| //! Constants for the `f32` single-precision floating point type. | |
| //! | |
| //! *[See also the `f32` primitive type][f32].* | |
| //! | |
| //! Mathematically significant numbers are provided in the `consts` sub-module. | |
| //! | |
| //! For the constants defined directly in this module | |
| //! (as distinct from those defined in the `consts` sub-module), | |
| //! new code should instead use the associated constants | |
| //! defined directly on the `f32` type. | |
| #![stable(feature = "rust1", since = "1.0.0")] | |
| use crate::convert::FloatToInt; | |
| use crate::num::FpCategory; | |
| use crate::panic::const_assert; | |
| use crate::{cfg_select, intrinsics, mem}; | |
| /// The radix or base of the internal representation of `f32`. | |
| /// Use [`f32::RADIX`] instead. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let r = std::f32::RADIX; | |
| /// | |
| /// // intended way | |
| /// let r = f32::RADIX; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated(since = "TBD", note = "replaced by the `RADIX` associated constant on `f32`")] | |
| #[rustc_diagnostic_item = "f32_legacy_const_radix"] | |
| pub const RADIX: u32 = f32::RADIX; | |
| /// Number of significant digits in base 2. | |
| /// Use [`f32::MANTISSA_DIGITS`] instead. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let d = std::f32::MANTISSA_DIGITS; | |
| /// | |
| /// // intended way | |
| /// let d = f32::MANTISSA_DIGITS; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated( | |
| since = "TBD", | |
| note = "replaced by the `MANTISSA_DIGITS` associated constant on `f32`" | |
| )] | |
| #[rustc_diagnostic_item = "f32_legacy_const_mantissa_dig"] | |
| pub const MANTISSA_DIGITS: u32 = f32::MANTISSA_DIGITS; | |
| /// Approximate number of significant digits in base 10. | |
| /// Use [`f32::DIGITS`] instead. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let d = std::f32::DIGITS; | |
| /// | |
| /// // intended way | |
| /// let d = f32::DIGITS; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated(since = "TBD", note = "replaced by the `DIGITS` associated constant on `f32`")] | |
| #[rustc_diagnostic_item = "f32_legacy_const_digits"] | |
| pub const DIGITS: u32 = f32::DIGITS; | |
| /// [Machine epsilon] value for `f32`. | |
| /// Use [`f32::EPSILON`] instead. | |
| /// | |
| /// This is the difference between `1.0` and the next larger representable number. | |
| /// | |
| /// [Machine epsilon]: https://en.wikipedia.org/wiki/Machine_epsilon | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let e = std::f32::EPSILON; | |
| /// | |
| /// // intended way | |
| /// let e = f32::EPSILON; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated(since = "TBD", note = "replaced by the `EPSILON` associated constant on `f32`")] | |
| #[rustc_diagnostic_item = "f32_legacy_const_epsilon"] | |
| pub const EPSILON: f32 = f32::EPSILON; | |
| /// Smallest finite `f32` value. | |
| /// Use [`f32::MIN`] instead. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let min = std::f32::MIN; | |
| /// | |
| /// // intended way | |
| /// let min = f32::MIN; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on `f32`")] | |
| #[rustc_diagnostic_item = "f32_legacy_const_min"] | |
| pub const MIN: f32 = f32::MIN; | |
| /// Smallest positive normal `f32` value. | |
| /// Use [`f32::MIN_POSITIVE`] instead. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let min = std::f32::MIN_POSITIVE; | |
| /// | |
| /// // intended way | |
| /// let min = f32::MIN_POSITIVE; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated(since = "TBD", note = "replaced by the `MIN_POSITIVE` associated constant on `f32`")] | |
| #[rustc_diagnostic_item = "f32_legacy_const_min_positive"] | |
| pub const MIN_POSITIVE: f32 = f32::MIN_POSITIVE; | |
| /// Largest finite `f32` value. | |
| /// Use [`f32::MAX`] instead. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let max = std::f32::MAX; | |
| /// | |
| /// // intended way | |
| /// let max = f32::MAX; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on `f32`")] | |
| #[rustc_diagnostic_item = "f32_legacy_const_max"] | |
| pub const MAX: f32 = f32::MAX; | |
| /// One greater than the minimum possible normal power of 2 exponent. | |
| /// Use [`f32::MIN_EXP`] instead. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let min = std::f32::MIN_EXP; | |
| /// | |
| /// // intended way | |
| /// let min = f32::MIN_EXP; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated(since = "TBD", note = "replaced by the `MIN_EXP` associated constant on `f32`")] | |
| #[rustc_diagnostic_item = "f32_legacy_const_min_exp"] | |
| pub const MIN_EXP: i32 = f32::MIN_EXP; | |
| /// Maximum possible power of 2 exponent. | |
| /// Use [`f32::MAX_EXP`] instead. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let max = std::f32::MAX_EXP; | |
| /// | |
| /// // intended way | |
| /// let max = f32::MAX_EXP; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated(since = "TBD", note = "replaced by the `MAX_EXP` associated constant on `f32`")] | |
| #[rustc_diagnostic_item = "f32_legacy_const_max_exp"] | |
| pub const MAX_EXP: i32 = f32::MAX_EXP; | |
| /// Minimum possible normal power of 10 exponent. | |
| /// Use [`f32::MIN_10_EXP`] instead. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let min = std::f32::MIN_10_EXP; | |
| /// | |
| /// // intended way | |
| /// let min = f32::MIN_10_EXP; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated(since = "TBD", note = "replaced by the `MIN_10_EXP` associated constant on `f32`")] | |
| #[rustc_diagnostic_item = "f32_legacy_const_min_10_exp"] | |
| pub const MIN_10_EXP: i32 = f32::MIN_10_EXP; | |
| /// Maximum possible power of 10 exponent. | |
| /// Use [`f32::MAX_10_EXP`] instead. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let max = std::f32::MAX_10_EXP; | |
| /// | |
| /// // intended way | |
| /// let max = f32::MAX_10_EXP; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated(since = "TBD", note = "replaced by the `MAX_10_EXP` associated constant on `f32`")] | |
| #[rustc_diagnostic_item = "f32_legacy_const_max_10_exp"] | |
| pub const MAX_10_EXP: i32 = f32::MAX_10_EXP; | |
| /// Not a Number (NaN). | |
| /// Use [`f32::NAN`] instead. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let nan = std::f32::NAN; | |
| /// | |
| /// // intended way | |
| /// let nan = f32::NAN; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated(since = "TBD", note = "replaced by the `NAN` associated constant on `f32`")] | |
| #[rustc_diagnostic_item = "f32_legacy_const_nan"] | |
| pub const NAN: f32 = f32::NAN; | |
| /// Infinity (∞). | |
| /// Use [`f32::INFINITY`] instead. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let inf = std::f32::INFINITY; | |
| /// | |
| /// // intended way | |
| /// let inf = f32::INFINITY; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated(since = "TBD", note = "replaced by the `INFINITY` associated constant on `f32`")] | |
| #[rustc_diagnostic_item = "f32_legacy_const_infinity"] | |
| pub const INFINITY: f32 = f32::INFINITY; | |
| /// Negative infinity (−∞). | |
| /// Use [`f32::NEG_INFINITY`] instead. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ```rust | |
| /// // deprecated way | |
| /// # #[allow(deprecated, deprecated_in_future)] | |
| /// let ninf = std::f32::NEG_INFINITY; | |
| /// | |
| /// // intended way | |
| /// let ninf = f32::NEG_INFINITY; | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated(since = "TBD", note = "replaced by the `NEG_INFINITY` associated constant on `f32`")] | |
| #[rustc_diagnostic_item = "f32_legacy_const_neg_infinity"] | |
| pub const NEG_INFINITY: f32 = f32::NEG_INFINITY; | |
| /// Basic mathematical constants. | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[rustc_diagnostic_item = "f32_consts_mod"] | |
| pub mod consts { | |
| // FIXME: replace with mathematical constants from cmath. | |
| /// Archimedes' constant (Ï€) | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const PI: f32 = 3.14159265358979323846264338327950288_f32; | |
| /// The full circle constant (Ï„) | |
| /// | |
| /// Equal to 2Ï€. | |
| #[stable(feature = "tau_constant", since = "1.47.0")] | |
| pub const TAU: f32 = 6.28318530717958647692528676655900577_f32; | |
| /// The golden ratio (φ) | |
| #[stable(feature = "euler_gamma_golden_ratio", since = "1.94.0")] | |
| pub const GOLDEN_RATIO: f32 = 1.618033988749894848204586834365638118_f32; | |
| /// The Euler-Mascheroni constant (γ) | |
| #[stable(feature = "euler_gamma_golden_ratio", since = "1.94.0")] | |
| pub const EULER_GAMMA: f32 = 0.577215664901532860606512090082402431_f32; | |
| /// π/2 | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const FRAC_PI_2: f32 = 1.57079632679489661923132169163975144_f32; | |
| /// π/3 | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const FRAC_PI_3: f32 = 1.04719755119659774615421446109316763_f32; | |
| /// π/4 | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const FRAC_PI_4: f32 = 0.785398163397448309615660845819875721_f32; | |
| /// π/6 | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const FRAC_PI_6: f32 = 0.52359877559829887307710723054658381_f32; | |
| /// π/8 | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const FRAC_PI_8: f32 = 0.39269908169872415480783042290993786_f32; | |
| /// 1/Ï€ | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const FRAC_1_PI: f32 = 0.318309886183790671537767526745028724_f32; | |
| /// 1/sqrt(Ï€) | |
| #[unstable(feature = "more_float_constants", issue = "146939")] | |
| pub const FRAC_1_SQRT_PI: f32 = 0.564189583547756286948079451560772586_f32; | |
| /// 1/sqrt(2Ï€) | |
| #[doc(alias = "FRAC_1_SQRT_TAU")] | |
| #[unstable(feature = "more_float_constants", issue = "146939")] | |
| pub const FRAC_1_SQRT_2PI: f32 = 0.398942280401432677939946059934381868_f32; | |
| /// 2/Ï€ | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const FRAC_2_PI: f32 = 0.636619772367581343075535053490057448_f32; | |
| /// 2/sqrt(Ï€) | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const FRAC_2_SQRT_PI: f32 = 1.12837916709551257389615890312154517_f32; | |
| /// sqrt(2) | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const SQRT_2: f32 = 1.41421356237309504880168872420969808_f32; | |
| /// 1/sqrt(2) | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const FRAC_1_SQRT_2: f32 = 0.707106781186547524400844362104849039_f32; | |
| /// sqrt(3) | |
| #[unstable(feature = "more_float_constants", issue = "146939")] | |
| pub const SQRT_3: f32 = 1.732050807568877293527446341505872367_f32; | |
| /// 1/sqrt(3) | |
| #[unstable(feature = "more_float_constants", issue = "146939")] | |
| pub const FRAC_1_SQRT_3: f32 = 0.577350269189625764509148780501957456_f32; | |
| /// sqrt(5) | |
| #[unstable(feature = "more_float_constants", issue = "146939")] | |
| pub const SQRT_5: f32 = 2.23606797749978969640917366873127623_f32; | |
| /// 1/sqrt(5) | |
| #[unstable(feature = "more_float_constants", issue = "146939")] | |
| pub const FRAC_1_SQRT_5: f32 = 0.44721359549995793928183473374625524_f32; | |
| /// Euler's number (e) | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const E: f32 = 2.71828182845904523536028747135266250_f32; | |
| /// log<sub>2</sub>(e) | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const LOG2_E: f32 = 1.44269504088896340735992468100189214_f32; | |
| /// log<sub>2</sub>(10) | |
| #[stable(feature = "extra_log_consts", since = "1.43.0")] | |
| pub const LOG2_10: f32 = 3.32192809488736234787031942948939018_f32; | |
| /// log<sub>10</sub>(e) | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const LOG10_E: f32 = 0.434294481903251827651128918916605082_f32; | |
| /// log<sub>10</sub>(2) | |
| #[stable(feature = "extra_log_consts", since = "1.43.0")] | |
| pub const LOG10_2: f32 = 0.301029995663981195213738894724493027_f32; | |
| /// ln(2) | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const LN_2: f32 = 0.693147180559945309417232121458176568_f32; | |
| /// ln(10) | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| pub const LN_10: f32 = 2.30258509299404568401799145468436421_f32; | |
| } | |
| #[doc(test(attr(allow(unused_features))))] | |
| impl f32 { | |
| /// The radix or base of the internal representation of `f32`. | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| pub const RADIX: u32 = 2; | |
| /// The size of this float type in bits. | |
| #[unstable(feature = "float_bits_const", issue = "151073")] | |
| pub const BITS: u32 = 32; | |
| /// Number of significant digits in base 2. | |
| /// | |
| /// Note that the size of the mantissa in the bitwise representation is one | |
| /// smaller than this since the leading 1 is not stored explicitly. | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| pub const MANTISSA_DIGITS: u32 = 24; | |
| /// Approximate number of significant digits in base 10. | |
| /// | |
| /// This is the maximum <i>x</i> such that any decimal number with <i>x</i> | |
| /// significant digits can be converted to `f32` and back without loss. | |
| /// | |
| /// Equal to floor(log<sub>10</sub> 2<sup>[`MANTISSA_DIGITS`] − 1</sup>). | |
| /// | |
| /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| pub const DIGITS: u32 = 6; | |
| /// [Machine epsilon] value for `f32`. | |
| /// | |
| /// This is the difference between `1.0` and the next larger representable number. | |
| /// | |
| /// Equal to 2<sup>1 − [`MANTISSA_DIGITS`]</sup>. | |
| /// | |
| /// [Machine epsilon]: https://en.wikipedia.org/wiki/Machine_epsilon | |
| /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| #[rustc_diagnostic_item = "f32_epsilon"] | |
| pub const EPSILON: f32 = 1.19209290e-07_f32; | |
| /// Smallest finite `f32` value. | |
| /// | |
| /// Equal to −[`MAX`]. | |
| /// | |
| /// [`MAX`]: f32::MAX | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| pub const MIN: f32 = -3.40282347e+38_f32; | |
| /// Smallest positive normal `f32` value. | |
| /// | |
| /// Equal to 2<sup>[`MIN_EXP`] − 1</sup>. | |
| /// | |
| /// [`MIN_EXP`]: f32::MIN_EXP | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| pub const MIN_POSITIVE: f32 = 1.17549435e-38_f32; | |
| /// Largest finite `f32` value. | |
| /// | |
| /// Equal to | |
| /// (1 − 2<sup>−[`MANTISSA_DIGITS`]</sup>) 2<sup>[`MAX_EXP`]</sup>. | |
| /// | |
| /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS | |
| /// [`MAX_EXP`]: f32::MAX_EXP | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| pub const MAX: f32 = 3.40282347e+38_f32; | |
| /// One greater than the minimum possible *normal* power of 2 exponent | |
| /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition). | |
| /// | |
| /// This corresponds to the exact minimum possible *normal* power of 2 exponent | |
| /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition). | |
| /// In other words, all normal numbers representable by this type are | |
| /// greater than or equal to 0.5 × 2<sup><i>MIN_EXP</i></sup>. | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| pub const MIN_EXP: i32 = -125; | |
| /// One greater than the maximum possible power of 2 exponent | |
| /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition). | |
| /// | |
| /// This corresponds to the exact maximum possible power of 2 exponent | |
| /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition). | |
| /// In other words, all numbers representable by this type are | |
| /// strictly less than 2<sup><i>MAX_EXP</i></sup>. | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| pub const MAX_EXP: i32 = 128; | |
| /// Minimum <i>x</i> for which 10<sup><i>x</i></sup> is normal. | |
| /// | |
| /// Equal to ceil(log<sub>10</sub> [`MIN_POSITIVE`]). | |
| /// | |
| /// [`MIN_POSITIVE`]: f32::MIN_POSITIVE | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| pub const MIN_10_EXP: i32 = -37; | |
| /// Maximum <i>x</i> for which 10<sup><i>x</i></sup> is normal. | |
| /// | |
| /// Equal to floor(log<sub>10</sub> [`MAX`]). | |
| /// | |
| /// [`MAX`]: f32::MAX | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| pub const MAX_10_EXP: i32 = 38; | |
| /// Not a Number (NaN). | |
| /// | |
| /// Note that IEEE 754 doesn't define just a single NaN value; a plethora of bit patterns are | |
| /// considered to be NaN. Furthermore, the standard makes a difference between a "signaling" and | |
| /// a "quiet" NaN, and allows inspecting its "payload" (the unspecified bits in the bit pattern) | |
| /// and its sign. See the [specification of NaN bit patterns](f32#nan-bit-patterns) for more | |
| /// info. | |
| /// | |
| /// This constant is guaranteed to be a quiet NaN (on targets that follow the Rust assumptions | |
| /// that the quiet/signaling bit being set to 1 indicates a quiet NaN). Beyond that, nothing is | |
| /// guaranteed about the specific bit pattern chosen here: both payload and sign are arbitrary. | |
| /// The concrete bit pattern may change across Rust versions and target platforms. | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| #[rustc_diagnostic_item = "f32_nan"] | |
| #[allow(clippy::eq_op)] | |
| pub const NAN: f32 = 0.0_f32 / 0.0_f32; | |
| /// Infinity (∞). | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| pub const INFINITY: f32 = 1.0_f32 / 0.0_f32; | |
| /// Negative infinity (−∞). | |
| #[stable(feature = "assoc_int_consts", since = "1.43.0")] | |
| pub const NEG_INFINITY: f32 = -1.0_f32 / 0.0_f32; | |
| /// Maximum integer that can be represented exactly in an [`f32`] value, | |
| /// with no other integer converting to the same floating point value. | |
| /// | |
| /// For an integer `x` which satisfies `MIN_EXACT_INTEGER <= x <= MAX_EXACT_INTEGER`, | |
| /// there is a "one-to-one" mapping between [`i32`] and [`f32`] values. | |
| /// `MAX_EXACT_INTEGER + 1` also converts losslessly to [`f32`] and back to | |
| /// [`i32`], but `MAX_EXACT_INTEGER + 2` converts to the same [`f32`] value | |
| /// (and back to `MAX_EXACT_INTEGER + 1` as an integer) so there is not a | |
| /// "one-to-one" mapping. | |
| /// | |
| /// [`MAX_EXACT_INTEGER`]: f32::MAX_EXACT_INTEGER | |
| /// [`MIN_EXACT_INTEGER`]: f32::MIN_EXACT_INTEGER | |
| /// ``` | |
| /// #![feature(float_exact_integer_constants)] | |
| /// # // FIXME(#152635): Float rounding on `i586` does not adhere to IEEE 754 | |
| /// # #[cfg(not(all(target_arch = "x86", not(target_feature = "sse"))))] { | |
| /// let max_exact_int = f32::MAX_EXACT_INTEGER; | |
| /// assert_eq!(max_exact_int, max_exact_int as f32 as i32); | |
| /// assert_eq!(max_exact_int + 1, (max_exact_int + 1) as f32 as i32); | |
| /// assert_ne!(max_exact_int + 2, (max_exact_int + 2) as f32 as i32); | |
| /// | |
| /// // Beyond `f32::MAX_EXACT_INTEGER`, multiple integers can map to one float value | |
| /// assert_eq!((max_exact_int + 1) as f32, (max_exact_int + 2) as f32); | |
| /// # } | |
| /// ``` | |
| #[unstable(feature = "float_exact_integer_constants", issue = "152466")] | |
| pub const MAX_EXACT_INTEGER: i32 = (1 << Self::MANTISSA_DIGITS) - 1; | |
| /// Minimum integer that can be represented exactly in an [`f32`] value, | |
| /// with no other integer converting to the same floating point value. | |
| /// | |
| /// For an integer `x` which satisfies `MIN_EXACT_INTEGER <= x <= MAX_EXACT_INTEGER`, | |
| /// there is a "one-to-one" mapping between [`i32`] and [`f32`] values. | |
| /// `MAX_EXACT_INTEGER + 1` also converts losslessly to [`f32`] and back to | |
| /// [`i32`], but `MAX_EXACT_INTEGER + 2` converts to the same [`f32`] value | |
| /// (and back to `MAX_EXACT_INTEGER + 1` as an integer) so there is not a | |
| /// "one-to-one" mapping. | |
| /// | |
| /// This constant is equivalent to `-MAX_EXACT_INTEGER`. | |
| /// | |
| /// [`MAX_EXACT_INTEGER`]: f32::MAX_EXACT_INTEGER | |
| /// [`MIN_EXACT_INTEGER`]: f32::MIN_EXACT_INTEGER | |
| /// ``` | |
| /// #![feature(float_exact_integer_constants)] | |
| /// # // FIXME(#152635): Float rounding on `i586` does not adhere to IEEE 754 | |
| /// # #[cfg(not(all(target_arch = "x86", not(target_feature = "sse"))))] { | |
| /// let min_exact_int = f32::MIN_EXACT_INTEGER; | |
| /// assert_eq!(min_exact_int, min_exact_int as f32 as i32); | |
| /// assert_eq!(min_exact_int - 1, (min_exact_int - 1) as f32 as i32); | |
| /// assert_ne!(min_exact_int - 2, (min_exact_int - 2) as f32 as i32); | |
| /// | |
| /// // Below `f32::MIN_EXACT_INTEGER`, multiple integers can map to one float value | |
| /// assert_eq!((min_exact_int - 1) as f32, (min_exact_int - 2) as f32); | |
| /// # } | |
| /// ``` | |
| #[unstable(feature = "float_exact_integer_constants", issue = "152466")] | |
| pub const MIN_EXACT_INTEGER: i32 = -Self::MAX_EXACT_INTEGER; | |
| /// Sign bit | |
| pub(crate) const SIGN_MASK: u32 = 0x8000_0000; | |
| /// Exponent mask | |
| pub(crate) const EXP_MASK: u32 = 0x7f80_0000; | |
| /// Mantissa mask | |
| pub(crate) const MAN_MASK: u32 = 0x007f_ffff; | |
| /// Minimum representable positive value (min subnormal) | |
| const TINY_BITS: u32 = 0x1; | |
| /// Minimum representable negative value (min negative subnormal) | |
| const NEG_TINY_BITS: u32 = Self::TINY_BITS | Self::SIGN_MASK; | |
| /// Returns `true` if this value is NaN. | |
| /// | |
| /// ``` | |
| /// let nan = f32::NAN; | |
| /// let f = 7.0_f32; | |
| /// | |
| /// assert!(nan.is_nan()); | |
| /// assert!(!f.is_nan()); | |
| /// ``` | |
| #[must_use] | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")] | |
| #[inline] | |
| #[allow(clippy::eq_op)] // > if you intended to check if the operand is NaN, use `.is_nan()` instead :) | |
| pub const fn is_nan(self) -> bool { | |
| self != self | |
| } | |
| /// Returns `true` if this value is positive infinity or negative infinity, and | |
| /// `false` otherwise. | |
| /// | |
| /// ``` | |
| /// let f = 7.0f32; | |
| /// let inf = f32::INFINITY; | |
| /// let neg_inf = f32::NEG_INFINITY; | |
| /// let nan = f32::NAN; | |
| /// | |
| /// assert!(!f.is_infinite()); | |
| /// assert!(!nan.is_infinite()); | |
| /// | |
| /// assert!(inf.is_infinite()); | |
| /// assert!(neg_inf.is_infinite()); | |
| /// ``` | |
| #[must_use] | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")] | |
| #[inline] | |
| pub const fn is_infinite(self) -> bool { | |
| // Getting clever with transmutation can result in incorrect answers on some FPUs | |
| // FIXME: alter the Rust <-> Rust calling convention to prevent this problem. | |
| // See https://github.com/rust-lang/rust/issues/72327 | |
| (self == f32::INFINITY) | (self == f32::NEG_INFINITY) | |
| } | |
| /// Returns `true` if this number is neither infinite nor NaN. | |
| /// | |
| /// ``` | |
| /// let f = 7.0f32; | |
| /// let inf = f32::INFINITY; | |
| /// let neg_inf = f32::NEG_INFINITY; | |
| /// let nan = f32::NAN; | |
| /// | |
| /// assert!(f.is_finite()); | |
| /// | |
| /// assert!(!nan.is_finite()); | |
| /// assert!(!inf.is_finite()); | |
| /// assert!(!neg_inf.is_finite()); | |
| /// ``` | |
| #[must_use] | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")] | |
| #[inline] | |
| pub const fn is_finite(self) -> bool { | |
| // There's no need to handle NaN separately: if self is NaN, | |
| // the comparison is not true, exactly as desired. | |
| self.abs() < Self::INFINITY | |
| } | |
| /// Returns `true` if the number is [subnormal]. | |
| /// | |
| /// ``` | |
| /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32 | |
| /// let max = f32::MAX; | |
| /// let lower_than_min = 1.0e-40_f32; | |
| /// let zero = 0.0_f32; | |
| /// | |
| /// assert!(!min.is_subnormal()); | |
| /// assert!(!max.is_subnormal()); | |
| /// | |
| /// assert!(!zero.is_subnormal()); | |
| /// assert!(!f32::NAN.is_subnormal()); | |
| /// assert!(!f32::INFINITY.is_subnormal()); | |
| /// // Values between `0` and `min` are Subnormal. | |
| /// assert!(lower_than_min.is_subnormal()); | |
| /// ``` | |
| /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number | |
| #[must_use] | |
| #[stable(feature = "is_subnormal", since = "1.53.0")] | |
| #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")] | |
| #[inline] | |
| pub const fn is_subnormal(self) -> bool { | |
| matches!(self.classify(), FpCategory::Subnormal) | |
| } | |
| /// Returns `true` if the number is neither zero, infinite, | |
| /// [subnormal], or NaN. | |
| /// | |
| /// ``` | |
| /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32 | |
| /// let max = f32::MAX; | |
| /// let lower_than_min = 1.0e-40_f32; | |
| /// let zero = 0.0_f32; | |
| /// | |
| /// 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()); | |
| /// ``` | |
| /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number | |
| #[must_use] | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")] | |
| #[inline] | |
| pub const fn is_normal(self) -> bool { | |
| matches!(self.classify(), FpCategory::Normal) | |
| } | |
| /// 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_f32; | |
| /// let inf = f32::INFINITY; | |
| /// | |
| /// assert_eq!(num.classify(), FpCategory::Normal); | |
| /// assert_eq!(inf.classify(), FpCategory::Infinite); | |
| /// ``` | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")] | |
| pub const fn classify(self) -> FpCategory { | |
| // We used to have complicated logic here that avoids the simple bit-based tests to work | |
| // around buggy codegen for x87 targets (see | |
| // https://github.com/rust-lang/rust/issues/114479). However, some LLVM versions later, none | |
| // of our tests is able to find any difference between the complicated and the naive | |
| // version, so now we are back to the naive version. | |
| let b = self.to_bits(); | |
| match (b & Self::MAN_MASK, b & Self::EXP_MASK) { | |
| (0, Self::EXP_MASK) => FpCategory::Infinite, | |
| (_, Self::EXP_MASK) => FpCategory::Nan, | |
| (0, 0) => FpCategory::Zero, | |
| (_, 0) => FpCategory::Subnormal, | |
| _ => FpCategory::Normal, | |
| } | |
| } | |
| /// Returns `true` if `self` has a positive sign, including `+0.0`, NaNs with | |
| /// positive sign bit and positive infinity. | |
| /// | |
| /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of | |
| /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are | |
| /// conserved over arithmetic operations, the result of `is_sign_positive` on | |
| /// a NaN might produce an unexpected or non-portable result. See the [specification | |
| /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == 1.0` | |
| /// if you need fully portable behavior (will return `false` for all NaNs). | |
| /// | |
| /// ``` | |
| /// let f = 7.0_f32; | |
| /// let g = -7.0_f32; | |
| /// | |
| /// assert!(f.is_sign_positive()); | |
| /// assert!(!g.is_sign_positive()); | |
| /// ``` | |
| #[must_use] | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")] | |
| #[inline] | |
| pub const fn is_sign_positive(self) -> bool { | |
| !self.is_sign_negative() | |
| } | |
| /// Returns `true` if `self` has a negative sign, including `-0.0`, NaNs with | |
| /// negative sign bit and negative infinity. | |
| /// | |
| /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of | |
| /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are | |
| /// conserved over arithmetic operations, the result of `is_sign_negative` on | |
| /// a NaN might produce an unexpected or non-portable result. See the [specification | |
| /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == -1.0` | |
| /// if you need fully portable behavior (will return `false` for all NaNs). | |
| /// | |
| /// ``` | |
| /// let f = 7.0f32; | |
| /// let g = -7.0f32; | |
| /// | |
| /// assert!(!f.is_sign_negative()); | |
| /// assert!(g.is_sign_negative()); | |
| /// ``` | |
| #[must_use] | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")] | |
| #[inline] | |
| pub const fn is_sign_negative(self) -> bool { | |
| // IEEE754 says: isSignMinus(x) is true if and only if x has negative sign. isSignMinus | |
| // applies to zeros and NaNs as well. | |
| self.to_bits() & 0x8000_0000 != 0 | |
| } | |
| /// Returns the least number greater than `self`. | |
| /// | |
| /// Let `TINY` be the smallest representable positive `f32`. Then, | |
| /// - if `self.is_nan()`, this returns `self`; | |
| /// - if `self` is [`NEG_INFINITY`], this returns [`MIN`]; | |
| /// - if `self` is `-TINY`, this returns -0.0; | |
| /// - if `self` is -0.0 or +0.0, this returns `TINY`; | |
| /// - if `self` is [`MAX`] or [`INFINITY`], this returns [`INFINITY`]; | |
| /// - otherwise the unique least value greater than `self` is returned. | |
| /// | |
| /// The identity `x.next_up() == -(-x).next_down()` holds for all non-NaN `x`. When `x` | |
| /// is finite `x == x.next_up().next_down()` also holds. | |
| /// | |
| /// ```rust | |
| /// // f32::EPSILON is the difference between 1.0 and the next number up. | |
| /// assert_eq!(1.0f32.next_up(), 1.0 + f32::EPSILON); | |
| /// // But not for most numbers. | |
| /// assert!(0.1f32.next_up() < 0.1 + f32::EPSILON); | |
| /// assert_eq!(16777216f32.next_up(), 16777218.0); | |
| /// ``` | |
| /// | |
| /// This operation corresponds to IEEE-754 `nextUp`. | |
| /// | |
| /// [`NEG_INFINITY`]: Self::NEG_INFINITY | |
| /// [`INFINITY`]: Self::INFINITY | |
| /// [`MIN`]: Self::MIN | |
| /// [`MAX`]: Self::MAX | |
| #[inline] | |
| #[doc(alias = "nextUp")] | |
| #[stable(feature = "float_next_up_down", since = "1.86.0")] | |
| #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")] | |
| pub const fn next_up(self) -> Self { | |
| // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing | |
| // denormals to zero. This is in general unsound and unsupported, but here | |
| // we do our best to still produce the correct result on such targets. | |
| let bits = self.to_bits(); | |
| if self.is_nan() || bits == Self::INFINITY.to_bits() { | |
| return self; | |
| } | |
| let abs = bits & !Self::SIGN_MASK; | |
| let next_bits = if abs == 0 { | |
| Self::TINY_BITS | |
| } else if bits == abs { | |
| bits + 1 | |
| } else { | |
| bits - 1 | |
| }; | |
| Self::from_bits(next_bits) | |
| } | |
| /// Returns the greatest number less than `self`. | |
| /// | |
| /// Let `TINY` be the smallest representable positive `f32`. Then, | |
| /// - if `self.is_nan()`, this returns `self`; | |
| /// - if `self` is [`INFINITY`], this returns [`MAX`]; | |
| /// - if `self` is `TINY`, this returns 0.0; | |
| /// - if `self` is -0.0 or +0.0, this returns `-TINY`; | |
| /// - if `self` is [`MIN`] or [`NEG_INFINITY`], this returns [`NEG_INFINITY`]; | |
| /// - otherwise the unique greatest value less than `self` is returned. | |
| /// | |
| /// The identity `x.next_down() == -(-x).next_up()` holds for all non-NaN `x`. When `x` | |
| /// is finite `x == x.next_down().next_up()` also holds. | |
| /// | |
| /// ```rust | |
| /// let x = 1.0f32; | |
| /// // Clamp value into range [0, 1). | |
| /// let clamped = x.clamp(0.0, 1.0f32.next_down()); | |
| /// assert!(clamped < 1.0); | |
| /// assert_eq!(clamped.next_up(), 1.0); | |
| /// ``` | |
| /// | |
| /// This operation corresponds to IEEE-754 `nextDown`. | |
| /// | |
| /// [`NEG_INFINITY`]: Self::NEG_INFINITY | |
| /// [`INFINITY`]: Self::INFINITY | |
| /// [`MIN`]: Self::MIN | |
| /// [`MAX`]: Self::MAX | |
| #[inline] | |
| #[doc(alias = "nextDown")] | |
| #[stable(feature = "float_next_up_down", since = "1.86.0")] | |
| #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")] | |
| pub const fn next_down(self) -> Self { | |
| // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing | |
| // denormals to zero. This is in general unsound and unsupported, but here | |
| // we do our best to still produce the correct result on such targets. | |
| let bits = self.to_bits(); | |
| if self.is_nan() || bits == Self::NEG_INFINITY.to_bits() { | |
| return self; | |
| } | |
| let abs = bits & !Self::SIGN_MASK; | |
| let next_bits = if abs == 0 { | |
| Self::NEG_TINY_BITS | |
| } else if bits == abs { | |
| bits - 1 | |
| } else { | |
| bits + 1 | |
| }; | |
| Self::from_bits(next_bits) | |
| } | |
| /// Takes the reciprocal (inverse) of a number, `1/x`. | |
| /// | |
| /// ``` | |
| /// let x = 2.0_f32; | |
| /// let abs_difference = (x.recip() - (1.0 / x)).abs(); | |
| /// | |
| /// assert!(abs_difference <= f32::EPSILON); | |
| /// ``` | |
| #[must_use = "this returns the result of the operation, without modifying the original"] | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")] | |
| #[inline] | |
| pub const fn recip(self) -> f32 { | |
| 1.0 / self | |
| } | |
| /// Converts radians to degrees. | |
| /// | |
| /// # Unspecified precision | |
| /// | |
| /// The precision of this function is non-deterministic. This means it varies by platform, | |
| /// Rust version, and can even differ within the same execution from one invocation to the next. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// let angle = std::f32::consts::PI; | |
| /// | |
| /// let abs_difference = (angle.to_degrees() - 180.0).abs(); | |
| /// # #[cfg(any(not(target_arch = "x86"), target_feature = "sse2"))] | |
| /// assert!(abs_difference <= f32::EPSILON); | |
| /// ``` | |
| #[must_use = "this returns the result of the operation, \ | |
| without modifying the original"] | |
| #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")] | |
| #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")] | |
| #[inline] | |
| pub const fn to_degrees(self) -> f32 { | |
| // Use a literal to avoid double rounding, consts::PI is already rounded, | |
| // and dividing would round again. | |
| const PIS_IN_180: f32 = 57.2957795130823208767981548141051703_f32; | |
| self * PIS_IN_180 | |
| } | |
| /// Converts degrees to radians. | |
| /// | |
| /// # Unspecified precision | |
| /// | |
| /// The precision of this function is non-deterministic. This means it varies by platform, | |
| /// Rust version, and can even differ within the same execution from one invocation to the next. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// let angle = 180.0f32; | |
| /// | |
| /// let abs_difference = (angle.to_radians() - std::f32::consts::PI).abs(); | |
| /// | |
| /// assert!(abs_difference <= f32::EPSILON); | |
| /// ``` | |
| #[must_use = "this returns the result of the operation, \ | |
| without modifying the original"] | |
| #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")] | |
| #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")] | |
| #[inline] | |
| pub const fn to_radians(self) -> f32 { | |
| // The division here is correctly rounded with respect to the true value of π/180. | |
| // Although π is irrational and already rounded, the double rounding happens | |
| // to produce correct result for f32. | |
| const RADS_PER_DEG: f32 = consts::PI / 180.0; | |
| self * RADS_PER_DEG | |
| } | |
| /// Returns the maximum of the two numbers, ignoring NaN. | |
| /// | |
| /// If exactly one of the arguments is NaN (quiet or signaling), then the other argument is | |
| /// returned. If both arguments are NaN, the return value is NaN, with the bit pattern picked | |
| /// using the usual [rules for arithmetic operations](f32#nan-bit-patterns). If the inputs | |
| /// compare equal (such as for the case of `+0.0` and `-0.0`), either input may be returned | |
| /// non-deterministically. | |
| /// | |
| /// The handling of NaNs follows the IEEE 754-2019 semantics for `maximumNumber`, treating all | |
| /// NaNs the same way to ensure the operation is associative. The handling of signed zeros | |
| /// follows the IEEE 754-2008 semantics for `maxNum`. | |
| /// | |
| /// ``` | |
| /// let x = 1.0f32; | |
| /// let y = 2.0f32; | |
| /// | |
| /// assert_eq!(x.max(y), y); | |
| /// assert_eq!(x.max(f32::NAN), x); | |
| /// ``` | |
| #[must_use = "this returns the result of the comparison, without modifying either input"] | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")] | |
| #[inline] | |
| pub const fn max(self, other: f32) -> f32 { | |
| intrinsics::maximum_number_nsz_f32(self, other) | |
| } | |
| /// Returns the minimum of the two numbers, ignoring NaN. | |
| /// | |
| /// If exactly one of the arguments is NaN (quiet or signaling), then the other argument is | |
| /// returned. If both arguments are NaN, the return value is NaN, with the bit pattern picked | |
| /// using the usual [rules for arithmetic operations](f32#nan-bit-patterns). If the inputs | |
| /// compare equal (such as for the case of `+0.0` and `-0.0`), either input may be returned | |
| /// non-deterministically. | |
| /// | |
| /// The handling of NaNs follows the IEEE 754-2019 semantics for `minimumNumber`, treating all | |
| /// NaNs the same way to ensure the operation is associative. The handling of signed zeros | |
| /// follows the IEEE 754-2008 semantics for `minNum`. | |
| /// | |
| /// ``` | |
| /// let x = 1.0f32; | |
| /// let y = 2.0f32; | |
| /// | |
| /// assert_eq!(x.min(y), x); | |
| /// assert_eq!(x.min(f32::NAN), x); | |
| /// ``` | |
| #[must_use = "this returns the result of the comparison, without modifying either input"] | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")] | |
| #[inline] | |
| pub const fn min(self, other: f32) -> f32 { | |
| intrinsics::minimum_number_nsz_f32(self, other) | |
| } | |
| /// Returns the maximum of the two numbers, propagating NaN. | |
| /// | |
| /// If at least one of the arguments is NaN, the return value is NaN, with the bit pattern | |
| /// picked using the usual [rules for arithmetic operations](f32#nan-bit-patterns). Furthermore, | |
| /// `-0.0` is considered to be less than `+0.0`, making this function fully deterministic for | |
| /// non-NaN inputs. | |
| /// | |
| /// This is in contrast to [`f32::max`] which only returns NaN when *both* arguments are NaN, | |
| /// and which does not reliably order `-0.0` and `+0.0`. | |
| /// | |
| /// This follows the IEEE 754-2019 semantics for `maximum`. | |
| /// | |
| /// ``` | |
| /// #![feature(float_minimum_maximum)] | |
| /// let x = 1.0f32; | |
| /// let y = 2.0f32; | |
| /// | |
| /// assert_eq!(x.maximum(y), y); | |
| /// assert!(x.maximum(f32::NAN).is_nan()); | |
| /// ``` | |
| #[must_use = "this returns the result of the comparison, without modifying either input"] | |
| #[unstable(feature = "float_minimum_maximum", issue = "91079")] | |
| #[inline] | |
| pub const fn maximum(self, other: f32) -> f32 { | |
| intrinsics::maximumf32(self, other) | |
| } | |
| /// Returns the minimum of the two numbers, propagating NaN. | |
| /// | |
| /// If at least one of the arguments is NaN, the return value is NaN, with the bit pattern | |
| /// picked using the usual [rules for arithmetic operations](f32#nan-bit-patterns). Furthermore, | |
| /// `-0.0` is considered to be less than `+0.0`, making this function fully deterministic for | |
| /// non-NaN inputs. | |
| /// | |
| /// This is in contrast to [`f32::min`] which only returns NaN when *both* arguments are NaN, | |
| /// and which does not reliably order `-0.0` and `+0.0`. | |
| /// | |
| /// This follows the IEEE 754-2019 semantics for `minimum`. | |
| /// | |
| /// ``` | |
| /// #![feature(float_minimum_maximum)] | |
| /// let x = 1.0f32; | |
| /// let y = 2.0f32; | |
| /// | |
| /// assert_eq!(x.minimum(y), x); | |
| /// assert!(x.minimum(f32::NAN).is_nan()); | |
| /// ``` | |
| #[must_use = "this returns the result of the comparison, without modifying either input"] | |
| #[unstable(feature = "float_minimum_maximum", issue = "91079")] | |
| #[inline] | |
| pub const fn minimum(self, other: f32) -> f32 { | |
| intrinsics::minimumf32(self, other) | |
| } | |
| /// Calculates the midpoint (average) between `self` and `rhs`. | |
| /// | |
| /// This returns NaN when *either* argument is NaN or if a combination of | |
| /// +inf and -inf is provided as arguments. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// assert_eq!(1f32.midpoint(4.0), 2.5); | |
| /// assert_eq!((-5.5f32).midpoint(8.0), 1.25); | |
| /// ``` | |
| #[inline] | |
| #[doc(alias = "average")] | |
| #[stable(feature = "num_midpoint", since = "1.85.0")] | |
| #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")] | |
| pub const fn midpoint(self, other: f32) -> f32 { | |
| cfg_select! { | |
| // Allow faster implementation that have known good 64-bit float | |
| // implementations. Falling back to the branchy code on targets that don't | |
| // have 64-bit hardware floats or buggy implementations. | |
| // https://github.com/rust-lang/rust/pull/121062#issuecomment-2123408114 | |
| any( | |
| target_arch = "x86_64", | |
| target_arch = "aarch64", | |
| all(any(target_arch = "riscv32", target_arch = "riscv64"), target_feature = "d"), | |
| all(target_arch = "loongarch64", target_feature = "d"), | |
| all(target_arch = "arm", target_feature = "vfp2"), | |
| target_arch = "wasm32", | |
| target_arch = "wasm64", | |
| ) => { | |
| ((self as f64 + other as f64) / 2.0) as f32 | |
| } | |
| _ => { | |
| const HI: f32 = f32::MAX / 2.; | |
| let (a, b) = (self, other); | |
| let abs_a = a.abs(); | |
| let abs_b = b.abs(); | |
| if abs_a <= HI && abs_b <= HI { | |
| // Overflow is impossible | |
| (a + b) / 2. | |
| } else { | |
| (a / 2.) + (b / 2.) | |
| } | |
| } | |
| } | |
| } | |
| /// 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_f32; | |
| /// let rounded = unsafe { value.to_int_unchecked::<u16>() }; | |
| /// assert_eq!(rounded, 4); | |
| /// | |
| /// let value = -128.9_f32; | |
| /// let rounded = unsafe { value.to_int_unchecked::<i8>() }; | |
| /// assert_eq!(rounded, i8::MIN); | |
| /// ``` | |
| /// | |
| /// # Safety | |
| /// | |
| /// The value must: | |
| /// | |
| /// * Not be `NaN` | |
| /// * Not be infinite | |
| /// * Be representable in the return type `Int`, after truncating off its fractional part | |
| #[must_use = "this returns the result of the operation, \ | |
| without modifying the original"] | |
| #[stable(feature = "float_approx_unchecked_to", since = "1.44.0")] | |
| #[inline] | |
| pub unsafe fn to_int_unchecked<Int>(self) -> Int | |
| where | |
| Self: FloatToInt<Int>, | |
| { | |
| // SAFETY: the caller must uphold the safety contract for | |
| // `FloatToInt::to_int_unchecked`. | |
| unsafe { FloatToInt::<Int>::to_int_unchecked(self) } | |
| } | |
| /// Raw transmutation to `u32`. | |
| /// | |
| /// This is currently identical to `transmute::<f32, u32>(self)` on all platforms. | |
| /// | |
| /// See [`from_bits`](Self::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_ne!((1f32).to_bits(), 1f32 as u32); // to_bits() is not casting! | |
| /// assert_eq!((12.5f32).to_bits(), 0x41480000); | |
| /// | |
| /// ``` | |
| #[must_use = "this returns the result of the operation, \ | |
| without modifying the original"] | |
| #[stable(feature = "float_bits_conv", since = "1.20.0")] | |
| #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")] | |
| #[inline] | |
| #[allow(unnecessary_transmutes)] | |
| pub const fn to_bits(self) -> u32 { | |
| // SAFETY: `u32` is a plain old datatype so we can always transmute to it. | |
| unsafe { mem::transmute(self) } | |
| } | |
| /// Raw transmutation from `u32`. | |
| /// | |
| /// This is currently identical to `transmute::<u32, f32>(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 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 = f32::from_bits(0x41480000); | |
| /// assert_eq!(v, 12.5); | |
| /// ``` | |
| #[stable(feature = "float_bits_conv", since = "1.20.0")] | |
| #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")] | |
| #[must_use] | |
| #[inline] | |
| #[allow(unnecessary_transmutes)] | |
| pub const fn from_bits(v: u32) -> Self { | |
| // It turns out the safety issues with sNaN were overblown! Hooray! | |
| // SAFETY: `u32` is a plain old datatype so we can always transmute from it. | |
| unsafe { mem::transmute(v) } | |
| } | |
| /// Returns the memory representation of this floating point number as a byte array in | |
| /// big-endian (network) byte order. | |
| /// | |
| /// See [`from_bits`](Self::from_bits) for some discussion of the | |
| /// portability of this operation (there are almost no issues). | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// let bytes = 12.5f32.to_be_bytes(); | |
| /// assert_eq!(bytes, [0x41, 0x48, 0x00, 0x00]); | |
| /// ``` | |
| #[must_use = "this returns the result of the operation, \ | |
| without modifying the original"] | |
| #[stable(feature = "float_to_from_bytes", since = "1.40.0")] | |
| #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")] | |
| #[inline] | |
| pub const fn to_be_bytes(self) -> [u8; 4] { | |
| self.to_bits().to_be_bytes() | |
| } | |
| /// Returns the memory representation of this floating point number as a byte array in | |
| /// little-endian byte order. | |
| /// | |
| /// See [`from_bits`](Self::from_bits) for some discussion of the | |
| /// portability of this operation (there are almost no issues). | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// let bytes = 12.5f32.to_le_bytes(); | |
| /// assert_eq!(bytes, [0x00, 0x00, 0x48, 0x41]); | |
| /// ``` | |
| #[must_use = "this returns the result of the operation, \ | |
| without modifying the original"] | |
| #[stable(feature = "float_to_from_bytes", since = "1.40.0")] | |
| #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")] | |
| #[inline] | |
| pub const fn to_le_bytes(self) -> [u8; 4] { | |
| self.to_bits().to_le_bytes() | |
| } | |
| /// Returns 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. | |
| /// | |
| /// [`to_be_bytes`]: f32::to_be_bytes | |
| /// [`to_le_bytes`]: f32::to_le_bytes | |
| /// | |
| /// See [`from_bits`](Self::from_bits) for some discussion of the | |
| /// portability of this operation (there are almost no issues). | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// let bytes = 12.5f32.to_ne_bytes(); | |
| /// assert_eq!( | |
| /// bytes, | |
| /// if cfg!(target_endian = "big") { | |
| /// [0x41, 0x48, 0x00, 0x00] | |
| /// } else { | |
| /// [0x00, 0x00, 0x48, 0x41] | |
| /// } | |
| /// ); | |
| /// ``` | |
| #[must_use = "this returns the result of the operation, \ | |
| without modifying the original"] | |
| #[stable(feature = "float_to_from_bytes", since = "1.40.0")] | |
| #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")] | |
| #[inline] | |
| pub const fn to_ne_bytes(self) -> [u8; 4] { | |
| self.to_bits().to_ne_bytes() | |
| } | |
| /// Creates a floating point value from its representation as a byte array in big endian. | |
| /// | |
| /// See [`from_bits`](Self::from_bits) for some discussion of the | |
| /// portability of this operation (there are almost no issues). | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// let value = f32::from_be_bytes([0x41, 0x48, 0x00, 0x00]); | |
| /// assert_eq!(value, 12.5); | |
| /// ``` | |
| #[stable(feature = "float_to_from_bytes", since = "1.40.0")] | |
| #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")] | |
| #[must_use] | |
| #[inline] | |
| pub const fn from_be_bytes(bytes: [u8; 4]) -> Self { | |
| Self::from_bits(u32::from_be_bytes(bytes)) | |
| } | |
| /// Creates a floating point value from its representation as a byte array in little endian. | |
| /// | |
| /// See [`from_bits`](Self::from_bits) for some discussion of the | |
| /// portability of this operation (there are almost no issues). | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// let value = f32::from_le_bytes([0x00, 0x00, 0x48, 0x41]); | |
| /// assert_eq!(value, 12.5); | |
| /// ``` | |
| #[stable(feature = "float_to_from_bytes", since = "1.40.0")] | |
| #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")] | |
| #[must_use] | |
| #[inline] | |
| pub const fn from_le_bytes(bytes: [u8; 4]) -> Self { | |
| Self::from_bits(u32::from_le_bytes(bytes)) | |
| } | |
| /// Creates 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. | |
| /// | |
| /// [`from_be_bytes`]: f32::from_be_bytes | |
| /// [`from_le_bytes`]: f32::from_le_bytes | |
| /// | |
| /// See [`from_bits`](Self::from_bits) for some discussion of the | |
| /// portability of this operation (there are almost no issues). | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// let value = f32::from_ne_bytes(if cfg!(target_endian = "big") { | |
| /// [0x41, 0x48, 0x00, 0x00] | |
| /// } else { | |
| /// [0x00, 0x00, 0x48, 0x41] | |
| /// }); | |
| /// assert_eq!(value, 12.5); | |
| /// ``` | |
| #[stable(feature = "float_to_from_bytes", since = "1.40.0")] | |
| #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")] | |
| #[must_use] | |
| #[inline] | |
| pub const fn from_ne_bytes(bytes: [u8; 4]) -> Self { | |
| Self::from_bits(u32::from_ne_bytes(bytes)) | |
| } | |
| /// Returns the ordering between `self` and `other`. | |
| /// | |
| /// Unlike the standard partial comparison between floating point numbers, | |
| /// this comparison always produces an ordering in accordance to | |
| /// the `totalOrder` predicate as defined in the IEEE 754 (2008 revision) | |
| /// floating point standard. The values are ordered in the following sequence: | |
| /// | |
| /// - 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. | |
| /// | |
| /// The ordering established by this function does not always agree with the | |
| /// [`PartialOrd`] and [`PartialEq`] implementations of `f32`. For example, | |
| /// they consider negative and positive zero equal, while `total_cmp` | |
| /// doesn't. | |
| /// | |
| /// The interpretation of the signaling NaN bit follows the definition in | |
| /// the IEEE 754 standard, which may not match the interpretation by some of | |
| /// the older, non-conformant (e.g. MIPS) hardware implementations. | |
| /// | |
| /// # Example | |
| /// | |
| /// ``` | |
| /// struct GoodBoy { | |
| /// name: String, | |
| /// weight: f32, | |
| /// } | |
| /// | |
| /// 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: f32::INFINITY }, | |
| /// GoodBoy { name: "Abs. Unit".to_owned(), weight: f32::NAN }, | |
| /// GoodBoy { name: "Floaty".to_owned(), weight: -5.0 }, | |
| /// ]; | |
| /// | |
| /// bois.sort_by(|a, b| a.weight.total_cmp(&b.weight)); | |
| /// | |
| /// // `f32::NAN` could be positive or negative, which will affect the sort order. | |
| /// if f32::NAN.is_sign_negative() { | |
| /// assert!(bois.into_iter().map(|b| b.weight) | |
| /// .zip([f32::NAN, -5.0, 0.1, 10.0, 99.0, f32::INFINITY].iter()) | |
| /// .all(|(a, b)| a.to_bits() == b.to_bits())) | |
| /// } else { | |
| /// assert!(bois.into_iter().map(|b| b.weight) | |
| /// .zip([-5.0, 0.1, 10.0, 99.0, f32::INFINITY, f32::NAN].iter()) | |
| /// .all(|(a, b)| a.to_bits() == b.to_bits())) | |
| /// } | |
| /// ``` | |
| #[stable(feature = "total_cmp", since = "1.62.0")] | |
| #[rustc_const_unstable(feature = "const_cmp", issue = "143800")] | |
| #[must_use] | |
| #[inline] | |
| pub const fn total_cmp(&self, other: &Self) -> crate::cmp::Ordering { | |
| let mut left = self.to_bits() as i32; | |
| let mut right = other.to_bits() as i32; | |
| // In case of negatives, flip all the bits except the sign | |
| // to achieve a similar layout as two's complement integers | |
| // | |
| // Why does this work? IEEE 754 floats consist of three fields: | |
| // Sign bit, exponent and mantissa. The set of exponent and mantissa | |
| // fields as a whole have the property that their bitwise order is | |
| // equal to the numeric magnitude where the magnitude is defined. | |
| // The magnitude is not normally defined on NaN values, but | |
| // IEEE 754 totalOrder defines the NaN values also to follow the | |
| // bitwise order. This leads to order explained in the doc comment. | |
| // However, the representation of magnitude is the same for negative | |
| // and positive numbers – only the sign bit is different. | |
| // To easily compare the floats as signed integers, we need to | |
| // flip the exponent and mantissa bits in case of negative numbers. | |
| // We effectively convert the numbers to "two's complement" form. | |
| // | |
| // To do the flipping, we construct a mask and XOR against it. | |
| // We branchlessly calculate an "all-ones except for the sign bit" | |
| // mask from negative-signed values: right shifting sign-extends | |
| // the integer, so we "fill" the mask with sign bits, and then | |
| // convert to unsigned to push one more zero bit. | |
| // On positive values, the mask is all zeros, so it's a no-op. | |
| left ^= (((left >> 31) as u32) >> 1) as i32; | |
| right ^= (((right >> 31) as u32) >> 1) as i32; | |
| left.cmp(&right) | |
| } | |
| /// 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. If the result is zero and among the three inputs `self`, `min`, and `max` there are | |
| /// zeros with different sign, either `0.0` or `-0.0` is returned non-deterministically. | |
| /// | |
| /// # Panics | |
| /// | |
| /// Panics if `min > max`, `min` is NaN, or `max` is NaN. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// assert!((-3.0f32).clamp(-2.0, 1.0) == -2.0); | |
| /// assert!((0.0f32).clamp(-2.0, 1.0) == 0.0); | |
| /// assert!((2.0f32).clamp(-2.0, 1.0) == 1.0); | |
| /// assert!((f32::NAN).clamp(-2.0, 1.0).is_nan()); | |
| /// | |
| /// // These always returns zero, but the sign (which is ignored by `==`) is non-deterministic. | |
| /// assert!((0.0f32).clamp(-0.0, -0.0) == 0.0); | |
| /// assert!((1.0f32).clamp(-0.0, 0.0) == 0.0); | |
| /// // This is definitely a negative zero. | |
| /// assert!((-1.0f32).clamp(-0.0, 1.0).is_sign_negative()); | |
| /// ``` | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[stable(feature = "clamp", since = "1.50.0")] | |
| #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")] | |
| #[inline] | |
| pub const fn clamp(mut self, min: f32, max: f32) -> f32 { | |
| const_assert!( | |
| min <= max, | |
| "min > max, or either was NaN", | |
| "min > max, or either was NaN. min = {min:?}, max = {max:?}", | |
| min: f32, | |
| max: f32, | |
| ); | |
| if self < min { | |
| self = min; | |
| } | |
| if self > max { | |
| self = max; | |
| } | |
| self | |
| } | |
| /// Clamps this number to a symmetric range centered around zero. | |
| /// | |
| /// The method clamps the number's magnitude (absolute value) to be at most `limit`. | |
| /// | |
| /// This is functionally equivalent to `self.clamp(-limit, limit)`, but is more | |
| /// explicit about the intent. | |
| /// | |
| /// # Panics | |
| /// | |
| /// Panics if `limit` is negative or NaN, as this indicates a logic error. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// #![feature(clamp_magnitude)] | |
| /// assert_eq!(5.0f32.clamp_magnitude(3.0), 3.0); | |
| /// assert_eq!((-5.0f32).clamp_magnitude(3.0), -3.0); | |
| /// assert_eq!(2.0f32.clamp_magnitude(3.0), 2.0); | |
| /// assert_eq!((-2.0f32).clamp_magnitude(3.0), -2.0); | |
| /// ``` | |
| #[must_use = "this returns the clamped value and does not modify the original"] | |
| #[unstable(feature = "clamp_magnitude", issue = "148519")] | |
| #[inline] | |
| pub fn clamp_magnitude(self, limit: f32) -> f32 { | |
| assert!(limit >= 0.0, "limit must be non-negative"); | |
| let limit = limit.abs(); // Canonicalises -0.0 to 0.0 | |
| self.clamp(-limit, limit) | |
| } | |
| /// Computes the absolute value of `self`. | |
| /// | |
| /// This function always returns the precise result. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// let x = 3.5_f32; | |
| /// let y = -3.5_f32; | |
| /// | |
| /// assert_eq!(x.abs(), x); | |
| /// assert_eq!(y.abs(), -y); | |
| /// | |
| /// assert!(f32::NAN.abs().is_nan()); | |
| /// ``` | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")] | |
| #[inline] | |
| pub const fn abs(self) -> f32 { | |
| intrinsics::fabsf32(self) | |
| } | |
| /// 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 | |
| /// | |
| /// ``` | |
| /// let f = 3.5_f32; | |
| /// | |
| /// assert_eq!(f.signum(), 1.0); | |
| /// assert_eq!(f32::NEG_INFINITY.signum(), -1.0); | |
| /// | |
| /// assert!(f32::NAN.signum().is_nan()); | |
| /// ``` | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")] | |
| #[inline] | |
| pub const fn signum(self) -> f32 { | |
| if self.is_nan() { Self::NAN } else { 1.0_f32.copysign(self) } | |
| } | |
| /// 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 same payload as `self` and the sign bit of `sign` is | |
| /// returned. | |
| /// | |
| /// If `sign` is a NaN, then this operation will still carry over its sign into the result. Note | |
| /// that IEEE 754 doesn't assign any meaning to the sign bit in case of a NaN, and as Rust | |
| /// doesn't guarantee that the bit pattern of NaNs are conserved over arithmetic operations, the | |
| /// result of `copysign` with `sign` being a NaN might produce an unexpected or non-portable | |
| /// result. See the [specification of NaN bit patterns](primitive@f32#nan-bit-patterns) for more | |
| /// info. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// let f = 3.5_f32; | |
| /// | |
| /// assert_eq!(f.copysign(0.42), 3.5_f32); | |
| /// assert_eq!(f.copysign(-0.42), -3.5_f32); | |
| /// assert_eq!((-f).copysign(0.42), 3.5_f32); | |
| /// assert_eq!((-f).copysign(-0.42), -3.5_f32); | |
| /// | |
| /// assert!(f32::NAN.copysign(1.0).is_nan()); | |
| /// ``` | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[inline] | |
| #[stable(feature = "copysign", since = "1.35.0")] | |
| #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")] | |
| pub const fn copysign(self, sign: f32) -> f32 { | |
| intrinsics::copysignf32(self, sign) | |
| } | |
| /// Float addition that allows optimizations based on algebraic rules. | |
| /// | |
| /// See [algebraic operators](primitive@f32#algebraic-operators) for more info. | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[unstable(feature = "float_algebraic", issue = "136469")] | |
| #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")] | |
| #[inline] | |
| pub const fn algebraic_add(self, rhs: f32) -> f32 { | |
| intrinsics::fadd_algebraic(self, rhs) | |
| } | |
| /// Float subtraction that allows optimizations based on algebraic rules. | |
| /// | |
| /// See [algebraic operators](primitive@f32#algebraic-operators) for more info. | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[unstable(feature = "float_algebraic", issue = "136469")] | |
| #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")] | |
| #[inline] | |
| pub const fn algebraic_sub(self, rhs: f32) -> f32 { | |
| intrinsics::fsub_algebraic(self, rhs) | |
| } | |
| /// Float multiplication that allows optimizations based on algebraic rules. | |
| /// | |
| /// See [algebraic operators](primitive@f32#algebraic-operators) for more info. | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[unstable(feature = "float_algebraic", issue = "136469")] | |
| #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")] | |
| #[inline] | |
| pub const fn algebraic_mul(self, rhs: f32) -> f32 { | |
| intrinsics::fmul_algebraic(self, rhs) | |
| } | |
| /// Float division that allows optimizations based on algebraic rules. | |
| /// | |
| /// See [algebraic operators](primitive@f32#algebraic-operators) for more info. | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[unstable(feature = "float_algebraic", issue = "136469")] | |
| #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")] | |
| #[inline] | |
| pub const fn algebraic_div(self, rhs: f32) -> f32 { | |
| intrinsics::fdiv_algebraic(self, rhs) | |
| } | |
| /// Float remainder that allows optimizations based on algebraic rules. | |
| /// | |
| /// See [algebraic operators](primitive@f32#algebraic-operators) for more info. | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[unstable(feature = "float_algebraic", issue = "136469")] | |
| #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")] | |
| #[inline] | |
| pub const fn algebraic_rem(self, rhs: f32) -> f32 { | |
| intrinsics::frem_algebraic(self, rhs) | |
| } | |
| } | |
| /// Experimental implementations of floating point functions in `core`. | |
| /// | |
| /// _The standalone functions in this module are for testing only. | |
| /// They will be stabilized as inherent methods._ | |
| #[unstable(feature = "core_float_math", issue = "137578")] | |
| pub mod math { | |
| use crate::intrinsics; | |
| use crate::num::imp::libm; | |
| /// Experimental version of `floor` in `core`. See [`f32::floor`] for details. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// #![feature(core_float_math)] | |
| /// | |
| /// use core::f32; | |
| /// | |
| /// let f = 3.7_f32; | |
| /// let g = 3.0_f32; | |
| /// let h = -3.7_f32; | |
| /// | |
| /// assert_eq!(f32::math::floor(f), 3.0); | |
| /// assert_eq!(f32::math::floor(g), 3.0); | |
| /// assert_eq!(f32::math::floor(h), -4.0); | |
| /// ``` | |
| /// | |
| /// _This standalone function is for testing only. | |
| /// It will be stabilized as an inherent method._ | |
| /// | |
| /// [`f32::floor`]: ../../../std/primitive.f32.html#method.floor | |
| #[inline] | |
| #[unstable(feature = "core_float_math", issue = "137578")] | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| pub const fn floor(x: f32) -> f32 { | |
| intrinsics::floorf32(x) | |
| } | |
| /// Experimental version of `ceil` in `core`. See [`f32::ceil`] for details. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// #![feature(core_float_math)] | |
| /// | |
| /// use core::f32; | |
| /// | |
| /// let f = 3.01_f32; | |
| /// let g = 4.0_f32; | |
| /// | |
| /// assert_eq!(f32::math::ceil(f), 4.0); | |
| /// assert_eq!(f32::math::ceil(g), 4.0); | |
| /// ``` | |
| /// | |
| /// _This standalone function is for testing only. | |
| /// It will be stabilized as an inherent method._ | |
| /// | |
| /// [`f32::ceil`]: ../../../std/primitive.f32.html#method.ceil | |
| #[inline] | |
| #[doc(alias = "ceiling")] | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[unstable(feature = "core_float_math", issue = "137578")] | |
| pub const fn ceil(x: f32) -> f32 { | |
| intrinsics::ceilf32(x) | |
| } | |
| /// Experimental version of `round` in `core`. See [`f32::round`] for details. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// #![feature(core_float_math)] | |
| /// | |
| /// use core::f32; | |
| /// | |
| /// let f = 3.3_f32; | |
| /// let g = -3.3_f32; | |
| /// let h = -3.7_f32; | |
| /// let i = 3.5_f32; | |
| /// let j = 4.5_f32; | |
| /// | |
| /// assert_eq!(f32::math::round(f), 3.0); | |
| /// assert_eq!(f32::math::round(g), -3.0); | |
| /// assert_eq!(f32::math::round(h), -4.0); | |
| /// assert_eq!(f32::math::round(i), 4.0); | |
| /// assert_eq!(f32::math::round(j), 5.0); | |
| /// ``` | |
| /// | |
| /// _This standalone function is for testing only. | |
| /// It will be stabilized as an inherent method._ | |
| /// | |
| /// [`f32::round`]: ../../../std/primitive.f32.html#method.round | |
| #[inline] | |
| #[unstable(feature = "core_float_math", issue = "137578")] | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| pub const fn round(x: f32) -> f32 { | |
| intrinsics::roundf32(x) | |
| } | |
| /// Experimental version of `round_ties_even` in `core`. See [`f32::round_ties_even`] for | |
| /// details. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// #![feature(core_float_math)] | |
| /// | |
| /// use core::f32; | |
| /// | |
| /// let f = 3.3_f32; | |
| /// let g = -3.3_f32; | |
| /// let h = 3.5_f32; | |
| /// let i = 4.5_f32; | |
| /// | |
| /// assert_eq!(f32::math::round_ties_even(f), 3.0); | |
| /// assert_eq!(f32::math::round_ties_even(g), -3.0); | |
| /// assert_eq!(f32::math::round_ties_even(h), 4.0); | |
| /// assert_eq!(f32::math::round_ties_even(i), 4.0); | |
| /// ``` | |
| /// | |
| /// _This standalone function is for testing only. | |
| /// It will be stabilized as an inherent method._ | |
| /// | |
| /// [`f32::round_ties_even`]: ../../../std/primitive.f32.html#method.round_ties_even | |
| #[inline] | |
| #[unstable(feature = "core_float_math", issue = "137578")] | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| pub const fn round_ties_even(x: f32) -> f32 { | |
| intrinsics::round_ties_even_f32(x) | |
| } | |
| /// Experimental version of `trunc` in `core`. See [`f32::trunc`] for details. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// #![feature(core_float_math)] | |
| /// | |
| /// use core::f32; | |
| /// | |
| /// let f = 3.7_f32; | |
| /// let g = 3.0_f32; | |
| /// let h = -3.7_f32; | |
| /// | |
| /// assert_eq!(f32::math::trunc(f), 3.0); | |
| /// assert_eq!(f32::math::trunc(g), 3.0); | |
| /// assert_eq!(f32::math::trunc(h), -3.0); | |
| /// ``` | |
| /// | |
| /// _This standalone function is for testing only. | |
| /// It will be stabilized as an inherent method._ | |
| /// | |
| /// [`f32::trunc`]: ../../../std/primitive.f32.html#method.trunc | |
| #[inline] | |
| #[doc(alias = "truncate")] | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[unstable(feature = "core_float_math", issue = "137578")] | |
| pub const fn trunc(x: f32) -> f32 { | |
| intrinsics::truncf32(x) | |
| } | |
| /// Experimental version of `fract` in `core`. See [`f32::fract`] for details. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// #![feature(core_float_math)] | |
| /// | |
| /// use core::f32; | |
| /// | |
| /// let x = 3.6_f32; | |
| /// let y = -3.6_f32; | |
| /// let abs_difference_x = (f32::math::fract(x) - 0.6).abs(); | |
| /// let abs_difference_y = (f32::math::fract(y) - (-0.6)).abs(); | |
| /// | |
| /// assert!(abs_difference_x <= f32::EPSILON); | |
| /// assert!(abs_difference_y <= f32::EPSILON); | |
| /// ``` | |
| /// | |
| /// _This standalone function is for testing only. | |
| /// It will be stabilized as an inherent method._ | |
| /// | |
| /// [`f32::fract`]: ../../../std/primitive.f32.html#method.fract | |
| #[inline] | |
| #[unstable(feature = "core_float_math", issue = "137578")] | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| pub const fn fract(x: f32) -> f32 { | |
| x - trunc(x) | |
| } | |
| /// Experimental version of `mul_add` in `core`. See [`f32::mul_add`] for details. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// # #![allow(unused_features)] | |
| /// #![feature(core_float_math)] | |
| /// | |
| /// # // FIXME(#140515): mingw has an incorrect fma | |
| /// # // https://sourceforge.net/p/mingw-w64/bugs/848/ | |
| /// # #[cfg(all(target_os = "windows", target_env = "gnu", not(target_abi = "llvm")))] { | |
| /// use core::f32; | |
| /// | |
| /// let m = 10.0_f32; | |
| /// let x = 4.0_f32; | |
| /// let b = 60.0_f32; | |
| /// | |
| /// assert_eq!(f32::math::mul_add(m, x, b), 100.0); | |
| /// assert_eq!(m * x + b, 100.0); | |
| /// | |
| /// let one_plus_eps = 1.0_f32 + f32::EPSILON; | |
| /// let one_minus_eps = 1.0_f32 - f32::EPSILON; | |
| /// let minus_one = -1.0_f32; | |
| /// | |
| /// // The exact result (1 + eps) * (1 - eps) = 1 - eps * eps. | |
| /// assert_eq!( | |
| /// f32::math::mul_add(one_plus_eps, one_minus_eps, minus_one), | |
| /// -f32::EPSILON * f32::EPSILON | |
| /// ); | |
| /// // Different rounding with the non-fused multiply and add. | |
| /// assert_eq!(one_plus_eps * one_minus_eps + minus_one, 0.0); | |
| /// # } | |
| /// ``` | |
| /// | |
| /// _This standalone function is for testing only. | |
| /// It will be stabilized as an inherent method._ | |
| /// | |
| /// [`f32::mul_add`]: ../../../std/primitive.f32.html#method.mul_add | |
| #[inline] | |
| #[doc(alias = "fmaf", alias = "fusedMultiplyAdd")] | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[unstable(feature = "core_float_math", issue = "137578")] | |
| pub const fn mul_add(x: f32, y: f32, z: f32) -> f32 { | |
| intrinsics::fmaf32(x, y, z) | |
| } | |
| /// Experimental version of `div_euclid` in `core`. See [`f32::div_euclid`] for details. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// #![feature(core_float_math)] | |
| /// | |
| /// use core::f32; | |
| /// | |
| /// let a: f32 = 7.0; | |
| /// let b = 4.0; | |
| /// assert_eq!(f32::math::div_euclid(a, b), 1.0); // 7.0 > 4.0 * 1.0 | |
| /// assert_eq!(f32::math::div_euclid(-a, b), -2.0); // -7.0 >= 4.0 * -2.0 | |
| /// assert_eq!(f32::math::div_euclid(a, -b), -1.0); // 7.0 >= -4.0 * -1.0 | |
| /// assert_eq!(f32::math::div_euclid(-a, -b), 2.0); // -7.0 >= -4.0 * 2.0 | |
| /// ``` | |
| /// | |
| /// _This standalone function is for testing only. | |
| /// It will be stabilized as an inherent method._ | |
| /// | |
| /// [`f32::div_euclid`]: ../../../std/primitive.f32.html#method.div_euclid | |
| #[inline] | |
| #[unstable(feature = "core_float_math", issue = "137578")] | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| pub fn div_euclid(x: f32, rhs: f32) -> f32 { | |
| let q = trunc(x / rhs); | |
| if x % rhs < 0.0 { | |
| return if rhs > 0.0 { q - 1.0 } else { q + 1.0 }; | |
| } | |
| q | |
| } | |
| /// Experimental version of `rem_euclid` in `core`. See [`f32::rem_euclid`] for details. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// #![feature(core_float_math)] | |
| /// | |
| /// use core::f32; | |
| /// | |
| /// let a: f32 = 7.0; | |
| /// let b = 4.0; | |
| /// assert_eq!(f32::math::rem_euclid(a, b), 3.0); | |
| /// assert_eq!(f32::math::rem_euclid(-a, b), 1.0); | |
| /// assert_eq!(f32::math::rem_euclid(a, -b), 3.0); | |
| /// assert_eq!(f32::math::rem_euclid(-a, -b), 1.0); | |
| /// // limitation due to round-off error | |
| /// assert!(f32::math::rem_euclid(-f32::EPSILON, 3.0) != 0.0); | |
| /// ``` | |
| /// | |
| /// _This standalone function is for testing only. | |
| /// It will be stabilized as an inherent method._ | |
| /// | |
| /// [`f32::rem_euclid`]: ../../../std/primitive.f32.html#method.rem_euclid | |
| #[inline] | |
| #[doc(alias = "modulo", alias = "mod")] | |
| #[unstable(feature = "core_float_math", issue = "137578")] | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| pub fn rem_euclid(x: f32, rhs: f32) -> f32 { | |
| let r = x % rhs; | |
| if r < 0.0 { r + rhs.abs() } else { r } | |
| } | |
| /// Experimental version of `powi` in `core`. See [`f32::powi`] for details. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// #![feature(core_float_math)] | |
| /// | |
| /// use core::f32; | |
| /// | |
| /// let x = 2.0_f32; | |
| /// let abs_difference = (f32::math::powi(x, 2) - (x * x)).abs(); | |
| /// assert!(abs_difference <= 1e-5); | |
| /// | |
| /// assert_eq!(f32::math::powi(f32::NAN, 0), 1.0); | |
| /// ``` | |
| /// | |
| /// _This standalone function is for testing only. | |
| /// It will be stabilized as an inherent method._ | |
| /// | |
| /// [`f32::powi`]: ../../../std/primitive.f32.html#method.powi | |
| #[inline] | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[unstable(feature = "core_float_math", issue = "137578")] | |
| pub fn powi(x: f32, n: i32) -> f32 { | |
| intrinsics::powif32(x, n) | |
| } | |
| /// Experimental version of `sqrt` in `core`. See [`f32::sqrt`] for details. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// #![feature(core_float_math)] | |
| /// | |
| /// use core::f32; | |
| /// | |
| /// let positive = 4.0_f32; | |
| /// let negative = -4.0_f32; | |
| /// let negative_zero = -0.0_f32; | |
| /// | |
| /// assert_eq!(f32::math::sqrt(positive), 2.0); | |
| /// assert!(f32::math::sqrt(negative).is_nan()); | |
| /// assert_eq!(f32::math::sqrt(negative_zero), negative_zero); | |
| /// ``` | |
| /// | |
| /// _This standalone function is for testing only. | |
| /// It will be stabilized as an inherent method._ | |
| /// | |
| /// [`f32::sqrt`]: ../../../std/primitive.f32.html#method.sqrt | |
| #[inline] | |
| #[doc(alias = "squareRoot")] | |
| #[unstable(feature = "core_float_math", issue = "137578")] | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| pub fn sqrt(x: f32) -> f32 { | |
| intrinsics::sqrtf32(x) | |
| } | |
| /// Experimental version of `abs_sub` in `core`. See [`f32::abs_sub`] for details. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// #![feature(core_float_math)] | |
| /// | |
| /// use core::f32; | |
| /// | |
| /// let x = 3.0f32; | |
| /// let y = -3.0f32; | |
| /// | |
| /// let abs_difference_x = (f32::math::abs_sub(x, 1.0) - 2.0).abs(); | |
| /// let abs_difference_y = (f32::math::abs_sub(y, 1.0) - 0.0).abs(); | |
| /// | |
| /// assert!(abs_difference_x <= 1e-6); | |
| /// assert!(abs_difference_y <= 1e-6); | |
| /// ``` | |
| /// | |
| /// _This standalone function is for testing only. | |
| /// It will be stabilized as an inherent method._ | |
| /// | |
| /// [`f32::abs_sub`]: ../../../std/primitive.f32.html#method.abs_sub | |
| #[inline] | |
| #[stable(feature = "rust1", since = "1.0.0")] | |
| #[deprecated( | |
| since = "1.10.0", | |
| note = "you probably meant `(self - other).abs()`: \ | |
| this operation is `(self - other).max(0.0)` \ | |
| except that `abs_sub` also propagates NaNs (also \ | |
| known as `fdimf` in C). If you truly need the positive \ | |
| difference, consider using that expression or the C function \ | |
| `fdimf`, depending on how you wish to handle NaN (please consider \ | |
| filing an issue describing your use-case too)." | |
| )] | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| pub fn abs_sub(x: f32, other: f32) -> f32 { | |
| libm::fdimf(x, other) | |
| } | |
| /// Experimental version of `cbrt` in `core`. See [`f32::cbrt`] for details. | |
| /// | |
| /// # Unspecified precision | |
| /// | |
| /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and | |
| /// can even differ within the same execution from one invocation to the next. | |
| /// This function currently corresponds to the `cbrtf` from libc on Unix | |
| /// and Windows. Note that this might change in the future. | |
| /// | |
| /// # Examples | |
| /// | |
| /// ``` | |
| /// #![feature(core_float_math)] | |
| /// | |
| /// use core::f32; | |
| /// | |
| /// let x = 8.0f32; | |
| /// | |
| /// // x^(1/3) - 2 == 0 | |
| /// let abs_difference = (f32::math::cbrt(x) - 2.0).abs(); | |
| /// | |
| /// assert!(abs_difference <= 1e-6); | |
| /// ``` | |
| /// | |
| /// _This standalone function is for testing only. | |
| /// It will be stabilized as an inherent method._ | |
| /// | |
| /// [`f32::cbrt`]: ../../../std/primitive.f32.html#method.cbrt | |
| #[inline] | |
| #[must_use = "method returns a new number and does not mutate the original value"] | |
| #[unstable(feature = "core_float_math", issue = "137578")] | |
| pub fn cbrt(x: f32) -> f32 { | |
| libm::cbrtf(x) | |
| } | |
| } |