std/num/
f32.rs

1//! Constants for the `f32` single-precision floating point type.
2//!
3//! *[See also the `f32` primitive type](primitive@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#![allow(missing_docs)]
14
15#[stable(feature = "rust1", since = "1.0.0")]
16#[allow(deprecated, deprecated_in_future)]
17pub use core::f32::{
18    DIGITS, EPSILON, INFINITY, MANTISSA_DIGITS, MAX, MAX_10_EXP, MAX_EXP, MIN, MIN_10_EXP, MIN_EXP,
19    MIN_POSITIVE, NAN, NEG_INFINITY, RADIX, consts,
20};
21
22#[cfg(not(test))]
23use crate::intrinsics;
24#[cfg(not(test))]
25use crate::sys::cmath;
26
27#[cfg(not(test))]
28impl f32 {
29    /// Returns the largest integer less than or equal to `self`.
30    ///
31    /// This function always returns the precise result.
32    ///
33    /// # Examples
34    ///
35    /// ```
36    /// let f = 3.7_f32;
37    /// let g = 3.0_f32;
38    /// let h = -3.7_f32;
39    ///
40    /// assert_eq!(f.floor(), 3.0);
41    /// assert_eq!(g.floor(), 3.0);
42    /// assert_eq!(h.floor(), -4.0);
43    /// ```
44    #[rustc_allow_incoherent_impl]
45    #[must_use = "method returns a new number and does not mutate the original value"]
46    #[stable(feature = "rust1", since = "1.0.0")]
47    #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")]
48    #[inline]
49    pub const fn floor(self) -> f32 {
50        core::f32::math::floor(self)
51    }
52
53    /// Returns the smallest integer greater than or equal to `self`.
54    ///
55    /// This function always returns the precise result.
56    ///
57    /// # Examples
58    ///
59    /// ```
60    /// let f = 3.01_f32;
61    /// let g = 4.0_f32;
62    ///
63    /// assert_eq!(f.ceil(), 4.0);
64    /// assert_eq!(g.ceil(), 4.0);
65    /// ```
66    #[doc(alias = "ceiling")]
67    #[rustc_allow_incoherent_impl]
68    #[must_use = "method returns a new number and does not mutate the original value"]
69    #[stable(feature = "rust1", since = "1.0.0")]
70    #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")]
71    #[inline]
72    pub const fn ceil(self) -> f32 {
73        core::f32::math::ceil(self)
74    }
75
76    /// Returns the nearest integer to `self`. If a value is half-way between two
77    /// integers, round away from `0.0`.
78    ///
79    /// This function always returns the precise result.
80    ///
81    /// # Examples
82    ///
83    /// ```
84    /// let f = 3.3_f32;
85    /// let g = -3.3_f32;
86    /// let h = -3.7_f32;
87    /// let i = 3.5_f32;
88    /// let j = 4.5_f32;
89    ///
90    /// assert_eq!(f.round(), 3.0);
91    /// assert_eq!(g.round(), -3.0);
92    /// assert_eq!(h.round(), -4.0);
93    /// assert_eq!(i.round(), 4.0);
94    /// assert_eq!(j.round(), 5.0);
95    /// ```
96    #[rustc_allow_incoherent_impl]
97    #[must_use = "method returns a new number and does not mutate the original value"]
98    #[stable(feature = "rust1", since = "1.0.0")]
99    #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")]
100    #[inline]
101    pub const fn round(self) -> f32 {
102        core::f32::math::round(self)
103    }
104
105    /// Returns the nearest integer to a number. Rounds half-way cases to the number
106    /// with an even least significant digit.
107    ///
108    /// This function always returns the precise result.
109    ///
110    /// # Examples
111    ///
112    /// ```
113    /// let f = 3.3_f32;
114    /// let g = -3.3_f32;
115    /// let h = 3.5_f32;
116    /// let i = 4.5_f32;
117    ///
118    /// assert_eq!(f.round_ties_even(), 3.0);
119    /// assert_eq!(g.round_ties_even(), -3.0);
120    /// assert_eq!(h.round_ties_even(), 4.0);
121    /// assert_eq!(i.round_ties_even(), 4.0);
122    /// ```
123    #[rustc_allow_incoherent_impl]
124    #[must_use = "method returns a new number and does not mutate the original value"]
125    #[stable(feature = "round_ties_even", since = "1.77.0")]
126    #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")]
127    #[inline]
128    pub const fn round_ties_even(self) -> f32 {
129        core::f32::math::round_ties_even(self)
130    }
131
132    /// Returns the integer part of `self`.
133    /// This means that non-integer numbers are always truncated towards zero.
134    ///
135    /// This function always returns the precise result.
136    ///
137    /// # Examples
138    ///
139    /// ```
140    /// let f = 3.7_f32;
141    /// let g = 3.0_f32;
142    /// let h = -3.7_f32;
143    ///
144    /// assert_eq!(f.trunc(), 3.0);
145    /// assert_eq!(g.trunc(), 3.0);
146    /// assert_eq!(h.trunc(), -3.0);
147    /// ```
148    #[doc(alias = "truncate")]
149    #[rustc_allow_incoherent_impl]
150    #[must_use = "method returns a new number and does not mutate the original value"]
151    #[stable(feature = "rust1", since = "1.0.0")]
152    #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")]
153    #[inline]
154    pub const fn trunc(self) -> f32 {
155        core::f32::math::trunc(self)
156    }
157
158    /// Returns the fractional part of `self`.
159    ///
160    /// This function always returns the precise result.
161    ///
162    /// # Examples
163    ///
164    /// ```
165    /// let x = 3.6_f32;
166    /// let y = -3.6_f32;
167    /// let abs_difference_x = (x.fract() - 0.6).abs();
168    /// let abs_difference_y = (y.fract() - (-0.6)).abs();
169    ///
170    /// assert!(abs_difference_x <= f32::EPSILON);
171    /// assert!(abs_difference_y <= f32::EPSILON);
172    /// ```
173    #[rustc_allow_incoherent_impl]
174    #[must_use = "method returns a new number and does not mutate the original value"]
175    #[stable(feature = "rust1", since = "1.0.0")]
176    #[rustc_const_stable(feature = "const_float_round_methods", since = "1.90.0")]
177    #[inline]
178    pub const fn fract(self) -> f32 {
179        core::f32::math::fract(self)
180    }
181
182    /// Fused multiply-add. Computes `(self * a) + b` with only one rounding
183    /// error, yielding a more accurate result than an unfused multiply-add.
184    ///
185    /// Using `mul_add` *may* be more performant than an unfused multiply-add if
186    /// the target architecture has a dedicated `fma` CPU instruction. However,
187    /// this is not always true, and will be heavily dependant on designing
188    /// algorithms with specific target hardware in mind.
189    ///
190    /// # Precision
191    ///
192    /// The result of this operation is guaranteed to be the rounded
193    /// infinite-precision result. It is specified by IEEE 754 as
194    /// `fusedMultiplyAdd` and guaranteed not to change.
195    ///
196    /// # Examples
197    ///
198    /// ```
199    /// let m = 10.0_f32;
200    /// let x = 4.0_f32;
201    /// let b = 60.0_f32;
202    ///
203    /// assert_eq!(m.mul_add(x, b), 100.0);
204    /// assert_eq!(m * x + b, 100.0);
205    ///
206    /// let one_plus_eps = 1.0_f32 + f32::EPSILON;
207    /// let one_minus_eps = 1.0_f32 - f32::EPSILON;
208    /// let minus_one = -1.0_f32;
209    ///
210    /// // The exact result (1 + eps) * (1 - eps) = 1 - eps * eps.
211    /// assert_eq!(one_plus_eps.mul_add(one_minus_eps, minus_one), -f32::EPSILON * f32::EPSILON);
212    /// // Different rounding with the non-fused multiply and add.
213    /// assert_eq!(one_plus_eps * one_minus_eps + minus_one, 0.0);
214    /// ```
215    #[rustc_allow_incoherent_impl]
216    #[doc(alias = "fmaf", alias = "fusedMultiplyAdd")]
217    #[must_use = "method returns a new number and does not mutate the original value"]
218    #[stable(feature = "rust1", since = "1.0.0")]
219    #[inline]
220    #[rustc_const_unstable(feature = "const_mul_add", issue = "146724")]
221    pub const fn mul_add(self, a: f32, b: f32) -> f32 {
222        core::f32::math::mul_add(self, a, b)
223    }
224
225    /// Calculates Euclidean division, the matching method for `rem_euclid`.
226    ///
227    /// This computes the integer `n` such that
228    /// `self = n * rhs + self.rem_euclid(rhs)`.
229    /// In other words, the result is `self / rhs` rounded to the integer `n`
230    /// such that `self >= n * rhs`.
231    ///
232    /// # Precision
233    ///
234    /// The result of this operation is guaranteed to be the rounded
235    /// infinite-precision result.
236    ///
237    /// # Examples
238    ///
239    /// ```
240    /// let a: f32 = 7.0;
241    /// let b = 4.0;
242    /// assert_eq!(a.div_euclid(b), 1.0); // 7.0 > 4.0 * 1.0
243    /// assert_eq!((-a).div_euclid(b), -2.0); // -7.0 >= 4.0 * -2.0
244    /// assert_eq!(a.div_euclid(-b), -1.0); // 7.0 >= -4.0 * -1.0
245    /// assert_eq!((-a).div_euclid(-b), 2.0); // -7.0 >= -4.0 * 2.0
246    /// ```
247    #[rustc_allow_incoherent_impl]
248    #[must_use = "method returns a new number and does not mutate the original value"]
249    #[inline]
250    #[stable(feature = "euclidean_division", since = "1.38.0")]
251    pub fn div_euclid(self, rhs: f32) -> f32 {
252        core::f32::math::div_euclid(self, rhs)
253    }
254
255    /// Calculates the least nonnegative remainder of `self` when divided by
256    /// `rhs`.
257    ///
258    /// In particular, the return value `r` satisfies `0.0 <= r < rhs.abs()` in
259    /// most cases. However, due to a floating point round-off error it can
260    /// result in `r == rhs.abs()`, violating the mathematical definition, if
261    /// `self` is much smaller than `rhs.abs()` in magnitude and `self < 0.0`.
262    /// This result is not an element of the function's codomain, but it is the
263    /// closest floating point number in the real numbers and thus fulfills the
264    /// property `self == self.div_euclid(rhs) * rhs + self.rem_euclid(rhs)`
265    /// approximately.
266    ///
267    /// # Precision
268    ///
269    /// The result of this operation is guaranteed to be the rounded
270    /// infinite-precision result.
271    ///
272    /// # Examples
273    ///
274    /// ```
275    /// let a: f32 = 7.0;
276    /// let b = 4.0;
277    /// assert_eq!(a.rem_euclid(b), 3.0);
278    /// assert_eq!((-a).rem_euclid(b), 1.0);
279    /// assert_eq!(a.rem_euclid(-b), 3.0);
280    /// assert_eq!((-a).rem_euclid(-b), 1.0);
281    /// // limitation due to round-off error
282    /// assert!((-f32::EPSILON).rem_euclid(3.0) != 0.0);
283    /// ```
284    #[doc(alias = "modulo", alias = "mod")]
285    #[rustc_allow_incoherent_impl]
286    #[must_use = "method returns a new number and does not mutate the original value"]
287    #[inline]
288    #[stable(feature = "euclidean_division", since = "1.38.0")]
289    pub fn rem_euclid(self, rhs: f32) -> f32 {
290        core::f32::math::rem_euclid(self, rhs)
291    }
292
293    /// Raises a number to an integer power.
294    ///
295    /// Using this function is generally faster than using `powf`.
296    /// It might have a different sequence of rounding operations than `powf`,
297    /// so the results are not guaranteed to agree.
298    ///
299    /// Note that this function is special in that it can return non-NaN results for NaN inputs. For
300    /// example, `f32::powi(f32::NAN, 0)` returns `1.0`. However, if an input is a *signaling*
301    /// NaN, then the result is non-deterministically either a NaN or the result that the
302    /// corresponding quiet NaN would produce.
303    ///
304    /// # Unspecified precision
305    ///
306    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
307    /// can even differ within the same execution from one invocation to the next.
308    ///
309    /// # Examples
310    ///
311    /// ```
312    /// let x = 2.0_f32;
313    /// let abs_difference = (x.powi(2) - (x * x)).abs();
314    /// assert!(abs_difference <= 1e-5);
315    ///
316    /// assert_eq!(f32::powi(f32::NAN, 0), 1.0);
317    /// assert_eq!(f32::powi(0.0, 0), 1.0);
318    /// ```
319    #[rustc_allow_incoherent_impl]
320    #[must_use = "method returns a new number and does not mutate the original value"]
321    #[stable(feature = "rust1", since = "1.0.0")]
322    #[inline]
323    pub fn powi(self, n: i32) -> f32 {
324        core::f32::math::powi(self, n)
325    }
326
327    /// Raises a number to a floating point power.
328    ///
329    /// Note that this function is special in that it can return non-NaN results for NaN inputs. For
330    /// example, `f32::powf(f32::NAN, 0.0)` returns `1.0`. However, if an input is a *signaling*
331    /// NaN, then the result is non-deterministically either a NaN or the result that the
332    /// corresponding quiet NaN would produce.
333    ///
334    /// # Unspecified precision
335    ///
336    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
337    /// can even differ within the same execution from one invocation to the next.
338    ///
339    /// # Examples
340    ///
341    /// ```
342    /// let x = 2.0_f32;
343    /// let abs_difference = (x.powf(2.0) - (x * x)).abs();
344    /// assert!(abs_difference <= 1e-5);
345    ///
346    /// assert_eq!(f32::powf(1.0, f32::NAN), 1.0);
347    /// assert_eq!(f32::powf(f32::NAN, 0.0), 1.0);
348    /// assert_eq!(f32::powf(0.0, 0.0), 1.0);
349    /// ```
350    #[rustc_allow_incoherent_impl]
351    #[must_use = "method returns a new number and does not mutate the original value"]
352    #[stable(feature = "rust1", since = "1.0.0")]
353    #[inline]
354    pub fn powf(self, n: f32) -> f32 {
355        intrinsics::powf32(self, n)
356    }
357
358    /// Returns the square root of a number.
359    ///
360    /// Returns NaN if `self` is a negative number other than `-0.0`.
361    ///
362    /// # Precision
363    ///
364    /// The result of this operation is guaranteed to be the rounded
365    /// infinite-precision result. It is specified by IEEE 754 as `squareRoot`
366    /// and guaranteed not to change.
367    ///
368    /// # Examples
369    ///
370    /// ```
371    /// let positive = 4.0_f32;
372    /// let negative = -4.0_f32;
373    /// let negative_zero = -0.0_f32;
374    ///
375    /// assert_eq!(positive.sqrt(), 2.0);
376    /// assert!(negative.sqrt().is_nan());
377    /// assert!(negative_zero.sqrt() == negative_zero);
378    /// ```
379    #[doc(alias = "squareRoot")]
380    #[rustc_allow_incoherent_impl]
381    #[must_use = "method returns a new number and does not mutate the original value"]
382    #[stable(feature = "rust1", since = "1.0.0")]
383    #[inline]
384    pub fn sqrt(self) -> f32 {
385        core::f32::math::sqrt(self)
386    }
387
388    /// Returns `e^(self)`, (the exponential function).
389    ///
390    /// # Unspecified precision
391    ///
392    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
393    /// can even differ within the same execution from one invocation to the next.
394    ///
395    /// # Examples
396    ///
397    /// ```
398    /// let one = 1.0f32;
399    /// // e^1
400    /// let e = one.exp();
401    ///
402    /// // ln(e) - 1 == 0
403    /// let abs_difference = (e.ln() - 1.0).abs();
404    ///
405    /// assert!(abs_difference <= 1e-6);
406    /// ```
407    #[rustc_allow_incoherent_impl]
408    #[must_use = "method returns a new number and does not mutate the original value"]
409    #[stable(feature = "rust1", since = "1.0.0")]
410    #[inline]
411    pub fn exp(self) -> f32 {
412        intrinsics::expf32(self)
413    }
414
415    /// Returns `2^(self)`.
416    ///
417    /// # Unspecified precision
418    ///
419    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
420    /// can even differ within the same execution from one invocation to the next.
421    ///
422    /// # Examples
423    ///
424    /// ```
425    /// let f = 2.0f32;
426    ///
427    /// // 2^2 - 4 == 0
428    /// let abs_difference = (f.exp2() - 4.0).abs();
429    ///
430    /// assert!(abs_difference <= 1e-5);
431    /// ```
432    #[rustc_allow_incoherent_impl]
433    #[must_use = "method returns a new number and does not mutate the original value"]
434    #[stable(feature = "rust1", since = "1.0.0")]
435    #[inline]
436    pub fn exp2(self) -> f32 {
437        intrinsics::exp2f32(self)
438    }
439
440    /// Returns the natural logarithm of the number.
441    ///
442    /// This returns NaN when the number is negative, and negative infinity when number is zero.
443    ///
444    /// # Unspecified precision
445    ///
446    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
447    /// can even differ within the same execution from one invocation to the next.
448    ///
449    /// # Examples
450    ///
451    /// ```
452    /// let one = 1.0f32;
453    /// // e^1
454    /// let e = one.exp();
455    ///
456    /// // ln(e) - 1 == 0
457    /// let abs_difference = (e.ln() - 1.0).abs();
458    ///
459    /// assert!(abs_difference <= 1e-6);
460    /// ```
461    ///
462    /// Non-positive values:
463    /// ```
464    /// assert_eq!(0_f32.ln(), f32::NEG_INFINITY);
465    /// assert!((-42_f32).ln().is_nan());
466    /// ```
467    #[rustc_allow_incoherent_impl]
468    #[must_use = "method returns a new number and does not mutate the original value"]
469    #[stable(feature = "rust1", since = "1.0.0")]
470    #[inline]
471    pub fn ln(self) -> f32 {
472        intrinsics::logf32(self)
473    }
474
475    /// Returns the logarithm of the number with respect to an arbitrary base.
476    ///
477    /// This returns NaN when the number is negative, and negative infinity when number is zero.
478    ///
479    /// The result might not be correctly rounded owing to implementation details;
480    /// `self.log2()` can produce more accurate results for base 2, and
481    /// `self.log10()` can produce more accurate results for base 10.
482    ///
483    /// # Unspecified precision
484    ///
485    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
486    /// can even differ within the same execution from one invocation to the next.
487    ///
488    /// # Examples
489    ///
490    /// ```
491    /// let five = 5.0f32;
492    ///
493    /// // log5(5) - 1 == 0
494    /// let abs_difference = (five.log(5.0) - 1.0).abs();
495    ///
496    /// assert!(abs_difference <= 1e-6);
497    /// ```
498    ///
499    /// Non-positive values:
500    /// ```
501    /// assert_eq!(0_f32.log(10.0), f32::NEG_INFINITY);
502    /// assert!((-42_f32).log(10.0).is_nan());
503    /// ```
504    #[rustc_allow_incoherent_impl]
505    #[must_use = "method returns a new number and does not mutate the original value"]
506    #[stable(feature = "rust1", since = "1.0.0")]
507    #[inline]
508    pub fn log(self, base: f32) -> f32 {
509        self.ln() / base.ln()
510    }
511
512    /// Returns the base 2 logarithm of the number.
513    ///
514    /// This returns NaN when the number is negative, and negative infinity when number is zero.
515    ///
516    /// # Unspecified precision
517    ///
518    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
519    /// can even differ within the same execution from one invocation to the next.
520    ///
521    /// # Examples
522    ///
523    /// ```
524    /// let two = 2.0f32;
525    ///
526    /// // log2(2) - 1 == 0
527    /// let abs_difference = (two.log2() - 1.0).abs();
528    ///
529    /// assert!(abs_difference <= 1e-6);
530    /// ```
531    ///
532    /// Non-positive values:
533    /// ```
534    /// assert_eq!(0_f32.log2(), f32::NEG_INFINITY);
535    /// assert!((-42_f32).log2().is_nan());
536    /// ```
537    #[rustc_allow_incoherent_impl]
538    #[must_use = "method returns a new number and does not mutate the original value"]
539    #[stable(feature = "rust1", since = "1.0.0")]
540    #[inline]
541    pub fn log2(self) -> f32 {
542        intrinsics::log2f32(self)
543    }
544
545    /// Returns the base 10 logarithm of the number.
546    ///
547    /// This returns NaN when the number is negative, and negative infinity when number is zero.
548    ///
549    /// # Unspecified precision
550    ///
551    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
552    /// can even differ within the same execution from one invocation to the next.
553    ///
554    /// # Examples
555    ///
556    /// ```
557    /// let ten = 10.0f32;
558    ///
559    /// // log10(10) - 1 == 0
560    /// let abs_difference = (ten.log10() - 1.0).abs();
561    ///
562    /// assert!(abs_difference <= 1e-6);
563    /// ```
564    ///
565    /// Non-positive values:
566    /// ```
567    /// assert_eq!(0_f32.log10(), f32::NEG_INFINITY);
568    /// assert!((-42_f32).log10().is_nan());
569    /// ```
570    #[rustc_allow_incoherent_impl]
571    #[must_use = "method returns a new number and does not mutate the original value"]
572    #[stable(feature = "rust1", since = "1.0.0")]
573    #[inline]
574    pub fn log10(self) -> f32 {
575        intrinsics::log10f32(self)
576    }
577
578    /// The positive difference of two numbers.
579    ///
580    /// * If `self <= other`: `0.0`
581    /// * Else: `self - other`
582    ///
583    /// # Unspecified precision
584    ///
585    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
586    /// can even differ within the same execution from one invocation to the next.
587    /// This function currently corresponds to the `fdimf` from libc on Unix
588    /// and Windows. Note that this might change in the future.
589    ///
590    /// # Examples
591    ///
592    /// ```
593    /// let x = 3.0f32;
594    /// let y = -3.0f32;
595    ///
596    /// let abs_difference_x = (x.abs_sub(1.0) - 2.0).abs();
597    /// let abs_difference_y = (y.abs_sub(1.0) - 0.0).abs();
598    ///
599    /// assert!(abs_difference_x <= 1e-6);
600    /// assert!(abs_difference_y <= 1e-6);
601    /// ```
602    #[rustc_allow_incoherent_impl]
603    #[must_use = "method returns a new number and does not mutate the original value"]
604    #[stable(feature = "rust1", since = "1.0.0")]
605    #[inline]
606    #[deprecated(
607        since = "1.10.0",
608        note = "you probably meant `(self - other).abs()`: \
609                this operation is `(self - other).max(0.0)` \
610                except that `abs_sub` also propagates NaNs (also \
611                known as `fdimf` in C). If you truly need the positive \
612                difference, consider using that expression or the C function \
613                `fdimf`, depending on how you wish to handle NaN (please consider \
614                filing an issue describing your use-case too)."
615    )]
616    pub fn abs_sub(self, other: f32) -> f32 {
617        #[allow(deprecated)]
618        core::f32::math::abs_sub(self, other)
619    }
620
621    /// Returns the cube root of a number.
622    ///
623    /// # Unspecified precision
624    ///
625    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
626    /// can even differ within the same execution from one invocation to the next.
627    /// This function currently corresponds to the `cbrtf` from libc on Unix
628    /// and Windows. Note that this might change in the future.
629    ///
630    /// # Examples
631    ///
632    /// ```
633    /// let x = 8.0f32;
634    ///
635    /// // x^(1/3) - 2 == 0
636    /// let abs_difference = (x.cbrt() - 2.0).abs();
637    ///
638    /// assert!(abs_difference <= 1e-6);
639    /// ```
640    #[rustc_allow_incoherent_impl]
641    #[must_use = "method returns a new number and does not mutate the original value"]
642    #[stable(feature = "rust1", since = "1.0.0")]
643    #[inline]
644    pub fn cbrt(self) -> f32 {
645        core::f32::math::cbrt(self)
646    }
647
648    /// Compute the distance between the origin and a point (`x`, `y`) on the
649    /// Euclidean plane. Equivalently, compute the length of the hypotenuse of a
650    /// right-angle triangle with other sides having length `x.abs()` and
651    /// `y.abs()`.
652    ///
653    /// # Unspecified precision
654    ///
655    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
656    /// can even differ within the same execution from one invocation to the next.
657    /// This function currently corresponds to the `hypotf` from libc on Unix
658    /// and Windows. Note that this might change in the future.
659    ///
660    /// # Examples
661    ///
662    /// ```
663    /// let x = 2.0f32;
664    /// let y = 3.0f32;
665    ///
666    /// // sqrt(x^2 + y^2)
667    /// let abs_difference = (x.hypot(y) - (x.powi(2) + y.powi(2)).sqrt()).abs();
668    ///
669    /// assert!(abs_difference <= 1e-5);
670    /// ```
671    #[rustc_allow_incoherent_impl]
672    #[must_use = "method returns a new number and does not mutate the original value"]
673    #[stable(feature = "rust1", since = "1.0.0")]
674    #[inline]
675    pub fn hypot(self, other: f32) -> f32 {
676        cmath::hypotf(self, other)
677    }
678
679    /// Computes the sine of a number (in radians).
680    ///
681    /// # Unspecified precision
682    ///
683    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
684    /// can even differ within the same execution from one invocation to the next.
685    ///
686    /// # Examples
687    ///
688    /// ```
689    /// let x = std::f32::consts::FRAC_PI_2;
690    ///
691    /// let abs_difference = (x.sin() - 1.0).abs();
692    ///
693    /// assert!(abs_difference <= 1e-6);
694    /// ```
695    #[rustc_allow_incoherent_impl]
696    #[must_use = "method returns a new number and does not mutate the original value"]
697    #[stable(feature = "rust1", since = "1.0.0")]
698    #[inline]
699    pub fn sin(self) -> f32 {
700        intrinsics::sinf32(self)
701    }
702
703    /// Computes the cosine of a number (in radians).
704    ///
705    /// # Unspecified precision
706    ///
707    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
708    /// can even differ within the same execution from one invocation to the next.
709    ///
710    /// # Examples
711    ///
712    /// ```
713    /// let x = 2.0 * std::f32::consts::PI;
714    ///
715    /// let abs_difference = (x.cos() - 1.0).abs();
716    ///
717    /// assert!(abs_difference <= 1e-6);
718    /// ```
719    #[rustc_allow_incoherent_impl]
720    #[must_use = "method returns a new number and does not mutate the original value"]
721    #[stable(feature = "rust1", since = "1.0.0")]
722    #[inline]
723    pub fn cos(self) -> f32 {
724        intrinsics::cosf32(self)
725    }
726
727    /// Computes the tangent of a number (in radians).
728    ///
729    /// # Unspecified precision
730    ///
731    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
732    /// can even differ within the same execution from one invocation to the next.
733    /// This function currently corresponds to the `tanf` from libc on Unix and
734    /// Windows. Note that this might change in the future.
735    ///
736    /// # Examples
737    ///
738    /// ```
739    /// let x = std::f32::consts::FRAC_PI_4;
740    /// let abs_difference = (x.tan() - 1.0).abs();
741    ///
742    /// assert!(abs_difference <= 1e-6);
743    /// ```
744    #[rustc_allow_incoherent_impl]
745    #[must_use = "method returns a new number and does not mutate the original value"]
746    #[stable(feature = "rust1", since = "1.0.0")]
747    #[inline]
748    pub fn tan(self) -> f32 {
749        cmath::tanf(self)
750    }
751
752    /// Computes the arcsine of a number. Return value is in radians in
753    /// the range [-pi/2, pi/2] or NaN if the number is outside the range
754    /// [-1, 1].
755    ///
756    /// # Unspecified precision
757    ///
758    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
759    /// can even differ within the same execution from one invocation to the next.
760    /// This function currently corresponds to the `asinf` from libc on Unix
761    /// and Windows. Note that this might change in the future.
762    ///
763    /// # Examples
764    ///
765    /// ```
766    /// let f = std::f32::consts::FRAC_PI_4;
767    ///
768    /// // asin(sin(pi/2))
769    /// let abs_difference = (f.sin().asin() - f).abs();
770    ///
771    /// assert!(abs_difference <= 1e-6);
772    /// ```
773    #[doc(alias = "arcsin")]
774    #[rustc_allow_incoherent_impl]
775    #[must_use = "method returns a new number and does not mutate the original value"]
776    #[stable(feature = "rust1", since = "1.0.0")]
777    #[inline]
778    pub fn asin(self) -> f32 {
779        cmath::asinf(self)
780    }
781
782    /// Computes the arccosine of a number. Return value is in radians in
783    /// the range [0, pi] or NaN if the number is outside the range
784    /// [-1, 1].
785    ///
786    /// # Unspecified precision
787    ///
788    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
789    /// can even differ within the same execution from one invocation to the next.
790    /// This function currently corresponds to the `acosf` from libc on Unix
791    /// and Windows. Note that this might change in the future.
792    ///
793    /// # Examples
794    ///
795    /// ```
796    /// let f = std::f32::consts::FRAC_PI_4;
797    ///
798    /// // acos(cos(pi/4))
799    /// let abs_difference = (f.cos().acos() - std::f32::consts::FRAC_PI_4).abs();
800    ///
801    /// assert!(abs_difference <= 1e-6);
802    /// ```
803    #[doc(alias = "arccos")]
804    #[rustc_allow_incoherent_impl]
805    #[must_use = "method returns a new number and does not mutate the original value"]
806    #[stable(feature = "rust1", since = "1.0.0")]
807    #[inline]
808    pub fn acos(self) -> f32 {
809        cmath::acosf(self)
810    }
811
812    /// Computes the arctangent of a number. Return value is in radians in the
813    /// range [-pi/2, pi/2];
814    ///
815    /// # Unspecified precision
816    ///
817    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
818    /// can even differ within the same execution from one invocation to the next.
819    /// This function currently corresponds to the `atanf` from libc on Unix
820    /// and Windows. Note that this might change in the future.
821    ///
822    /// # Examples
823    ///
824    /// ```
825    /// let f = 1.0f32;
826    ///
827    /// // atan(tan(1))
828    /// let abs_difference = (f.tan().atan() - 1.0).abs();
829    ///
830    /// assert!(abs_difference <= 1e-6);
831    /// ```
832    #[doc(alias = "arctan")]
833    #[rustc_allow_incoherent_impl]
834    #[must_use = "method returns a new number and does not mutate the original value"]
835    #[stable(feature = "rust1", since = "1.0.0")]
836    #[inline]
837    pub fn atan(self) -> f32 {
838        cmath::atanf(self)
839    }
840
841    /// Computes the four quadrant arctangent of `self` (`y`) and `other` (`x`) in radians.
842    ///
843    ///  | `x`     | `y`     | Piecewise Definition | Range         |
844    ///  |---------|---------|----------------------|---------------|
845    ///  | `>= +0` | `>= +0` | `arctan(y/x)`        | `[+0, +pi/2]` |
846    ///  | `>= +0` | `<= -0` | `arctan(y/x)`        | `[-pi/2, -0]` |
847    ///  | `<= -0` | `>= +0` | `arctan(y/x) + pi`   | `[+pi/2, +pi]`|
848    ///  | `<= -0` | `<= -0` | `arctan(y/x) - pi`   | `[-pi, -pi/2]`|
849    ///
850    /// # Unspecified precision
851    ///
852    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
853    /// can even differ within the same execution from one invocation to the next.
854    /// This function currently corresponds to the `atan2f` from libc on Unix
855    /// and Windows. Note that this might change in the future.
856    ///
857    /// # Examples
858    ///
859    /// ```
860    /// // Positive angles measured counter-clockwise
861    /// // from positive x axis
862    /// // -pi/4 radians (45 deg clockwise)
863    /// let x1 = 3.0f32;
864    /// let y1 = -3.0f32;
865    ///
866    /// // 3pi/4 radians (135 deg counter-clockwise)
867    /// let x2 = -3.0f32;
868    /// let y2 = 3.0f32;
869    ///
870    /// let abs_difference_1 = (y1.atan2(x1) - (-std::f32::consts::FRAC_PI_4)).abs();
871    /// let abs_difference_2 = (y2.atan2(x2) - (3.0 * std::f32::consts::FRAC_PI_4)).abs();
872    ///
873    /// assert!(abs_difference_1 <= 1e-5);
874    /// assert!(abs_difference_2 <= 1e-5);
875    /// ```
876    #[rustc_allow_incoherent_impl]
877    #[must_use = "method returns a new number and does not mutate the original value"]
878    #[stable(feature = "rust1", since = "1.0.0")]
879    #[inline]
880    pub fn atan2(self, other: f32) -> f32 {
881        cmath::atan2f(self, other)
882    }
883
884    /// Simultaneously computes the sine and cosine of the number, `x`. Returns
885    /// `(sin(x), cos(x))`.
886    ///
887    /// # Unspecified precision
888    ///
889    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
890    /// can even differ within the same execution from one invocation to the next.
891    /// This function currently corresponds to the `(f32::sin(x),
892    /// f32::cos(x))`. Note that this might change in the future.
893    ///
894    /// # Examples
895    ///
896    /// ```
897    /// let x = std::f32::consts::FRAC_PI_4;
898    /// let f = x.sin_cos();
899    ///
900    /// let abs_difference_0 = (f.0 - x.sin()).abs();
901    /// let abs_difference_1 = (f.1 - x.cos()).abs();
902    ///
903    /// assert!(abs_difference_0 <= 1e-4);
904    /// assert!(abs_difference_1 <= 1e-4);
905    /// ```
906    #[doc(alias = "sincos")]
907    #[rustc_allow_incoherent_impl]
908    #[stable(feature = "rust1", since = "1.0.0")]
909    #[inline]
910    pub fn sin_cos(self) -> (f32, f32) {
911        (self.sin(), self.cos())
912    }
913
914    /// Returns `e^(self) - 1` in a way that is accurate even if the
915    /// number is close to zero.
916    ///
917    /// # Unspecified precision
918    ///
919    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
920    /// can even differ within the same execution from one invocation to the next.
921    /// This function currently corresponds to the `expm1f` from libc on Unix
922    /// and Windows. Note that this might change in the future.
923    ///
924    /// # Examples
925    ///
926    /// ```
927    /// let x = 1e-8_f32;
928    ///
929    /// // for very small x, e^x is approximately 1 + x + x^2 / 2
930    /// let approx = x + x * x / 2.0;
931    /// let abs_difference = (x.exp_m1() - approx).abs();
932    ///
933    /// assert!(abs_difference < 1e-10);
934    /// ```
935    #[rustc_allow_incoherent_impl]
936    #[must_use = "method returns a new number and does not mutate the original value"]
937    #[stable(feature = "rust1", since = "1.0.0")]
938    #[inline]
939    pub fn exp_m1(self) -> f32 {
940        cmath::expm1f(self)
941    }
942
943    /// Returns `ln(1+n)` (natural logarithm) more accurately than if
944    /// the operations were performed separately.
945    ///
946    /// This returns NaN when `n < -1.0`, and negative infinity when `n == -1.0`.
947    ///
948    /// # Unspecified precision
949    ///
950    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
951    /// can even differ within the same execution from one invocation to the next.
952    /// This function currently corresponds to the `log1pf` from libc on Unix
953    /// and Windows. Note that this might change in the future.
954    ///
955    /// # Examples
956    ///
957    /// ```
958    /// let x = 1e-8_f32;
959    ///
960    /// // for very small x, ln(1 + x) is approximately x - x^2 / 2
961    /// let approx = x - x * x / 2.0;
962    /// let abs_difference = (x.ln_1p() - approx).abs();
963    ///
964    /// assert!(abs_difference < 1e-10);
965    /// ```
966    ///
967    /// Out-of-range values:
968    /// ```
969    /// assert_eq!((-1.0_f32).ln_1p(), f32::NEG_INFINITY);
970    /// assert!((-2.0_f32).ln_1p().is_nan());
971    /// ```
972    #[doc(alias = "log1p")]
973    #[rustc_allow_incoherent_impl]
974    #[must_use = "method returns a new number and does not mutate the original value"]
975    #[stable(feature = "rust1", since = "1.0.0")]
976    #[inline]
977    pub fn ln_1p(self) -> f32 {
978        cmath::log1pf(self)
979    }
980
981    /// Hyperbolic sine function.
982    ///
983    /// # Unspecified precision
984    ///
985    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
986    /// can even differ within the same execution from one invocation to the next.
987    /// This function currently corresponds to the `sinhf` from libc on Unix
988    /// and Windows. Note that this might change in the future.
989    ///
990    /// # Examples
991    ///
992    /// ```
993    /// let e = std::f32::consts::E;
994    /// let x = 1.0f32;
995    ///
996    /// let f = x.sinh();
997    /// // Solving sinh() at 1 gives `(e^2-1)/(2e)`
998    /// let g = ((e * e) - 1.0) / (2.0 * e);
999    /// let abs_difference = (f - g).abs();
1000    ///
1001    /// assert!(abs_difference <= 1e-6);
1002    /// ```
1003    #[rustc_allow_incoherent_impl]
1004    #[must_use = "method returns a new number and does not mutate the original value"]
1005    #[stable(feature = "rust1", since = "1.0.0")]
1006    #[inline]
1007    pub fn sinh(self) -> f32 {
1008        cmath::sinhf(self)
1009    }
1010
1011    /// Hyperbolic cosine function.
1012    ///
1013    /// # Unspecified precision
1014    ///
1015    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
1016    /// can even differ within the same execution from one invocation to the next.
1017    /// This function currently corresponds to the `coshf` from libc on Unix
1018    /// and Windows. Note that this might change in the future.
1019    ///
1020    /// # Examples
1021    ///
1022    /// ```
1023    /// let e = std::f32::consts::E;
1024    /// let x = 1.0f32;
1025    /// let f = x.cosh();
1026    /// // Solving cosh() at 1 gives this result
1027    /// let g = ((e * e) + 1.0) / (2.0 * e);
1028    /// let abs_difference = (f - g).abs();
1029    ///
1030    /// // Same result
1031    /// assert!(abs_difference <= 1e-6);
1032    /// ```
1033    #[rustc_allow_incoherent_impl]
1034    #[must_use = "method returns a new number and does not mutate the original value"]
1035    #[stable(feature = "rust1", since = "1.0.0")]
1036    #[inline]
1037    pub fn cosh(self) -> f32 {
1038        cmath::coshf(self)
1039    }
1040
1041    /// Hyperbolic tangent function.
1042    ///
1043    /// # Unspecified precision
1044    ///
1045    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
1046    /// can even differ within the same execution from one invocation to the next.
1047    /// This function currently corresponds to the `tanhf` from libc on Unix
1048    /// and Windows. Note that this might change in the future.
1049    ///
1050    /// # Examples
1051    ///
1052    /// ```
1053    /// let e = std::f32::consts::E;
1054    /// let x = 1.0f32;
1055    ///
1056    /// let f = x.tanh();
1057    /// // Solving tanh() at 1 gives `(1 - e^(-2))/(1 + e^(-2))`
1058    /// let g = (1.0 - e.powi(-2)) / (1.0 + e.powi(-2));
1059    /// let abs_difference = (f - g).abs();
1060    ///
1061    /// assert!(abs_difference <= 1e-6);
1062    /// ```
1063    #[rustc_allow_incoherent_impl]
1064    #[must_use = "method returns a new number and does not mutate the original value"]
1065    #[stable(feature = "rust1", since = "1.0.0")]
1066    #[inline]
1067    pub fn tanh(self) -> f32 {
1068        cmath::tanhf(self)
1069    }
1070
1071    /// Inverse hyperbolic sine function.
1072    ///
1073    /// # Unspecified precision
1074    ///
1075    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
1076    /// can even differ within the same execution from one invocation to the next.
1077    ///
1078    /// # Examples
1079    ///
1080    /// ```
1081    /// let x = 1.0f32;
1082    /// let f = x.sinh().asinh();
1083    ///
1084    /// let abs_difference = (f - x).abs();
1085    ///
1086    /// assert!(abs_difference <= 1e-6);
1087    /// ```
1088    #[doc(alias = "arcsinh")]
1089    #[rustc_allow_incoherent_impl]
1090    #[must_use = "method returns a new number and does not mutate the original value"]
1091    #[stable(feature = "rust1", since = "1.0.0")]
1092    #[inline]
1093    pub fn asinh(self) -> f32 {
1094        let ax = self.abs();
1095        let ix = 1.0 / ax;
1096        (ax + (ax / (Self::hypot(1.0, ix) + ix))).ln_1p().copysign(self)
1097    }
1098
1099    /// Inverse hyperbolic cosine function.
1100    ///
1101    /// # Unspecified precision
1102    ///
1103    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
1104    /// can even differ within the same execution from one invocation to the next.
1105    ///
1106    /// # Examples
1107    ///
1108    /// ```
1109    /// let x = 1.0f32;
1110    /// let f = x.cosh().acosh();
1111    ///
1112    /// let abs_difference = (f - x).abs();
1113    ///
1114    /// assert!(abs_difference <= 1e-6);
1115    /// ```
1116    #[doc(alias = "arccosh")]
1117    #[rustc_allow_incoherent_impl]
1118    #[must_use = "method returns a new number and does not mutate the original value"]
1119    #[stable(feature = "rust1", since = "1.0.0")]
1120    #[inline]
1121    pub fn acosh(self) -> f32 {
1122        if self < 1.0 {
1123            Self::NAN
1124        } else {
1125            (self + ((self - 1.0).sqrt() * (self + 1.0).sqrt())).ln()
1126        }
1127    }
1128
1129    /// Inverse hyperbolic tangent function.
1130    ///
1131    /// # Unspecified precision
1132    ///
1133    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
1134    /// can even differ within the same execution from one invocation to the next.
1135    ///
1136    /// # Examples
1137    ///
1138    /// ```
1139    /// let x = std::f32::consts::FRAC_PI_6;
1140    /// let f = x.tanh().atanh();
1141    ///
1142    /// let abs_difference = (f - x).abs();
1143    ///
1144    /// assert!(abs_difference <= 1e-5);
1145    /// ```
1146    #[doc(alias = "arctanh")]
1147    #[rustc_allow_incoherent_impl]
1148    #[must_use = "method returns a new number and does not mutate the original value"]
1149    #[stable(feature = "rust1", since = "1.0.0")]
1150    #[inline]
1151    pub fn atanh(self) -> f32 {
1152        0.5 * ((2.0 * self) / (1.0 - self)).ln_1p()
1153    }
1154
1155    /// Gamma function.
1156    ///
1157    /// # Unspecified precision
1158    ///
1159    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
1160    /// can even differ within the same execution from one invocation to the next.
1161    /// This function currently corresponds to the `tgammaf` from libc on Unix
1162    /// and Windows. Note that this might change in the future.
1163    ///
1164    /// # Examples
1165    ///
1166    /// ```
1167    /// #![feature(float_gamma)]
1168    /// let x = 5.0f32;
1169    ///
1170    /// let abs_difference = (x.gamma() - 24.0).abs();
1171    ///
1172    /// assert!(abs_difference <= 1e-5);
1173    /// ```
1174    #[rustc_allow_incoherent_impl]
1175    #[must_use = "method returns a new number and does not mutate the original value"]
1176    #[unstable(feature = "float_gamma", issue = "99842")]
1177    #[inline]
1178    pub fn gamma(self) -> f32 {
1179        cmath::tgammaf(self)
1180    }
1181
1182    /// Natural logarithm of the absolute value of the gamma function
1183    ///
1184    /// The integer part of the tuple indicates the sign of the gamma function.
1185    ///
1186    /// # Unspecified precision
1187    ///
1188    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
1189    /// can even differ within the same execution from one invocation to the next.
1190    /// This function currently corresponds to the `lgamma_r` from libc on Unix
1191    /// and Windows. Note that this might change in the future.
1192    ///
1193    /// # Examples
1194    ///
1195    /// ```
1196    /// #![feature(float_gamma)]
1197    /// let x = 2.0f32;
1198    ///
1199    /// let abs_difference = (x.ln_gamma().0 - 0.0).abs();
1200    ///
1201    /// assert!(abs_difference <= f32::EPSILON);
1202    /// ```
1203    #[rustc_allow_incoherent_impl]
1204    #[must_use = "method returns a new number and does not mutate the original value"]
1205    #[unstable(feature = "float_gamma", issue = "99842")]
1206    #[inline]
1207    pub fn ln_gamma(self) -> (f32, i32) {
1208        let mut signgamp: i32 = 0;
1209        let x = cmath::lgammaf_r(self, &mut signgamp);
1210        (x, signgamp)
1211    }
1212
1213    /// Error function.
1214    ///
1215    /// # Unspecified precision
1216    ///
1217    /// The precision of this function is non-deterministic. This means it varies by platform,
1218    /// Rust version, and can even differ within the same execution from one invocation to the next.
1219    ///
1220    /// This function currently corresponds to the `erff` from libc on Unix
1221    /// and Windows. Note that this might change in the future.
1222    ///
1223    /// # Examples
1224    ///
1225    /// ```
1226    /// #![feature(float_erf)]
1227    /// /// The error function relates what percent of a normal distribution lies
1228    /// /// within `x` standard deviations (scaled by `1/sqrt(2)`).
1229    /// fn within_standard_deviations(x: f32) -> f32 {
1230    ///     (x * std::f32::consts::FRAC_1_SQRT_2).erf() * 100.0
1231    /// }
1232    ///
1233    /// // 68% of a normal distribution is within one standard deviation
1234    /// assert!((within_standard_deviations(1.0) - 68.269).abs() < 0.01);
1235    /// // 95% of a normal distribution is within two standard deviations
1236    /// assert!((within_standard_deviations(2.0) - 95.450).abs() < 0.01);
1237    /// // 99.7% of a normal distribution is within three standard deviations
1238    /// assert!((within_standard_deviations(3.0) - 99.730).abs() < 0.01);
1239    /// ```
1240    #[rustc_allow_incoherent_impl]
1241    #[must_use = "method returns a new number and does not mutate the original value"]
1242    #[unstable(feature = "float_erf", issue = "136321")]
1243    #[inline]
1244    pub fn erf(self) -> f32 {
1245        cmath::erff(self)
1246    }
1247
1248    /// Complementary error function.
1249    ///
1250    /// # Unspecified precision
1251    ///
1252    /// The precision of this function is non-deterministic. This means it varies by platform,
1253    /// Rust version, and can even differ within the same execution from one invocation to the next.
1254    ///
1255    /// This function currently corresponds to the `erfcf` from libc on Unix
1256    /// and Windows. Note that this might change in the future.
1257    ///
1258    /// # Examples
1259    ///
1260    /// ```
1261    /// #![feature(float_erf)]
1262    /// let x: f32 = 0.123;
1263    ///
1264    /// let one = x.erf() + x.erfc();
1265    /// let abs_difference = (one - 1.0).abs();
1266    ///
1267    /// assert!(abs_difference <= 1e-6);
1268    /// ```
1269    #[rustc_allow_incoherent_impl]
1270    #[must_use = "method returns a new number and does not mutate the original value"]
1271    #[unstable(feature = "float_erf", issue = "136321")]
1272    #[inline]
1273    pub fn erfc(self) -> f32 {
1274        cmath::erfcf(self)
1275    }
1276}