = (ten.log10() - 1.0).abs(); assert!(abs_difference < 1e-10); }use num_traits::Float; let ten = 10.0; // log10(10) - 1 == 0 let abs_difference = (ten.log10() - 1.0).abs(); assert!(abs_difference < 1e-10);Run
fn max(self, other: Self) -> Self
Returns the maximum of the two numbers.
extern crate num; fn main() { use num_traits::Float; let x = 1.0; let y = 2.0; assert_eq!(x.max(y), y); }use num_traits::Float; let x = 1.0; let y = 2.0; assert_eq!(x.max(y), y);Run
fn min(self, other: Self) -> Self
Returns the minimum of the two numbers.
extern crate num; fn main() { use num_traits::Float; let x = 1.0; let y = 2.0; assert_eq!(x.min(y), x); }use num_traits::Float; let x = 1.0; let y = 2.0; assert_eq!(x.min(y), x);Run
fn abs_sub(self, other: Self) -> Self
The positive difference of two numbers.
- If
self <= other:0:0 - Else:
self - other
use num_traits::Float; let x = 3.0; let y = -3.0; 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
fn cbrt(self) -> Self
Take the cubic root of a number.
extern crate num; fn main() { use num_traits::Float; let x = 8.0; // x^(1/3) - 2 == 0 let abs_difference = (x.cbrt() - 2.0).abs(); assert!(abs_difference < 1e-10); }use num_traits::Float; let x = 8.0; // x^(1/3) - 2 == 0 let abs_difference = (x.cbrt() - 2.0).abs(); assert!(abs_difference < 1e-10);Run
fn hypot(self, other: Self) -> Self
Calculate the length of the hypotenuse of a right-angle triangle given
legs of length x and y.
use num_traits::Float; let x = 2.0; let y = 3.0; // 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
fn sin(self) -> Self
Computes the sine of a number (in radians).
extern crate num; fn main() { use num_traits::Float; use std::f64; let x = f64::consts::PI/2.0; let abs_difference = (x.sin() - 1.0).abs(); assert!(abs_difference < 1e-10); }use num_traits::Float; use std::f64; let x = f64::consts::PI/2.0; let abs_difference = (x.sin() - 1.0).abs(); assert!(abs_difference < 1e-10);Run
fn cos(self) -> Self
Computes the cosine of a number (in radians).
extern crate num; fn main() { use num_traits::Float; use std::f64; let x = 2.0*f64::consts::PI; let abs_difference = (x.cos() - 1.0).abs(); assert!(abs_difference < 1e-10); }use num_traits::Float; use std::f64; let x = 2.0*f64::consts::PI; let abs_difference = (x.cos() - 1.0).abs(); assert!(abs_difference < 1e-10);Run
fn tan(self) -> Self
Computes the tangent of a number (in radians).
extern crate num; fn main() { use num_traits::Float; use std::f64; let x = f64::consts::PI/4.0; let abs_difference = (x.tan() - 1.0).abs(); assert!(abs_difference < 1e-14); }use num_traits::Float; use std::f64; let x = f64::consts::PI/4.0; let abs_difference = (x.tan() - 1.0).abs(); assert!(abs_difference < 1e-14);Run
fn asin(self) -> Self
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].
extern crate num; fn main() { use num_traits::Float; use std::f64; let f = f64::consts::PI / 2.0; // asin(sin(pi/2)) let abs_difference = (f.sin().asin() - f64::consts::PI / 2.0).abs(); assert!(abs_difference < 1e-10); }use num_traits::Float; use std::f64; let f = f64::consts::PI / 2.0; // asin(sin(pi/2)) let abs_difference = (f.sin().asin() - f64::consts::PI / 2.0).abs(); assert!(abs_difference < 1e-10);Run
fn acos(self) -> Self
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].
extern crate num; fn main() { use num_traits::Float; use std::f64; let f = f64::consts::PI / 4.0; // acos(cos(pi/4)) let abs_difference = (f.cos().acos() - f64::consts::PI / 4.0).abs(); assert!(abs_difference < 1e-10); }use num_traits::Float; use std::f64; let f = f64::consts::PI / 4.0; // acos(cos(pi/4)) let abs_difference = (f.cos().acos() - f64::consts::PI / 4.0).abs(); assert!(abs_difference < 1e-10);Run
fn atan(self) -> Self
Computes the arctangent of a number. Return value is in radians in the range [-pi/2, pi/2];
extern crate num; fn main() { use num_traits::Float; let f = 1.0; // atan(tan(1)) let abs_difference = (f.tan().atan() - 1.0).abs(); assert!(abs_difference < 1e-10); }use num_traits::Float; let f = 1.0; // atan(tan(1)) let abs_difference = (f.tan().atan() - 1.0).abs(); assert!(abs_difference < 1e-10);Run
fn atan2(self, other: Self) -> Self
Computes the four quadrant arctangent of self (y) and other (x).
x = 0,y = 0:0x >= 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)
use num_traits::Float; use std::f64; let pi = f64::consts::PI; // All angles from horizontal right (+x) // 45 deg counter-clockwise let x1 = 3.0; let y1 = -3.0; // 135 deg clockwise let x2 = -3.0; let y2 = 3.0; let abs_difference_1 = (y1.atan2(x1) - (-pi/4.0)).abs(); let abs_difference_2 = (y2.atan2(x2) - 3.0*pi/4.0).abs(); assert!(abs_difference_1 < 1e-10); assert!(abs_difference_2 < 1e-10);Run
fn sin_cos(self) -> (Self, Self)
Simultaneously computes the sine and cosine of the number, x. Returns
(sin(x), cos(x)).
use num_traits::Float; use std::f64; let x = f64::consts::PI/4.0; 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_0 < 1e-10);Run
fn exp_m1(self) -> Self
Returns e^(self) - 1 in a way that is accurate even if the
number is close to zero.
use num_traits::Float; let x = 7.0; // e^(ln(7)) - 1 let abs_difference = (x.ln().exp_m1() - 6.0).abs(); assert!(abs_difference < 1e-10);Run
fn ln_1p(self) -> Self
Returns ln(1+n) (natural logarithm) more accurately than if
the operations were performed separately.
use num_traits::Float; 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
fn sinh(self) -> Self
Hyperbolic sine function.
extern crate num; fn main() { use num_traits::Float; use std::f64; let e = f64::consts::E; let x = 1.0; 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); }use num_traits::Float; use std::f64; let e = f64::consts::E; let x = 1.0; 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
fn cosh(self) -> Self
Hyperbolic cosine function.
extern crate num; fn main() { use num_traits::Float; use std::f64; let e = f64::consts::E; let x = 1.0; 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); }use num_traits::Float; use std::f64; let e = f64::consts::E; let x = 1.0; 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
fn tanh(self) -> Self
Hyperbolic tangent function.
extern crate num; fn main() { use num_traits::Float; use std::f64; let e = f64::consts::E; let x = 1.0; 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); }use num_traits::Float; use std::f64; let e = f64::consts::E; let x = 1.0; 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
fn asinh(self) -> Self
Inverse hyperbolic sine function.
extern crate num; fn main() { use num_traits::Float; let x = 1.0; let f = x.sinh().asinh(); let abs_difference = (f - x).abs(); assert!(abs_difference < 1.0e-10); }use num_traits::Float; let x = 1.0; let f = x.sinh().asinh(); let abs_difference = (f - x).abs(); assert!(abs_difference < 1.0e-10);Run
fn acosh(self) -> Self
Inverse hyperbolic cosine function.
extern crate num; fn main() { use num_traits::Float; let x = 1.0; let f = x.cosh().acosh(); let abs_difference = (f - x).abs(); assert!(abs_difference < 1.0e-10); }use num_traits::Float; let x = 1.0; let f = x.cosh().acosh(); let abs_difference = (f - x).abs(); assert!(abs_difference < 1.0e-10);Run
fn atanh(self) -> Self
Inverse hyperbolic tangent function.
extern crate num; fn main() { use num_traits::Float; 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); }use num_traits::Float; 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
fn integer_decode(self) -> (u64, i16, i8)
Returns the mantissa, base 2 exponent, and sign as integers, respectively.
The original number can be recovered by sign * mantissa * 2 ^ exponent.
The floating point encoding is documented in the Reference.
use num_traits::Float; let num = 2.0f32; // (8388608, -22, 1) let (mantissa, exponent, sign) = Float::integer_decode(num); let sign_f = sign as f32; let mantissa_f = mantissa as f32; let exponent_f = num.powf(exponent as f32); // 1 * 8388608 * 2^(-22) == 2 let abs_difference = (sign_f * mantissa_f * exponent_f - num).abs(); assert!(abs_difference < 1e-10);Run
Provided Methods
fn epsilon() -> Self
Returns epsilon, a small positive value.
extern crate num; fn main() { use num_traits::Float; use std::f64; let x: f64 = Float::epsilon(); assert_eq!(x, f64::EPSILON); }use num_traits::Float; use std::f64; let x: f64 = Float::epsilon(); assert_eq!(x, f64::EPSILON);Run
Panics
The default implementation will panic if f32::EPSILON cannot
be cast to Self.
fn to_degrees(self) -> Self
Converts radians to degrees.
fn main() { use std::f64::consts; let angle = consts::PI; let abs_difference = (angle.to_degrees() - 180.0).abs(); assert!(abs_difference < 1e-10); }use std::f64::consts; let angle = consts::PI; let abs_difference = (angle.to_degrees() - 180.0).abs(); assert!(abs_difference < 1e-10);Run
fn to_radians(self) -> Self
Converts degrees to radians.
fn main() { use std::f64::consts; let angle = 180.0_f64; let abs_difference = (angle.to_radians() - consts::PI).abs(); assert!(abs_difference < 1e-10); }use std::f64::consts; let angle = 180.0_f64; let abs_difference = (angle.to_radians() - consts::PI).abs(); assert!(abs_difference < 1e-10);Run