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