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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    #[stable(feature = "euler_gamma_golden_ratio", since = "1.94.0")]
296    pub const GOLDEN_RATIO: f32 = 1.618033988749894848204586834365638118_f32;
297
298    /// The Euler-Mascheroni constant (γ)
299    #[stable(feature = "euler_gamma_golden_ratio", since = "1.94.0")]
300    pub const EULER_GAMMA: 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    /// sqrt(5)
360    #[unstable(feature = "more_float_constants", issue = "146939")]
361    pub const SQRT_5: f32 = 2.23606797749978969640917366873127623_f32;
362
363    /// 1/sqrt(5)
364    #[unstable(feature = "more_float_constants", issue = "146939")]
365    pub const FRAC_1_SQRT_5: f32 = 0.44721359549995793928183473374625524_f32;
366
367    /// Euler's number (e)
368    #[stable(feature = "rust1", since = "1.0.0")]
369    pub const E: f32 = 2.71828182845904523536028747135266250_f32;
370
371    /// log<sub>2</sub>(e)
372    #[stable(feature = "rust1", since = "1.0.0")]
373    pub const LOG2_E: f32 = 1.44269504088896340735992468100189214_f32;
374
375    /// log<sub>2</sub>(10)
376    #[stable(feature = "extra_log_consts", since = "1.43.0")]
377    pub const LOG2_10: f32 = 3.32192809488736234787031942948939018_f32;
378
379    /// log<sub>10</sub>(e)
380    #[stable(feature = "rust1", since = "1.0.0")]
381    pub const LOG10_E: f32 = 0.434294481903251827651128918916605082_f32;
382
383    /// log<sub>10</sub>(2)
384    #[stable(feature = "extra_log_consts", since = "1.43.0")]
385    pub const LOG10_2: f32 = 0.301029995663981195213738894724493027_f32;
386
387    /// ln(2)
388    #[stable(feature = "rust1", since = "1.0.0")]
389    pub const LN_2: f32 = 0.693147180559945309417232121458176568_f32;
390
391    /// ln(10)
392    #[stable(feature = "rust1", since = "1.0.0")]
393    pub const LN_10: f32 = 2.30258509299404568401799145468436421_f32;
394}
395
396#[doc(test(attr(allow(unused_features))))]
397impl f32 {
398    /// The radix or base of the internal representation of `f32`.
399    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
400    pub const RADIX: u32 = 2;
401
402    /// The size of this float type in bits.
403    #[unstable(feature = "float_bits_const", issue = "151073")]
404    pub const BITS: u32 = 32;
405
406    /// Number of significant digits in base 2.
407    ///
408    /// Note that the size of the mantissa in the bitwise representation is one
409    /// smaller than this since the leading 1 is not stored explicitly.
410    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
411    pub const MANTISSA_DIGITS: u32 = 24;
412
413    /// Approximate number of significant digits in base 10.
414    ///
415    /// This is the maximum <i>x</i> such that any decimal number with <i>x</i>
416    /// significant digits can be converted to `f32` and back without loss.
417    ///
418    /// Equal to floor(log<sub>10</sub>&nbsp;2<sup>[`MANTISSA_DIGITS`]&nbsp;&minus;&nbsp;1</sup>).
419    ///
420    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
421    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
422    pub const DIGITS: u32 = 6;
423
424    /// [Machine epsilon] value for `f32`.
425    ///
426    /// This is the difference between `1.0` and the next larger representable number.
427    ///
428    /// Equal to 2<sup>1&nbsp;&minus;&nbsp;[`MANTISSA_DIGITS`]</sup>.
429    ///
430    /// [Machine epsilon]: https://en.wikipedia.org/wiki/Machine_epsilon
431    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
432    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
433    #[rustc_diagnostic_item = "f32_epsilon"]
434    pub const EPSILON: f32 = 1.19209290e-07_f32;
435
436    /// Smallest finite `f32` value.
437    ///
438    /// Equal to &minus;[`MAX`].
439    ///
440    /// [`MAX`]: f32::MAX
441    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
442    pub const MIN: f32 = -3.40282347e+38_f32;
443    /// Smallest positive normal `f32` value.
444    ///
445    /// Equal to 2<sup>[`MIN_EXP`]&nbsp;&minus;&nbsp;1</sup>.
446    ///
447    /// [`MIN_EXP`]: f32::MIN_EXP
448    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
449    pub const MIN_POSITIVE: f32 = 1.17549435e-38_f32;
450    /// Largest finite `f32` value.
451    ///
452    /// Equal to
453    /// (1&nbsp;&minus;&nbsp;2<sup>&minus;[`MANTISSA_DIGITS`]</sup>)&nbsp;2<sup>[`MAX_EXP`]</sup>.
454    ///
455    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
456    /// [`MAX_EXP`]: f32::MAX_EXP
457    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
458    pub const MAX: f32 = 3.40282347e+38_f32;
459
460    /// One greater than the minimum possible *normal* power of 2 exponent
461    /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition).
462    ///
463    /// This corresponds to the exact minimum possible *normal* power of 2 exponent
464    /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition).
465    /// In other words, all normal numbers representable by this type are
466    /// greater than or equal to 0.5&nbsp;×&nbsp;2<sup><i>MIN_EXP</i></sup>.
467    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
468    pub const MIN_EXP: i32 = -125;
469    /// One greater than the maximum possible power of 2 exponent
470    /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition).
471    ///
472    /// This corresponds to the exact maximum possible power of 2 exponent
473    /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition).
474    /// In other words, all numbers representable by this type are
475    /// strictly less than 2<sup><i>MAX_EXP</i></sup>.
476    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
477    pub const MAX_EXP: i32 = 128;
478
479    /// Minimum <i>x</i> for which 10<sup><i>x</i></sup> is normal.
480    ///
481    /// Equal to ceil(log<sub>10</sub>&nbsp;[`MIN_POSITIVE`]).
482    ///
483    /// [`MIN_POSITIVE`]: f32::MIN_POSITIVE
484    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
485    pub const MIN_10_EXP: i32 = -37;
486    /// Maximum <i>x</i> for which 10<sup><i>x</i></sup> is normal.
487    ///
488    /// Equal to floor(log<sub>10</sub>&nbsp;[`MAX`]).
489    ///
490    /// [`MAX`]: f32::MAX
491    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
492    pub const MAX_10_EXP: i32 = 38;
493
494    /// Not a Number (NaN).
495    ///
496    /// Note that IEEE 754 doesn't define just a single NaN value; a plethora of bit patterns are
497    /// considered to be NaN. Furthermore, the standard makes a difference between a "signaling" and
498    /// a "quiet" NaN, and allows inspecting its "payload" (the unspecified bits in the bit pattern)
499    /// and its sign. See the [specification of NaN bit patterns](f32#nan-bit-patterns) for more
500    /// info.
501    ///
502    /// This constant is guaranteed to be a quiet NaN (on targets that follow the Rust assumptions
503    /// that the quiet/signaling bit being set to 1 indicates a quiet NaN). Beyond that, nothing is
504    /// guaranteed about the specific bit pattern chosen here: both payload and sign are arbitrary.
505    /// The concrete bit pattern may change across Rust versions and target platforms.
506    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
507    #[rustc_diagnostic_item = "f32_nan"]
508    #[allow(clippy::eq_op)]
509    pub const NAN: f32 = 0.0_f32 / 0.0_f32;
510    /// Infinity (∞).
511    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
512    pub const INFINITY: f32 = 1.0_f32 / 0.0_f32;
513    /// Negative infinity (−∞).
514    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
515    pub const NEG_INFINITY: f32 = -1.0_f32 / 0.0_f32;
516
517    /// Maximum integer that can be represented exactly in an [`f32`] value,
518    /// with no other integer converting to the same floating point value.
519    ///
520    /// For an integer `x` which satisfies `MIN_EXACT_INTEGER <= x <= MAX_EXACT_INTEGER`,
521    /// there is a "one-to-one" mapping between [`i32`] and [`f32`] values.
522    /// `MAX_EXACT_INTEGER + 1` also converts losslessly to [`f32`] and back to
523    /// [`i32`], but `MAX_EXACT_INTEGER + 2` converts to the same [`f32`] value
524    /// (and back to `MAX_EXACT_INTEGER + 1` as an integer) so there is not a
525    /// "one-to-one" mapping.
526    ///
527    /// [`MAX_EXACT_INTEGER`]: f32::MAX_EXACT_INTEGER
528    /// [`MIN_EXACT_INTEGER`]: f32::MIN_EXACT_INTEGER
529    /// ```
530    /// #![feature(float_exact_integer_constants)]
531    /// # // FIXME(#152635): Float rounding on `i586` does not adhere to IEEE 754
532    /// # #[cfg(not(all(target_arch = "x86", not(target_feature = "sse"))))] {
533    /// let max_exact_int = f32::MAX_EXACT_INTEGER;
534    /// assert_eq!(max_exact_int, max_exact_int as f32 as i32);
535    /// assert_eq!(max_exact_int + 1, (max_exact_int + 1) as f32 as i32);
536    /// assert_ne!(max_exact_int + 2, (max_exact_int + 2) as f32 as i32);
537    ///
538    /// // Beyond `f32::MAX_EXACT_INTEGER`, multiple integers can map to one float value
539    /// assert_eq!((max_exact_int + 1) as f32, (max_exact_int + 2) as f32);
540    /// # }
541    /// ```
542    #[unstable(feature = "float_exact_integer_constants", issue = "152466")]
543    pub const MAX_EXACT_INTEGER: i32 = (1 << Self::MANTISSA_DIGITS) - 1;
544
545    /// Minimum integer that can be represented exactly in an [`f32`] value,
546    /// with no other integer converting to the same floating point value.
547    ///
548    /// For an integer `x` which satisfies `MIN_EXACT_INTEGER <= x <= MAX_EXACT_INTEGER`,
549    /// there is a "one-to-one" mapping between [`i32`] and [`f32`] values.
550    /// `MAX_EXACT_INTEGER + 1` also converts losslessly to [`f32`] and back to
551    /// [`i32`], but `MAX_EXACT_INTEGER + 2` converts to the same [`f32`] value
552    /// (and back to `MAX_EXACT_INTEGER + 1` as an integer) so there is not a
553    /// "one-to-one" mapping.
554    ///
555    /// This constant is equivalent to `-MAX_EXACT_INTEGER`.
556    ///
557    /// [`MAX_EXACT_INTEGER`]: f32::MAX_EXACT_INTEGER
558    /// [`MIN_EXACT_INTEGER`]: f32::MIN_EXACT_INTEGER
559    /// ```
560    /// #![feature(float_exact_integer_constants)]
561    /// # // FIXME(#152635): Float rounding on `i586` does not adhere to IEEE 754
562    /// # #[cfg(not(all(target_arch = "x86", not(target_feature = "sse"))))] {
563    /// let min_exact_int = f32::MIN_EXACT_INTEGER;
564    /// assert_eq!(min_exact_int, min_exact_int as f32 as i32);
565    /// assert_eq!(min_exact_int - 1, (min_exact_int - 1) as f32 as i32);
566    /// assert_ne!(min_exact_int - 2, (min_exact_int - 2) as f32 as i32);
567    ///
568    /// // Below `f32::MIN_EXACT_INTEGER`, multiple integers can map to one float value
569    /// assert_eq!((min_exact_int - 1) as f32, (min_exact_int - 2) as f32);
570    /// # }
571    /// ```
572    #[unstable(feature = "float_exact_integer_constants", issue = "152466")]
573    pub const MIN_EXACT_INTEGER: i32 = -Self::MAX_EXACT_INTEGER;
574
575    /// Sign bit
576    pub(crate) const SIGN_MASK: u32 = 0x8000_0000;
577
578    /// Exponent mask
579    pub(crate) const EXP_MASK: u32 = 0x7f80_0000;
580
581    /// Mantissa mask
582    pub(crate) const MAN_MASK: u32 = 0x007f_ffff;
583
584    /// Minimum representable positive value (min subnormal)
585    const TINY_BITS: u32 = 0x1;
586
587    /// Minimum representable negative value (min negative subnormal)
588    const NEG_TINY_BITS: u32 = Self::TINY_BITS | Self::SIGN_MASK;
589
590    /// Returns `true` if this value is NaN.
591    ///
592    /// ```
593    /// let nan = f32::NAN;
594    /// let f = 7.0_f32;
595    ///
596    /// assert!(nan.is_nan());
597    /// assert!(!f.is_nan());
598    /// ```
599    #[must_use]
600    #[stable(feature = "rust1", since = "1.0.0")]
601    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
602    #[inline]
603    #[allow(clippy::eq_op)] // > if you intended to check if the operand is NaN, use `.is_nan()` instead :)
604    #[ferrocene::prevalidated]
605    pub const fn is_nan(self) -> bool {
606        self != self
607    }
608
609    /// Returns `true` if this value is positive infinity or negative infinity, and
610    /// `false` otherwise.
611    ///
612    /// ```
613    /// let f = 7.0f32;
614    /// let inf = f32::INFINITY;
615    /// let neg_inf = f32::NEG_INFINITY;
616    /// let nan = f32::NAN;
617    ///
618    /// assert!(!f.is_infinite());
619    /// assert!(!nan.is_infinite());
620    ///
621    /// assert!(inf.is_infinite());
622    /// assert!(neg_inf.is_infinite());
623    /// ```
624    #[must_use]
625    #[stable(feature = "rust1", since = "1.0.0")]
626    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
627    #[inline]
628    #[ferrocene::prevalidated]
629    pub const fn is_infinite(self) -> bool {
630        // Getting clever with transmutation can result in incorrect answers on some FPUs
631        // FIXME: alter the Rust <-> Rust calling convention to prevent this problem.
632        // See https://github.com/rust-lang/rust/issues/72327
633        (self == f32::INFINITY) | (self == f32::NEG_INFINITY)
634    }
635
636    /// Returns `true` if this number is neither infinite nor NaN.
637    ///
638    /// ```
639    /// let f = 7.0f32;
640    /// let inf = f32::INFINITY;
641    /// let neg_inf = f32::NEG_INFINITY;
642    /// let nan = f32::NAN;
643    ///
644    /// assert!(f.is_finite());
645    ///
646    /// assert!(!nan.is_finite());
647    /// assert!(!inf.is_finite());
648    /// assert!(!neg_inf.is_finite());
649    /// ```
650    #[must_use]
651    #[stable(feature = "rust1", since = "1.0.0")]
652    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
653    #[inline]
654    pub const fn is_finite(self) -> bool {
655        // There's no need to handle NaN separately: if self is NaN,
656        // the comparison is not true, exactly as desired.
657        self.abs() < Self::INFINITY
658    }
659
660    /// Returns `true` if the number is [subnormal].
661    ///
662    /// ```
663    /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
664    /// let max = f32::MAX;
665    /// let lower_than_min = 1.0e-40_f32;
666    /// let zero = 0.0_f32;
667    ///
668    /// assert!(!min.is_subnormal());
669    /// assert!(!max.is_subnormal());
670    ///
671    /// assert!(!zero.is_subnormal());
672    /// assert!(!f32::NAN.is_subnormal());
673    /// assert!(!f32::INFINITY.is_subnormal());
674    /// // Values between `0` and `min` are Subnormal.
675    /// assert!(lower_than_min.is_subnormal());
676    /// ```
677    /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number
678    #[must_use]
679    #[stable(feature = "is_subnormal", since = "1.53.0")]
680    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
681    #[inline]
682    pub const fn is_subnormal(self) -> bool {
683        matches!(self.classify(), FpCategory::Subnormal)
684    }
685
686    /// Returns `true` if the number is neither zero, infinite,
687    /// [subnormal], or NaN.
688    ///
689    /// ```
690    /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
691    /// let max = f32::MAX;
692    /// let lower_than_min = 1.0e-40_f32;
693    /// let zero = 0.0_f32;
694    ///
695    /// assert!(min.is_normal());
696    /// assert!(max.is_normal());
697    ///
698    /// assert!(!zero.is_normal());
699    /// assert!(!f32::NAN.is_normal());
700    /// assert!(!f32::INFINITY.is_normal());
701    /// // Values between `0` and `min` are Subnormal.
702    /// assert!(!lower_than_min.is_normal());
703    /// ```
704    /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number
705    #[must_use]
706    #[stable(feature = "rust1", since = "1.0.0")]
707    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
708    #[inline]
709    pub const fn is_normal(self) -> bool {
710        matches!(self.classify(), FpCategory::Normal)
711    }
712
713    /// Returns the floating point category of the number. If only one property
714    /// is going to be tested, it is generally faster to use the specific
715    /// predicate instead.
716    ///
717    /// ```
718    /// use std::num::FpCategory;
719    ///
720    /// let num = 12.4_f32;
721    /// let inf = f32::INFINITY;
722    ///
723    /// assert_eq!(num.classify(), FpCategory::Normal);
724    /// assert_eq!(inf.classify(), FpCategory::Infinite);
725    /// ```
726    #[ferrocene::prevalidated]
727    #[stable(feature = "rust1", since = "1.0.0")]
728    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
729    #[must_use]
730    pub const fn classify(self) -> FpCategory {
731        // We used to have complicated logic here that avoids the simple bit-based tests to work
732        // around buggy codegen for x87 targets (see
733        // https://github.com/rust-lang/rust/issues/114479). However, some LLVM versions later, none
734        // of our tests is able to find any difference between the complicated and the naive
735        // version, so now we are back to the naive version.
736        let b = self.to_bits();
737        match (b & Self::MAN_MASK, b & Self::EXP_MASK) {
738            (0, Self::EXP_MASK) => FpCategory::Infinite,
739            (_, Self::EXP_MASK) => FpCategory::Nan,
740            (0, 0) => FpCategory::Zero,
741            (_, 0) => FpCategory::Subnormal,
742            _ => FpCategory::Normal,
743        }
744    }
745
746    /// Returns `true` if `self` has a positive sign, including `+0.0`, NaNs with
747    /// positive sign bit and positive infinity.
748    ///
749    /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of
750    /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are
751    /// conserved over arithmetic operations, the result of `is_sign_positive` on
752    /// a NaN might produce an unexpected or non-portable result. See the [specification
753    /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == 1.0`
754    /// if you need fully portable behavior (will return `false` for all NaNs).
755    ///
756    /// ```
757    /// let f = 7.0_f32;
758    /// let g = -7.0_f32;
759    ///
760    /// assert!(f.is_sign_positive());
761    /// assert!(!g.is_sign_positive());
762    /// ```
763    #[must_use]
764    #[stable(feature = "rust1", since = "1.0.0")]
765    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
766    #[inline]
767    pub const fn is_sign_positive(self) -> bool {
768        !self.is_sign_negative()
769    }
770
771    /// Returns `true` if `self` has a negative sign, including `-0.0`, NaNs with
772    /// negative sign bit and negative infinity.
773    ///
774    /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of
775    /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are
776    /// conserved over arithmetic operations, the result of `is_sign_negative` on
777    /// a NaN might produce an unexpected or non-portable result. See the [specification
778    /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == -1.0`
779    /// if you need fully portable behavior (will return `false` for all NaNs).
780    ///
781    /// ```
782    /// let f = 7.0f32;
783    /// let g = -7.0f32;
784    ///
785    /// assert!(!f.is_sign_negative());
786    /// assert!(g.is_sign_negative());
787    /// ```
788    #[must_use]
789    #[stable(feature = "rust1", since = "1.0.0")]
790    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
791    #[inline]
792    #[ferrocene::prevalidated]
793    pub const fn is_sign_negative(self) -> bool {
794        // IEEE754 says: isSignMinus(x) is true if and only if x has negative sign. isSignMinus
795        // applies to zeros and NaNs as well.
796        self.to_bits() & 0x8000_0000 != 0
797    }
798
799    /// Returns the least number greater than `self`.
800    ///
801    /// Let `TINY` be the smallest representable positive `f32`. Then,
802    ///  - if `self.is_nan()`, this returns `self`;
803    ///  - if `self` is [`NEG_INFINITY`], this returns [`MIN`];
804    ///  - if `self` is `-TINY`, this returns -0.0;
805    ///  - if `self` is -0.0 or +0.0, this returns `TINY`;
806    ///  - if `self` is [`MAX`] or [`INFINITY`], this returns [`INFINITY`];
807    ///  - otherwise the unique least value greater than `self` is returned.
808    ///
809    /// The identity `x.next_up() == -(-x).next_down()` holds for all non-NaN `x`. When `x`
810    /// is finite `x == x.next_up().next_down()` also holds.
811    ///
812    /// ```rust
813    /// // f32::EPSILON is the difference between 1.0 and the next number up.
814    /// assert_eq!(1.0f32.next_up(), 1.0 + f32::EPSILON);
815    /// // But not for most numbers.
816    /// assert!(0.1f32.next_up() < 0.1 + f32::EPSILON);
817    /// assert_eq!(16777216f32.next_up(), 16777218.0);
818    /// ```
819    ///
820    /// This operation corresponds to IEEE-754 `nextUp`.
821    ///
822    /// [`NEG_INFINITY`]: Self::NEG_INFINITY
823    /// [`INFINITY`]: Self::INFINITY
824    /// [`MIN`]: Self::MIN
825    /// [`MAX`]: Self::MAX
826    #[inline]
827    #[doc(alias = "nextUp")]
828    #[stable(feature = "float_next_up_down", since = "1.86.0")]
829    #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")]
830    #[must_use = "method returns a new number and does not mutate the original value"]
831    pub const fn next_up(self) -> Self {
832        // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
833        // denormals to zero. This is in general unsound and unsupported, but here
834        // we do our best to still produce the correct result on such targets.
835        let bits = self.to_bits();
836        if self.is_nan() || bits == Self::INFINITY.to_bits() {
837            return self;
838        }
839
840        let abs = bits & !Self::SIGN_MASK;
841        let next_bits = if abs == 0 {
842            Self::TINY_BITS
843        } else if bits == abs {
844            bits + 1
845        } else {
846            bits - 1
847        };
848        Self::from_bits(next_bits)
849    }
850
851    /// Returns the greatest number less than `self`.
852    ///
853    /// Let `TINY` be the smallest representable positive `f32`. Then,
854    ///  - if `self.is_nan()`, this returns `self`;
855    ///  - if `self` is [`INFINITY`], this returns [`MAX`];
856    ///  - if `self` is `TINY`, this returns 0.0;
857    ///  - if `self` is -0.0 or +0.0, this returns `-TINY`;
858    ///  - if `self` is [`MIN`] or [`NEG_INFINITY`], this returns [`NEG_INFINITY`];
859    ///  - otherwise the unique greatest value less than `self` is returned.
860    ///
861    /// The identity `x.next_down() == -(-x).next_up()` holds for all non-NaN `x`. When `x`
862    /// is finite `x == x.next_down().next_up()` also holds.
863    ///
864    /// ```rust
865    /// let x = 1.0f32;
866    /// // Clamp value into range [0, 1).
867    /// let clamped = x.clamp(0.0, 1.0f32.next_down());
868    /// assert!(clamped < 1.0);
869    /// assert_eq!(clamped.next_up(), 1.0);
870    /// ```
871    ///
872    /// This operation corresponds to IEEE-754 `nextDown`.
873    ///
874    /// [`NEG_INFINITY`]: Self::NEG_INFINITY
875    /// [`INFINITY`]: Self::INFINITY
876    /// [`MIN`]: Self::MIN
877    /// [`MAX`]: Self::MAX
878    #[inline]
879    #[doc(alias = "nextDown")]
880    #[stable(feature = "float_next_up_down", since = "1.86.0")]
881    #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")]
882    #[must_use = "method returns a new number and does not mutate the original value"]
883    pub const fn next_down(self) -> Self {
884        // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
885        // denormals to zero. This is in general unsound and unsupported, but here
886        // we do our best to still produce the correct result on such targets.
887        let bits = self.to_bits();
888        if self.is_nan() || bits == Self::NEG_INFINITY.to_bits() {
889            return self;
890        }
891
892        let abs = bits & !Self::SIGN_MASK;
893        let next_bits = if abs == 0 {
894            Self::NEG_TINY_BITS
895        } else if bits == abs {
896            bits - 1
897        } else {
898            bits + 1
899        };
900        Self::from_bits(next_bits)
901    }
902
903    /// Takes the reciprocal (inverse) of a number, `1/x`.
904    ///
905    /// ```
906    /// let x = 2.0_f32;
907    /// let abs_difference = (x.recip() - (1.0 / x)).abs();
908    ///
909    /// assert!(abs_difference <= f32::EPSILON);
910    /// ```
911    #[must_use = "this returns the result of the operation, without modifying the original"]
912    #[stable(feature = "rust1", since = "1.0.0")]
913    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
914    #[inline]
915    pub const fn recip(self) -> f32 {
916        1.0 / self
917    }
918
919    /// Converts radians to degrees.
920    ///
921    /// # Unspecified precision
922    ///
923    /// The precision of this function is non-deterministic. This means it varies by platform,
924    /// Rust version, and can even differ within the same execution from one invocation to the next.
925    ///
926    /// # Examples
927    ///
928    /// ```
929    /// let angle = std::f32::consts::PI;
930    ///
931    /// let abs_difference = (angle.to_degrees() - 180.0).abs();
932    /// # #[cfg(any(not(target_arch = "x86"), target_feature = "sse2"))]
933    /// assert!(abs_difference <= f32::EPSILON);
934    /// ```
935    #[must_use = "this returns the result of the operation, \
936                  without modifying the original"]
937    #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
938    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
939    #[inline]
940    pub const fn to_degrees(self) -> f32 {
941        // Use a literal to avoid double rounding, consts::PI is already rounded,
942        // and dividing would round again.
943        const PIS_IN_180: f32 = 57.2957795130823208767981548141051703_f32;
944        self * PIS_IN_180
945    }
946
947    /// Converts degrees to radians.
948    ///
949    /// # Unspecified precision
950    ///
951    /// The precision of this function is non-deterministic. This means it varies by platform,
952    /// Rust version, and can even differ within the same execution from one invocation to the next.
953    ///
954    /// # Examples
955    ///
956    /// ```
957    /// let angle = 180.0f32;
958    ///
959    /// let abs_difference = (angle.to_radians() - std::f32::consts::PI).abs();
960    ///
961    /// assert!(abs_difference <= f32::EPSILON);
962    /// ```
963    #[must_use = "this returns the result of the operation, \
964                  without modifying the original"]
965    #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
966    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
967    #[inline]
968    pub const fn to_radians(self) -> f32 {
969        // The division here is correctly rounded with respect to the true value of π/180.
970        // Although π is irrational and already rounded, the double rounding happens
971        // to produce correct result for f32.
972        const RADS_PER_DEG: f32 = consts::PI / 180.0;
973        self * RADS_PER_DEG
974    }
975
976    /// Returns the maximum of the two numbers, ignoring NaN.
977    ///
978    /// If exactly one of the arguments is NaN (quiet or signaling), then the other argument is
979    /// returned. If both arguments are NaN, the return value is NaN, with the bit pattern picked
980    /// using the usual [rules for arithmetic operations](f32#nan-bit-patterns). If the inputs
981    /// compare equal (such as for the case of `+0.0` and `-0.0`), either input may be returned
982    /// non-deterministically.
983    ///
984    /// The handling of NaNs follows the IEEE 754-2019 semantics for `maximumNumber`, treating all
985    /// NaNs the same way to ensure the operation is associative. The handling of signed zeros
986    /// follows the IEEE 754-2008 semantics for `maxNum`.
987    ///
988    /// ```
989    /// let x = 1.0f32;
990    /// let y = 2.0f32;
991    ///
992    /// assert_eq!(x.max(y), y);
993    /// assert_eq!(x.max(f32::NAN), x);
994    /// ```
995    #[must_use = "this returns the result of the comparison, without modifying either input"]
996    #[stable(feature = "rust1", since = "1.0.0")]
997    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
998    #[inline]
999    #[ferrocene::prevalidated]
1000    pub const fn max(self, other: f32) -> f32 {
1001        intrinsics::maximum_number_nsz_f32(self, other)
1002    }
1003
1004    /// Returns the minimum of the two numbers, ignoring NaN.
1005    ///
1006    /// If exactly one of the arguments is NaN (quiet or signaling), then the other argument is
1007    /// returned. If both arguments are NaN, the return value is NaN, with the bit pattern picked
1008    /// using the usual [rules for arithmetic operations](f32#nan-bit-patterns). If the inputs
1009    /// compare equal (such as for the case of `+0.0` and `-0.0`), either input may be returned
1010    /// non-deterministically.
1011    ///
1012    /// The handling of NaNs follows the IEEE 754-2019 semantics for `minimumNumber`, treating all
1013    /// NaNs the same way to ensure the operation is associative. The handling of signed zeros
1014    /// follows the IEEE 754-2008 semantics for `minNum`.
1015    ///
1016    /// ```
1017    /// let x = 1.0f32;
1018    /// let y = 2.0f32;
1019    ///
1020    /// assert_eq!(x.min(y), x);
1021    /// assert_eq!(x.min(f32::NAN), x);
1022    /// ```
1023    #[must_use = "this returns the result of the comparison, without modifying either input"]
1024    #[stable(feature = "rust1", since = "1.0.0")]
1025    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1026    #[inline]
1027    #[ferrocene::prevalidated]
1028    pub const fn min(self, other: f32) -> f32 {
1029        intrinsics::minimum_number_nsz_f32(self, other)
1030    }
1031
1032    /// Returns the maximum of the two numbers, propagating NaN.
1033    ///
1034    /// If at least one of the arguments is NaN, the return value is NaN, with the bit pattern
1035    /// picked using the usual [rules for arithmetic operations](f32#nan-bit-patterns). Furthermore,
1036    /// `-0.0` is considered to be less than `+0.0`, making this function fully deterministic for
1037    /// non-NaN inputs.
1038    ///
1039    /// This is in contrast to [`f32::max`] which only returns NaN when *both* arguments are NaN,
1040    /// and which does not reliably order `-0.0` and `+0.0`.
1041    ///
1042    /// This follows the IEEE 754-2019 semantics for `maximum`.
1043    ///
1044    /// ```
1045    /// #![feature(float_minimum_maximum)]
1046    /// let x = 1.0f32;
1047    /// let y = 2.0f32;
1048    ///
1049    /// assert_eq!(x.maximum(y), y);
1050    /// assert!(x.maximum(f32::NAN).is_nan());
1051    /// ```
1052    #[must_use = "this returns the result of the comparison, without modifying either input"]
1053    #[unstable(feature = "float_minimum_maximum", issue = "91079")]
1054    #[inline]
1055    pub const fn maximum(self, other: f32) -> f32 {
1056        intrinsics::maximumf32(self, other)
1057    }
1058
1059    /// Returns the minimum of the two numbers, propagating NaN.
1060    ///
1061    /// If at least one of the arguments is NaN, the return value is NaN, with the bit pattern
1062    /// picked using the usual [rules for arithmetic operations](f32#nan-bit-patterns). Furthermore,
1063    /// `-0.0` is considered to be less than `+0.0`, making this function fully deterministic for
1064    /// non-NaN inputs.
1065    ///
1066    /// This is in contrast to [`f32::min`] which only returns NaN when *both* arguments are NaN,
1067    /// and which does not reliably order `-0.0` and `+0.0`.
1068    ///
1069    /// This follows the IEEE 754-2019 semantics for `minimum`.
1070    ///
1071    /// ```
1072    /// #![feature(float_minimum_maximum)]
1073    /// let x = 1.0f32;
1074    /// let y = 2.0f32;
1075    ///
1076    /// assert_eq!(x.minimum(y), x);
1077    /// assert!(x.minimum(f32::NAN).is_nan());
1078    /// ```
1079    #[must_use = "this returns the result of the comparison, without modifying either input"]
1080    #[unstable(feature = "float_minimum_maximum", issue = "91079")]
1081    #[inline]
1082    pub const fn minimum(self, other: f32) -> f32 {
1083        intrinsics::minimumf32(self, other)
1084    }
1085
1086    /// Calculates the midpoint (average) between `self` and `rhs`.
1087    ///
1088    /// This returns NaN when *either* argument is NaN or if a combination of
1089    /// +inf and -inf is provided as arguments.
1090    ///
1091    /// # Examples
1092    ///
1093    /// ```
1094    /// assert_eq!(1f32.midpoint(4.0), 2.5);
1095    /// assert_eq!((-5.5f32).midpoint(8.0), 1.25);
1096    /// ```
1097    #[inline]
1098    #[doc(alias = "average")]
1099    #[stable(feature = "num_midpoint", since = "1.85.0")]
1100    #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")]
1101    #[must_use = "this returns the result of the operation, \
1102                  without modifying the original"]
1103    pub const fn midpoint(self, other: f32) -> f32 {
1104        cfg_select! {
1105            // Allow faster implementation that have known good 64-bit float
1106            // implementations. Falling back to the branchy code on targets that don't
1107            // have 64-bit hardware floats or buggy implementations.
1108            // https://github.com/rust-lang/rust/pull/121062#issuecomment-2123408114
1109            any(
1110                target_arch = "x86_64",
1111                target_arch = "aarch64",
1112                all(any(target_arch = "riscv32", target_arch = "riscv64"), target_feature = "d"),
1113                all(target_arch = "loongarch64", target_feature = "d"),
1114                all(target_arch = "arm", target_feature = "vfp2"),
1115                target_arch = "wasm32",
1116                target_arch = "wasm64",
1117            ) => {
1118                ((self as f64 + other as f64) / 2.0) as f32
1119            }
1120            _ => {
1121                const HI: f32 = f32::MAX / 2.;
1122
1123                let (a, b) = (self, other);
1124                let abs_a = a.abs();
1125                let abs_b = b.abs();
1126
1127                if abs_a <= HI && abs_b <= HI {
1128                    // Overflow is impossible
1129                    (a + b) / 2.
1130                } else {
1131                    (a / 2.) + (b / 2.)
1132                }
1133            }
1134        }
1135    }
1136
1137    /// Rounds toward zero and converts to any primitive integer type,
1138    /// assuming that the value is finite and fits in that type.
1139    ///
1140    /// ```
1141    /// let value = 4.6_f32;
1142    /// let rounded = unsafe { value.to_int_unchecked::<u16>() };
1143    /// assert_eq!(rounded, 4);
1144    ///
1145    /// let value = -128.9_f32;
1146    /// let rounded = unsafe { value.to_int_unchecked::<i8>() };
1147    /// assert_eq!(rounded, i8::MIN);
1148    /// ```
1149    ///
1150    /// # Safety
1151    ///
1152    /// The value must:
1153    ///
1154    /// * Not be `NaN`
1155    /// * Not be infinite
1156    /// * Be representable in the return type `Int`, after truncating off its fractional part
1157    #[must_use = "this returns the result of the operation, \
1158                  without modifying the original"]
1159    #[stable(feature = "float_approx_unchecked_to", since = "1.44.0")]
1160    #[inline]
1161    pub unsafe fn to_int_unchecked<Int>(self) -> Int
1162    where
1163        Self: FloatToInt<Int>,
1164    {
1165        // SAFETY: the caller must uphold the safety contract for
1166        // `FloatToInt::to_int_unchecked`.
1167        unsafe { FloatToInt::<Int>::to_int_unchecked(self) }
1168    }
1169
1170    /// Raw transmutation to `u32`.
1171    ///
1172    /// This is currently identical to `transmute::<f32, u32>(self)` on all platforms.
1173    ///
1174    /// See [`from_bits`](Self::from_bits) for some discussion of the
1175    /// portability of this operation (there are almost no issues).
1176    ///
1177    /// Note that this function is distinct from `as` casting, which attempts to
1178    /// preserve the *numeric* value, and not the bitwise value.
1179    ///
1180    /// # Examples
1181    ///
1182    /// ```
1183    /// assert_ne!((1f32).to_bits(), 1f32 as u32); // to_bits() is not casting!
1184    /// assert_eq!((12.5f32).to_bits(), 0x41480000);
1185    ///
1186    /// ```
1187    #[must_use = "this returns the result of the operation, \
1188                  without modifying the original"]
1189    #[stable(feature = "float_bits_conv", since = "1.20.0")]
1190    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1191    #[inline]
1192    #[allow(unnecessary_transmutes)]
1193    #[ferrocene::prevalidated]
1194    pub const fn to_bits(self) -> u32 {
1195        // SAFETY: `u32` is a plain old datatype so we can always transmute to it.
1196        unsafe { mem::transmute(self) }
1197    }
1198
1199    /// Raw transmutation from `u32`.
1200    ///
1201    /// This is currently identical to `transmute::<u32, f32>(v)` on all platforms.
1202    /// It turns out this is incredibly portable, for two reasons:
1203    ///
1204    /// * Floats and Ints have the same endianness on all supported platforms.
1205    /// * IEEE 754 very precisely specifies the bit layout of floats.
1206    ///
1207    /// However there is one caveat: prior to the 2008 version of IEEE 754, how
1208    /// to interpret the NaN signaling bit wasn't actually specified. Most platforms
1209    /// (notably x86 and ARM) picked the interpretation that was ultimately
1210    /// standardized in 2008, but some didn't (notably MIPS). As a result, all
1211    /// signaling NaNs on MIPS are quiet NaNs on x86, and vice-versa.
1212    ///
1213    /// Rather than trying to preserve signaling-ness cross-platform, this
1214    /// implementation favors preserving the exact bits. This means that
1215    /// any payloads encoded in NaNs will be preserved even if the result of
1216    /// this method is sent over the network from an x86 machine to a MIPS one.
1217    ///
1218    /// If the results of this method are only manipulated by the same
1219    /// architecture that produced them, then there is no portability concern.
1220    ///
1221    /// If the input isn't NaN, then there is no portability concern.
1222    ///
1223    /// If you don't care about signalingness (very likely), then there is no
1224    /// portability concern.
1225    ///
1226    /// Note that this function is distinct from `as` casting, which attempts to
1227    /// preserve the *numeric* value, and not the bitwise value.
1228    ///
1229    /// # Examples
1230    ///
1231    /// ```
1232    /// let v = f32::from_bits(0x41480000);
1233    /// assert_eq!(v, 12.5);
1234    /// ```
1235    #[stable(feature = "float_bits_conv", since = "1.20.0")]
1236    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1237    #[must_use]
1238    #[inline]
1239    #[allow(unnecessary_transmutes)]
1240    #[ferrocene::prevalidated]
1241    pub const fn from_bits(v: u32) -> Self {
1242        // It turns out the safety issues with sNaN were overblown! Hooray!
1243        // SAFETY: `u32` is a plain old datatype so we can always transmute from it.
1244        unsafe { mem::transmute(v) }
1245    }
1246
1247    /// Returns the memory representation of this floating point number as a byte array in
1248    /// big-endian (network) byte order.
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 bytes = 12.5f32.to_be_bytes();
1257    /// assert_eq!(bytes, [0x41, 0x48, 0x00, 0x00]);
1258    /// ```
1259    #[must_use = "this returns the result of the operation, \
1260                  without modifying the original"]
1261    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1262    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1263    #[inline]
1264    pub const fn to_be_bytes(self) -> [u8; 4] {
1265        self.to_bits().to_be_bytes()
1266    }
1267
1268    /// Returns the memory representation of this floating point number as a byte array in
1269    /// little-endian byte order.
1270    ///
1271    /// See [`from_bits`](Self::from_bits) for some discussion of the
1272    /// portability of this operation (there are almost no issues).
1273    ///
1274    /// # Examples
1275    ///
1276    /// ```
1277    /// let bytes = 12.5f32.to_le_bytes();
1278    /// assert_eq!(bytes, [0x00, 0x00, 0x48, 0x41]);
1279    /// ```
1280    #[must_use = "this returns the result of the operation, \
1281                  without modifying the original"]
1282    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1283    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1284    #[inline]
1285    #[ferrocene::prevalidated]
1286    pub const fn to_le_bytes(self) -> [u8; 4] {
1287        self.to_bits().to_le_bytes()
1288    }
1289
1290    /// Returns the memory representation of this floating point number as a byte array in
1291    /// native byte order.
1292    ///
1293    /// As the target platform's native endianness is used, portable code
1294    /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate, instead.
1295    ///
1296    /// [`to_be_bytes`]: f32::to_be_bytes
1297    /// [`to_le_bytes`]: f32::to_le_bytes
1298    ///
1299    /// See [`from_bits`](Self::from_bits) for some discussion of the
1300    /// portability of this operation (there are almost no issues).
1301    ///
1302    /// # Examples
1303    ///
1304    /// ```
1305    /// let bytes = 12.5f32.to_ne_bytes();
1306    /// assert_eq!(
1307    ///     bytes,
1308    ///     if cfg!(target_endian = "big") {
1309    ///         [0x41, 0x48, 0x00, 0x00]
1310    ///     } else {
1311    ///         [0x00, 0x00, 0x48, 0x41]
1312    ///     }
1313    /// );
1314    /// ```
1315    #[must_use = "this returns the result of the operation, \
1316                  without modifying the original"]
1317    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1318    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1319    #[inline]
1320    pub const fn to_ne_bytes(self) -> [u8; 4] {
1321        self.to_bits().to_ne_bytes()
1322    }
1323
1324    /// Creates a floating point value from its representation as a byte array in big endian.
1325    ///
1326    /// See [`from_bits`](Self::from_bits) for some discussion of the
1327    /// portability of this operation (there are almost no issues).
1328    ///
1329    /// # Examples
1330    ///
1331    /// ```
1332    /// let value = f32::from_be_bytes([0x41, 0x48, 0x00, 0x00]);
1333    /// assert_eq!(value, 12.5);
1334    /// ```
1335    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1336    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1337    #[must_use]
1338    #[inline]
1339    pub const fn from_be_bytes(bytes: [u8; 4]) -> Self {
1340        Self::from_bits(u32::from_be_bytes(bytes))
1341    }
1342
1343    /// Creates a floating point value from its representation as a byte array in little endian.
1344    ///
1345    /// See [`from_bits`](Self::from_bits) for some discussion of the
1346    /// portability of this operation (there are almost no issues).
1347    ///
1348    /// # Examples
1349    ///
1350    /// ```
1351    /// let value = f32::from_le_bytes([0x00, 0x00, 0x48, 0x41]);
1352    /// assert_eq!(value, 12.5);
1353    /// ```
1354    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1355    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1356    #[must_use]
1357    #[inline]
1358    #[ferrocene::prevalidated]
1359    pub const fn from_le_bytes(bytes: [u8; 4]) -> Self {
1360        Self::from_bits(u32::from_le_bytes(bytes))
1361    }
1362
1363    /// Creates a floating point value from its representation as a byte array in native endian.
1364    ///
1365    /// As the target platform's native endianness is used, portable code
1366    /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
1367    /// appropriate instead.
1368    ///
1369    /// [`from_be_bytes`]: f32::from_be_bytes
1370    /// [`from_le_bytes`]: f32::from_le_bytes
1371    ///
1372    /// See [`from_bits`](Self::from_bits) for some discussion of the
1373    /// portability of this operation (there are almost no issues).
1374    ///
1375    /// # Examples
1376    ///
1377    /// ```
1378    /// let value = f32::from_ne_bytes(if cfg!(target_endian = "big") {
1379    ///     [0x41, 0x48, 0x00, 0x00]
1380    /// } else {
1381    ///     [0x00, 0x00, 0x48, 0x41]
1382    /// });
1383    /// assert_eq!(value, 12.5);
1384    /// ```
1385    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1386    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1387    #[must_use]
1388    #[inline]
1389    pub const fn from_ne_bytes(bytes: [u8; 4]) -> Self {
1390        Self::from_bits(u32::from_ne_bytes(bytes))
1391    }
1392
1393    /// Returns the ordering between `self` and `other`.
1394    ///
1395    /// Unlike the standard partial comparison between floating point numbers,
1396    /// this comparison always produces an ordering in accordance to
1397    /// the `totalOrder` predicate as defined in the IEEE 754 (2008 revision)
1398    /// floating point standard. The values are ordered in the following sequence:
1399    ///
1400    /// - negative quiet NaN
1401    /// - negative signaling NaN
1402    /// - negative infinity
1403    /// - negative numbers
1404    /// - negative subnormal numbers
1405    /// - negative zero
1406    /// - positive zero
1407    /// - positive subnormal numbers
1408    /// - positive numbers
1409    /// - positive infinity
1410    /// - positive signaling NaN
1411    /// - positive quiet NaN.
1412    ///
1413    /// The ordering established by this function does not always agree with the
1414    /// [`PartialOrd`] and [`PartialEq`] implementations of `f32`. For example,
1415    /// they consider negative and positive zero equal, while `total_cmp`
1416    /// doesn't.
1417    ///
1418    /// The interpretation of the signaling NaN bit follows the definition in
1419    /// the IEEE 754 standard, which may not match the interpretation by some of
1420    /// the older, non-conformant (e.g. MIPS) hardware implementations.
1421    ///
1422    /// # Example
1423    ///
1424    /// ```
1425    /// struct GoodBoy {
1426    ///     name: String,
1427    ///     weight: f32,
1428    /// }
1429    ///
1430    /// let mut bois = vec![
1431    ///     GoodBoy { name: "Pucci".to_owned(), weight: 0.1 },
1432    ///     GoodBoy { name: "Woofer".to_owned(), weight: 99.0 },
1433    ///     GoodBoy { name: "Yapper".to_owned(), weight: 10.0 },
1434    ///     GoodBoy { name: "Chonk".to_owned(), weight: f32::INFINITY },
1435    ///     GoodBoy { name: "Abs. Unit".to_owned(), weight: f32::NAN },
1436    ///     GoodBoy { name: "Floaty".to_owned(), weight: -5.0 },
1437    /// ];
1438    ///
1439    /// bois.sort_by(|a, b| a.weight.total_cmp(&b.weight));
1440    ///
1441    /// // `f32::NAN` could be positive or negative, which will affect the sort order.
1442    /// if f32::NAN.is_sign_negative() {
1443    ///     assert!(bois.into_iter().map(|b| b.weight)
1444    ///         .zip([f32::NAN, -5.0, 0.1, 10.0, 99.0, f32::INFINITY].iter())
1445    ///         .all(|(a, b)| a.to_bits() == b.to_bits()))
1446    /// } else {
1447    ///     assert!(bois.into_iter().map(|b| b.weight)
1448    ///         .zip([-5.0, 0.1, 10.0, 99.0, f32::INFINITY, f32::NAN].iter())
1449    ///         .all(|(a, b)| a.to_bits() == b.to_bits()))
1450    /// }
1451    /// ```
1452    #[stable(feature = "total_cmp", since = "1.62.0")]
1453    #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
1454    #[must_use]
1455    #[inline]
1456    pub const fn total_cmp(&self, other: &Self) -> crate::cmp::Ordering {
1457        let mut left = self.to_bits() as i32;
1458        let mut right = other.to_bits() as i32;
1459
1460        // In case of negatives, flip all the bits except the sign
1461        // to achieve a similar layout as two's complement integers
1462        //
1463        // Why does this work? IEEE 754 floats consist of three fields:
1464        // Sign bit, exponent and mantissa. The set of exponent and mantissa
1465        // fields as a whole have the property that their bitwise order is
1466        // equal to the numeric magnitude where the magnitude is defined.
1467        // The magnitude is not normally defined on NaN values, but
1468        // IEEE 754 totalOrder defines the NaN values also to follow the
1469        // bitwise order. This leads to order explained in the doc comment.
1470        // However, the representation of magnitude is the same for negative
1471        // and positive numbers – only the sign bit is different.
1472        // To easily compare the floats as signed integers, we need to
1473        // flip the exponent and mantissa bits in case of negative numbers.
1474        // We effectively convert the numbers to "two's complement" form.
1475        //
1476        // To do the flipping, we construct a mask and XOR against it.
1477        // We branchlessly calculate an "all-ones except for the sign bit"
1478        // mask from negative-signed values: right shifting sign-extends
1479        // the integer, so we "fill" the mask with sign bits, and then
1480        // convert to unsigned to push one more zero bit.
1481        // On positive values, the mask is all zeros, so it's a no-op.
1482        left ^= (((left >> 31) as u32) >> 1) as i32;
1483        right ^= (((right >> 31) as u32) >> 1) as i32;
1484
1485        left.cmp(&right)
1486    }
1487
1488    /// Restrict a value to a certain interval unless it is NaN.
1489    ///
1490    /// Returns `max` if `self` is greater than `max`, and `min` if `self` is
1491    /// less than `min`. Otherwise this returns `self`.
1492    ///
1493    /// Note that this function returns NaN if the initial value was NaN as
1494    /// well. If the result is zero and among the three inputs `self`, `min`, and `max` there are
1495    /// zeros with different sign, either `0.0` or `-0.0` is returned non-deterministically.
1496    ///
1497    /// # Panics
1498    ///
1499    /// Panics if `min > max`, `min` is NaN, or `max` is NaN.
1500    ///
1501    /// # Examples
1502    ///
1503    /// ```
1504    /// assert!((-3.0f32).clamp(-2.0, 1.0) == -2.0);
1505    /// assert!((0.0f32).clamp(-2.0, 1.0) == 0.0);
1506    /// assert!((2.0f32).clamp(-2.0, 1.0) == 1.0);
1507    /// assert!((f32::NAN).clamp(-2.0, 1.0).is_nan());
1508    ///
1509    /// // These always returns zero, but the sign (which is ignored by `==`) is non-deterministic.
1510    /// assert!((0.0f32).clamp(-0.0, -0.0) == 0.0);
1511    /// assert!((1.0f32).clamp(-0.0, 0.0) == 0.0);
1512    /// // This is definitely a negative zero.
1513    /// assert!((-1.0f32).clamp(-0.0, 1.0).is_sign_negative());
1514    /// ```
1515    #[must_use = "method returns a new number and does not mutate the original value"]
1516    #[stable(feature = "clamp", since = "1.50.0")]
1517    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1518    #[inline]
1519    pub const fn clamp(mut self, min: f32, max: f32) -> f32 {
1520        const_assert!(
1521            min <= max,
1522            "min > max, or either was NaN",
1523            "min > max, or either was NaN. min = {min:?}, max = {max:?}",
1524            min: f32,
1525            max: f32,
1526        );
1527
1528        if self < min {
1529            self = min;
1530        }
1531        if self > max {
1532            self = max;
1533        }
1534        self
1535    }
1536
1537    /// Clamps this number to a symmetric range centered around zero.
1538    ///
1539    /// The method clamps the number's magnitude (absolute value) to be at most `limit`.
1540    ///
1541    /// This is functionally equivalent to `self.clamp(-limit, limit)`, but is more
1542    /// explicit about the intent.
1543    ///
1544    /// # Panics
1545    ///
1546    /// Panics if `limit` is negative or NaN, as this indicates a logic error.
1547    ///
1548    /// # Examples
1549    ///
1550    /// ```
1551    /// #![feature(clamp_magnitude)]
1552    /// assert_eq!(5.0f32.clamp_magnitude(3.0), 3.0);
1553    /// assert_eq!((-5.0f32).clamp_magnitude(3.0), -3.0);
1554    /// assert_eq!(2.0f32.clamp_magnitude(3.0), 2.0);
1555    /// assert_eq!((-2.0f32).clamp_magnitude(3.0), -2.0);
1556    /// ```
1557    #[must_use = "this returns the clamped value and does not modify the original"]
1558    #[unstable(feature = "clamp_magnitude", issue = "148519")]
1559    #[inline]
1560    pub fn clamp_magnitude(self, limit: f32) -> f32 {
1561        assert!(limit >= 0.0, "limit must be non-negative");
1562        let limit = limit.abs(); // Canonicalises -0.0 to 0.0
1563        self.clamp(-limit, limit)
1564    }
1565
1566    /// Computes the absolute value of `self`.
1567    ///
1568    /// This function always returns the precise result.
1569    ///
1570    /// # Examples
1571    ///
1572    /// ```
1573    /// let x = 3.5_f32;
1574    /// let y = -3.5_f32;
1575    ///
1576    /// assert_eq!(x.abs(), x);
1577    /// assert_eq!(y.abs(), -y);
1578    ///
1579    /// assert!(f32::NAN.abs().is_nan());
1580    /// ```
1581    #[must_use = "method returns a new number and does not mutate the original value"]
1582    #[stable(feature = "rust1", since = "1.0.0")]
1583    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1584    #[inline]
1585    #[ferrocene::prevalidated]
1586    pub const fn abs(self) -> f32 {
1587        intrinsics::fabs(self)
1588    }
1589
1590    /// Returns a number that represents the sign of `self`.
1591    ///
1592    /// - `1.0` if the number is positive, `+0.0` or `INFINITY`
1593    /// - `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY`
1594    /// - NaN if the number is NaN
1595    ///
1596    /// # Examples
1597    ///
1598    /// ```
1599    /// let f = 3.5_f32;
1600    ///
1601    /// assert_eq!(f.signum(), 1.0);
1602    /// assert_eq!(f32::NEG_INFINITY.signum(), -1.0);
1603    ///
1604    /// assert!(f32::NAN.signum().is_nan());
1605    /// ```
1606    #[must_use = "method returns a new number and does not mutate the original value"]
1607    #[stable(feature = "rust1", since = "1.0.0")]
1608    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1609    #[inline]
1610    #[ferrocene::prevalidated]
1611    pub const fn signum(self) -> f32 {
1612        if self.is_nan() { Self::NAN } else { 1.0_f32.copysign(self) }
1613    }
1614
1615    /// Returns a number composed of the magnitude of `self` and the sign of
1616    /// `sign`.
1617    ///
1618    /// Equal to `self` if the sign of `self` and `sign` are the same, otherwise equal to `-self`.
1619    /// If `self` is a NaN, then a NaN with the same payload as `self` and the sign bit of `sign` is
1620    /// returned.
1621    ///
1622    /// If `sign` is a NaN, then this operation will still carry over its sign into the result. Note
1623    /// that IEEE 754 doesn't assign any meaning to the sign bit in case of a NaN, and as Rust
1624    /// doesn't guarantee that the bit pattern of NaNs are conserved over arithmetic operations, the
1625    /// result of `copysign` with `sign` being a NaN might produce an unexpected or non-portable
1626    /// result. See the [specification of NaN bit patterns](primitive@f32#nan-bit-patterns) for more
1627    /// info.
1628    ///
1629    /// # Examples
1630    ///
1631    /// ```
1632    /// let f = 3.5_f32;
1633    ///
1634    /// assert_eq!(f.copysign(0.42), 3.5_f32);
1635    /// assert_eq!(f.copysign(-0.42), -3.5_f32);
1636    /// assert_eq!((-f).copysign(0.42), 3.5_f32);
1637    /// assert_eq!((-f).copysign(-0.42), -3.5_f32);
1638    ///
1639    /// assert!(f32::NAN.copysign(1.0).is_nan());
1640    /// ```
1641    #[must_use = "method returns a new number and does not mutate the original value"]
1642    #[inline]
1643    #[stable(feature = "copysign", since = "1.35.0")]
1644    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1645    #[ferrocene::prevalidated]
1646    pub const fn copysign(self, sign: f32) -> f32 {
1647        intrinsics::copysignf32(self, sign)
1648    }
1649
1650    /// Float addition that allows optimizations based on algebraic rules.
1651    ///
1652    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1653    #[must_use = "method returns a new number and does not mutate the original value"]
1654    #[unstable(feature = "float_algebraic", issue = "136469")]
1655    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1656    #[inline]
1657    pub const fn algebraic_add(self, rhs: f32) -> f32 {
1658        intrinsics::fadd_algebraic(self, rhs)
1659    }
1660
1661    /// Float subtraction that allows optimizations based on algebraic rules.
1662    ///
1663    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1664    #[must_use = "method returns a new number and does not mutate the original value"]
1665    #[unstable(feature = "float_algebraic", issue = "136469")]
1666    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1667    #[inline]
1668    pub const fn algebraic_sub(self, rhs: f32) -> f32 {
1669        intrinsics::fsub_algebraic(self, rhs)
1670    }
1671
1672    /// Float multiplication that allows optimizations based on algebraic rules.
1673    ///
1674    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1675    #[must_use = "method returns a new number and does not mutate the original value"]
1676    #[unstable(feature = "float_algebraic", issue = "136469")]
1677    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1678    #[inline]
1679    pub const fn algebraic_mul(self, rhs: f32) -> f32 {
1680        intrinsics::fmul_algebraic(self, rhs)
1681    }
1682
1683    /// Float division that allows optimizations based on algebraic rules.
1684    ///
1685    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1686    #[must_use = "method returns a new number and does not mutate the original value"]
1687    #[unstable(feature = "float_algebraic", issue = "136469")]
1688    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1689    #[inline]
1690    pub const fn algebraic_div(self, rhs: f32) -> f32 {
1691        intrinsics::fdiv_algebraic(self, rhs)
1692    }
1693
1694    /// Float remainder that allows optimizations based on algebraic rules.
1695    ///
1696    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1697    #[must_use = "method returns a new number and does not mutate the original value"]
1698    #[unstable(feature = "float_algebraic", issue = "136469")]
1699    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1700    #[inline]
1701    pub const fn algebraic_rem(self, rhs: f32) -> f32 {
1702        intrinsics::frem_algebraic(self, rhs)
1703    }
1704}
1705
1706/// Experimental implementations of floating point functions in `core`.
1707///
1708/// _The standalone functions in this module are for testing only.
1709/// They will be stabilized as inherent methods._
1710#[unstable(feature = "core_float_math", issue = "137578")]
1711pub mod math {
1712    use crate::intrinsics;
1713    use crate::num::imp::libm;
1714
1715    /// Experimental version of `floor` in `core`. See [`f32::floor`] for details.
1716    ///
1717    /// # Examples
1718    ///
1719    /// ```
1720    /// #![feature(core_float_math)]
1721    ///
1722    /// use core::f32;
1723    ///
1724    /// let f = 3.7_f32;
1725    /// let g = 3.0_f32;
1726    /// let h = -3.7_f32;
1727    ///
1728    /// assert_eq!(f32::math::floor(f), 3.0);
1729    /// assert_eq!(f32::math::floor(g), 3.0);
1730    /// assert_eq!(f32::math::floor(h), -4.0);
1731    /// ```
1732    ///
1733    /// _This standalone function is for testing only.
1734    /// It will be stabilized as an inherent method._
1735    ///
1736    /// [`f32::floor`]: ../../../std/primitive.f32.html#method.floor
1737    #[inline]
1738    #[unstable(feature = "core_float_math", issue = "137578")]
1739    #[must_use = "method returns a new number and does not mutate the original value"]
1740    pub const fn floor(x: f32) -> f32 {
1741        intrinsics::floorf32(x)
1742    }
1743
1744    /// Experimental version of `ceil` in `core`. See [`f32::ceil`] for details.
1745    ///
1746    /// # Examples
1747    ///
1748    /// ```
1749    /// #![feature(core_float_math)]
1750    ///
1751    /// use core::f32;
1752    ///
1753    /// let f = 3.01_f32;
1754    /// let g = 4.0_f32;
1755    ///
1756    /// assert_eq!(f32::math::ceil(f), 4.0);
1757    /// assert_eq!(f32::math::ceil(g), 4.0);
1758    /// ```
1759    ///
1760    /// _This standalone function is for testing only.
1761    /// It will be stabilized as an inherent method._
1762    ///
1763    /// [`f32::ceil`]: ../../../std/primitive.f32.html#method.ceil
1764    #[inline]
1765    #[doc(alias = "ceiling")]
1766    #[must_use = "method returns a new number and does not mutate the original value"]
1767    #[unstable(feature = "core_float_math", issue = "137578")]
1768    pub const fn ceil(x: f32) -> f32 {
1769        intrinsics::ceilf32(x)
1770    }
1771
1772    /// Experimental version of `round` in `core`. See [`f32::round`] for details.
1773    ///
1774    /// # Examples
1775    ///
1776    /// ```
1777    /// #![feature(core_float_math)]
1778    ///
1779    /// use core::f32;
1780    ///
1781    /// let f = 3.3_f32;
1782    /// let g = -3.3_f32;
1783    /// let h = -3.7_f32;
1784    /// let i = 3.5_f32;
1785    /// let j = 4.5_f32;
1786    ///
1787    /// assert_eq!(f32::math::round(f), 3.0);
1788    /// assert_eq!(f32::math::round(g), -3.0);
1789    /// assert_eq!(f32::math::round(h), -4.0);
1790    /// assert_eq!(f32::math::round(i), 4.0);
1791    /// assert_eq!(f32::math::round(j), 5.0);
1792    /// ```
1793    ///
1794    /// _This standalone function is for testing only.
1795    /// It will be stabilized as an inherent method._
1796    ///
1797    /// [`f32::round`]: ../../../std/primitive.f32.html#method.round
1798    #[inline]
1799    #[unstable(feature = "core_float_math", issue = "137578")]
1800    #[must_use = "method returns a new number and does not mutate the original value"]
1801    pub const fn round(x: f32) -> f32 {
1802        intrinsics::roundf32(x)
1803    }
1804
1805    /// Experimental version of `round_ties_even` in `core`. See [`f32::round_ties_even`] for
1806    /// details.
1807    ///
1808    /// # Examples
1809    ///
1810    /// ```
1811    /// #![feature(core_float_math)]
1812    ///
1813    /// use core::f32;
1814    ///
1815    /// let f = 3.3_f32;
1816    /// let g = -3.3_f32;
1817    /// let h = 3.5_f32;
1818    /// let i = 4.5_f32;
1819    ///
1820    /// assert_eq!(f32::math::round_ties_even(f), 3.0);
1821    /// assert_eq!(f32::math::round_ties_even(g), -3.0);
1822    /// assert_eq!(f32::math::round_ties_even(h), 4.0);
1823    /// assert_eq!(f32::math::round_ties_even(i), 4.0);
1824    /// ```
1825    ///
1826    /// _This standalone function is for testing only.
1827    /// It will be stabilized as an inherent method._
1828    ///
1829    /// [`f32::round_ties_even`]: ../../../std/primitive.f32.html#method.round_ties_even
1830    #[inline]
1831    #[unstable(feature = "core_float_math", issue = "137578")]
1832    #[must_use = "method returns a new number and does not mutate the original value"]
1833    pub const fn round_ties_even(x: f32) -> f32 {
1834        intrinsics::round_ties_even_f32(x)
1835    }
1836
1837    /// Experimental version of `trunc` in `core`. See [`f32::trunc`] for details.
1838    ///
1839    /// # Examples
1840    ///
1841    /// ```
1842    /// #![feature(core_float_math)]
1843    ///
1844    /// use core::f32;
1845    ///
1846    /// let f = 3.7_f32;
1847    /// let g = 3.0_f32;
1848    /// let h = -3.7_f32;
1849    ///
1850    /// assert_eq!(f32::math::trunc(f), 3.0);
1851    /// assert_eq!(f32::math::trunc(g), 3.0);
1852    /// assert_eq!(f32::math::trunc(h), -3.0);
1853    /// ```
1854    ///
1855    /// _This standalone function is for testing only.
1856    /// It will be stabilized as an inherent method._
1857    ///
1858    /// [`f32::trunc`]: ../../../std/primitive.f32.html#method.trunc
1859    #[inline]
1860    #[doc(alias = "truncate")]
1861    #[must_use = "method returns a new number and does not mutate the original value"]
1862    #[unstable(feature = "core_float_math", issue = "137578")]
1863    pub const fn trunc(x: f32) -> f32 {
1864        intrinsics::truncf32(x)
1865    }
1866
1867    /// Experimental version of `fract` in `core`. See [`f32::fract`] for details.
1868    ///
1869    /// # Examples
1870    ///
1871    /// ```
1872    /// #![feature(core_float_math)]
1873    ///
1874    /// use core::f32;
1875    ///
1876    /// let x = 3.6_f32;
1877    /// let y = -3.6_f32;
1878    /// let abs_difference_x = (f32::math::fract(x) - 0.6).abs();
1879    /// let abs_difference_y = (f32::math::fract(y) - (-0.6)).abs();
1880    ///
1881    /// assert!(abs_difference_x <= f32::EPSILON);
1882    /// assert!(abs_difference_y <= f32::EPSILON);
1883    /// ```
1884    ///
1885    /// _This standalone function is for testing only.
1886    /// It will be stabilized as an inherent method._
1887    ///
1888    /// [`f32::fract`]: ../../../std/primitive.f32.html#method.fract
1889    #[inline]
1890    #[unstable(feature = "core_float_math", issue = "137578")]
1891    #[must_use = "method returns a new number and does not mutate the original value"]
1892    pub const fn fract(x: f32) -> f32 {
1893        x - trunc(x)
1894    }
1895
1896    /// Experimental version of `mul_add` in `core`. See [`f32::mul_add`] for details.
1897    ///
1898    /// # Examples
1899    ///
1900    /// ```
1901    /// # #![allow(unused_features)]
1902    /// #![feature(core_float_math)]
1903    ///
1904    /// # // FIXME(#140515): mingw has an incorrect fma
1905    /// # // https://sourceforge.net/p/mingw-w64/bugs/848/
1906    /// # #[cfg(all(target_os = "windows", target_env = "gnu", not(target_abi = "llvm")))] {
1907    /// use core::f32;
1908    ///
1909    /// let m = 10.0_f32;
1910    /// let x = 4.0_f32;
1911    /// let b = 60.0_f32;
1912    ///
1913    /// assert_eq!(f32::math::mul_add(m, x, b), 100.0);
1914    /// assert_eq!(m * x + b, 100.0);
1915    ///
1916    /// let one_plus_eps = 1.0_f32 + f32::EPSILON;
1917    /// let one_minus_eps = 1.0_f32 - f32::EPSILON;
1918    /// let minus_one = -1.0_f32;
1919    ///
1920    /// // The exact result (1 + eps) * (1 - eps) = 1 - eps * eps.
1921    /// assert_eq!(
1922    ///     f32::math::mul_add(one_plus_eps, one_minus_eps, minus_one),
1923    ///     -f32::EPSILON * f32::EPSILON
1924    /// );
1925    /// // Different rounding with the non-fused multiply and add.
1926    /// assert_eq!(one_plus_eps * one_minus_eps + minus_one, 0.0);
1927    /// # }
1928    /// ```
1929    ///
1930    /// _This standalone function is for testing only.
1931    /// It will be stabilized as an inherent method._
1932    ///
1933    /// [`f32::mul_add`]: ../../../std/primitive.f32.html#method.mul_add
1934    #[inline]
1935    #[doc(alias = "fmaf", alias = "fusedMultiplyAdd")]
1936    #[must_use = "method returns a new number and does not mutate the original value"]
1937    #[unstable(feature = "core_float_math", issue = "137578")]
1938    pub const fn mul_add(x: f32, y: f32, z: f32) -> f32 {
1939        intrinsics::fmaf32(x, y, z)
1940    }
1941
1942    /// Experimental version of `div_euclid` in `core`. See [`f32::div_euclid`] for details.
1943    ///
1944    /// # Examples
1945    ///
1946    /// ```
1947    /// #![feature(core_float_math)]
1948    ///
1949    /// use core::f32;
1950    ///
1951    /// let a: f32 = 7.0;
1952    /// let b = 4.0;
1953    /// assert_eq!(f32::math::div_euclid(a, b), 1.0); // 7.0 > 4.0 * 1.0
1954    /// assert_eq!(f32::math::div_euclid(-a, b), -2.0); // -7.0 >= 4.0 * -2.0
1955    /// assert_eq!(f32::math::div_euclid(a, -b), -1.0); // 7.0 >= -4.0 * -1.0
1956    /// assert_eq!(f32::math::div_euclid(-a, -b), 2.0); // -7.0 >= -4.0 * 2.0
1957    /// ```
1958    ///
1959    /// _This standalone function is for testing only.
1960    /// It will be stabilized as an inherent method._
1961    ///
1962    /// [`f32::div_euclid`]: ../../../std/primitive.f32.html#method.div_euclid
1963    #[inline]
1964    #[unstable(feature = "core_float_math", issue = "137578")]
1965    #[must_use = "method returns a new number and does not mutate the original value"]
1966    pub fn div_euclid(x: f32, rhs: f32) -> f32 {
1967        let q = trunc(x / rhs);
1968        if x % rhs < 0.0 {
1969            return if rhs > 0.0 { q - 1.0 } else { q + 1.0 };
1970        }
1971        q
1972    }
1973
1974    /// Experimental version of `rem_euclid` in `core`. See [`f32::rem_euclid`] for details.
1975    ///
1976    /// # Examples
1977    ///
1978    /// ```
1979    /// #![feature(core_float_math)]
1980    ///
1981    /// use core::f32;
1982    ///
1983    /// let a: f32 = 7.0;
1984    /// let b = 4.0;
1985    /// assert_eq!(f32::math::rem_euclid(a, b), 3.0);
1986    /// assert_eq!(f32::math::rem_euclid(-a, b), 1.0);
1987    /// assert_eq!(f32::math::rem_euclid(a, -b), 3.0);
1988    /// assert_eq!(f32::math::rem_euclid(-a, -b), 1.0);
1989    /// // limitation due to round-off error
1990    /// assert!(f32::math::rem_euclid(-f32::EPSILON, 3.0) != 0.0);
1991    /// ```
1992    ///
1993    /// _This standalone function is for testing only.
1994    /// It will be stabilized as an inherent method._
1995    ///
1996    /// [`f32::rem_euclid`]: ../../../std/primitive.f32.html#method.rem_euclid
1997    #[inline]
1998    #[doc(alias = "modulo", alias = "mod")]
1999    #[unstable(feature = "core_float_math", issue = "137578")]
2000    #[must_use = "method returns a new number and does not mutate the original value"]
2001    pub fn rem_euclid(x: f32, rhs: f32) -> f32 {
2002        let r = x % rhs;
2003        if r < 0.0 { r + rhs.abs() } else { r }
2004    }
2005
2006    /// Experimental version of `powi` in `core`. See [`f32::powi`] for details.
2007    ///
2008    /// # Examples
2009    ///
2010    /// ```
2011    /// #![feature(core_float_math)]
2012    ///
2013    /// use core::f32;
2014    ///
2015    /// let x = 2.0_f32;
2016    /// let abs_difference = (f32::math::powi(x, 2) - (x * x)).abs();
2017    /// assert!(abs_difference <= 1e-5);
2018    ///
2019    /// assert_eq!(f32::math::powi(f32::NAN, 0), 1.0);
2020    /// ```
2021    ///
2022    /// _This standalone function is for testing only.
2023    /// It will be stabilized as an inherent method._
2024    ///
2025    /// [`f32::powi`]: ../../../std/primitive.f32.html#method.powi
2026    #[inline]
2027    #[must_use = "method returns a new number and does not mutate the original value"]
2028    #[unstable(feature = "core_float_math", issue = "137578")]
2029    pub fn powi(x: f32, n: i32) -> f32 {
2030        intrinsics::powif32(x, n)
2031    }
2032
2033    /// Experimental version of `sqrt` in `core`. See [`f32::sqrt`] for details.
2034    ///
2035    /// # Examples
2036    ///
2037    /// ```
2038    /// #![feature(core_float_math)]
2039    ///
2040    /// use core::f32;
2041    ///
2042    /// let positive = 4.0_f32;
2043    /// let negative = -4.0_f32;
2044    /// let negative_zero = -0.0_f32;
2045    ///
2046    /// assert_eq!(f32::math::sqrt(positive), 2.0);
2047    /// assert!(f32::math::sqrt(negative).is_nan());
2048    /// assert_eq!(f32::math::sqrt(negative_zero), negative_zero);
2049    /// ```
2050    ///
2051    /// _This standalone function is for testing only.
2052    /// It will be stabilized as an inherent method._
2053    ///
2054    /// [`f32::sqrt`]: ../../../std/primitive.f32.html#method.sqrt
2055    #[inline]
2056    #[doc(alias = "squareRoot")]
2057    #[unstable(feature = "core_float_math", issue = "137578")]
2058    #[must_use = "method returns a new number and does not mutate the original value"]
2059    pub fn sqrt(x: f32) -> f32 {
2060        intrinsics::sqrtf32(x)
2061    }
2062
2063    /// Experimental version of `abs_sub` in `core`. See [`f32::abs_sub`] for details.
2064    ///
2065    /// # Examples
2066    ///
2067    /// ```
2068    /// #![feature(core_float_math)]
2069    ///
2070    /// use core::f32;
2071    ///
2072    /// let x = 3.0f32;
2073    /// let y = -3.0f32;
2074    ///
2075    /// let abs_difference_x = (f32::math::abs_sub(x, 1.0) - 2.0).abs();
2076    /// let abs_difference_y = (f32::math::abs_sub(y, 1.0) - 0.0).abs();
2077    ///
2078    /// assert!(abs_difference_x <= 1e-6);
2079    /// assert!(abs_difference_y <= 1e-6);
2080    /// ```
2081    ///
2082    /// _This standalone function is for testing only.
2083    /// It will be stabilized as an inherent method._
2084    ///
2085    /// [`f32::abs_sub`]: ../../../std/primitive.f32.html#method.abs_sub
2086    #[inline]
2087    #[stable(feature = "rust1", since = "1.0.0")]
2088    #[deprecated(
2089        since = "1.10.0",
2090        note = "you probably meant `(self - other).abs()`: \
2091            this operation is `(self - other).max(0.0)` \
2092            except that `abs_sub` also propagates NaNs (also \
2093            known as `fdimf` in C). If you truly need the positive \
2094            difference, consider using that expression or the C function \
2095            `fdimf`, depending on how you wish to handle NaN (please consider \
2096            filing an issue describing your use-case too)."
2097    )]
2098    #[must_use = "method returns a new number and does not mutate the original value"]
2099    pub fn abs_sub(x: f32, other: f32) -> f32 {
2100        libm::fdimf(x, other)
2101    }
2102
2103    /// Experimental version of `cbrt` in `core`. See [`f32::cbrt`] for details.
2104    ///
2105    /// # Unspecified precision
2106    ///
2107    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
2108    /// can even differ within the same execution from one invocation to the next.
2109    /// This function currently corresponds to the `cbrtf` from libc on Unix
2110    /// and Windows. Note that this might change in the future.
2111    ///
2112    /// # Examples
2113    ///
2114    /// ```
2115    /// #![feature(core_float_math)]
2116    ///
2117    /// use core::f32;
2118    ///
2119    /// let x = 8.0f32;
2120    ///
2121    /// // x^(1/3) - 2 == 0
2122    /// let abs_difference = (f32::math::cbrt(x) - 2.0).abs();
2123    ///
2124    /// assert!(abs_difference <= 1e-6);
2125    /// ```
2126    ///
2127    /// _This standalone function is for testing only.
2128    /// It will be stabilized as an inherent method._
2129    ///
2130    /// [`f32::cbrt`]: ../../../std/primitive.f32.html#method.cbrt
2131    #[inline]
2132    #[must_use = "method returns a new number and does not mutate the original value"]
2133    #[unstable(feature = "core_float_math", issue = "137578")]
2134    pub fn cbrt(x: f32) -> f32 {
2135        libm::cbrtf(x)
2136    }
2137}