glibc/sysdeps/generic/s_ctanh.c
Ulrich Drepper abfbdde177 Update.
1999-07-14 00:54:57 +00:00

75 lines
1.9 KiB
C

/* Complex hyperbole tangent for double.
Copyright (C) 1997 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. 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
__ctanh (__complex__ double x)
{
__complex__ double res;
if (!isfinite (__real__ x) || !isfinite (__imag__ x))
{
if (__isinf (__real__ x))
{
__real__ res = __copysign (1.0, __real__ x);
__imag__ res = __copysign (0.0, __imag__ x);
}
else if (__imag__ x == 0.0)
{
res = x;
}
else
{
__real__ res = __nan ("");
__imag__ res = __nan ("");
#ifdef FE_INVALID
if (__isinf (__imag__ x))
feraiseexcept (FE_INVALID);
#endif
}
}
else
{
double sin2ix, cos2ix;
double den;
__sincos (2.0 * __imag__ x, &sin2ix, &cos2ix);
den = (__ieee754_cosh (2.0 * __real__ x) + cos2ix);
__real__ res = __ieee754_sinh (2.0 * __real__ x) / den;
__imag__ res = sin2ix / den;
}
return res;
}
weak_alias (__ctanh, ctanh)
#ifdef NO_LONG_DOUBLE
strong_alias (__ctanh, __ctanhl)
weak_alias (__ctanh, ctanhl)
#endif