| use super::expf; |
| use super::expm1f; |
| use super::k_expo2f; |
| |
| /// Hyperbolic cosine (f64) |
| /// |
| /// Computes the hyperbolic cosine of the argument x. |
| /// Is defined as `(exp(x) + exp(-x))/2` |
| /// Angles are specified in radians. |
| #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] |
| pub fn coshf(mut x: f32) -> f32 { |
| let x1p120 = f32::from_bits(0x7b800000); // 0x1p120f === 2 ^ 120 |
| |
| /* |x| */ |
| let mut ix = x.to_bits(); |
| ix &= 0x7fffffff; |
| x = f32::from_bits(ix); |
| let w = ix; |
| |
| /* |x| < log(2) */ |
| if w < 0x3f317217 { |
| if w < (0x3f800000 - (12 << 23)) { |
| force_eval!(x + x1p120); |
| return 1.; |
| } |
| let t = expm1f(x); |
| return 1. + t * t / (2. * (1. + t)); |
| } |
| |
| /* |x| < log(FLT_MAX) */ |
| if w < 0x42b17217 { |
| let t = expf(x); |
| return 0.5 * (t + 1. / t); |
| } |
| |
| /* |x| > log(FLT_MAX) or nan */ |
| k_expo2f(x) |
| } |
