| /** | |
| * This file has no copyright assigned and is placed in the Public Domain. | |
| * This file is part of the mingw-w64 runtime package. | |
| * No warranty is given; refer to the file DISCLAIMER.PD within this package. | |
| */ | |
| #include <math.h> | |
| double atanh(double x) | |
| { | |
| if (x > 1 || x < -1) | |
| return NAN; | |
| if (-1e-6 < x && x < 1e-6) | |
| return x + x*x*x/3; | |
| else | |
| return (log(1 + x) - log(1 - x)) / 2; | |
| } |