diff options
Diffstat (limited to 'library/std/src/f64.rs')
| -rw-r--r-- | library/std/src/f64.rs | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/library/std/src/f64.rs b/library/std/src/f64.rs index 31351a879..ec67fdad4 100644 --- a/library/std/src/f64.rs +++ b/library/std/src/f64.rs @@ -77,9 +77,11 @@ impl f64 { /// ``` /// let f = 3.3_f64; /// let g = -3.3_f64; + /// let h = -3.7_f64; /// /// assert_eq!(f.round(), 3.0); /// assert_eq!(g.round(), -3.0); + /// assert_eq!(h.round(), -4.0); /// ``` #[rustc_allow_incoherent_impl] #[must_use = "method returns a new number and does not mutate the original value"] @@ -275,7 +277,7 @@ impl f64 { /// This result is not an element of the function's codomain, but it is the /// closest floating point number in the real numbers and thus fulfills the /// property `self == self.div_euclid(rhs) * rhs + self.rem_euclid(rhs)` - /// approximatively. + /// approximately. /// /// # Examples /// @@ -880,7 +882,9 @@ impl f64 { #[stable(feature = "rust1", since = "1.0.0")] #[inline] pub fn asinh(self) -> f64 { - (self.abs() + ((self * self) + 1.0).sqrt()).ln().copysign(self) + let ax = self.abs(); + let ix = 1.0 / ax; + (ax + (ax / (Self::hypot(1.0, ix) + ix))).ln_1p().copysign(self) } /// Inverse hyperbolic cosine function. @@ -900,7 +904,11 @@ impl f64 { #[stable(feature = "rust1", since = "1.0.0")] #[inline] pub fn acosh(self) -> f64 { - if self < 1.0 { Self::NAN } else { (self + ((self * self) - 1.0).sqrt()).ln() } + if self < 1.0 { + Self::NAN + } else { + (self + ((self - 1.0).sqrt() * (self + 1.0).sqrt())).ln() + } } /// Inverse hyperbolic tangent function. |