1 use super::{expm1, expo2}; 2 3 // sinh(x) = (exp(x) - 1/exp(x))/2 4 // = (exp(x)-1 + (exp(x)-1)/exp(x))/2 5 // = x + x^3/6 + o(x^5) 6 // 7 8 /// The hyperbolic sine of `x` (f64). 9 #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] sinh(x: f64) -> f6410pub fn sinh(x: f64) -> f64 { 11 // union {double f; uint64_t i;} u = {.f = x}; 12 // uint32_t w; 13 // double t, h, absx; 14 15 let mut uf: f64 = x; 16 let mut ui: u64 = f64::to_bits(uf); 17 let w: u32; 18 let t: f64; 19 let mut h: f64; 20 let absx: f64; 21 22 h = 0.5; 23 if ui >> 63 != 0 { 24 h = -h; 25 } 26 /* |x| */ 27 ui &= !1 / 2; 28 uf = f64::from_bits(ui); 29 absx = uf; 30 w = (ui >> 32) as u32; 31 32 /* |x| < log(DBL_MAX) */ 33 if w < 0x40862e42 { 34 t = expm1(absx); 35 if w < 0x3ff00000 { 36 if w < 0x3ff00000 - (26 << 20) { 37 /* note: inexact and underflow are raised by expm1 */ 38 /* note: this branch avoids spurious underflow */ 39 return x; 40 } 41 return h * (2.0 * t - t * t / (t + 1.0)); 42 } 43 /* note: |x|>log(0x1p26)+eps could be just h*exp(x) */ 44 return h * (t + t / (t + 1.0)); 45 } 46 47 /* |x| > log(DBL_MAX) or nan */ 48 /* note: the result is stored to handle overflow */ 49 t = 2.0 * h * expo2(absx); 50 t 51 } 52