mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-26 20:51:11 +00:00
130 lines
3.4 KiB
C
130 lines
3.4 KiB
C
/* Complex hyperbole tangent for double.
|
|
Copyright (C) 1997-2016 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, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <complex.h>
|
|
#include <fenv.h>
|
|
#include <math.h>
|
|
#include <math_private.h>
|
|
#include <float.h>
|
|
|
|
__complex__ double
|
|
__ctanh (__complex__ double x)
|
|
{
|
|
__complex__ double res;
|
|
|
|
if (__glibc_unlikely (!isfinite (__real__ x) || !isfinite (__imag__ x)))
|
|
{
|
|
if (isinf (__real__ x))
|
|
{
|
|
__real__ res = __copysign (1.0, __real__ x);
|
|
if (isfinite (__imag__ x) && fabs (__imag__ x) > 1.0)
|
|
{
|
|
double sinix, cosix;
|
|
__sincos (__imag__ x, &sinix, &cosix);
|
|
__imag__ res = __copysign (0.0, sinix * cosix);
|
|
}
|
|
else
|
|
__imag__ res = __copysign (0.0, __imag__ x);
|
|
}
|
|
else if (__imag__ x == 0.0)
|
|
{
|
|
res = x;
|
|
}
|
|
else
|
|
{
|
|
__real__ res = __nan ("");
|
|
__imag__ res = __nan ("");
|
|
|
|
if (isinf (__imag__ x))
|
|
feraiseexcept (FE_INVALID);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
double sinix, cosix;
|
|
double den;
|
|
const int t = (int) ((DBL_MAX_EXP - 1) * M_LN2 / 2);
|
|
|
|
/* tanh(x+iy) = (sinh(2x) + i*sin(2y))/(cosh(2x) + cos(2y))
|
|
= (sinh(x)*cosh(x) + i*sin(y)*cos(y))/(sinh(x)^2 + cos(y)^2). */
|
|
|
|
if (__glibc_likely (fabs (__imag__ x) > DBL_MIN))
|
|
{
|
|
__sincos (__imag__ x, &sinix, &cosix);
|
|
}
|
|
else
|
|
{
|
|
sinix = __imag__ x;
|
|
cosix = 1.0;
|
|
}
|
|
|
|
if (fabs (__real__ x) > t)
|
|
{
|
|
/* Avoid intermediate overflow when the imaginary part of
|
|
the result may be subnormal. Ignoring negligible terms,
|
|
the real part is +/- 1, the imaginary part is
|
|
sin(y)*cos(y)/sinh(x)^2 = 4*sin(y)*cos(y)/exp(2x). */
|
|
double exp_2t = __ieee754_exp (2 * t);
|
|
|
|
__real__ res = __copysign (1.0, __real__ x);
|
|
__imag__ res = 4 * sinix * cosix;
|
|
__real__ x = fabs (__real__ x);
|
|
__real__ x -= t;
|
|
__imag__ res /= exp_2t;
|
|
if (__real__ x > t)
|
|
{
|
|
/* Underflow (original real part of x has absolute value
|
|
> 2t). */
|
|
__imag__ res /= exp_2t;
|
|
}
|
|
else
|
|
__imag__ res /= __ieee754_exp (2 * __real__ x);
|
|
}
|
|
else
|
|
{
|
|
double sinhrx, coshrx;
|
|
if (fabs (__real__ x) > DBL_MIN)
|
|
{
|
|
sinhrx = __ieee754_sinh (__real__ x);
|
|
coshrx = __ieee754_cosh (__real__ x);
|
|
}
|
|
else
|
|
{
|
|
sinhrx = __real__ x;
|
|
coshrx = 1.0;
|
|
}
|
|
|
|
if (fabs (sinhrx) > fabs (cosix) * DBL_EPSILON)
|
|
den = sinhrx * sinhrx + cosix * cosix;
|
|
else
|
|
den = cosix * cosix;
|
|
__real__ res = sinhrx * coshrx / den;
|
|
__imag__ res = sinix * cosix / den;
|
|
}
|
|
math_check_force_underflow_complex (res);
|
|
}
|
|
|
|
return res;
|
|
}
|
|
weak_alias (__ctanh, ctanh)
|
|
#ifdef NO_LONG_DOUBLE
|
|
strong_alias (__ctanh, __ctanhl)
|
|
weak_alias (__ctanh, ctanhl)
|
|
#endif
|