core/num/
f32.rs

1//! Constants for the `f32` single-precision floating point type.
2//!
3//! *[See also the `f32` primitive type][f32].*
4//!
5//! Mathematically significant numbers are provided in the `consts` sub-module.
6//!
7//! For the constants defined directly in this module
8//! (as distinct from those defined in the `consts` sub-module),
9//! new code should instead use the associated constants
10//! defined directly on the `f32` type.
11
12#![stable(feature = "rust1", since = "1.0.0")]
13
14use crate::convert::FloatToInt;
15use crate::num::FpCategory;
16use crate::panic::const_assert;
17use crate::{cfg_select, intrinsics, mem};
18
19/// The radix or base of the internal representation of `f32`.
20/// Use [`f32::RADIX`] instead.
21///
22/// # Examples
23///
24/// ```rust
25/// // deprecated way
26/// # #[allow(deprecated, deprecated_in_future)]
27/// let r = std::f32::RADIX;
28///
29/// // intended way
30/// let r = f32::RADIX;
31/// ```
32#[stable(feature = "rust1", since = "1.0.0")]
33#[deprecated(since = "TBD", note = "replaced by the `RADIX` associated constant on `f32`")]
34#[rustc_diagnostic_item = "f32_legacy_const_radix"]
35pub const RADIX: u32 = f32::RADIX;
36
37/// Number of significant digits in base 2.
38/// Use [`f32::MANTISSA_DIGITS`] instead.
39///
40/// # Examples
41///
42/// ```rust
43/// // deprecated way
44/// # #[allow(deprecated, deprecated_in_future)]
45/// let d = std::f32::MANTISSA_DIGITS;
46///
47/// // intended way
48/// let d = f32::MANTISSA_DIGITS;
49/// ```
50#[stable(feature = "rust1", since = "1.0.0")]
51#[deprecated(
52    since = "TBD",
53    note = "replaced by the `MANTISSA_DIGITS` associated constant on `f32`"
54)]
55#[rustc_diagnostic_item = "f32_legacy_const_mantissa_dig"]
56pub const MANTISSA_DIGITS: u32 = f32::MANTISSA_DIGITS;
57
58/// Approximate number of significant digits in base 10.
59/// Use [`f32::DIGITS`] instead.
60///
61/// # Examples
62///
63/// ```rust
64/// // deprecated way
65/// # #[allow(deprecated, deprecated_in_future)]
66/// let d = std::f32::DIGITS;
67///
68/// // intended way
69/// let d = f32::DIGITS;
70/// ```
71#[stable(feature = "rust1", since = "1.0.0")]
72#[deprecated(since = "TBD", note = "replaced by the `DIGITS` associated constant on `f32`")]
73#[rustc_diagnostic_item = "f32_legacy_const_digits"]
74pub const DIGITS: u32 = f32::DIGITS;
75
76/// [Machine epsilon] value for `f32`.
77/// Use [`f32::EPSILON`] instead.
78///
79/// This is the difference between `1.0` and the next larger representable number.
80///
81/// [Machine epsilon]: https://en.wikipedia.org/wiki/Machine_epsilon
82///
83/// # Examples
84///
85/// ```rust
86/// // deprecated way
87/// # #[allow(deprecated, deprecated_in_future)]
88/// let e = std::f32::EPSILON;
89///
90/// // intended way
91/// let e = f32::EPSILON;
92/// ```
93#[stable(feature = "rust1", since = "1.0.0")]
94#[deprecated(since = "TBD", note = "replaced by the `EPSILON` associated constant on `f32`")]
95#[rustc_diagnostic_item = "f32_legacy_const_epsilon"]
96pub const EPSILON: f32 = f32::EPSILON;
97
98/// Smallest finite `f32` value.
99/// Use [`f32::MIN`] instead.
100///
101/// # Examples
102///
103/// ```rust
104/// // deprecated way
105/// # #[allow(deprecated, deprecated_in_future)]
106/// let min = std::f32::MIN;
107///
108/// // intended way
109/// let min = f32::MIN;
110/// ```
111#[stable(feature = "rust1", since = "1.0.0")]
112#[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on `f32`")]
113#[rustc_diagnostic_item = "f32_legacy_const_min"]
114pub const MIN: f32 = f32::MIN;
115
116/// Smallest positive normal `f32` value.
117/// Use [`f32::MIN_POSITIVE`] instead.
118///
119/// # Examples
120///
121/// ```rust
122/// // deprecated way
123/// # #[allow(deprecated, deprecated_in_future)]
124/// let min = std::f32::MIN_POSITIVE;
125///
126/// // intended way
127/// let min = f32::MIN_POSITIVE;
128/// ```
129#[stable(feature = "rust1", since = "1.0.0")]
130#[deprecated(since = "TBD", note = "replaced by the `MIN_POSITIVE` associated constant on `f32`")]
131#[rustc_diagnostic_item = "f32_legacy_const_min_positive"]
132pub const MIN_POSITIVE: f32 = f32::MIN_POSITIVE;
133
134/// Largest finite `f32` value.
135/// Use [`f32::MAX`] instead.
136///
137/// # Examples
138///
139/// ```rust
140/// // deprecated way
141/// # #[allow(deprecated, deprecated_in_future)]
142/// let max = std::f32::MAX;
143///
144/// // intended way
145/// let max = f32::MAX;
146/// ```
147#[stable(feature = "rust1", since = "1.0.0")]
148#[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on `f32`")]
149#[rustc_diagnostic_item = "f32_legacy_const_max"]
150pub const MAX: f32 = f32::MAX;
151
152/// One greater than the minimum possible normal power of 2 exponent.
153/// Use [`f32::MIN_EXP`] instead.
154///
155/// # Examples
156///
157/// ```rust
158/// // deprecated way
159/// # #[allow(deprecated, deprecated_in_future)]
160/// let min = std::f32::MIN_EXP;
161///
162/// // intended way
163/// let min = f32::MIN_EXP;
164/// ```
165#[stable(feature = "rust1", since = "1.0.0")]
166#[deprecated(since = "TBD", note = "replaced by the `MIN_EXP` associated constant on `f32`")]
167#[rustc_diagnostic_item = "f32_legacy_const_min_exp"]
168pub const MIN_EXP: i32 = f32::MIN_EXP;
169
170/// Maximum possible power of 2 exponent.
171/// Use [`f32::MAX_EXP`] instead.
172///
173/// # Examples
174///
175/// ```rust
176/// // deprecated way
177/// # #[allow(deprecated, deprecated_in_future)]
178/// let max = std::f32::MAX_EXP;
179///
180/// // intended way
181/// let max = f32::MAX_EXP;
182/// ```
183#[stable(feature = "rust1", since = "1.0.0")]
184#[deprecated(since = "TBD", note = "replaced by the `MAX_EXP` associated constant on `f32`")]
185#[rustc_diagnostic_item = "f32_legacy_const_max_exp"]
186pub const MAX_EXP: i32 = f32::MAX_EXP;
187
188/// Minimum possible normal power of 10 exponent.
189/// Use [`f32::MIN_10_EXP`] instead.
190///
191/// # Examples
192///
193/// ```rust
194/// // deprecated way
195/// # #[allow(deprecated, deprecated_in_future)]
196/// let min = std::f32::MIN_10_EXP;
197///
198/// // intended way
199/// let min = f32::MIN_10_EXP;
200/// ```
201#[stable(feature = "rust1", since = "1.0.0")]
202#[deprecated(since = "TBD", note = "replaced by the `MIN_10_EXP` associated constant on `f32`")]
203#[rustc_diagnostic_item = "f32_legacy_const_min_10_exp"]
204pub const MIN_10_EXP: i32 = f32::MIN_10_EXP;
205
206/// Maximum possible power of 10 exponent.
207/// Use [`f32::MAX_10_EXP`] instead.
208///
209/// # Examples
210///
211/// ```rust
212/// // deprecated way
213/// # #[allow(deprecated, deprecated_in_future)]
214/// let max = std::f32::MAX_10_EXP;
215///
216/// // intended way
217/// let max = f32::MAX_10_EXP;
218/// ```
219#[stable(feature = "rust1", since = "1.0.0")]
220#[deprecated(since = "TBD", note = "replaced by the `MAX_10_EXP` associated constant on `f32`")]
221#[rustc_diagnostic_item = "f32_legacy_const_max_10_exp"]
222pub const MAX_10_EXP: i32 = f32::MAX_10_EXP;
223
224/// Not a Number (NaN).
225/// Use [`f32::NAN`] instead.
226///
227/// # Examples
228///
229/// ```rust
230/// // deprecated way
231/// # #[allow(deprecated, deprecated_in_future)]
232/// let nan = std::f32::NAN;
233///
234/// // intended way
235/// let nan = f32::NAN;
236/// ```
237#[stable(feature = "rust1", since = "1.0.0")]
238#[deprecated(since = "TBD", note = "replaced by the `NAN` associated constant on `f32`")]
239#[rustc_diagnostic_item = "f32_legacy_const_nan"]
240pub const NAN: f32 = f32::NAN;
241
242/// Infinity (∞).
243/// Use [`f32::INFINITY`] instead.
244///
245/// # Examples
246///
247/// ```rust
248/// // deprecated way
249/// # #[allow(deprecated, deprecated_in_future)]
250/// let inf = std::f32::INFINITY;
251///
252/// // intended way
253/// let inf = f32::INFINITY;
254/// ```
255#[stable(feature = "rust1", since = "1.0.0")]
256#[deprecated(since = "TBD", note = "replaced by the `INFINITY` associated constant on `f32`")]
257#[rustc_diagnostic_item = "f32_legacy_const_infinity"]
258pub const INFINITY: f32 = f32::INFINITY;
259
260/// Negative infinity (−∞).
261/// Use [`f32::NEG_INFINITY`] instead.
262///
263/// # Examples
264///
265/// ```rust
266/// // deprecated way
267/// # #[allow(deprecated, deprecated_in_future)]
268/// let ninf = std::f32::NEG_INFINITY;
269///
270/// // intended way
271/// let ninf = f32::NEG_INFINITY;
272/// ```
273#[stable(feature = "rust1", since = "1.0.0")]
274#[deprecated(since = "TBD", note = "replaced by the `NEG_INFINITY` associated constant on `f32`")]
275#[rustc_diagnostic_item = "f32_legacy_const_neg_infinity"]
276pub const NEG_INFINITY: f32 = f32::NEG_INFINITY;
277
278/// Basic mathematical constants.
279#[stable(feature = "rust1", since = "1.0.0")]
280#[rustc_diagnostic_item = "f32_consts_mod"]
281pub mod consts {
282    // FIXME: replace with mathematical constants from cmath.
283
284    /// Archimedes' constant (π)
285    #[stable(feature = "rust1", since = "1.0.0")]
286    pub const PI: f32 = 3.14159265358979323846264338327950288_f32;
287
288    /// The full circle constant (τ)
289    ///
290    /// Equal to 2π.
291    #[stable(feature = "tau_constant", since = "1.47.0")]
292    pub const TAU: f32 = 6.28318530717958647692528676655900577_f32;
293
294    /// The golden ratio (φ)
295    #[unstable(feature = "more_float_constants", issue = "146939")]
296    pub const PHI: f32 = 1.618033988749894848204586834365638118_f32;
297
298    /// The Euler-Mascheroni constant (γ)
299    #[unstable(feature = "more_float_constants", issue = "146939")]
300    pub const EGAMMA: f32 = 0.577215664901532860606512090082402431_f32;
301
302    /// π/2
303    #[stable(feature = "rust1", since = "1.0.0")]
304    pub const FRAC_PI_2: f32 = 1.57079632679489661923132169163975144_f32;
305
306    /// π/3
307    #[stable(feature = "rust1", since = "1.0.0")]
308    pub const FRAC_PI_3: f32 = 1.04719755119659774615421446109316763_f32;
309
310    /// π/4
311    #[stable(feature = "rust1", since = "1.0.0")]
312    pub const FRAC_PI_4: f32 = 0.785398163397448309615660845819875721_f32;
313
314    /// π/6
315    #[stable(feature = "rust1", since = "1.0.0")]
316    pub const FRAC_PI_6: f32 = 0.52359877559829887307710723054658381_f32;
317
318    /// π/8
319    #[stable(feature = "rust1", since = "1.0.0")]
320    pub const FRAC_PI_8: f32 = 0.39269908169872415480783042290993786_f32;
321
322    /// 1/π
323    #[stable(feature = "rust1", since = "1.0.0")]
324    pub const FRAC_1_PI: f32 = 0.318309886183790671537767526745028724_f32;
325
326    /// 1/sqrt(π)
327    #[unstable(feature = "more_float_constants", issue = "146939")]
328    pub const FRAC_1_SQRT_PI: f32 = 0.564189583547756286948079451560772586_f32;
329
330    /// 1/sqrt(2π)
331    #[doc(alias = "FRAC_1_SQRT_TAU")]
332    #[unstable(feature = "more_float_constants", issue = "146939")]
333    pub const FRAC_1_SQRT_2PI: f32 = 0.398942280401432677939946059934381868_f32;
334
335    /// 2/π
336    #[stable(feature = "rust1", since = "1.0.0")]
337    pub const FRAC_2_PI: f32 = 0.636619772367581343075535053490057448_f32;
338
339    /// 2/sqrt(π)
340    #[stable(feature = "rust1", since = "1.0.0")]
341    pub const FRAC_2_SQRT_PI: f32 = 1.12837916709551257389615890312154517_f32;
342
343    /// sqrt(2)
344    #[stable(feature = "rust1", since = "1.0.0")]
345    pub const SQRT_2: f32 = 1.41421356237309504880168872420969808_f32;
346
347    /// 1/sqrt(2)
348    #[stable(feature = "rust1", since = "1.0.0")]
349    pub const FRAC_1_SQRT_2: f32 = 0.707106781186547524400844362104849039_f32;
350
351    /// sqrt(3)
352    #[unstable(feature = "more_float_constants", issue = "146939")]
353    pub const SQRT_3: f32 = 1.732050807568877293527446341505872367_f32;
354
355    /// 1/sqrt(3)
356    #[unstable(feature = "more_float_constants", issue = "146939")]
357    pub const FRAC_1_SQRT_3: f32 = 0.577350269189625764509148780501957456_f32;
358
359    /// Euler's number (e)
360    #[stable(feature = "rust1", since = "1.0.0")]
361    pub const E: f32 = 2.71828182845904523536028747135266250_f32;
362
363    /// log<sub>2</sub>(e)
364    #[stable(feature = "rust1", since = "1.0.0")]
365    pub const LOG2_E: f32 = 1.44269504088896340735992468100189214_f32;
366
367    /// log<sub>2</sub>(10)
368    #[stable(feature = "extra_log_consts", since = "1.43.0")]
369    pub const LOG2_10: f32 = 3.32192809488736234787031942948939018_f32;
370
371    /// log<sub>10</sub>(e)
372    #[stable(feature = "rust1", since = "1.0.0")]
373    pub const LOG10_E: f32 = 0.434294481903251827651128918916605082_f32;
374
375    /// log<sub>10</sub>(2)
376    #[stable(feature = "extra_log_consts", since = "1.43.0")]
377    pub const LOG10_2: f32 = 0.301029995663981195213738894724493027_f32;
378
379    /// ln(2)
380    #[stable(feature = "rust1", since = "1.0.0")]
381    pub const LN_2: f32 = 0.693147180559945309417232121458176568_f32;
382
383    /// ln(10)
384    #[stable(feature = "rust1", since = "1.0.0")]
385    pub const LN_10: f32 = 2.30258509299404568401799145468436421_f32;
386}
387
388impl f32 {
389    /// The radix or base of the internal representation of `f32`.
390    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
391    pub const RADIX: u32 = 2;
392
393    /// Number of significant digits in base 2.
394    ///
395    /// Note that the size of the mantissa in the bitwise representation is one
396    /// smaller than this since the leading 1 is not stored explicitly.
397    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
398    pub const MANTISSA_DIGITS: u32 = 24;
399
400    /// Approximate number of significant digits in base 10.
401    ///
402    /// This is the maximum <i>x</i> such that any decimal number with <i>x</i>
403    /// significant digits can be converted to `f32` and back without loss.
404    ///
405    /// Equal to floor(log<sub>10</sub>&nbsp;2<sup>[`MANTISSA_DIGITS`]&nbsp;&minus;&nbsp;1</sup>).
406    ///
407    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
408    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
409    pub const DIGITS: u32 = 6;
410
411    /// [Machine epsilon] value for `f32`.
412    ///
413    /// This is the difference between `1.0` and the next larger representable number.
414    ///
415    /// Equal to 2<sup>1&nbsp;&minus;&nbsp;[`MANTISSA_DIGITS`]</sup>.
416    ///
417    /// [Machine epsilon]: https://en.wikipedia.org/wiki/Machine_epsilon
418    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
419    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
420    #[rustc_diagnostic_item = "f32_epsilon"]
421    pub const EPSILON: f32 = 1.19209290e-07_f32;
422
423    /// Smallest finite `f32` value.
424    ///
425    /// Equal to &minus;[`MAX`].
426    ///
427    /// [`MAX`]: f32::MAX
428    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
429    pub const MIN: f32 = -3.40282347e+38_f32;
430    /// Smallest positive normal `f32` value.
431    ///
432    /// Equal to 2<sup>[`MIN_EXP`]&nbsp;&minus;&nbsp;1</sup>.
433    ///
434    /// [`MIN_EXP`]: f32::MIN_EXP
435    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
436    pub const MIN_POSITIVE: f32 = 1.17549435e-38_f32;
437    /// Largest finite `f32` value.
438    ///
439    /// Equal to
440    /// (1&nbsp;&minus;&nbsp;2<sup>&minus;[`MANTISSA_DIGITS`]</sup>)&nbsp;2<sup>[`MAX_EXP`]</sup>.
441    ///
442    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
443    /// [`MAX_EXP`]: f32::MAX_EXP
444    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
445    pub const MAX: f32 = 3.40282347e+38_f32;
446
447    /// One greater than the minimum possible *normal* power of 2 exponent
448    /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition).
449    ///
450    /// This corresponds to the exact minimum possible *normal* power of 2 exponent
451    /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition).
452    /// In other words, all normal numbers representable by this type are
453    /// greater than or equal to 0.5&nbsp;×&nbsp;2<sup><i>MIN_EXP</i></sup>.
454    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
455    pub const MIN_EXP: i32 = -125;
456    /// One greater than the maximum possible power of 2 exponent
457    /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition).
458    ///
459    /// This corresponds to the exact maximum possible power of 2 exponent
460    /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition).
461    /// In other words, all numbers representable by this type are
462    /// strictly less than 2<sup><i>MAX_EXP</i></sup>.
463    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
464    pub const MAX_EXP: i32 = 128;
465
466    /// Minimum <i>x</i> for which 10<sup><i>x</i></sup> is normal.
467    ///
468    /// Equal to ceil(log<sub>10</sub>&nbsp;[`MIN_POSITIVE`]).
469    ///
470    /// [`MIN_POSITIVE`]: f32::MIN_POSITIVE
471    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
472    pub const MIN_10_EXP: i32 = -37;
473    /// Maximum <i>x</i> for which 10<sup><i>x</i></sup> is normal.
474    ///
475    /// Equal to floor(log<sub>10</sub>&nbsp;[`MAX`]).
476    ///
477    /// [`MAX`]: f32::MAX
478    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
479    pub const MAX_10_EXP: i32 = 38;
480
481    /// Not a Number (NaN).
482    ///
483    /// Note that IEEE 754 doesn't define just a single NaN value; a plethora of bit patterns are
484    /// considered to be NaN. Furthermore, the standard makes a difference between a "signaling" and
485    /// a "quiet" NaN, and allows inspecting its "payload" (the unspecified bits in the bit pattern)
486    /// and its sign. See the [specification of NaN bit patterns](f32#nan-bit-patterns) for more
487    /// info.
488    ///
489    /// This constant is guaranteed to be a quiet NaN (on targets that follow the Rust assumptions
490    /// that the quiet/signaling bit being set to 1 indicates a quiet NaN). Beyond that, nothing is
491    /// guaranteed about the specific bit pattern chosen here: both payload and sign are arbitrary.
492    /// The concrete bit pattern may change across Rust versions and target platforms.
493    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
494    #[rustc_diagnostic_item = "f32_nan"]
495    #[allow(clippy::eq_op)]
496    pub const NAN: f32 = 0.0_f32 / 0.0_f32;
497    /// Infinity (∞).
498    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
499    pub const INFINITY: f32 = 1.0_f32 / 0.0_f32;
500    /// Negative infinity (−∞).
501    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
502    pub const NEG_INFINITY: f32 = -1.0_f32 / 0.0_f32;
503
504    /// Sign bit
505    pub(crate) const SIGN_MASK: u32 = 0x8000_0000;
506
507    /// Exponent mask
508    pub(crate) const EXP_MASK: u32 = 0x7f80_0000;
509
510    /// Mantissa mask
511    pub(crate) const MAN_MASK: u32 = 0x007f_ffff;
512
513    /// Minimum representable positive value (min subnormal)
514    const TINY_BITS: u32 = 0x1;
515
516    /// Minimum representable negative value (min negative subnormal)
517    const NEG_TINY_BITS: u32 = Self::TINY_BITS | Self::SIGN_MASK;
518
519    /// Returns `true` if this value is NaN.
520    ///
521    /// ```
522    /// let nan = f32::NAN;
523    /// let f = 7.0_f32;
524    ///
525    /// assert!(nan.is_nan());
526    /// assert!(!f.is_nan());
527    /// ```
528    #[must_use]
529    #[stable(feature = "rust1", since = "1.0.0")]
530    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
531    #[inline]
532    #[allow(clippy::eq_op)] // > if you intended to check if the operand is NaN, use `.is_nan()` instead :)
533    pub const fn is_nan(self) -> bool {
534        self != self
535    }
536
537    /// Returns `true` if this value is positive infinity or negative infinity, and
538    /// `false` otherwise.
539    ///
540    /// ```
541    /// let f = 7.0f32;
542    /// let inf = f32::INFINITY;
543    /// let neg_inf = f32::NEG_INFINITY;
544    /// let nan = f32::NAN;
545    ///
546    /// assert!(!f.is_infinite());
547    /// assert!(!nan.is_infinite());
548    ///
549    /// assert!(inf.is_infinite());
550    /// assert!(neg_inf.is_infinite());
551    /// ```
552    #[must_use]
553    #[stable(feature = "rust1", since = "1.0.0")]
554    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
555    #[inline]
556    pub const fn is_infinite(self) -> bool {
557        // Getting clever with transmutation can result in incorrect answers on some FPUs
558        // FIXME: alter the Rust <-> Rust calling convention to prevent this problem.
559        // See https://github.com/rust-lang/rust/issues/72327
560        (self == f32::INFINITY) | (self == f32::NEG_INFINITY)
561    }
562
563    /// Returns `true` if this number is neither infinite nor NaN.
564    ///
565    /// ```
566    /// let f = 7.0f32;
567    /// let inf = f32::INFINITY;
568    /// let neg_inf = f32::NEG_INFINITY;
569    /// let nan = f32::NAN;
570    ///
571    /// assert!(f.is_finite());
572    ///
573    /// assert!(!nan.is_finite());
574    /// assert!(!inf.is_finite());
575    /// assert!(!neg_inf.is_finite());
576    /// ```
577    #[must_use]
578    #[stable(feature = "rust1", since = "1.0.0")]
579    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
580    #[inline]
581    pub const fn is_finite(self) -> bool {
582        // There's no need to handle NaN separately: if self is NaN,
583        // the comparison is not true, exactly as desired.
584        self.abs() < Self::INFINITY
585    }
586
587    /// Returns `true` if the number is [subnormal].
588    ///
589    /// ```
590    /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
591    /// let max = f32::MAX;
592    /// let lower_than_min = 1.0e-40_f32;
593    /// let zero = 0.0_f32;
594    ///
595    /// assert!(!min.is_subnormal());
596    /// assert!(!max.is_subnormal());
597    ///
598    /// assert!(!zero.is_subnormal());
599    /// assert!(!f32::NAN.is_subnormal());
600    /// assert!(!f32::INFINITY.is_subnormal());
601    /// // Values between `0` and `min` are Subnormal.
602    /// assert!(lower_than_min.is_subnormal());
603    /// ```
604    /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number
605    #[must_use]
606    #[stable(feature = "is_subnormal", since = "1.53.0")]
607    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
608    #[inline]
609    pub const fn is_subnormal(self) -> bool {
610        matches!(self.classify(), FpCategory::Subnormal)
611    }
612
613    /// Returns `true` if the number is neither zero, infinite,
614    /// [subnormal], or NaN.
615    ///
616    /// ```
617    /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
618    /// let max = f32::MAX;
619    /// let lower_than_min = 1.0e-40_f32;
620    /// let zero = 0.0_f32;
621    ///
622    /// assert!(min.is_normal());
623    /// assert!(max.is_normal());
624    ///
625    /// assert!(!zero.is_normal());
626    /// assert!(!f32::NAN.is_normal());
627    /// assert!(!f32::INFINITY.is_normal());
628    /// // Values between `0` and `min` are Subnormal.
629    /// assert!(!lower_than_min.is_normal());
630    /// ```
631    /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number
632    #[must_use]
633    #[stable(feature = "rust1", since = "1.0.0")]
634    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
635    #[inline]
636    pub const fn is_normal(self) -> bool {
637        matches!(self.classify(), FpCategory::Normal)
638    }
639
640    /// Returns the floating point category of the number. If only one property
641    /// is going to be tested, it is generally faster to use the specific
642    /// predicate instead.
643    ///
644    /// ```
645    /// use std::num::FpCategory;
646    ///
647    /// let num = 12.4_f32;
648    /// let inf = f32::INFINITY;
649    ///
650    /// assert_eq!(num.classify(), FpCategory::Normal);
651    /// assert_eq!(inf.classify(), FpCategory::Infinite);
652    /// ```
653    #[stable(feature = "rust1", since = "1.0.0")]
654    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
655    pub const fn classify(self) -> FpCategory {
656        // We used to have complicated logic here that avoids the simple bit-based tests to work
657        // around buggy codegen for x87 targets (see
658        // https://github.com/rust-lang/rust/issues/114479). However, some LLVM versions later, none
659        // of our tests is able to find any difference between the complicated and the naive
660        // version, so now we are back to the naive version.
661        let b = self.to_bits();
662        match (b & Self::MAN_MASK, b & Self::EXP_MASK) {
663            (0, Self::EXP_MASK) => FpCategory::Infinite,
664            (_, Self::EXP_MASK) => FpCategory::Nan,
665            (0, 0) => FpCategory::Zero,
666            (_, 0) => FpCategory::Subnormal,
667            _ => FpCategory::Normal,
668        }
669    }
670
671    /// Returns `true` if `self` has a positive sign, including `+0.0`, NaNs with
672    /// positive sign bit and positive infinity.
673    ///
674    /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of
675    /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are
676    /// conserved over arithmetic operations, the result of `is_sign_positive` on
677    /// a NaN might produce an unexpected or non-portable result. See the [specification
678    /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == 1.0`
679    /// if you need fully portable behavior (will return `false` for all NaNs).
680    ///
681    /// ```
682    /// let f = 7.0_f32;
683    /// let g = -7.0_f32;
684    ///
685    /// assert!(f.is_sign_positive());
686    /// assert!(!g.is_sign_positive());
687    /// ```
688    #[must_use]
689    #[stable(feature = "rust1", since = "1.0.0")]
690    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
691    #[inline]
692    pub const fn is_sign_positive(self) -> bool {
693        !self.is_sign_negative()
694    }
695
696    /// Returns `true` if `self` has a negative sign, including `-0.0`, NaNs with
697    /// negative sign bit and negative infinity.
698    ///
699    /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of
700    /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are
701    /// conserved over arithmetic operations, the result of `is_sign_negative` on
702    /// a NaN might produce an unexpected or non-portable result. See the [specification
703    /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == -1.0`
704    /// if you need fully portable behavior (will return `false` for all NaNs).
705    ///
706    /// ```
707    /// let f = 7.0f32;
708    /// let g = -7.0f32;
709    ///
710    /// assert!(!f.is_sign_negative());
711    /// assert!(g.is_sign_negative());
712    /// ```
713    #[must_use]
714    #[stable(feature = "rust1", since = "1.0.0")]
715    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
716    #[inline]
717    pub const fn is_sign_negative(self) -> bool {
718        // IEEE754 says: isSignMinus(x) is true if and only if x has negative sign. isSignMinus
719        // applies to zeros and NaNs as well.
720        self.to_bits() & 0x8000_0000 != 0
721    }
722
723    /// Returns the least number greater than `self`.
724    ///
725    /// Let `TINY` be the smallest representable positive `f32`. Then,
726    ///  - if `self.is_nan()`, this returns `self`;
727    ///  - if `self` is [`NEG_INFINITY`], this returns [`MIN`];
728    ///  - if `self` is `-TINY`, this returns -0.0;
729    ///  - if `self` is -0.0 or +0.0, this returns `TINY`;
730    ///  - if `self` is [`MAX`] or [`INFINITY`], this returns [`INFINITY`];
731    ///  - otherwise the unique least value greater than `self` is returned.
732    ///
733    /// The identity `x.next_up() == -(-x).next_down()` holds for all non-NaN `x`. When `x`
734    /// is finite `x == x.next_up().next_down()` also holds.
735    ///
736    /// ```rust
737    /// // f32::EPSILON is the difference between 1.0 and the next number up.
738    /// assert_eq!(1.0f32.next_up(), 1.0 + f32::EPSILON);
739    /// // But not for most numbers.
740    /// assert!(0.1f32.next_up() < 0.1 + f32::EPSILON);
741    /// assert_eq!(16777216f32.next_up(), 16777218.0);
742    /// ```
743    ///
744    /// This operation corresponds to IEEE-754 `nextUp`.
745    ///
746    /// [`NEG_INFINITY`]: Self::NEG_INFINITY
747    /// [`INFINITY`]: Self::INFINITY
748    /// [`MIN`]: Self::MIN
749    /// [`MAX`]: Self::MAX
750    #[inline]
751    #[doc(alias = "nextUp")]
752    #[stable(feature = "float_next_up_down", since = "1.86.0")]
753    #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")]
754    pub const fn next_up(self) -> Self {
755        // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
756        // denormals to zero. This is in general unsound and unsupported, but here
757        // we do our best to still produce the correct result on such targets.
758        let bits = self.to_bits();
759        if self.is_nan() || bits == Self::INFINITY.to_bits() {
760            return self;
761        }
762
763        let abs = bits & !Self::SIGN_MASK;
764        let next_bits = if abs == 0 {
765            Self::TINY_BITS
766        } else if bits == abs {
767            bits + 1
768        } else {
769            bits - 1
770        };
771        Self::from_bits(next_bits)
772    }
773
774    /// Returns the greatest number less than `self`.
775    ///
776    /// Let `TINY` be the smallest representable positive `f32`. Then,
777    ///  - if `self.is_nan()`, this returns `self`;
778    ///  - if `self` is [`INFINITY`], this returns [`MAX`];
779    ///  - if `self` is `TINY`, this returns 0.0;
780    ///  - if `self` is -0.0 or +0.0, this returns `-TINY`;
781    ///  - if `self` is [`MIN`] or [`NEG_INFINITY`], this returns [`NEG_INFINITY`];
782    ///  - otherwise the unique greatest value less than `self` is returned.
783    ///
784    /// The identity `x.next_down() == -(-x).next_up()` holds for all non-NaN `x`. When `x`
785    /// is finite `x == x.next_down().next_up()` also holds.
786    ///
787    /// ```rust
788    /// let x = 1.0f32;
789    /// // Clamp value into range [0, 1).
790    /// let clamped = x.clamp(0.0, 1.0f32.next_down());
791    /// assert!(clamped < 1.0);
792    /// assert_eq!(clamped.next_up(), 1.0);
793    /// ```
794    ///
795    /// This operation corresponds to IEEE-754 `nextDown`.
796    ///
797    /// [`NEG_INFINITY`]: Self::NEG_INFINITY
798    /// [`INFINITY`]: Self::INFINITY
799    /// [`MIN`]: Self::MIN
800    /// [`MAX`]: Self::MAX
801    #[inline]
802    #[doc(alias = "nextDown")]
803    #[stable(feature = "float_next_up_down", since = "1.86.0")]
804    #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")]
805    pub const fn next_down(self) -> Self {
806        // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
807        // denormals to zero. This is in general unsound and unsupported, but here
808        // we do our best to still produce the correct result on such targets.
809        let bits = self.to_bits();
810        if self.is_nan() || bits == Self::NEG_INFINITY.to_bits() {
811            return self;
812        }
813
814        let abs = bits & !Self::SIGN_MASK;
815        let next_bits = if abs == 0 {
816            Self::NEG_TINY_BITS
817        } else if bits == abs {
818            bits - 1
819        } else {
820            bits + 1
821        };
822        Self::from_bits(next_bits)
823    }
824
825    /// Takes the reciprocal (inverse) of a number, `1/x`.
826    ///
827    /// ```
828    /// let x = 2.0_f32;
829    /// let abs_difference = (x.recip() - (1.0 / x)).abs();
830    ///
831    /// assert!(abs_difference <= f32::EPSILON);
832    /// ```
833    #[must_use = "this returns the result of the operation, without modifying the original"]
834    #[stable(feature = "rust1", since = "1.0.0")]
835    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
836    #[inline]
837    pub const fn recip(self) -> f32 {
838        1.0 / self
839    }
840
841    /// Converts radians to degrees.
842    ///
843    /// # Unspecified precision
844    ///
845    /// The precision of this function is non-deterministic. This means it varies by platform,
846    /// Rust version, and can even differ within the same execution from one invocation to the next.
847    ///
848    /// # Examples
849    ///
850    /// ```
851    /// let angle = std::f32::consts::PI;
852    ///
853    /// let abs_difference = (angle.to_degrees() - 180.0).abs();
854    /// # #[cfg(any(not(target_arch = "x86"), target_feature = "sse2"))]
855    /// assert!(abs_difference <= f32::EPSILON);
856    /// ```
857    #[must_use = "this returns the result of the operation, \
858                  without modifying the original"]
859    #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
860    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
861    #[inline]
862    pub const fn to_degrees(self) -> f32 {
863        // Use a literal to avoid double rounding, consts::PI is already rounded,
864        // and dividing would round again.
865        const PIS_IN_180: f32 = 57.2957795130823208767981548141051703_f32;
866        self * PIS_IN_180
867    }
868
869    /// Converts degrees to radians.
870    ///
871    /// # Unspecified precision
872    ///
873    /// The precision of this function is non-deterministic. This means it varies by platform,
874    /// Rust version, and can even differ within the same execution from one invocation to the next.
875    ///
876    /// # Examples
877    ///
878    /// ```
879    /// let angle = 180.0f32;
880    ///
881    /// let abs_difference = (angle.to_radians() - std::f32::consts::PI).abs();
882    ///
883    /// assert!(abs_difference <= f32::EPSILON);
884    /// ```
885    #[must_use = "this returns the result of the operation, \
886                  without modifying the original"]
887    #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
888    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
889    #[inline]
890    pub const fn to_radians(self) -> f32 {
891        // The division here is correctly rounded with respect to the true value of π/180.
892        // Although π is irrational and already rounded, the double rounding happens
893        // to produce correct result for f32.
894        const RADS_PER_DEG: f32 = consts::PI / 180.0;
895        self * RADS_PER_DEG
896    }
897
898    /// Returns the maximum of the two numbers, ignoring NaN.
899    ///
900    /// If one of the arguments is NaN, then the other argument is returned.
901    /// This follows the IEEE 754-2008 semantics for maxNum, except for handling of signaling NaNs;
902    /// this function handles all NaNs the same way and avoids maxNum's problems with associativity.
903    /// This also matches the behavior of libm’s fmax. In particular, if the inputs compare equal
904    /// (such as for the case of `+0.0` and `-0.0`), either input may be returned non-deterministically.
905    ///
906    /// ```
907    /// let x = 1.0f32;
908    /// let y = 2.0f32;
909    ///
910    /// assert_eq!(x.max(y), y);
911    /// ```
912    #[must_use = "this returns the result of the comparison, without modifying either input"]
913    #[stable(feature = "rust1", since = "1.0.0")]
914    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
915    #[inline]
916    pub const fn max(self, other: f32) -> f32 {
917        intrinsics::maxnumf32(self, other)
918    }
919
920    /// Returns the minimum of the two numbers, ignoring NaN.
921    ///
922    /// If one of the arguments is NaN, then the other argument is returned.
923    /// This follows the IEEE 754-2008 semantics for minNum, except for handling of signaling NaNs;
924    /// this function handles all NaNs the same way and avoids minNum's problems with associativity.
925    /// This also matches the behavior of libm’s fmin. In particular, if the inputs compare equal
926    /// (such as for the case of `+0.0` and `-0.0`), either input may be returned non-deterministically.
927    ///
928    /// ```
929    /// let x = 1.0f32;
930    /// let y = 2.0f32;
931    ///
932    /// assert_eq!(x.min(y), x);
933    /// ```
934    #[must_use = "this returns the result of the comparison, without modifying either input"]
935    #[stable(feature = "rust1", since = "1.0.0")]
936    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
937    #[inline]
938    pub const fn min(self, other: f32) -> f32 {
939        intrinsics::minnumf32(self, other)
940    }
941
942    /// Returns the maximum of the two numbers, propagating NaN.
943    ///
944    /// This returns NaN when *either* argument is NaN, as opposed to
945    /// [`f32::max`] which only returns NaN when *both* arguments are NaN.
946    ///
947    /// ```
948    /// #![feature(float_minimum_maximum)]
949    /// let x = 1.0f32;
950    /// let y = 2.0f32;
951    ///
952    /// assert_eq!(x.maximum(y), y);
953    /// assert!(x.maximum(f32::NAN).is_nan());
954    /// ```
955    ///
956    /// If one of the arguments is NaN, then NaN is returned. Otherwise this returns the greater
957    /// of the two numbers. For this operation, -0.0 is considered to be less than +0.0.
958    /// Note that this follows the semantics specified in IEEE 754-2019.
959    ///
960    /// Also note that "propagation" of NaNs here doesn't necessarily mean that the bitpattern of a NaN
961    /// operand is conserved; see the [specification of NaN bit patterns](f32#nan-bit-patterns) for more info.
962    #[must_use = "this returns the result of the comparison, without modifying either input"]
963    #[unstable(feature = "float_minimum_maximum", issue = "91079")]
964    #[inline]
965    pub const fn maximum(self, other: f32) -> f32 {
966        intrinsics::maximumf32(self, other)
967    }
968
969    /// Returns the minimum of the two numbers, propagating NaN.
970    ///
971    /// This returns NaN when *either* argument is NaN, as opposed to
972    /// [`f32::min`] which only returns NaN when *both* arguments are NaN.
973    ///
974    /// ```
975    /// #![feature(float_minimum_maximum)]
976    /// let x = 1.0f32;
977    /// let y = 2.0f32;
978    ///
979    /// assert_eq!(x.minimum(y), x);
980    /// assert!(x.minimum(f32::NAN).is_nan());
981    /// ```
982    ///
983    /// If one of the arguments is NaN, then NaN is returned. Otherwise this returns the lesser
984    /// of the two numbers. For this operation, -0.0 is considered to be less than +0.0.
985    /// Note that this follows the semantics specified in IEEE 754-2019.
986    ///
987    /// Also note that "propagation" of NaNs here doesn't necessarily mean that the bitpattern of a NaN
988    /// operand is conserved; see the [specification of NaN bit patterns](f32#nan-bit-patterns) for more info.
989    #[must_use = "this returns the result of the comparison, without modifying either input"]
990    #[unstable(feature = "float_minimum_maximum", issue = "91079")]
991    #[inline]
992    pub const fn minimum(self, other: f32) -> f32 {
993        intrinsics::minimumf32(self, other)
994    }
995
996    /// Calculates the midpoint (average) between `self` and `rhs`.
997    ///
998    /// This returns NaN when *either* argument is NaN or if a combination of
999    /// +inf and -inf is provided as arguments.
1000    ///
1001    /// # Examples
1002    ///
1003    /// ```
1004    /// assert_eq!(1f32.midpoint(4.0), 2.5);
1005    /// assert_eq!((-5.5f32).midpoint(8.0), 1.25);
1006    /// ```
1007    #[inline]
1008    #[doc(alias = "average")]
1009    #[stable(feature = "num_midpoint", since = "1.85.0")]
1010    #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")]
1011    pub const fn midpoint(self, other: f32) -> f32 {
1012        cfg_select! {
1013            // Allow faster implementation that have known good 64-bit float
1014            // implementations. Falling back to the branchy code on targets that don't
1015            // have 64-bit hardware floats or buggy implementations.
1016            // https://github.com/rust-lang/rust/pull/121062#issuecomment-2123408114
1017            any(
1018                target_arch = "x86_64",
1019                target_arch = "aarch64",
1020                all(any(target_arch = "riscv32", target_arch = "riscv64"), target_feature = "d"),
1021                all(target_arch = "loongarch64", target_feature = "d"),
1022                all(target_arch = "arm", target_feature = "vfp2"),
1023                target_arch = "wasm32",
1024                target_arch = "wasm64",
1025            ) => {
1026                ((self as f64 + other as f64) / 2.0) as f32
1027            }
1028            _ => {
1029                const HI: f32 = f32::MAX / 2.;
1030
1031                let (a, b) = (self, other);
1032                let abs_a = a.abs();
1033                let abs_b = b.abs();
1034
1035                if abs_a <= HI && abs_b <= HI {
1036                    // Overflow is impossible
1037                    (a + b) / 2.
1038                } else {
1039                    (a / 2.) + (b / 2.)
1040                }
1041            }
1042        }
1043    }
1044
1045    /// Rounds toward zero and converts to any primitive integer type,
1046    /// assuming that the value is finite and fits in that type.
1047    ///
1048    /// ```
1049    /// let value = 4.6_f32;
1050    /// let rounded = unsafe { value.to_int_unchecked::<u16>() };
1051    /// assert_eq!(rounded, 4);
1052    ///
1053    /// let value = -128.9_f32;
1054    /// let rounded = unsafe { value.to_int_unchecked::<i8>() };
1055    /// assert_eq!(rounded, i8::MIN);
1056    /// ```
1057    ///
1058    /// # Safety
1059    ///
1060    /// The value must:
1061    ///
1062    /// * Not be `NaN`
1063    /// * Not be infinite
1064    /// * Be representable in the return type `Int`, after truncating off its fractional part
1065    #[must_use = "this returns the result of the operation, \
1066                  without modifying the original"]
1067    #[stable(feature = "float_approx_unchecked_to", since = "1.44.0")]
1068    #[inline]
1069    pub unsafe fn to_int_unchecked<Int>(self) -> Int
1070    where
1071        Self: FloatToInt<Int>,
1072    {
1073        // SAFETY: the caller must uphold the safety contract for
1074        // `FloatToInt::to_int_unchecked`.
1075        unsafe { FloatToInt::<Int>::to_int_unchecked(self) }
1076    }
1077
1078    /// Raw transmutation to `u32`.
1079    ///
1080    /// This is currently identical to `transmute::<f32, u32>(self)` on all platforms.
1081    ///
1082    /// See [`from_bits`](Self::from_bits) for some discussion of the
1083    /// portability of this operation (there are almost no issues).
1084    ///
1085    /// Note that this function is distinct from `as` casting, which attempts to
1086    /// preserve the *numeric* value, and not the bitwise value.
1087    ///
1088    /// # Examples
1089    ///
1090    /// ```
1091    /// assert_ne!((1f32).to_bits(), 1f32 as u32); // to_bits() is not casting!
1092    /// assert_eq!((12.5f32).to_bits(), 0x41480000);
1093    ///
1094    /// ```
1095    #[must_use = "this returns the result of the operation, \
1096                  without modifying the original"]
1097    #[stable(feature = "float_bits_conv", since = "1.20.0")]
1098    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1099    #[inline]
1100    #[allow(unnecessary_transmutes)]
1101    pub const fn to_bits(self) -> u32 {
1102        // SAFETY: `u32` is a plain old datatype so we can always transmute to it.
1103        unsafe { mem::transmute(self) }
1104    }
1105
1106    /// Raw transmutation from `u32`.
1107    ///
1108    /// This is currently identical to `transmute::<u32, f32>(v)` on all platforms.
1109    /// It turns out this is incredibly portable, for two reasons:
1110    ///
1111    /// * Floats and Ints have the same endianness on all supported platforms.
1112    /// * IEEE 754 very precisely specifies the bit layout of floats.
1113    ///
1114    /// However there is one caveat: prior to the 2008 version of IEEE 754, how
1115    /// to interpret the NaN signaling bit wasn't actually specified. Most platforms
1116    /// (notably x86 and ARM) picked the interpretation that was ultimately
1117    /// standardized in 2008, but some didn't (notably MIPS). As a result, all
1118    /// signaling NaNs on MIPS are quiet NaNs on x86, and vice-versa.
1119    ///
1120    /// Rather than trying to preserve signaling-ness cross-platform, this
1121    /// implementation favors preserving the exact bits. This means that
1122    /// any payloads encoded in NaNs will be preserved even if the result of
1123    /// this method is sent over the network from an x86 machine to a MIPS one.
1124    ///
1125    /// If the results of this method are only manipulated by the same
1126    /// architecture that produced them, then there is no portability concern.
1127    ///
1128    /// If the input isn't NaN, then there is no portability concern.
1129    ///
1130    /// If you don't care about signalingness (very likely), then there is no
1131    /// portability concern.
1132    ///
1133    /// Note that this function is distinct from `as` casting, which attempts to
1134    /// preserve the *numeric* value, and not the bitwise value.
1135    ///
1136    /// # Examples
1137    ///
1138    /// ```
1139    /// let v = f32::from_bits(0x41480000);
1140    /// assert_eq!(v, 12.5);
1141    /// ```
1142    #[stable(feature = "float_bits_conv", since = "1.20.0")]
1143    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1144    #[must_use]
1145    #[inline]
1146    #[allow(unnecessary_transmutes)]
1147    pub const fn from_bits(v: u32) -> Self {
1148        // It turns out the safety issues with sNaN were overblown! Hooray!
1149        // SAFETY: `u32` is a plain old datatype so we can always transmute from it.
1150        unsafe { mem::transmute(v) }
1151    }
1152
1153    /// Returns the memory representation of this floating point number as a byte array in
1154    /// big-endian (network) byte order.
1155    ///
1156    /// See [`from_bits`](Self::from_bits) for some discussion of the
1157    /// portability of this operation (there are almost no issues).
1158    ///
1159    /// # Examples
1160    ///
1161    /// ```
1162    /// let bytes = 12.5f32.to_be_bytes();
1163    /// assert_eq!(bytes, [0x41, 0x48, 0x00, 0x00]);
1164    /// ```
1165    #[must_use = "this returns the result of the operation, \
1166                  without modifying the original"]
1167    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1168    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1169    #[inline]
1170    pub const fn to_be_bytes(self) -> [u8; 4] {
1171        self.to_bits().to_be_bytes()
1172    }
1173
1174    /// Returns the memory representation of this floating point number as a byte array in
1175    /// little-endian byte order.
1176    ///
1177    /// See [`from_bits`](Self::from_bits) for some discussion of the
1178    /// portability of this operation (there are almost no issues).
1179    ///
1180    /// # Examples
1181    ///
1182    /// ```
1183    /// let bytes = 12.5f32.to_le_bytes();
1184    /// assert_eq!(bytes, [0x00, 0x00, 0x48, 0x41]);
1185    /// ```
1186    #[must_use = "this returns the result of the operation, \
1187                  without modifying the original"]
1188    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1189    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1190    #[inline]
1191    pub const fn to_le_bytes(self) -> [u8; 4] {
1192        self.to_bits().to_le_bytes()
1193    }
1194
1195    /// Returns the memory representation of this floating point number as a byte array in
1196    /// native byte order.
1197    ///
1198    /// As the target platform's native endianness is used, portable code
1199    /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate, instead.
1200    ///
1201    /// [`to_be_bytes`]: f32::to_be_bytes
1202    /// [`to_le_bytes`]: f32::to_le_bytes
1203    ///
1204    /// See [`from_bits`](Self::from_bits) for some discussion of the
1205    /// portability of this operation (there are almost no issues).
1206    ///
1207    /// # Examples
1208    ///
1209    /// ```
1210    /// let bytes = 12.5f32.to_ne_bytes();
1211    /// assert_eq!(
1212    ///     bytes,
1213    ///     if cfg!(target_endian = "big") {
1214    ///         [0x41, 0x48, 0x00, 0x00]
1215    ///     } else {
1216    ///         [0x00, 0x00, 0x48, 0x41]
1217    ///     }
1218    /// );
1219    /// ```
1220    #[must_use = "this returns the result of the operation, \
1221                  without modifying the original"]
1222    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1223    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1224    #[inline]
1225    pub const fn to_ne_bytes(self) -> [u8; 4] {
1226        self.to_bits().to_ne_bytes()
1227    }
1228
1229    /// Creates a floating point value from its representation as a byte array in big endian.
1230    ///
1231    /// See [`from_bits`](Self::from_bits) for some discussion of the
1232    /// portability of this operation (there are almost no issues).
1233    ///
1234    /// # Examples
1235    ///
1236    /// ```
1237    /// let value = f32::from_be_bytes([0x41, 0x48, 0x00, 0x00]);
1238    /// assert_eq!(value, 12.5);
1239    /// ```
1240    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1241    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1242    #[must_use]
1243    #[inline]
1244    pub const fn from_be_bytes(bytes: [u8; 4]) -> Self {
1245        Self::from_bits(u32::from_be_bytes(bytes))
1246    }
1247
1248    /// Creates a floating point value from its representation as a byte array in little endian.
1249    ///
1250    /// See [`from_bits`](Self::from_bits) for some discussion of the
1251    /// portability of this operation (there are almost no issues).
1252    ///
1253    /// # Examples
1254    ///
1255    /// ```
1256    /// let value = f32::from_le_bytes([0x00, 0x00, 0x48, 0x41]);
1257    /// assert_eq!(value, 12.5);
1258    /// ```
1259    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1260    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1261    #[must_use]
1262    #[inline]
1263    pub const fn from_le_bytes(bytes: [u8; 4]) -> Self {
1264        Self::from_bits(u32::from_le_bytes(bytes))
1265    }
1266
1267    /// Creates a floating point value from its representation as a byte array in native endian.
1268    ///
1269    /// As the target platform's native endianness is used, portable code
1270    /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
1271    /// appropriate instead.
1272    ///
1273    /// [`from_be_bytes`]: f32::from_be_bytes
1274    /// [`from_le_bytes`]: f32::from_le_bytes
1275    ///
1276    /// See [`from_bits`](Self::from_bits) for some discussion of the
1277    /// portability of this operation (there are almost no issues).
1278    ///
1279    /// # Examples
1280    ///
1281    /// ```
1282    /// let value = f32::from_ne_bytes(if cfg!(target_endian = "big") {
1283    ///     [0x41, 0x48, 0x00, 0x00]
1284    /// } else {
1285    ///     [0x00, 0x00, 0x48, 0x41]
1286    /// });
1287    /// assert_eq!(value, 12.5);
1288    /// ```
1289    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1290    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1291    #[must_use]
1292    #[inline]
1293    pub const fn from_ne_bytes(bytes: [u8; 4]) -> Self {
1294        Self::from_bits(u32::from_ne_bytes(bytes))
1295    }
1296
1297    /// Returns the ordering between `self` and `other`.
1298    ///
1299    /// Unlike the standard partial comparison between floating point numbers,
1300    /// this comparison always produces an ordering in accordance to
1301    /// the `totalOrder` predicate as defined in the IEEE 754 (2008 revision)
1302    /// floating point standard. The values are ordered in the following sequence:
1303    ///
1304    /// - negative quiet NaN
1305    /// - negative signaling NaN
1306    /// - negative infinity
1307    /// - negative numbers
1308    /// - negative subnormal numbers
1309    /// - negative zero
1310    /// - positive zero
1311    /// - positive subnormal numbers
1312    /// - positive numbers
1313    /// - positive infinity
1314    /// - positive signaling NaN
1315    /// - positive quiet NaN.
1316    ///
1317    /// The ordering established by this function does not always agree with the
1318    /// [`PartialOrd`] and [`PartialEq`] implementations of `f32`. For example,
1319    /// they consider negative and positive zero equal, while `total_cmp`
1320    /// doesn't.
1321    ///
1322    /// The interpretation of the signaling NaN bit follows the definition in
1323    /// the IEEE 754 standard, which may not match the interpretation by some of
1324    /// the older, non-conformant (e.g. MIPS) hardware implementations.
1325    ///
1326    /// # Example
1327    ///
1328    /// ```
1329    /// struct GoodBoy {
1330    ///     name: String,
1331    ///     weight: f32,
1332    /// }
1333    ///
1334    /// let mut bois = vec![
1335    ///     GoodBoy { name: "Pucci".to_owned(), weight: 0.1 },
1336    ///     GoodBoy { name: "Woofer".to_owned(), weight: 99.0 },
1337    ///     GoodBoy { name: "Yapper".to_owned(), weight: 10.0 },
1338    ///     GoodBoy { name: "Chonk".to_owned(), weight: f32::INFINITY },
1339    ///     GoodBoy { name: "Abs. Unit".to_owned(), weight: f32::NAN },
1340    ///     GoodBoy { name: "Floaty".to_owned(), weight: -5.0 },
1341    /// ];
1342    ///
1343    /// bois.sort_by(|a, b| a.weight.total_cmp(&b.weight));
1344    ///
1345    /// // `f32::NAN` could be positive or negative, which will affect the sort order.
1346    /// if f32::NAN.is_sign_negative() {
1347    ///     assert!(bois.into_iter().map(|b| b.weight)
1348    ///         .zip([f32::NAN, -5.0, 0.1, 10.0, 99.0, f32::INFINITY].iter())
1349    ///         .all(|(a, b)| a.to_bits() == b.to_bits()))
1350    /// } else {
1351    ///     assert!(bois.into_iter().map(|b| b.weight)
1352    ///         .zip([-5.0, 0.1, 10.0, 99.0, f32::INFINITY, f32::NAN].iter())
1353    ///         .all(|(a, b)| a.to_bits() == b.to_bits()))
1354    /// }
1355    /// ```
1356    #[stable(feature = "total_cmp", since = "1.62.0")]
1357    #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
1358    #[must_use]
1359    #[inline]
1360    pub const fn total_cmp(&self, other: &Self) -> crate::cmp::Ordering {
1361        let mut left = self.to_bits() as i32;
1362        let mut right = other.to_bits() as i32;
1363
1364        // In case of negatives, flip all the bits except the sign
1365        // to achieve a similar layout as two's complement integers
1366        //
1367        // Why does this work? IEEE 754 floats consist of three fields:
1368        // Sign bit, exponent and mantissa. The set of exponent and mantissa
1369        // fields as a whole have the property that their bitwise order is
1370        // equal to the numeric magnitude where the magnitude is defined.
1371        // The magnitude is not normally defined on NaN values, but
1372        // IEEE 754 totalOrder defines the NaN values also to follow the
1373        // bitwise order. This leads to order explained in the doc comment.
1374        // However, the representation of magnitude is the same for negative
1375        // and positive numbers – only the sign bit is different.
1376        // To easily compare the floats as signed integers, we need to
1377        // flip the exponent and mantissa bits in case of negative numbers.
1378        // We effectively convert the numbers to "two's complement" form.
1379        //
1380        // To do the flipping, we construct a mask and XOR against it.
1381        // We branchlessly calculate an "all-ones except for the sign bit"
1382        // mask from negative-signed values: right shifting sign-extends
1383        // the integer, so we "fill" the mask with sign bits, and then
1384        // convert to unsigned to push one more zero bit.
1385        // On positive values, the mask is all zeros, so it's a no-op.
1386        left ^= (((left >> 31) as u32) >> 1) as i32;
1387        right ^= (((right >> 31) as u32) >> 1) as i32;
1388
1389        left.cmp(&right)
1390    }
1391
1392    /// Restrict a value to a certain interval unless it is NaN.
1393    ///
1394    /// Returns `max` if `self` is greater than `max`, and `min` if `self` is
1395    /// less than `min`. Otherwise this returns `self`.
1396    ///
1397    /// Note that this function returns NaN if the initial value was NaN as
1398    /// well.
1399    ///
1400    /// # Panics
1401    ///
1402    /// Panics if `min > max`, `min` is NaN, or `max` is NaN.
1403    ///
1404    /// # Examples
1405    ///
1406    /// ```
1407    /// assert!((-3.0f32).clamp(-2.0, 1.0) == -2.0);
1408    /// assert!((0.0f32).clamp(-2.0, 1.0) == 0.0);
1409    /// assert!((2.0f32).clamp(-2.0, 1.0) == 1.0);
1410    /// assert!((f32::NAN).clamp(-2.0, 1.0).is_nan());
1411    /// ```
1412    #[must_use = "method returns a new number and does not mutate the original value"]
1413    #[stable(feature = "clamp", since = "1.50.0")]
1414    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1415    #[inline]
1416    pub const fn clamp(mut self, min: f32, max: f32) -> f32 {
1417        const_assert!(
1418            min <= max,
1419            "min > max, or either was NaN",
1420            "min > max, or either was NaN. min = {min:?}, max = {max:?}",
1421            min: f32,
1422            max: f32,
1423        );
1424
1425        if self < min {
1426            self = min;
1427        }
1428        if self > max {
1429            self = max;
1430        }
1431        self
1432    }
1433
1434    /// Computes the absolute value of `self`.
1435    ///
1436    /// This function always returns the precise result.
1437    ///
1438    /// # Examples
1439    ///
1440    /// ```
1441    /// let x = 3.5_f32;
1442    /// let y = -3.5_f32;
1443    ///
1444    /// assert_eq!(x.abs(), x);
1445    /// assert_eq!(y.abs(), -y);
1446    ///
1447    /// assert!(f32::NAN.abs().is_nan());
1448    /// ```
1449    #[must_use = "method returns a new number and does not mutate the original value"]
1450    #[stable(feature = "rust1", since = "1.0.0")]
1451    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1452    #[inline]
1453    pub const fn abs(self) -> f32 {
1454        intrinsics::fabsf32(self)
1455    }
1456
1457    /// Returns a number that represents the sign of `self`.
1458    ///
1459    /// - `1.0` if the number is positive, `+0.0` or `INFINITY`
1460    /// - `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY`
1461    /// - NaN if the number is NaN
1462    ///
1463    /// # Examples
1464    ///
1465    /// ```
1466    /// let f = 3.5_f32;
1467    ///
1468    /// assert_eq!(f.signum(), 1.0);
1469    /// assert_eq!(f32::NEG_INFINITY.signum(), -1.0);
1470    ///
1471    /// assert!(f32::NAN.signum().is_nan());
1472    /// ```
1473    #[must_use = "method returns a new number and does not mutate the original value"]
1474    #[stable(feature = "rust1", since = "1.0.0")]
1475    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1476    #[inline]
1477    pub const fn signum(self) -> f32 {
1478        if self.is_nan() { Self::NAN } else { 1.0_f32.copysign(self) }
1479    }
1480
1481    /// Returns a number composed of the magnitude of `self` and the sign of
1482    /// `sign`.
1483    ///
1484    /// Equal to `self` if the sign of `self` and `sign` are the same, otherwise equal to `-self`.
1485    /// If `self` is a NaN, then a NaN with the same payload as `self` and the sign bit of `sign` is
1486    /// returned.
1487    ///
1488    /// If `sign` is a NaN, then this operation will still carry over its sign into the result. Note
1489    /// that IEEE 754 doesn't assign any meaning to the sign bit in case of a NaN, and as Rust
1490    /// doesn't guarantee that the bit pattern of NaNs are conserved over arithmetic operations, the
1491    /// result of `copysign` with `sign` being a NaN might produce an unexpected or non-portable
1492    /// result. See the [specification of NaN bit patterns](primitive@f32#nan-bit-patterns) for more
1493    /// info.
1494    ///
1495    /// # Examples
1496    ///
1497    /// ```
1498    /// let f = 3.5_f32;
1499    ///
1500    /// assert_eq!(f.copysign(0.42), 3.5_f32);
1501    /// assert_eq!(f.copysign(-0.42), -3.5_f32);
1502    /// assert_eq!((-f).copysign(0.42), 3.5_f32);
1503    /// assert_eq!((-f).copysign(-0.42), -3.5_f32);
1504    ///
1505    /// assert!(f32::NAN.copysign(1.0).is_nan());
1506    /// ```
1507    #[must_use = "method returns a new number and does not mutate the original value"]
1508    #[inline]
1509    #[stable(feature = "copysign", since = "1.35.0")]
1510    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1511    pub const fn copysign(self, sign: f32) -> f32 {
1512        intrinsics::copysignf32(self, sign)
1513    }
1514
1515    /// Float addition that allows optimizations based on algebraic rules.
1516    ///
1517    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1518    #[must_use = "method returns a new number and does not mutate the original value"]
1519    #[unstable(feature = "float_algebraic", issue = "136469")]
1520    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1521    #[inline]
1522    pub const fn algebraic_add(self, rhs: f32) -> f32 {
1523        intrinsics::fadd_algebraic(self, rhs)
1524    }
1525
1526    /// Float subtraction that allows optimizations based on algebraic rules.
1527    ///
1528    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1529    #[must_use = "method returns a new number and does not mutate the original value"]
1530    #[unstable(feature = "float_algebraic", issue = "136469")]
1531    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1532    #[inline]
1533    pub const fn algebraic_sub(self, rhs: f32) -> f32 {
1534        intrinsics::fsub_algebraic(self, rhs)
1535    }
1536
1537    /// Float multiplication that allows optimizations based on algebraic rules.
1538    ///
1539    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1540    #[must_use = "method returns a new number and does not mutate the original value"]
1541    #[unstable(feature = "float_algebraic", issue = "136469")]
1542    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1543    #[inline]
1544    pub const fn algebraic_mul(self, rhs: f32) -> f32 {
1545        intrinsics::fmul_algebraic(self, rhs)
1546    }
1547
1548    /// Float division that allows optimizations based on algebraic rules.
1549    ///
1550    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1551    #[must_use = "method returns a new number and does not mutate the original value"]
1552    #[unstable(feature = "float_algebraic", issue = "136469")]
1553    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1554    #[inline]
1555    pub const fn algebraic_div(self, rhs: f32) -> f32 {
1556        intrinsics::fdiv_algebraic(self, rhs)
1557    }
1558
1559    /// Float remainder that allows optimizations based on algebraic rules.
1560    ///
1561    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1562    #[must_use = "method returns a new number and does not mutate the original value"]
1563    #[unstable(feature = "float_algebraic", issue = "136469")]
1564    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1565    #[inline]
1566    pub const fn algebraic_rem(self, rhs: f32) -> f32 {
1567        intrinsics::frem_algebraic(self, rhs)
1568    }
1569}
1570
1571/// Experimental implementations of floating point functions in `core`.
1572///
1573/// _The standalone functions in this module are for testing only.
1574/// They will be stabilized as inherent methods._
1575#[unstable(feature = "core_float_math", issue = "137578")]
1576pub mod math {
1577    use crate::intrinsics;
1578    use crate::num::libm;
1579
1580    /// Experimental version of `floor` in `core`. See [`f32::floor`] for details.
1581    ///
1582    /// # Examples
1583    ///
1584    /// ```
1585    /// #![feature(core_float_math)]
1586    ///
1587    /// use core::f32;
1588    ///
1589    /// let f = 3.7_f32;
1590    /// let g = 3.0_f32;
1591    /// let h = -3.7_f32;
1592    ///
1593    /// assert_eq!(f32::math::floor(f), 3.0);
1594    /// assert_eq!(f32::math::floor(g), 3.0);
1595    /// assert_eq!(f32::math::floor(h), -4.0);
1596    /// ```
1597    ///
1598    /// _This standalone function is for testing only.
1599    /// It will be stabilized as an inherent method._
1600    ///
1601    /// [`f32::floor`]: ../../../std/primitive.f32.html#method.floor
1602    #[inline]
1603    #[unstable(feature = "core_float_math", issue = "137578")]
1604    #[must_use = "method returns a new number and does not mutate the original value"]
1605    pub const fn floor(x: f32) -> f32 {
1606        intrinsics::floorf32(x)
1607    }
1608
1609    /// Experimental version of `ceil` in `core`. See [`f32::ceil`] for details.
1610    ///
1611    /// # Examples
1612    ///
1613    /// ```
1614    /// #![feature(core_float_math)]
1615    ///
1616    /// use core::f32;
1617    ///
1618    /// let f = 3.01_f32;
1619    /// let g = 4.0_f32;
1620    ///
1621    /// assert_eq!(f32::math::ceil(f), 4.0);
1622    /// assert_eq!(f32::math::ceil(g), 4.0);
1623    /// ```
1624    ///
1625    /// _This standalone function is for testing only.
1626    /// It will be stabilized as an inherent method._
1627    ///
1628    /// [`f32::ceil`]: ../../../std/primitive.f32.html#method.ceil
1629    #[inline]
1630    #[doc(alias = "ceiling")]
1631    #[must_use = "method returns a new number and does not mutate the original value"]
1632    #[unstable(feature = "core_float_math", issue = "137578")]
1633    pub const fn ceil(x: f32) -> f32 {
1634        intrinsics::ceilf32(x)
1635    }
1636
1637    /// Experimental version of `round` in `core`. See [`f32::round`] for details.
1638    ///
1639    /// # Examples
1640    ///
1641    /// ```
1642    /// #![feature(core_float_math)]
1643    ///
1644    /// use core::f32;
1645    ///
1646    /// let f = 3.3_f32;
1647    /// let g = -3.3_f32;
1648    /// let h = -3.7_f32;
1649    /// let i = 3.5_f32;
1650    /// let j = 4.5_f32;
1651    ///
1652    /// assert_eq!(f32::math::round(f), 3.0);
1653    /// assert_eq!(f32::math::round(g), -3.0);
1654    /// assert_eq!(f32::math::round(h), -4.0);
1655    /// assert_eq!(f32::math::round(i), 4.0);
1656    /// assert_eq!(f32::math::round(j), 5.0);
1657    /// ```
1658    ///
1659    /// _This standalone function is for testing only.
1660    /// It will be stabilized as an inherent method._
1661    ///
1662    /// [`f32::round`]: ../../../std/primitive.f32.html#method.round
1663    #[inline]
1664    #[unstable(feature = "core_float_math", issue = "137578")]
1665    #[must_use = "method returns a new number and does not mutate the original value"]
1666    pub const fn round(x: f32) -> f32 {
1667        intrinsics::roundf32(x)
1668    }
1669
1670    /// Experimental version of `round_ties_even` in `core`. See [`f32::round_ties_even`] for
1671    /// details.
1672    ///
1673    /// # Examples
1674    ///
1675    /// ```
1676    /// #![feature(core_float_math)]
1677    ///
1678    /// use core::f32;
1679    ///
1680    /// let f = 3.3_f32;
1681    /// let g = -3.3_f32;
1682    /// let h = 3.5_f32;
1683    /// let i = 4.5_f32;
1684    ///
1685    /// assert_eq!(f32::math::round_ties_even(f), 3.0);
1686    /// assert_eq!(f32::math::round_ties_even(g), -3.0);
1687    /// assert_eq!(f32::math::round_ties_even(h), 4.0);
1688    /// assert_eq!(f32::math::round_ties_even(i), 4.0);
1689    /// ```
1690    ///
1691    /// _This standalone function is for testing only.
1692    /// It will be stabilized as an inherent method._
1693    ///
1694    /// [`f32::round_ties_even`]: ../../../std/primitive.f32.html#method.round_ties_even
1695    #[inline]
1696    #[unstable(feature = "core_float_math", issue = "137578")]
1697    #[must_use = "method returns a new number and does not mutate the original value"]
1698    pub const fn round_ties_even(x: f32) -> f32 {
1699        intrinsics::round_ties_even_f32(x)
1700    }
1701
1702    /// Experimental version of `trunc` in `core`. See [`f32::trunc`] for details.
1703    ///
1704    /// # Examples
1705    ///
1706    /// ```
1707    /// #![feature(core_float_math)]
1708    ///
1709    /// use core::f32;
1710    ///
1711    /// let f = 3.7_f32;
1712    /// let g = 3.0_f32;
1713    /// let h = -3.7_f32;
1714    ///
1715    /// assert_eq!(f32::math::trunc(f), 3.0);
1716    /// assert_eq!(f32::math::trunc(g), 3.0);
1717    /// assert_eq!(f32::math::trunc(h), -3.0);
1718    /// ```
1719    ///
1720    /// _This standalone function is for testing only.
1721    /// It will be stabilized as an inherent method._
1722    ///
1723    /// [`f32::trunc`]: ../../../std/primitive.f32.html#method.trunc
1724    #[inline]
1725    #[doc(alias = "truncate")]
1726    #[must_use = "method returns a new number and does not mutate the original value"]
1727    #[unstable(feature = "core_float_math", issue = "137578")]
1728    pub const fn trunc(x: f32) -> f32 {
1729        intrinsics::truncf32(x)
1730    }
1731
1732    /// Experimental version of `fract` in `core`. See [`f32::fract`] for details.
1733    ///
1734    /// # Examples
1735    ///
1736    /// ```
1737    /// #![feature(core_float_math)]
1738    ///
1739    /// use core::f32;
1740    ///
1741    /// let x = 3.6_f32;
1742    /// let y = -3.6_f32;
1743    /// let abs_difference_x = (f32::math::fract(x) - 0.6).abs();
1744    /// let abs_difference_y = (f32::math::fract(y) - (-0.6)).abs();
1745    ///
1746    /// assert!(abs_difference_x <= f32::EPSILON);
1747    /// assert!(abs_difference_y <= f32::EPSILON);
1748    /// ```
1749    ///
1750    /// _This standalone function is for testing only.
1751    /// It will be stabilized as an inherent method._
1752    ///
1753    /// [`f32::fract`]: ../../../std/primitive.f32.html#method.fract
1754    #[inline]
1755    #[unstable(feature = "core_float_math", issue = "137578")]
1756    #[must_use = "method returns a new number and does not mutate the original value"]
1757    pub const fn fract(x: f32) -> f32 {
1758        x - trunc(x)
1759    }
1760
1761    /// Experimental version of `mul_add` in `core`. See [`f32::mul_add`] for details.
1762    ///
1763    /// # Examples
1764    ///
1765    /// ```
1766    /// #![feature(core_float_math)]
1767    ///
1768    /// # // FIXME(#140515): mingw has an incorrect fma
1769    /// # // https://sourceforge.net/p/mingw-w64/bugs/848/
1770    /// # #[cfg(all(target_os = "windows", target_env = "gnu", not(target_abi = "llvm")))] {
1771    /// use core::f32;
1772    ///
1773    /// let m = 10.0_f32;
1774    /// let x = 4.0_f32;
1775    /// let b = 60.0_f32;
1776    ///
1777    /// assert_eq!(f32::math::mul_add(m, x, b), 100.0);
1778    /// assert_eq!(m * x + b, 100.0);
1779    ///
1780    /// let one_plus_eps = 1.0_f32 + f32::EPSILON;
1781    /// let one_minus_eps = 1.0_f32 - f32::EPSILON;
1782    /// let minus_one = -1.0_f32;
1783    ///
1784    /// // The exact result (1 + eps) * (1 - eps) = 1 - eps * eps.
1785    /// assert_eq!(
1786    ///     f32::math::mul_add(one_plus_eps, one_minus_eps, minus_one),
1787    ///     -f32::EPSILON * f32::EPSILON
1788    /// );
1789    /// // Different rounding with the non-fused multiply and add.
1790    /// assert_eq!(one_plus_eps * one_minus_eps + minus_one, 0.0);
1791    /// # }
1792    /// ```
1793    ///
1794    /// _This standalone function is for testing only.
1795    /// It will be stabilized as an inherent method._
1796    ///
1797    /// [`f32::mul_add`]: ../../../std/primitive.f32.html#method.mul_add
1798    #[inline]
1799    #[doc(alias = "fmaf", alias = "fusedMultiplyAdd")]
1800    #[must_use = "method returns a new number and does not mutate the original value"]
1801    #[unstable(feature = "core_float_math", issue = "137578")]
1802    #[rustc_const_unstable(feature = "const_mul_add", issue = "146724")]
1803    pub const fn mul_add(x: f32, y: f32, z: f32) -> f32 {
1804        intrinsics::fmaf32(x, y, z)
1805    }
1806
1807    /// Experimental version of `div_euclid` in `core`. See [`f32::div_euclid`] for details.
1808    ///
1809    /// # Examples
1810    ///
1811    /// ```
1812    /// #![feature(core_float_math)]
1813    ///
1814    /// use core::f32;
1815    ///
1816    /// let a: f32 = 7.0;
1817    /// let b = 4.0;
1818    /// assert_eq!(f32::math::div_euclid(a, b), 1.0); // 7.0 > 4.0 * 1.0
1819    /// assert_eq!(f32::math::div_euclid(-a, b), -2.0); // -7.0 >= 4.0 * -2.0
1820    /// assert_eq!(f32::math::div_euclid(a, -b), -1.0); // 7.0 >= -4.0 * -1.0
1821    /// assert_eq!(f32::math::div_euclid(-a, -b), 2.0); // -7.0 >= -4.0 * 2.0
1822    /// ```
1823    ///
1824    /// _This standalone function is for testing only.
1825    /// It will be stabilized as an inherent method._
1826    ///
1827    /// [`f32::div_euclid`]: ../../../std/primitive.f32.html#method.div_euclid
1828    #[inline]
1829    #[unstable(feature = "core_float_math", issue = "137578")]
1830    #[must_use = "method returns a new number and does not mutate the original value"]
1831    pub fn div_euclid(x: f32, rhs: f32) -> f32 {
1832        let q = trunc(x / rhs);
1833        if x % rhs < 0.0 {
1834            return if rhs > 0.0 { q - 1.0 } else { q + 1.0 };
1835        }
1836        q
1837    }
1838
1839    /// Experimental version of `rem_euclid` in `core`. See [`f32::rem_euclid`] for details.
1840    ///
1841    /// # Examples
1842    ///
1843    /// ```
1844    /// #![feature(core_float_math)]
1845    ///
1846    /// use core::f32;
1847    ///
1848    /// let a: f32 = 7.0;
1849    /// let b = 4.0;
1850    /// assert_eq!(f32::math::rem_euclid(a, b), 3.0);
1851    /// assert_eq!(f32::math::rem_euclid(-a, b), 1.0);
1852    /// assert_eq!(f32::math::rem_euclid(a, -b), 3.0);
1853    /// assert_eq!(f32::math::rem_euclid(-a, -b), 1.0);
1854    /// // limitation due to round-off error
1855    /// assert!(f32::math::rem_euclid(-f32::EPSILON, 3.0) != 0.0);
1856    /// ```
1857    ///
1858    /// _This standalone function is for testing only.
1859    /// It will be stabilized as an inherent method._
1860    ///
1861    /// [`f32::rem_euclid`]: ../../../std/primitive.f32.html#method.rem_euclid
1862    #[inline]
1863    #[doc(alias = "modulo", alias = "mod")]
1864    #[unstable(feature = "core_float_math", issue = "137578")]
1865    #[must_use = "method returns a new number and does not mutate the original value"]
1866    pub fn rem_euclid(x: f32, rhs: f32) -> f32 {
1867        let r = x % rhs;
1868        if r < 0.0 { r + rhs.abs() } else { r }
1869    }
1870
1871    /// Experimental version of `powi` in `core`. See [`f32::powi`] for details.
1872    ///
1873    /// # Examples
1874    ///
1875    /// ```
1876    /// #![feature(core_float_math)]
1877    ///
1878    /// use core::f32;
1879    ///
1880    /// let x = 2.0_f32;
1881    /// let abs_difference = (f32::math::powi(x, 2) - (x * x)).abs();
1882    /// assert!(abs_difference <= 1e-5);
1883    ///
1884    /// assert_eq!(f32::math::powi(f32::NAN, 0), 1.0);
1885    /// ```
1886    ///
1887    /// _This standalone function is for testing only.
1888    /// It will be stabilized as an inherent method._
1889    ///
1890    /// [`f32::powi`]: ../../../std/primitive.f32.html#method.powi
1891    #[inline]
1892    #[must_use = "method returns a new number and does not mutate the original value"]
1893    #[unstable(feature = "core_float_math", issue = "137578")]
1894    pub fn powi(x: f32, n: i32) -> f32 {
1895        intrinsics::powif32(x, n)
1896    }
1897
1898    /// Experimental version of `sqrt` in `core`. See [`f32::sqrt`] for details.
1899    ///
1900    /// # Examples
1901    ///
1902    /// ```
1903    /// #![feature(core_float_math)]
1904    ///
1905    /// use core::f32;
1906    ///
1907    /// let positive = 4.0_f32;
1908    /// let negative = -4.0_f32;
1909    /// let negative_zero = -0.0_f32;
1910    ///
1911    /// assert_eq!(f32::math::sqrt(positive), 2.0);
1912    /// assert!(f32::math::sqrt(negative).is_nan());
1913    /// assert_eq!(f32::math::sqrt(negative_zero), negative_zero);
1914    /// ```
1915    ///
1916    /// _This standalone function is for testing only.
1917    /// It will be stabilized as an inherent method._
1918    ///
1919    /// [`f32::sqrt`]: ../../../std/primitive.f32.html#method.sqrt
1920    #[inline]
1921    #[doc(alias = "squareRoot")]
1922    #[unstable(feature = "core_float_math", issue = "137578")]
1923    #[must_use = "method returns a new number and does not mutate the original value"]
1924    pub fn sqrt(x: f32) -> f32 {
1925        intrinsics::sqrtf32(x)
1926    }
1927
1928    /// Experimental version of `abs_sub` in `core`. See [`f32::abs_sub`] for details.
1929    ///
1930    /// # Examples
1931    ///
1932    /// ```
1933    /// #![feature(core_float_math)]
1934    ///
1935    /// use core::f32;
1936    ///
1937    /// let x = 3.0f32;
1938    /// let y = -3.0f32;
1939    ///
1940    /// let abs_difference_x = (f32::math::abs_sub(x, 1.0) - 2.0).abs();
1941    /// let abs_difference_y = (f32::math::abs_sub(y, 1.0) - 0.0).abs();
1942    ///
1943    /// assert!(abs_difference_x <= 1e-6);
1944    /// assert!(abs_difference_y <= 1e-6);
1945    /// ```
1946    ///
1947    /// _This standalone function is for testing only.
1948    /// It will be stabilized as an inherent method._
1949    ///
1950    /// [`f32::abs_sub`]: ../../../std/primitive.f32.html#method.abs_sub
1951    #[inline]
1952    #[stable(feature = "rust1", since = "1.0.0")]
1953    #[deprecated(
1954        since = "1.10.0",
1955        note = "you probably meant `(self - other).abs()`: \
1956            this operation is `(self - other).max(0.0)` \
1957            except that `abs_sub` also propagates NaNs (also \
1958            known as `fdimf` in C). If you truly need the positive \
1959            difference, consider using that expression or the C function \
1960            `fdimf`, depending on how you wish to handle NaN (please consider \
1961            filing an issue describing your use-case too)."
1962    )]
1963    #[must_use = "method returns a new number and does not mutate the original value"]
1964    pub fn abs_sub(x: f32, other: f32) -> f32 {
1965        libm::fdimf(x, other)
1966    }
1967
1968    /// Experimental version of `cbrt` in `core`. See [`f32::cbrt`] for details.
1969    ///
1970    /// # Unspecified precision
1971    ///
1972    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
1973    /// can even differ within the same execution from one invocation to the next.
1974    /// This function currently corresponds to the `cbrtf` from libc on Unix
1975    /// and Windows. Note that this might change in the future.
1976    ///
1977    /// # Examples
1978    ///
1979    /// ```
1980    /// #![feature(core_float_math)]
1981    ///
1982    /// use core::f32;
1983    ///
1984    /// let x = 8.0f32;
1985    ///
1986    /// // x^(1/3) - 2 == 0
1987    /// let abs_difference = (f32::math::cbrt(x) - 2.0).abs();
1988    ///
1989    /// assert!(abs_difference <= 1e-6);
1990    /// ```
1991    ///
1992    /// _This standalone function is for testing only.
1993    /// It will be stabilized as an inherent method._
1994    ///
1995    /// [`f32::cbrt`]: ../../../std/primitive.f32.html#method.cbrt
1996    #[inline]
1997    #[must_use = "method returns a new number and does not mutate the original value"]
1998    #[unstable(feature = "core_float_math", issue = "137578")]
1999    pub fn cbrt(x: f32) -> f32 {
2000        libm::cbrtf(x)
2001    }
2002}