Permalink
Cannot retrieve contributors at this time
Name already in use
A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
glibc/math/s_ctanhl.c
Go to fileThis commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
132 lines (118 sloc)
3.56 KB
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/* Complex hyperbole tangent for long 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> | |
/* To avoid spurious underflows, use this definition to treat IBM long | |
double as approximating an IEEE-style format. */ | |
#if LDBL_MANT_DIG == 106 | |
# undef LDBL_EPSILON | |
# define LDBL_EPSILON 0x1p-106L | |
#endif | |
__complex__ long double | |
__ctanhl (__complex__ long double x) | |
{ | |
__complex__ long double res; | |
if (__glibc_unlikely (!isfinite (__real__ x) || !isfinite (__imag__ x))) | |
{ | |
if (isinf (__real__ x)) | |
{ | |
__real__ res = __copysignl (1.0, __real__ x); | |
if (isfinite (__imag__ x) && fabsl (__imag__ x) > 1.0L) | |
{ | |
long double sinix, cosix; | |
__sincosl (__imag__ x, &sinix, &cosix); | |
__imag__ res = __copysignl (0.0L, sinix * cosix); | |
} | |
else | |
__imag__ res = __copysignl (0.0, __imag__ x); | |
} | |
else if (__imag__ x == 0.0) | |
{ | |
res = x; | |
} | |
else | |
{ | |
__real__ res = __nanl (""); | |
__imag__ res = __nanl (""); | |
if (isinf (__imag__ x)) | |
feraiseexcept (FE_INVALID); | |
} | |
} | |
else | |
{ | |
long double sinix, cosix; | |
long double den; | |
const int t = (int) ((LDBL_MAX_EXP - 1) * M_LN2l / 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 (fabsl (__imag__ x) > LDBL_MIN)) | |
{ | |
__sincosl (__imag__ x, &sinix, &cosix); | |
} | |
else | |
{ | |
sinix = __imag__ x; | |
cosix = 1.0; | |
} | |
if (fabsl (__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). */ | |
long double exp_2t = __ieee754_expl (2 * t); | |
__real__ res = __copysignl (1.0, __real__ x); | |
__imag__ res = 4 * sinix * cosix; | |
__real__ x = fabsl (__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_expl (2 * __real__ x); | |
} | |
else | |
{ | |
long double sinhrx, coshrx; | |
if (fabsl (__real__ x) > LDBL_MIN) | |
{ | |
sinhrx = __ieee754_sinhl (__real__ x); | |
coshrx = __ieee754_coshl (__real__ x); | |
} | |
else | |
{ | |
sinhrx = __real__ x; | |
coshrx = 1.0L; | |
} | |
if (fabsl (sinhrx) > fabsl (cosix) * LDBL_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 (__ctanhl, ctanhl) |