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[glibc/history.git] / math / s_ctanhf.c
blobc331dbaabbd15c0b4e9dbcc557197d03c3a7f1eb
1 /* Complex hyperbole tangent for float.
2 Copyright (C) 1997, 2005 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19 02111-1307 USA. */
21 #include <complex.h>
22 #include <fenv.h>
23 #include <math.h>
25 #include "math_private.h"
28 __complex__ float
29 __ctanhf (__complex__ float x)
31 __complex__ float res;
33 if (!isfinite (__real__ x) || !isfinite (__imag__ x))
35 if (__isinff (__real__ x))
37 __real__ res = __copysignf (1.0, __real__ x);
38 __imag__ res = __copysignf (0.0, __imag__ x);
40 else if (__imag__ x == 0.0)
42 res = x;
44 else
46 __real__ res = __nanf ("");
47 __imag__ res = __nanf ("");
49 #ifdef FE_INVALID
50 if (__isinff (__imag__ x))
51 feraiseexcept (FE_INVALID);
52 #endif
55 else
57 float sin2ix, cos2ix;
58 float den;
60 __sincosf (2.0 * __imag__ x, &sin2ix, &cos2ix);
62 den = (__ieee754_coshf (2.0 * __real__ x) + cos2ix);
64 if (den == 0.0f)
66 __complex__ float ez = __cexpf (x);
67 __complex__ float emz = __cexpf (-x);
69 res = (ez - emz) / (ez + emz);
71 else
73 __real__ res = __ieee754_sinhf (2.0 * __real__ x) / den;
74 __imag__ res = sin2ix / den;
78 return res;
80 #ifndef __ctanhf
81 weak_alias (__ctanhf, ctanhf)
82 #endif