Trait num_traits::float::FloatCore

source · [−]
pub trait FloatCore: Num + NumCast + Neg<Output = Self> + PartialOrd + Copy {

Show 30 methods    fn infinity() -> Self;
    fn neg_infinity() -> Self;
    fn nan() -> Self;
    fn neg_zero() -> Self;
    fn min_value() -> Self;
    fn min_positive_value() -> Self;
    fn epsilon() -> Self;
    fn max_value() -> Self;
    fn classify(self) -> FpCategory;
    fn to_degrees(self) -> Self;
    fn to_radians(self) -> Self;
    fn integer_decode(self) -> (u64, i16, i8);

    fn is_nan(self) -> bool { ... }
    fn is_infinite(self) -> bool { ... }
    fn is_finite(self) -> bool { ... }
    fn is_normal(self) -> bool { ... }
    fn is_subnormal(self) -> bool { ... }
    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 min(self, other: Self) -> Self { ... }
    fn max(self, other: Self) -> Self { ... }
    fn recip(self) -> Self { ... }
    fn powi(self, exp: i32) -> Self { ... }

}
Expand description

Generic trait for floating point numbers that works with no_std.

This trait implements a subset of the Float trait.

Required Methods

Returns positive infinity.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T) {
    assert!(T::infinity() == x);
}

check(f32::INFINITY);
check(f64::INFINITY);

Returns negative infinity.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T) {
    assert!(T::neg_infinity() == x);
}

check(f32::NEG_INFINITY);
check(f64::NEG_INFINITY);

Returns NaN.

Examples
use num_traits::float::FloatCore;

fn check<T: FloatCore>() {
    let n = T::nan();
    assert!(n != n);
}

check::<f32>();
check::<f64>();

Returns -0.0.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(n: T) {
    let z = T::neg_zero();
    assert!(z.is_zero());
    assert!(T::one() / z == n);
}

check(f32::NEG_INFINITY);
check(f64::NEG_INFINITY);

Returns the smallest finite value that this type can represent.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T) {
    assert!(T::min_value() == x);
}

check(f32::MIN);
check(f64::MIN);

Returns the smallest positive, normalized value that this type can represent.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T) {
    assert!(T::min_positive_value() == x);
}

check(f32::MIN_POSITIVE);
check(f64::MIN_POSITIVE);

Returns epsilon, a small positive value.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T) {
    assert!(T::epsilon() == x);
}

check(f32::EPSILON);
check(f64::EPSILON);

Returns the largest finite value that this type can represent.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T) {
    assert!(T::max_value() == x);
}

check(f32::MAX);
check(f64::MAX);

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.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};
use std::num::FpCategory;

fn check<T: FloatCore>(x: T, c: FpCategory) {
    assert!(x.classify() == c);
}

check(f32::INFINITY, FpCategory::Infinite);
check(f32::MAX, FpCategory::Normal);
check(f64::NAN, FpCategory::Nan);
check(f64::MIN_POSITIVE, FpCategory::Normal);
check(f64::MIN_POSITIVE / 2.0, FpCategory::Subnormal);
check(0.0f64, FpCategory::Zero);

Converts to degrees, assuming the number is in radians.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(rad: T, deg: T) {
    assert!(rad.to_degrees() == deg);
}

check(0.0f32, 0.0);
check(f32::consts::PI, 180.0);
check(f64::consts::FRAC_PI_4, 45.0);
check(f64::INFINITY, f64::INFINITY);

Converts to radians, assuming the number is in degrees.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(deg: T, rad: T) {
    assert!(deg.to_radians() == rad);
}

check(0.0f32, 0.0);
check(180.0, f32::consts::PI);
check(45.0, f64::consts::FRAC_PI_4);
check(f64::INFINITY, f64::INFINITY);

Returns the mantissa, base 2 exponent, and sign as integers, respectively. The original number can be recovered by sign * mantissa * 2 ^ exponent.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, m: u64, e: i16, s:i8) {
    let (mantissa, exponent, sign) = x.integer_decode();
    assert_eq!(mantissa, m);
    assert_eq!(exponent, e);
    assert_eq!(sign, s);
}

check(2.0f32, 1 << 23, -22, 1);
check(-2.0f32, 1 << 23, -22, -1);
check(f32::INFINITY, 1 << 23, 105, 1);
check(f64::NEG_INFINITY, 1 << 52, 972, -1);

Provided Methods

Returns true if the number is NaN.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, p: bool) {
    assert!(x.is_nan() == p);
}

check(f32::NAN, true);
check(f32::INFINITY, false);
check(f64::NAN, true);
check(0.0f64, false);

Returns true if the number is infinite.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, p: bool) {
    assert!(x.is_infinite() == p);
}

check(f32::INFINITY, true);
check(f32::NEG_INFINITY, true);
check(f32::NAN, false);
check(f64::INFINITY, true);
check(f64::NEG_INFINITY, true);
check(0.0f64, false);

Returns true if the number is neither infinite or NaN.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, p: bool) {
    assert!(x.is_finite() == p);
}

check(f32::INFINITY, false);
check(f32::MAX, true);
check(f64::NEG_INFINITY, false);
check(f64::MIN_POSITIVE, true);
check(f64::NAN, false);

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

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, p: bool) {
    assert!(x.is_normal() == p);
}

check(f32::INFINITY, false);
check(f32::MAX, true);
check(f64::NEG_INFINITY, false);
check(f64::MIN_POSITIVE, true);
check(0.0f64, false);

Returns true if the number is subnormal.

use num_traits::float::FloatCore;
use std::f64;

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());

Returns the largest integer less than or equal to a number.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, y: T) {
    assert!(x.floor() == y);
}

check(f32::INFINITY, f32::INFINITY);
check(0.9f32, 0.0);
check(1.0f32, 1.0);
check(1.1f32, 1.0);
check(-0.0f64, 0.0);
check(-0.9f64, -1.0);
check(-1.0f64, -1.0);
check(-1.1f64, -2.0);
check(f64::MIN, f64::MIN);

Returns the smallest integer greater than or equal to a number.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, y: T) {
    assert!(x.ceil() == y);
}

check(f32::INFINITY, f32::INFINITY);
check(0.9f32, 1.0);
check(1.0f32, 1.0);
check(1.1f32, 2.0);
check(-0.0f64, 0.0);
check(-0.9f64, -0.0);
check(-1.0f64, -1.0);
check(-1.1f64, -1.0);
check(f64::MIN, f64::MIN);

Returns the nearest integer to a number. Round half-way cases away from 0.0.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, y: T) {
    assert!(x.round() == y);
}

check(f32::INFINITY, f32::INFINITY);
check(0.4f32, 0.0);
check(0.5f32, 1.0);
check(0.6f32, 1.0);
check(-0.4f64, 0.0);
check(-0.5f64, -1.0);
check(-0.6f64, -1.0);
check(f64::MIN, f64::MIN);

Return the integer part of a number.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, y: T) {
    assert!(x.trunc() == y);
}

check(f32::INFINITY, f32::INFINITY);
check(0.9f32, 0.0);
check(1.0f32, 1.0);
check(1.1f32, 1.0);
check(-0.0f64, 0.0);
check(-0.9f64, -0.0);
check(-1.0f64, -1.0);
check(-1.1f64, -1.0);
check(f64::MIN, f64::MIN);

Returns the fractional part of a number.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, y: T) {
    assert!(x.fract() == y);
}

check(f32::MAX, 0.0);
check(0.75f32, 0.75);
check(1.0f32, 0.0);
check(1.25f32, 0.25);
check(-0.0f64, 0.0);
check(-0.75f64, -0.75);
check(-1.0f64, 0.0);
check(-1.25f64, -0.25);
check(f64::MIN, 0.0);

Computes the absolute value of self. Returns FloatCore::nan() if the number is FloatCore::nan().

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, y: T) {
    assert!(x.abs() == y);
}

check(f32::INFINITY, f32::INFINITY);
check(1.0f32, 1.0);
check(0.0f64, 0.0);
check(-0.0f64, 0.0);
check(-1.0f64, 1.0);
check(f64::MIN, f64::MAX);

Returns a number that represents the sign of self.

  • 1.0 if the number is positive, +0.0 or FloatCore::infinity()
  • -1.0 if the number is negative, -0.0 or FloatCore::neg_infinity()
  • FloatCore::nan() if the number is FloatCore::nan()
Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, y: T) {
    assert!(x.signum() == y);
}

check(f32::INFINITY, 1.0);
check(3.0f32, 1.0);
check(0.0f32, 1.0);
check(-0.0f64, -1.0);
check(-3.0f64, -1.0);
check(f64::MIN, -1.0);

Returns true if self is positive, including +0.0 and FloatCore::infinity(), and FloatCore::nan().

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, p: bool) {
    assert!(x.is_sign_positive() == p);
}

check(f32::INFINITY, true);
check(f32::MAX, true);
check(0.0f32, true);
check(-0.0f64, false);
check(f64::NEG_INFINITY, false);
check(f64::MIN_POSITIVE, true);
check(f64::NAN, true);
check(-f64::NAN, false);

Returns true if self is negative, including -0.0 and FloatCore::neg_infinity(), and -FloatCore::nan().

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, p: bool) {
    assert!(x.is_sign_negative() == p);
}

check(f32::INFINITY, false);
check(f32::MAX, false);
check(0.0f32, false);
check(-0.0f64, true);
check(f64::NEG_INFINITY, true);
check(f64::MIN_POSITIVE, false);
check(f64::NAN, false);
check(-f64::NAN, true);

Returns the minimum of the two numbers.

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

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, y: T, min: T) {
    assert!(x.min(y) == min);
}

check(1.0f32, 2.0, 1.0);
check(f32::NAN, 2.0, 2.0);
check(1.0f64, -2.0, -2.0);
check(1.0f64, f64::NAN, 1.0);

Returns the maximum of the two numbers.

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

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, y: T, max: T) {
    assert!(x.max(y) == max);
}

check(1.0f32, 2.0, 2.0);
check(1.0f32, f32::NAN, 1.0);
check(-1.0f64, 2.0, 2.0);
check(-1.0f64, f64::NAN, -1.0);

Returns the reciprocal (multiplicative inverse) of the number.

Examples
use num_traits::float::FloatCore;
use std::{f32, f64};

fn check<T: FloatCore>(x: T, y: T) {
    assert!(x.recip() == y);
    assert!(y.recip() == x);
}

check(f32::INFINITY, 0.0);
check(2.0f32, 0.5);
check(-0.25f64, -4.0);
check(-0.0f64, f64::NEG_INFINITY);

Raise a number to an integer power.

Using this function is generally faster than using powf

Examples
use num_traits::float::FloatCore;

fn check<T: FloatCore>(x: T, exp: i32, powi: T) {
    assert!(x.powi(exp) == powi);
}

check(9.0f32, 2, 81.0);
check(1.0f32, -2, 1.0);
check(10.0f64, 20, 1e20);
check(4.0f64, -2, 0.0625);
check(-1.0f64, std::i32::MIN, 1.0);

Implementations on Foreign Types

Implementors