std/num/
f128.rs

1//! Constants for the `f128` quadruple-precision floating point type.
2//!
3//! *[See also the `f128` primitive type](primitive@f128).*
4//!
5//! Mathematically significant numbers are provided in the `consts` sub-module.
6
7#![unstable(feature = "f128", issue = "116909")]
8#![doc(test(attr(feature(cfg_target_has_reliable_f16_f128), expect(internal_features))))]
9
10#[unstable(feature = "f128", issue = "116909")]
11pub use core::f128::consts;
12
13#[cfg(not(test))]
14use crate::intrinsics;
15#[cfg(not(test))]
16use crate::sys::cmath;
17
18#[cfg(not(test))]
19impl f128 {
20    /// Raises a number to a floating point power.
21    ///
22    /// # Unspecified precision
23    ///
24    /// The precision of this function is non-deterministic. This means it varies by platform,
25    /// Rust version, and can even differ within the same execution from one invocation to the next.
26    ///
27    /// # Examples
28    ///
29    /// ```
30    /// #![feature(f128)]
31    /// # #[cfg(not(miri))]
32    /// # #[cfg(target_has_reliable_f128_math)] {
33    ///
34    /// let x = 2.0_f128;
35    /// let abs_difference = (x.powf(2.0) - (x * x)).abs();
36    /// assert!(abs_difference <= f128::EPSILON);
37    ///
38    /// assert_eq!(f128::powf(1.0, f128::NAN), 1.0);
39    /// assert_eq!(f128::powf(f128::NAN, 0.0), 1.0);
40    /// assert_eq!(f128::powf(0.0, 0.0), 1.0);
41    /// # }
42    /// ```
43    #[inline]
44    #[rustc_allow_incoherent_impl]
45    #[unstable(feature = "f128", issue = "116909")]
46    #[must_use = "method returns a new number and does not mutate the original value"]
47    pub fn powf(self, n: f128) -> f128 {
48        intrinsics::powf128(self, n)
49    }
50
51    /// Returns `e^(self)`, (the exponential function).
52    ///
53    /// # Unspecified precision
54    ///
55    /// The precision of this function is non-deterministic. This means it varies by platform,
56    /// Rust version, and can even differ within the same execution from one invocation to the next.
57    ///
58    /// # Examples
59    ///
60    /// ```
61    /// #![feature(f128)]
62    /// # #[cfg(not(miri))]
63    /// # #[cfg(target_has_reliable_f128_math)] {
64    ///
65    /// let one = 1.0f128;
66    /// // e^1
67    /// let e = one.exp();
68    ///
69    /// // ln(e) - 1 == 0
70    /// let abs_difference = (e.ln() - 1.0).abs();
71    ///
72    /// assert!(abs_difference <= f128::EPSILON);
73    /// # }
74    /// ```
75    #[inline]
76    #[rustc_allow_incoherent_impl]
77    #[unstable(feature = "f128", issue = "116909")]
78    #[must_use = "method returns a new number and does not mutate the original value"]
79    pub fn exp(self) -> f128 {
80        intrinsics::expf128(self)
81    }
82
83    /// Returns `2^(self)`.
84    ///
85    /// # Unspecified precision
86    ///
87    /// The precision of this function is non-deterministic. This means it varies by platform,
88    /// Rust version, and can even differ within the same execution from one invocation to the next.
89    ///
90    /// # Examples
91    ///
92    /// ```
93    /// #![feature(f128)]
94    /// # #[cfg(not(miri))]
95    /// # #[cfg(target_has_reliable_f128_math)] {
96    ///
97    /// let f = 2.0f128;
98    ///
99    /// // 2^2 - 4 == 0
100    /// let abs_difference = (f.exp2() - 4.0).abs();
101    ///
102    /// assert!(abs_difference <= f128::EPSILON);
103    /// # }
104    /// ```
105    #[inline]
106    #[rustc_allow_incoherent_impl]
107    #[unstable(feature = "f128", issue = "116909")]
108    #[must_use = "method returns a new number and does not mutate the original value"]
109    pub fn exp2(self) -> f128 {
110        intrinsics::exp2f128(self)
111    }
112
113    /// Returns the natural logarithm of the number.
114    ///
115    /// This returns NaN when the number is negative, and negative infinity when number is zero.
116    ///
117    /// # Unspecified precision
118    ///
119    /// The precision of this function is non-deterministic. This means it varies by platform,
120    /// Rust version, and can even differ within the same execution from one invocation to the next.
121    ///
122    /// # Examples
123    ///
124    /// ```
125    /// #![feature(f128)]
126    /// # #[cfg(not(miri))]
127    /// # #[cfg(target_has_reliable_f128_math)] {
128    ///
129    /// let one = 1.0f128;
130    /// // e^1
131    /// let e = one.exp();
132    ///
133    /// // ln(e) - 1 == 0
134    /// let abs_difference = (e.ln() - 1.0).abs();
135    ///
136    /// assert!(abs_difference <= f128::EPSILON);
137    /// # }
138    /// ```
139    ///
140    /// Non-positive values:
141    /// ```
142    /// #![feature(f128)]
143    /// # #[cfg(not(miri))]
144    /// # #[cfg(target_has_reliable_f128_math)] {
145    ///
146    /// assert_eq!(0_f128.ln(), f128::NEG_INFINITY);
147    /// assert!((-42_f128).ln().is_nan());
148    /// # }
149    /// ```
150    #[inline]
151    #[rustc_allow_incoherent_impl]
152    #[unstable(feature = "f128", issue = "116909")]
153    #[must_use = "method returns a new number and does not mutate the original value"]
154    pub fn ln(self) -> f128 {
155        intrinsics::logf128(self)
156    }
157
158    /// Returns the logarithm of the number with respect to an arbitrary base.
159    ///
160    /// This returns NaN when the number is negative, and negative infinity when number is zero.
161    ///
162    /// The result might not be correctly rounded owing to implementation details;
163    /// `self.log2()` can produce more accurate results for base 2, and
164    /// `self.log10()` can produce more accurate results for base 10.
165    ///
166    /// # Unspecified precision
167    ///
168    /// The precision of this function is non-deterministic. This means it varies by platform,
169    /// Rust version, and can even differ within the same execution from one invocation to the next.
170    ///
171    /// # Examples
172    ///
173    /// ```
174    /// #![feature(f128)]
175    /// # #[cfg(not(miri))]
176    /// # #[cfg(target_has_reliable_f128_math)] {
177    ///
178    /// let five = 5.0f128;
179    ///
180    /// // log5(5) - 1 == 0
181    /// let abs_difference = (five.log(5.0) - 1.0).abs();
182    ///
183    /// assert!(abs_difference <= f128::EPSILON);
184    /// # }
185    /// ```
186    ///
187    /// Non-positive values:
188    /// ```
189    /// #![feature(f128)]
190    /// # #[cfg(not(miri))]
191    /// # #[cfg(target_has_reliable_f128_math)] {
192    ///
193    /// assert_eq!(0_f128.log(10.0), f128::NEG_INFINITY);
194    /// assert!((-42_f128).log(10.0).is_nan());
195    /// # }
196    /// ```
197    #[inline]
198    #[rustc_allow_incoherent_impl]
199    #[unstable(feature = "f128", issue = "116909")]
200    #[must_use = "method returns a new number and does not mutate the original value"]
201    pub fn log(self, base: f128) -> f128 {
202        self.ln() / base.ln()
203    }
204
205    /// Returns the base 2 logarithm of the number.
206    ///
207    /// This returns NaN when the number is negative, and negative infinity when number is zero.
208    ///
209    /// # Unspecified precision
210    ///
211    /// The precision of this function is non-deterministic. This means it varies by platform,
212    /// Rust version, and can even differ within the same execution from one invocation to the next.
213    ///
214    /// # Examples
215    ///
216    /// ```
217    /// #![feature(f128)]
218    /// # #[cfg(not(miri))]
219    /// # #[cfg(target_has_reliable_f128_math)] {
220    ///
221    /// let two = 2.0f128;
222    ///
223    /// // log2(2) - 1 == 0
224    /// let abs_difference = (two.log2() - 1.0).abs();
225    ///
226    /// assert!(abs_difference <= f128::EPSILON);
227    /// # }
228    /// ```
229    ///
230    /// Non-positive values:
231    /// ```
232    /// #![feature(f128)]
233    /// # #[cfg(not(miri))]
234    /// # #[cfg(target_has_reliable_f128_math)] {
235    ///
236    /// assert_eq!(0_f128.log2(), f128::NEG_INFINITY);
237    /// assert!((-42_f128).log2().is_nan());
238    /// # }
239    /// ```
240    #[inline]
241    #[rustc_allow_incoherent_impl]
242    #[unstable(feature = "f128", issue = "116909")]
243    #[must_use = "method returns a new number and does not mutate the original value"]
244    pub fn log2(self) -> f128 {
245        intrinsics::log2f128(self)
246    }
247
248    /// Returns the base 10 logarithm of the number.
249    ///
250    /// This returns NaN when the number is negative, and negative infinity when number is zero.
251    ///
252    /// # Unspecified precision
253    ///
254    /// The precision of this function is non-deterministic. This means it varies by platform,
255    /// Rust version, and can even differ within the same execution from one invocation to the next.
256    ///
257    /// # Examples
258    ///
259    /// ```
260    /// #![feature(f128)]
261    /// # #[cfg(not(miri))]
262    /// # #[cfg(target_has_reliable_f128_math)] {
263    ///
264    /// let ten = 10.0f128;
265    ///
266    /// // log10(10) - 1 == 0
267    /// let abs_difference = (ten.log10() - 1.0).abs();
268    ///
269    /// assert!(abs_difference <= f128::EPSILON);
270    /// # }
271    /// ```
272    ///
273    /// Non-positive values:
274    /// ```
275    /// #![feature(f128)]
276    /// # #[cfg(not(miri))]
277    /// # #[cfg(target_has_reliable_f128_math)] {
278    ///
279    /// assert_eq!(0_f128.log10(), f128::NEG_INFINITY);
280    /// assert!((-42_f128).log10().is_nan());
281    /// # }
282    /// ```
283    #[inline]
284    #[rustc_allow_incoherent_impl]
285    #[unstable(feature = "f128", issue = "116909")]
286    #[must_use = "method returns a new number and does not mutate the original value"]
287    pub fn log10(self) -> f128 {
288        intrinsics::log10f128(self)
289    }
290
291    /// Returns the cube root of a number.
292    ///
293    /// # Unspecified precision
294    ///
295    /// The precision of this function is non-deterministic. This means it varies by platform,
296    /// Rust version, and can even differ within the same execution from one invocation to the next.
297    ///
298    ///
299    /// This function currently corresponds to the `cbrtf128` from libc on Unix
300    /// and Windows. Note that this might change in the future.
301    ///
302    /// # Examples
303    ///
304    /// ```
305    /// #![feature(f128)]
306    /// # #[cfg(not(miri))]
307    /// # #[cfg(target_has_reliable_f128_math)] {
308    ///
309    /// let x = 8.0f128;
310    ///
311    /// // x^(1/3) - 2 == 0
312    /// let abs_difference = (x.cbrt() - 2.0).abs();
313    ///
314    /// assert!(abs_difference <= f128::EPSILON);
315    /// # }
316    /// ```
317    #[inline]
318    #[rustc_allow_incoherent_impl]
319    #[unstable(feature = "f128", issue = "116909")]
320    #[must_use = "method returns a new number and does not mutate the original value"]
321    pub fn cbrt(self) -> f128 {
322        cmath::cbrtf128(self)
323    }
324
325    /// Compute the distance between the origin and a point (`x`, `y`) on the
326    /// Euclidean plane. Equivalently, compute the length of the hypotenuse of a
327    /// right-angle triangle with other sides having length `x.abs()` and
328    /// `y.abs()`.
329    ///
330    /// # Unspecified precision
331    ///
332    /// The precision of this function is non-deterministic. This means it varies by platform,
333    /// Rust version, and can even differ within the same execution from one invocation to the next.
334    ///
335    ///
336    /// This function currently corresponds to the `hypotf128` from libc on Unix
337    /// and Windows. Note that this might change in the future.
338    ///
339    /// # Examples
340    ///
341    /// ```
342    /// #![feature(f128)]
343    /// # #[cfg(not(miri))]
344    /// # #[cfg(target_has_reliable_f128_math)] {
345    ///
346    /// let x = 2.0f128;
347    /// let y = 3.0f128;
348    ///
349    /// // sqrt(x^2 + y^2)
350    /// let abs_difference = (x.hypot(y) - (x.powi(2) + y.powi(2)).sqrt()).abs();
351    ///
352    /// assert!(abs_difference <= f128::EPSILON);
353    /// # }
354    /// ```
355    #[inline]
356    #[rustc_allow_incoherent_impl]
357    #[unstable(feature = "f128", issue = "116909")]
358    #[must_use = "method returns a new number and does not mutate the original value"]
359    pub fn hypot(self, other: f128) -> f128 {
360        cmath::hypotf128(self, other)
361    }
362
363    /// Computes the sine of a number (in radians).
364    ///
365    /// # Unspecified precision
366    ///
367    /// The precision of this function is non-deterministic. This means it varies by platform,
368    /// Rust version, and can even differ within the same execution from one invocation to the next.
369    ///
370    /// # Examples
371    ///
372    /// ```
373    /// #![feature(f128)]
374    /// # #[cfg(not(miri))]
375    /// # #[cfg(target_has_reliable_f128_math)] {
376    ///
377    /// let x = std::f128::consts::FRAC_PI_2;
378    ///
379    /// let abs_difference = (x.sin() - 1.0).abs();
380    ///
381    /// assert!(abs_difference <= f128::EPSILON);
382    /// # }
383    /// ```
384    #[inline]
385    #[rustc_allow_incoherent_impl]
386    #[unstable(feature = "f128", issue = "116909")]
387    #[must_use = "method returns a new number and does not mutate the original value"]
388    pub fn sin(self) -> f128 {
389        intrinsics::sinf128(self)
390    }
391
392    /// Computes the cosine of a number (in radians).
393    ///
394    /// # Unspecified precision
395    ///
396    /// The precision of this function is non-deterministic. This means it varies by platform,
397    /// Rust version, and can even differ within the same execution from one invocation to the next.
398    ///
399    /// # Examples
400    ///
401    /// ```
402    /// #![feature(f128)]
403    /// # #[cfg(not(miri))]
404    /// # #[cfg(target_has_reliable_f128_math)] {
405    ///
406    /// let x = 2.0 * std::f128::consts::PI;
407    ///
408    /// let abs_difference = (x.cos() - 1.0).abs();
409    ///
410    /// assert!(abs_difference <= f128::EPSILON);
411    /// # }
412    /// ```
413    #[inline]
414    #[rustc_allow_incoherent_impl]
415    #[unstable(feature = "f128", issue = "116909")]
416    #[must_use = "method returns a new number and does not mutate the original value"]
417    pub fn cos(self) -> f128 {
418        intrinsics::cosf128(self)
419    }
420
421    /// Computes the tangent of a number (in radians).
422    ///
423    /// # Unspecified precision
424    ///
425    /// The precision of this function is non-deterministic. This means it varies by platform,
426    /// Rust version, and can even differ within the same execution from one invocation to the next.
427    ///
428    /// This function currently corresponds to the `tanf128` from libc on Unix and
429    /// Windows. Note that this might change in the future.
430    ///
431    /// # Examples
432    ///
433    /// ```
434    /// #![feature(f128)]
435    /// # #[cfg(not(miri))]
436    /// # #[cfg(target_has_reliable_f128_math)] {
437    ///
438    /// let x = std::f128::consts::FRAC_PI_4;
439    /// let abs_difference = (x.tan() - 1.0).abs();
440    ///
441    /// assert!(abs_difference <= f128::EPSILON);
442    /// # }
443    /// ```
444    #[inline]
445    #[rustc_allow_incoherent_impl]
446    #[unstable(feature = "f128", issue = "116909")]
447    #[must_use = "method returns a new number and does not mutate the original value"]
448    pub fn tan(self) -> f128 {
449        cmath::tanf128(self)
450    }
451
452    /// Computes the arcsine of a number. Return value is in radians in
453    /// the range [-pi/2, pi/2] or NaN if the number is outside the range
454    /// [-1, 1].
455    ///
456    /// # Unspecified precision
457    ///
458    /// The precision of this function is non-deterministic. This means it varies by platform,
459    /// Rust version, and can even differ within the same execution from one invocation to the next.
460    ///
461    /// This function currently corresponds to the `asinf128` from libc on Unix
462    /// and Windows. Note that this might change in the future.
463    ///
464    /// # Examples
465    ///
466    /// ```
467    /// #![feature(f128)]
468    /// # #[cfg(not(miri))]
469    /// # #[cfg(target_has_reliable_f128_math)] {
470    ///
471    /// let f = std::f128::consts::FRAC_PI_4;
472    ///
473    /// // asin(sin(pi/2))
474    /// let abs_difference = (f.sin().asin() - f).abs();
475    ///
476    /// assert!(abs_difference <= f128::EPSILON);
477    /// # }
478    /// ```
479    #[inline]
480    #[doc(alias = "arcsin")]
481    #[rustc_allow_incoherent_impl]
482    #[unstable(feature = "f128", issue = "116909")]
483    #[must_use = "method returns a new number and does not mutate the original value"]
484    pub fn asin(self) -> f128 {
485        cmath::asinf128(self)
486    }
487
488    /// Computes the arccosine of a number. Return value is in radians in
489    /// the range [0, pi] or NaN if the number is outside the range
490    /// [-1, 1].
491    ///
492    /// # Unspecified precision
493    ///
494    /// The precision of this function is non-deterministic. This means it varies by platform,
495    /// Rust version, and can even differ within the same execution from one invocation to the next.
496    ///
497    /// This function currently corresponds to the `acosf128` from libc on Unix
498    /// and Windows. Note that this might change in the future.
499    ///
500    /// # Examples
501    ///
502    /// ```
503    /// #![feature(f128)]
504    /// # #[cfg(not(miri))]
505    /// # #[cfg(target_has_reliable_f128_math)] {
506    ///
507    /// let f = std::f128::consts::FRAC_PI_4;
508    ///
509    /// // acos(cos(pi/4))
510    /// let abs_difference = (f.cos().acos() - std::f128::consts::FRAC_PI_4).abs();
511    ///
512    /// assert!(abs_difference <= f128::EPSILON);
513    /// # }
514    /// ```
515    #[inline]
516    #[doc(alias = "arccos")]
517    #[rustc_allow_incoherent_impl]
518    #[unstable(feature = "f128", issue = "116909")]
519    #[must_use = "method returns a new number and does not mutate the original value"]
520    pub fn acos(self) -> f128 {
521        cmath::acosf128(self)
522    }
523
524    /// Computes the arctangent of a number. Return value is in radians in the
525    /// range [-pi/2, pi/2];
526    ///
527    /// # Unspecified precision
528    ///
529    /// The precision of this function is non-deterministic. This means it varies by platform,
530    /// Rust version, and can even differ within the same execution from one invocation to the next.
531    ///
532    /// This function currently corresponds to the `atanf128` from libc on Unix
533    /// and Windows. Note that this might change in the future.
534    ///
535    /// # Examples
536    ///
537    /// ```
538    /// #![feature(f128)]
539    /// # #[cfg(not(miri))]
540    /// # #[cfg(target_has_reliable_f128_math)] {
541    ///
542    /// let f = 1.0f128;
543    ///
544    /// // atan(tan(1))
545    /// let abs_difference = (f.tan().atan() - 1.0).abs();
546    ///
547    /// assert!(abs_difference <= f128::EPSILON);
548    /// # }
549    /// ```
550    #[inline]
551    #[doc(alias = "arctan")]
552    #[rustc_allow_incoherent_impl]
553    #[unstable(feature = "f128", issue = "116909")]
554    #[must_use = "method returns a new number and does not mutate the original value"]
555    pub fn atan(self) -> f128 {
556        cmath::atanf128(self)
557    }
558
559    /// Computes the four quadrant arctangent of `self` (`y`) and `other` (`x`) in radians.
560    ///
561    ///  | `x`     | `y`     | Piecewise Definition | Range         |
562    ///  |---------|---------|----------------------|---------------|
563    ///  | `>= +0` | `>= +0` | `arctan(y/x)`        | `[+0, +pi/2]` |
564    ///  | `>= +0` | `<= -0` | `arctan(y/x)`        | `[-pi/2, -0]` |
565    ///  | `<= -0` | `>= +0` | `arctan(y/x) + pi`   | `[+pi/2, +pi]`|
566    ///  | `<= -0` | `<= -0` | `arctan(y/x) - pi`   | `[-pi, -pi/2]`|
567    ///
568    /// # Unspecified precision
569    ///
570    /// The precision of this function is non-deterministic. This means it varies by platform,
571    /// Rust version, and can even differ within the same execution from one invocation to the next.
572    ///
573    /// This function currently corresponds to the `atan2f128` from libc on Unix
574    /// and Windows. Note that this might change in the future.
575    ///
576    /// # Examples
577    ///
578    /// ```
579    /// #![feature(f128)]
580    /// # #[cfg(not(miri))]
581    /// # #[cfg(target_has_reliable_f128_math)] {
582    ///
583    /// // Positive angles measured counter-clockwise
584    /// // from positive x axis
585    /// // -pi/4 radians (45 deg clockwise)
586    /// let x1 = 3.0f128;
587    /// let y1 = -3.0f128;
588    ///
589    /// // 3pi/4 radians (135 deg counter-clockwise)
590    /// let x2 = -3.0f128;
591    /// let y2 = 3.0f128;
592    ///
593    /// let abs_difference_1 = (y1.atan2(x1) - (-std::f128::consts::FRAC_PI_4)).abs();
594    /// let abs_difference_2 = (y2.atan2(x2) - (3.0 * std::f128::consts::FRAC_PI_4)).abs();
595    ///
596    /// assert!(abs_difference_1 <= f128::EPSILON);
597    /// assert!(abs_difference_2 <= f128::EPSILON);
598    /// # }
599    /// ```
600    #[inline]
601    #[rustc_allow_incoherent_impl]
602    #[unstable(feature = "f128", issue = "116909")]
603    #[must_use = "method returns a new number and does not mutate the original value"]
604    pub fn atan2(self, other: f128) -> f128 {
605        cmath::atan2f128(self, other)
606    }
607
608    /// Simultaneously computes the sine and cosine of the number, `x`. Returns
609    /// `(sin(x), cos(x))`.
610    ///
611    /// # Unspecified precision
612    ///
613    /// The precision of this function is non-deterministic. This means it varies by platform,
614    /// Rust version, and can even differ within the same execution from one invocation to the next.
615    ///
616    /// This function currently corresponds to the `(f128::sin(x),
617    /// f128::cos(x))`. Note that this might change in the future.
618    ///
619    /// # Examples
620    ///
621    /// ```
622    /// #![feature(f128)]
623    /// # #[cfg(not(miri))]
624    /// # #[cfg(target_has_reliable_f128_math)] {
625    ///
626    /// let x = std::f128::consts::FRAC_PI_4;
627    /// let f = x.sin_cos();
628    ///
629    /// let abs_difference_0 = (f.0 - x.sin()).abs();
630    /// let abs_difference_1 = (f.1 - x.cos()).abs();
631    ///
632    /// assert!(abs_difference_0 <= f128::EPSILON);
633    /// assert!(abs_difference_1 <= f128::EPSILON);
634    /// # }
635    /// ```
636    #[inline]
637    #[doc(alias = "sincos")]
638    #[rustc_allow_incoherent_impl]
639    #[unstable(feature = "f128", issue = "116909")]
640    pub fn sin_cos(self) -> (f128, f128) {
641        (self.sin(), self.cos())
642    }
643
644    /// Returns `e^(self) - 1` in a way that is accurate even if the
645    /// number is close to zero.
646    ///
647    /// # Unspecified precision
648    ///
649    /// The precision of this function is non-deterministic. This means it varies by platform,
650    /// Rust version, and can even differ within the same execution from one invocation to the next.
651    ///
652    /// This function currently corresponds to the `expm1f128` from libc on Unix
653    /// and Windows. Note that this might change in the future.
654    ///
655    /// # Examples
656    ///
657    /// ```
658    /// #![feature(f128)]
659    /// # #[cfg(not(miri))]
660    /// # #[cfg(target_has_reliable_f128_math)] {
661    ///
662    /// let x = 1e-8_f128;
663    ///
664    /// // for very small x, e^x is approximately 1 + x + x^2 / 2
665    /// let approx = x + x * x / 2.0;
666    /// let abs_difference = (x.exp_m1() - approx).abs();
667    ///
668    /// assert!(abs_difference < 1e-10);
669    /// # }
670    /// ```
671    #[inline]
672    #[rustc_allow_incoherent_impl]
673    #[unstable(feature = "f128", issue = "116909")]
674    #[must_use = "method returns a new number and does not mutate the original value"]
675    pub fn exp_m1(self) -> f128 {
676        cmath::expm1f128(self)
677    }
678
679    /// Returns `ln(1+n)` (natural logarithm) more accurately than if
680    /// the operations were performed separately.
681    ///
682    /// This returns NaN when `n < -1.0`, and negative infinity when `n == -1.0`.
683    ///
684    /// # Unspecified precision
685    ///
686    /// The precision of this function is non-deterministic. This means it varies by platform,
687    /// Rust version, and can even differ within the same execution from one invocation to the next.
688    ///
689    /// This function currently corresponds to the `log1pf128` from libc on Unix
690    /// and Windows. Note that this might change in the future.
691    ///
692    /// # Examples
693    ///
694    /// ```
695    /// #![feature(f128)]
696    /// # #[cfg(not(miri))]
697    /// # #[cfg(target_has_reliable_f128_math)] {
698    ///
699    /// let x = 1e-8_f128;
700    ///
701    /// // for very small x, ln(1 + x) is approximately x - x^2 / 2
702    /// let approx = x - x * x / 2.0;
703    /// let abs_difference = (x.ln_1p() - approx).abs();
704    ///
705    /// assert!(abs_difference < 1e-10);
706    /// # }
707    /// ```
708    ///
709    /// Out-of-range values:
710    /// ```
711    /// #![feature(f128)]
712    /// # #[cfg(not(miri))]
713    /// # #[cfg(target_has_reliable_f128_math)] {
714    ///
715    /// assert_eq!((-1.0_f128).ln_1p(), f128::NEG_INFINITY);
716    /// assert!((-2.0_f128).ln_1p().is_nan());
717    /// # }
718    /// ```
719    #[inline]
720    #[doc(alias = "log1p")]
721    #[must_use = "method returns a new number and does not mutate the original value"]
722    #[rustc_allow_incoherent_impl]
723    #[unstable(feature = "f128", issue = "116909")]
724    pub fn ln_1p(self) -> f128 {
725        cmath::log1pf128(self)
726    }
727
728    /// Hyperbolic sine function.
729    ///
730    /// # Unspecified precision
731    ///
732    /// The precision of this function is non-deterministic. This means it varies by platform,
733    /// Rust version, and can even differ within the same execution from one invocation to the next.
734    ///
735    /// This function currently corresponds to the `sinhf128` from libc on Unix
736    /// and Windows. Note that this might change in the future.
737    ///
738    /// # Examples
739    ///
740    /// ```
741    /// #![feature(f128)]
742    /// # #[cfg(not(miri))]
743    /// # #[cfg(target_has_reliable_f128_math)] {
744    ///
745    /// let e = std::f128::consts::E;
746    /// let x = 1.0f128;
747    ///
748    /// let f = x.sinh();
749    /// // Solving sinh() at 1 gives `(e^2-1)/(2e)`
750    /// let g = ((e * e) - 1.0) / (2.0 * e);
751    /// let abs_difference = (f - g).abs();
752    ///
753    /// assert!(abs_difference <= f128::EPSILON);
754    /// # }
755    /// ```
756    #[inline]
757    #[rustc_allow_incoherent_impl]
758    #[unstable(feature = "f128", issue = "116909")]
759    #[must_use = "method returns a new number and does not mutate the original value"]
760    pub fn sinh(self) -> f128 {
761        cmath::sinhf128(self)
762    }
763
764    /// Hyperbolic cosine function.
765    ///
766    /// # Unspecified precision
767    ///
768    /// The precision of this function is non-deterministic. This means it varies by platform,
769    /// Rust version, and can even differ within the same execution from one invocation to the next.
770    ///
771    /// This function currently corresponds to the `coshf128` from libc on Unix
772    /// and Windows. Note that this might change in the future.
773    ///
774    /// # Examples
775    ///
776    /// ```
777    /// #![feature(f128)]
778    /// # #[cfg(not(miri))]
779    /// # #[cfg(target_has_reliable_f128_math)] {
780    ///
781    /// let e = std::f128::consts::E;
782    /// let x = 1.0f128;
783    /// let f = x.cosh();
784    /// // Solving cosh() at 1 gives this result
785    /// let g = ((e * e) + 1.0) / (2.0 * e);
786    /// let abs_difference = (f - g).abs();
787    ///
788    /// // Same result
789    /// assert!(abs_difference <= f128::EPSILON);
790    /// # }
791    /// ```
792    #[inline]
793    #[rustc_allow_incoherent_impl]
794    #[unstable(feature = "f128", issue = "116909")]
795    #[must_use = "method returns a new number and does not mutate the original value"]
796    pub fn cosh(self) -> f128 {
797        cmath::coshf128(self)
798    }
799
800    /// Hyperbolic tangent function.
801    ///
802    /// # Unspecified precision
803    ///
804    /// The precision of this function is non-deterministic. This means it varies by platform,
805    /// Rust version, and can even differ within the same execution from one invocation to the next.
806    ///
807    /// This function currently corresponds to the `tanhf128` from libc on Unix
808    /// and Windows. Note that this might change in the future.
809    ///
810    /// # Examples
811    ///
812    /// ```
813    /// #![feature(f128)]
814    /// # #[cfg(not(miri))]
815    /// # #[cfg(target_has_reliable_f128_math)] {
816    ///
817    /// let e = std::f128::consts::E;
818    /// let x = 1.0f128;
819    ///
820    /// let f = x.tanh();
821    /// // Solving tanh() at 1 gives `(1 - e^(-2))/(1 + e^(-2))`
822    /// let g = (1.0 - e.powi(-2)) / (1.0 + e.powi(-2));
823    /// let abs_difference = (f - g).abs();
824    ///
825    /// assert!(abs_difference <= f128::EPSILON);
826    /// # }
827    /// ```
828    #[inline]
829    #[rustc_allow_incoherent_impl]
830    #[unstable(feature = "f128", issue = "116909")]
831    #[must_use = "method returns a new number and does not mutate the original value"]
832    pub fn tanh(self) -> f128 {
833        cmath::tanhf128(self)
834    }
835
836    /// Inverse hyperbolic sine function.
837    ///
838    /// # Unspecified precision
839    ///
840    /// The precision of this function is non-deterministic. This means it varies by platform,
841    /// Rust version, and can even differ within the same execution from one invocation to the next.
842    ///
843    /// # Examples
844    ///
845    /// ```
846    /// #![feature(f128)]
847    /// # #[cfg(not(miri))]
848    /// # #[cfg(target_has_reliable_f128_math)] {
849    ///
850    /// let x = 1.0f128;
851    /// let f = x.sinh().asinh();
852    ///
853    /// let abs_difference = (f - x).abs();
854    ///
855    /// assert!(abs_difference <= f128::EPSILON);
856    /// # }
857    /// ```
858    #[inline]
859    #[doc(alias = "arcsinh")]
860    #[rustc_allow_incoherent_impl]
861    #[unstable(feature = "f128", issue = "116909")]
862    #[must_use = "method returns a new number and does not mutate the original value"]
863    pub fn asinh(self) -> f128 {
864        let ax = self.abs();
865        let ix = 1.0 / ax;
866        (ax + (ax / (Self::hypot(1.0, ix) + ix))).ln_1p().copysign(self)
867    }
868
869    /// Inverse hyperbolic cosine function.
870    ///
871    /// # Unspecified precision
872    ///
873    /// The precision of this function is non-deterministic. This means it varies by platform,
874    /// Rust version, and can even differ within the same execution from one invocation to the next.
875    ///
876    /// # Examples
877    ///
878    /// ```
879    /// #![feature(f128)]
880    /// # #[cfg(not(miri))]
881    /// # #[cfg(target_has_reliable_f128_math)] {
882    ///
883    /// let x = 1.0f128;
884    /// let f = x.cosh().acosh();
885    ///
886    /// let abs_difference = (f - x).abs();
887    ///
888    /// assert!(abs_difference <= f128::EPSILON);
889    /// # }
890    /// ```
891    #[inline]
892    #[doc(alias = "arccosh")]
893    #[rustc_allow_incoherent_impl]
894    #[unstable(feature = "f128", issue = "116909")]
895    #[must_use = "method returns a new number and does not mutate the original value"]
896    pub fn acosh(self) -> f128 {
897        if self < 1.0 {
898            Self::NAN
899        } else {
900            (self + ((self - 1.0).sqrt() * (self + 1.0).sqrt())).ln()
901        }
902    }
903
904    /// Inverse hyperbolic tangent function.
905    ///
906    /// # Unspecified precision
907    ///
908    /// The precision of this function is non-deterministic. This means it varies by platform,
909    /// Rust version, and can even differ within the same execution from one invocation to the next.
910    ///
911    /// # Examples
912    ///
913    /// ```
914    /// #![feature(f128)]
915    /// # #[cfg(not(miri))]
916    /// # #[cfg(target_has_reliable_f128_math)] {
917    ///
918    /// let x = std::f128::consts::FRAC_PI_6;
919    /// let f = x.tanh().atanh();
920    ///
921    /// let abs_difference = (f - x).abs();
922    ///
923    /// assert!(abs_difference <= 1e-5);
924    /// # }
925    /// ```
926    #[inline]
927    #[doc(alias = "arctanh")]
928    #[rustc_allow_incoherent_impl]
929    #[unstable(feature = "f128", issue = "116909")]
930    #[must_use = "method returns a new number and does not mutate the original value"]
931    pub fn atanh(self) -> f128 {
932        0.5 * ((2.0 * self) / (1.0 - self)).ln_1p()
933    }
934
935    /// Gamma function.
936    ///
937    /// # Unspecified precision
938    ///
939    /// The precision of this function is non-deterministic. This means it varies by platform,
940    /// Rust version, and can even differ within the same execution from one invocation to the next.
941    ///
942    /// This function currently corresponds to the `tgammaf128` from libc on Unix
943    /// and Windows. Note that this might change in the future.
944    ///
945    /// # Examples
946    ///
947    /// ```
948    /// #![feature(f128)]
949    /// #![feature(float_gamma)]
950    /// # #[cfg(not(miri))]
951    /// # #[cfg(target_has_reliable_f128_math)] {
952    ///
953    /// let x = 5.0f128;
954    ///
955    /// let abs_difference = (x.gamma() - 24.0).abs();
956    ///
957    /// assert!(abs_difference <= f128::EPSILON);
958    /// # }
959    /// ```
960    #[inline]
961    #[rustc_allow_incoherent_impl]
962    #[unstable(feature = "f128", issue = "116909")]
963    // #[unstable(feature = "float_gamma", issue = "99842")]
964    #[must_use = "method returns a new number and does not mutate the original value"]
965    pub fn gamma(self) -> f128 {
966        cmath::tgammaf128(self)
967    }
968
969    /// Natural logarithm of the absolute value of the gamma function
970    ///
971    /// The integer part of the tuple indicates the sign of the gamma function.
972    ///
973    /// # Unspecified precision
974    ///
975    /// The precision of this function is non-deterministic. This means it varies by platform,
976    /// Rust version, and can even differ within the same execution from one invocation to the next.
977    ///
978    /// This function currently corresponds to the `lgammaf128_r` from libc on Unix
979    /// and Windows. Note that this might change in the future.
980    ///
981    /// # Examples
982    ///
983    /// ```
984    /// #![feature(f128)]
985    /// #![feature(float_gamma)]
986    /// # #[cfg(not(miri))]
987    /// # #[cfg(target_has_reliable_f128_math)] {
988    ///
989    /// let x = 2.0f128;
990    ///
991    /// let abs_difference = (x.ln_gamma().0 - 0.0).abs();
992    ///
993    /// assert!(abs_difference <= f128::EPSILON);
994    /// # }
995    /// ```
996    #[inline]
997    #[rustc_allow_incoherent_impl]
998    #[unstable(feature = "f128", issue = "116909")]
999    // #[unstable(feature = "float_gamma", issue = "99842")]
1000    #[must_use = "method returns a new number and does not mutate the original value"]
1001    pub fn ln_gamma(self) -> (f128, i32) {
1002        let mut signgamp: i32 = 0;
1003        let x = cmath::lgammaf128_r(self, &mut signgamp);
1004        (x, signgamp)
1005    }
1006
1007    /// Error function.
1008    ///
1009    /// # Unspecified precision
1010    ///
1011    /// The precision of this function is non-deterministic. This means it varies by platform,
1012    /// Rust version, and can even differ within the same execution from one invocation to the next.
1013    ///
1014    /// This function currently corresponds to the `erff128` from libc on Unix
1015    /// and Windows. Note that this might change in the future.
1016    ///
1017    /// # Examples
1018    ///
1019    /// ```
1020    /// #![feature(f128)]
1021    /// #![feature(float_erf)]
1022    /// # #[cfg(not(miri))]
1023    /// # #[cfg(target_has_reliable_f128_math)] {
1024    /// /// The error function relates what percent of a normal distribution lies
1025    /// /// within `x` standard deviations (scaled by `1/sqrt(2)`).
1026    /// fn within_standard_deviations(x: f128) -> f128 {
1027    ///     (x * std::f128::consts::FRAC_1_SQRT_2).erf() * 100.0
1028    /// }
1029    ///
1030    /// // 68% of a normal distribution is within one standard deviation
1031    /// assert!((within_standard_deviations(1.0) - 68.269).abs() < 0.01);
1032    /// // 95% of a normal distribution is within two standard deviations
1033    /// assert!((within_standard_deviations(2.0) - 95.450).abs() < 0.01);
1034    /// // 99.7% of a normal distribution is within three standard deviations
1035    /// assert!((within_standard_deviations(3.0) - 99.730).abs() < 0.01);
1036    /// # }
1037    /// ```
1038    #[rustc_allow_incoherent_impl]
1039    #[must_use = "method returns a new number and does not mutate the original value"]
1040    #[unstable(feature = "f128", issue = "116909")]
1041    // #[unstable(feature = "float_erf", issue = "136321")]
1042    #[inline]
1043    pub fn erf(self) -> f128 {
1044        cmath::erff128(self)
1045    }
1046
1047    /// Complementary error function.
1048    ///
1049    /// # Unspecified precision
1050    ///
1051    /// The precision of this function is non-deterministic. This means it varies by platform,
1052    /// Rust version, and can even differ within the same execution from one invocation to the next.
1053    ///
1054    /// This function currently corresponds to the `erfcf128` from libc on Unix
1055    /// and Windows. Note that this might change in the future.
1056    ///
1057    /// # Examples
1058    ///
1059    /// ```
1060    /// #![feature(f128)]
1061    /// #![feature(float_erf)]
1062    /// # #[cfg(not(miri))]
1063    /// # #[cfg(target_has_reliable_f128_math)] {
1064    /// let x: f128 = 0.123;
1065    ///
1066    /// let one = x.erf() + x.erfc();
1067    /// let abs_difference = (one - 1.0).abs();
1068    ///
1069    /// assert!(abs_difference <= f128::EPSILON);
1070    /// # }
1071    /// ```
1072    #[rustc_allow_incoherent_impl]
1073    #[must_use = "method returns a new number and does not mutate the original value"]
1074    #[unstable(feature = "f128", issue = "116909")]
1075    // #[unstable(feature = "float_erf", issue = "136321")]
1076    #[inline]
1077    pub fn erfc(self) -> f128 {
1078        cmath::erfcf128(self)
1079    }
1080}