diff options
Diffstat (limited to 'math/k_casinh.c')
| -rw-r--r-- | math/k_casinh.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/math/k_casinh.c b/math/k_casinh.c index 41cd5ec47d..45845e2164 100644 --- a/math/k_casinh.c +++ b/math/k_casinh.c @@ -77,6 +77,31 @@ __kernel_casinh (__complex__ double x, int adj) else __imag__ res = __ieee754_atan2 (s, rx); } + else if (ix == 1.0 && rx < 0.5) + { + if (rx < DBL_EPSILON / 8.0) + { + __real__ res = __log1p (2.0 * (rx + __ieee754_sqrt (rx))) / 2.0; + if (adj) + __imag__ res = __ieee754_atan2 (__ieee754_sqrt (rx), + __copysign (1.0, __imag__ x)); + else + __imag__ res = __ieee754_atan2 (1.0, __ieee754_sqrt (rx)); + } + else + { + double d = rx * __ieee754_sqrt (4.0 + rx * rx); + double s1 = __ieee754_sqrt ((d + rx * rx) / 2.0); + double s2 = __ieee754_sqrt ((d - rx * rx) / 2.0); + + __real__ res = __log1p (rx * rx + d + 2.0 * (rx * s1 + s2)) / 2.0; + if (adj) + __imag__ res = __ieee754_atan2 (rx + s1, __copysign (1.0 + s2, + __imag__ x)); + else + __imag__ res = __ieee754_atan2 (1.0 + s2, rx + s1); + } + } else { __real__ y = (rx - ix) * (rx + ix) + 1.0; |