Trait num_traits::float::FloatCore

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pub trait FloatCore: Num + NumCast + Neg<Output = Self> + PartialOrd + Copy {

Show 29 methods    // Required 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);

    // Provided methods
    fn is_nan(self) -> bool { ... }
    fn is_infinite(self) -> bool { ... }
    fn is_finite(self) -> bool { ... }
    fn is_normal(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§

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fn infinity() -> Self

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);
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fn neg_infinity() -> Self

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);
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fn nan() -> Self

Returns NaN.

Examples
use num_traits::float::FloatCore;

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

check::<f32>();
check::<f64>();
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fn neg_zero() -> Self

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);
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fn min_value() -> Self

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);
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fn min_positive_value() -> Self

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);
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fn epsilon() -> Self

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);
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fn max_value() -> Self

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);
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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.

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);
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fn to_degrees(self) -> Self

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);
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fn to_radians(self) -> Self

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);
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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.

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§

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fn is_nan(self) -> bool

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);
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fn is_infinite(self) -> bool

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);
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fn is_finite(self) -> bool

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);
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fn is_normal(self) -> bool

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);
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fn floor(self) -> Self

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);
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fn ceil(self) -> Self

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);
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fn round(self) -> Self

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);
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fn trunc(self) -> Self

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);
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fn fract(self) -> Self

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);
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fn abs(self) -> Self

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);
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fn signum(self) -> Self

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);
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fn is_sign_positive(self) -> bool

Returns true if self is positive, including +0.0 and FloatCore::infinity(), and since Rust 1.20 also 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, false);
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fn is_sign_negative(self) -> bool

Returns true if self is negative, including -0.0 and FloatCore::neg_infinity(), and since Rust 1.20 also -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);
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fn min(self, other: Self) -> Self

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);
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fn max(self, other: Self) -> Self

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);
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fn recip(self) -> Self

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);
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fn powi(self, exp: i32) -> Self

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§

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impl FloatCore for f32

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fn infinity() -> Self

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fn neg_infinity() -> Self

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fn nan() -> Self

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fn neg_zero() -> Self

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fn min_value() -> Self

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fn min_positive_value() -> Self

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fn epsilon() -> Self

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fn max_value() -> Self

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fn integer_decode(self) -> (u64, i16, i8)

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fn is_nan(self) -> bool

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fn is_infinite(self) -> bool

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fn is_finite(self) -> bool

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fn is_normal(self) -> bool

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fn classify(self) -> FpCategory

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fn floor(self) -> Self

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fn ceil(self) -> Self

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fn round(self) -> Self

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fn trunc(self) -> Self

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fn fract(self) -> Self

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fn abs(self) -> Self

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fn signum(self) -> Self

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fn is_sign_positive(self) -> bool

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fn is_sign_negative(self) -> bool

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fn min(self, other: Self) -> Self

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fn max(self, other: Self) -> Self

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fn recip(self) -> Self

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fn powi(self, n: i32) -> Self

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fn to_degrees(self) -> Self

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fn to_radians(self) -> Self

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impl FloatCore for f64

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fn infinity() -> Self

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fn neg_infinity() -> Self

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fn nan() -> Self

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fn neg_zero() -> Self

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fn min_value() -> Self

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fn min_positive_value() -> Self

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fn epsilon() -> Self

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fn max_value() -> Self

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fn integer_decode(self) -> (u64, i16, i8)

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fn is_nan(self) -> bool

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fn is_infinite(self) -> bool

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fn is_finite(self) -> bool

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fn is_normal(self) -> bool

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fn classify(self) -> FpCategory

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fn floor(self) -> Self

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fn ceil(self) -> Self

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fn round(self) -> Self

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fn trunc(self) -> Self

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fn fract(self) -> Self

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fn abs(self) -> Self

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fn signum(self) -> Self

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fn is_sign_positive(self) -> bool

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fn is_sign_negative(self) -> bool

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fn min(self, other: Self) -> Self

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fn max(self, other: Self) -> Self

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fn recip(self) -> Self

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fn powi(self, n: i32) -> Self

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fn to_degrees(self) -> Self

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fn to_radians(self) -> Self

Implementors§