/* 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 <drepper@cygnus.com>, 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 <complex.h> #include <fenv.h> #include <math.h> #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