]>
git.ipfire.org Git - thirdparty/glibc.git/blob - sysdeps/libm-ieee754/s_ctanh.c
1 /* Complex hyperbole tangent for double.
2 Copyright (C) 1997 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 Library General Public License as
8 published by the Free Software Foundation; either version 2 of the
9 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 Library General Public License for more details.
16 You should have received a copy of the GNU Library General Public
17 License along with the GNU C Library; see the file COPYING.LIB. If not,
18 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
24 #include "math_private.h"
28 __ctanh (__complex__
double x
)
30 __complex__
double res
;
32 if (!isfinite (__real__ x
) || !isfinite (__imag__ x
))
34 if (__isinf (__real__ x
))
36 __real__ res
= __copysign (1.0, __real__ x
);
37 __imag__ res
= __copysign (0.0, __imag__ x
);
39 else if (__imag__ x
== 0.0)
45 __real__ res
= __nan ("");
46 __imag__ res
= __nan ("");
51 double sin2ix
, cos2ix
;
54 __sincos (2.0 * __imag__ x
, &sin2ix
, &cos2ix
);
56 den
= (__ieee754_cosh (2.0 * __real__ x
) + cos2ix
);
58 __real__ res
= __ieee754_sinh (2.0 * __real__ x
) / den
;
59 __imag__ res
= sin2ix
/ den
;
64 weak_alias (__ctanh
, ctanh
)
66 strong_alias (__ctanh
, __ctanhl
)
67 weak_alias (__ctanh
, ctanhl
)