1 use super::expf; 2 use super::expm1f; 3 use super::k_expo2f; 4 5 /// Hyperbolic cosine (f64) 6 /// 7 /// Computes the hyperbolic cosine of the argument x. 8 /// Is defined as `(exp(x) + exp(-x))/2` 9 /// Angles are specified in radians. 10 #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] coshf(mut x: f32) -> f3211pub fn coshf(mut x: f32) -> f32 { 12 let x1p120 = f32::from_bits(0x7b800000); // 0x1p120f === 2 ^ 120 13 14 /* |x| */ 15 let mut ix = x.to_bits(); 16 ix &= 0x7fffffff; 17 x = f32::from_bits(ix); 18 let w = ix; 19 20 /* |x| < log(2) */ 21 if w < 0x3f317217 { 22 if w < (0x3f800000 - (12 << 23)) { 23 force_eval!(x + x1p120); 24 return 1.; 25 } 26 let t = expm1f(x); 27 return 1. + t * t / (2. * (1. + t)); 28 } 29 30 /* |x| < log(FLT_MAX) */ 31 if w < 0x42b17217 { 32 let t = expf(x); 33 return 0.5 * (t + 1. / t); 34 } 35 36 /* |x| > log(FLT_MAX) or nan */ 37 k_expo2f(x) 38 } 39