From 0ecb606cb6cf65de1d9fc8a919bceb4be476c602 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Thu, 12 Jul 2007 18:26:36 +0000 Subject: 2.5-18.1 --- math/s_catanh.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 math/s_catanh.c (limited to 'math/s_catanh.c') diff --git a/math/s_catanh.c b/math/s_catanh.c new file mode 100644 index 0000000..e15c073 --- /dev/null +++ b/math/s_catanh.c @@ -0,0 +1,84 @@ +/* Return arc hyperbole tangent for double value. + Copyright (C) 1997 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper , 1997. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include +#include + +#include "math_private.h" + + +__complex__ double +__catanh (__complex__ double x) +{ + __complex__ double res; + int rcls = fpclassify (__real__ x); + int icls = fpclassify (__imag__ x); + + if (rcls <= FP_INFINITE || icls <= FP_INFINITE) + { + if (icls == FP_INFINITE) + { + __real__ res = __copysign (0.0, __real__ x); + __imag__ res = __copysign (M_PI_2, __imag__ x); + } + else if (rcls == FP_INFINITE || rcls == FP_ZERO) + { + __real__ res = __copysign (0.0, __real__ x); + if (icls >= FP_ZERO) + __imag__ res = __copysign (M_PI_2, __imag__ x); + else + __imag__ res = __nan (""); + } + else + { + __real__ res = __nan (""); + __imag__ res = __nan (""); + } + } + else if (rcls == FP_ZERO && icls == FP_ZERO) + { + res = x; + } + else + { + double i2, num, den; + + i2 = __imag__ x * __imag__ x; + + num = 1.0 + __real__ x; + num = i2 + num * num; + + den = 1.0 - __real__ x; + den = i2 + den * den; + + __real__ res = 0.25 * (__ieee754_log (num) - __ieee754_log (den)); + + den = 1 - __real__ x * __real__ x - i2; + + __imag__ res = 0.5 * __ieee754_atan2 (2.0 * __imag__ x, den); + } + + return res; +} +weak_alias (__catanh, catanh) +#ifdef NO_LONG_DOUBLE +strong_alias (__catanh, __catanhl) +weak_alias (__catanh, catanhl) +#endif -- cgit v1.1