diff options
Diffstat (limited to 'vendor/libm/src/math/cosh.rs')
-rw-r--r-- | vendor/libm/src/math/cosh.rs | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/vendor/libm/src/math/cosh.rs b/vendor/libm/src/math/cosh.rs new file mode 100644 index 000000000..bac875566 --- /dev/null +++ b/vendor/libm/src/math/cosh.rs @@ -0,0 +1,39 @@ +use super::exp; +use super::expm1; +use super::k_expo2; + +/// Hyperbolic cosine (f64) +/// +/// Computes the hyperbolic cosine of the argument x. +/// Is defined as `(exp(x) + exp(-x))/2` +/// Angles are specified in radians. +#[inline] +#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] +pub fn cosh(mut x: f64) -> f64 { + /* |x| */ + let mut ix = x.to_bits(); + ix &= 0x7fffffffffffffff; + x = f64::from_bits(ix); + let w = ix >> 32; + + /* |x| < log(2) */ + if w < 0x3fe62e42 { + if w < 0x3ff00000 - (26 << 20) { + let x1p120 = f64::from_bits(0x4770000000000000); + force_eval!(x + x1p120); + return 1.; + } + let t = expm1(x); // exponential minus 1 + return 1. + t * t / (2. * (1. + t)); + } + + /* |x| < log(DBL_MAX) */ + if w < 0x40862e42 { + let t = exp(x); + /* note: if x>log(0x1p26) then the 1/t is not needed */ + return 0.5 * (t + 1. / t); + } + + /* |x| > log(DBL_MAX) or nan */ + k_expo2(x) +} |