third-party-mirror / mingw-w64 / 79951edef1e76a79d7ce0fa1cf94391b2f6b3d94 / . / mingw-w64-crt / math / arm-common / atanh.c

/** | |

* 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; | |

} |