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_ctan.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 math/s_ctan.c (limited to 'math/s_ctan.c') diff --git a/math/s_ctan.c b/math/s_ctan.c new file mode 100644 index 0000000..0464ab8 --- /dev/null +++ b/math/s_ctan.c @@ -0,0 +1,84 @@ +/* Complex tangent function for double. + Copyright (C) 1997, 2005 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 + +#include "math_private.h" + + +__complex__ double +__ctan (__complex__ double x) +{ + __complex__ double res; + + if (!isfinite (__real__ x) || !isfinite (__imag__ x)) + { + if (__isinf (__imag__ x)) + { + __real__ res = __copysign (0.0, __real__ x); + __imag__ res = __copysign (1.0, __imag__ x); + } + else if (__real__ x == 0.0) + { + res = x; + } + else + { + __real__ res = __nan (""); + __imag__ res = __nan (""); + +#ifdef FE_INVALID + if (__isinf (__real__ x)) + feraiseexcept (FE_INVALID); +#endif + } + } + else + { + double sin2rx, cos2rx; + double den; + + __sincos (2.0 * __real__ x, &sin2rx, &cos2rx); + + den = cos2rx + __ieee754_cosh (2.0 * __imag__ x); + + if (den == 0.0) + { + __complex__ double ez = __cexp (1.0i * x); + __complex__ double emz = __cexp (-1.0i * x); + + res = (ez - emz) / (ez + emz) * -1.0i; + } + else + { + __real__ res = sin2rx / den; + __imag__ res = __ieee754_sinh (2.0 * __imag__ x) / den; + } + } + + return res; +} +weak_alias (__ctan, ctan) +#ifdef NO_LONG_DOUBLE +strong_alias (__ctan, __ctanl) +weak_alias (__ctan, ctanl) +#endif -- cgit v1.1