glibc/math/s_catanf.c

86 lines
2.3 KiB
C

/* Return arc tangent of complex float value.
Copyright (C) 1997, 2011 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 <math.h>
#include <math_private.h>
__complex__ float
__catanf (__complex__ float x)
{
__complex__ float res;
int rcls = fpclassify (__real__ x);
int icls = fpclassify (__imag__ x);
if (__builtin_expect (rcls <= FP_INFINITE || icls <= FP_INFINITE, 0))
{
if (rcls == FP_INFINITE)
{
__real__ res = __copysignf (M_PI_2, __real__ x);
__imag__ res = __copysignf (0.0, __imag__ x);
}
else if (icls == FP_INFINITE)
{
if (rcls >= FP_ZERO)
__real__ res = __copysignf (M_PI_2, __real__ x);
else
__real__ res = __nanf ("");
__imag__ res = __copysignf (0.0, __imag__ x);
}
else if (icls == FP_ZERO || icls == FP_INFINITE)
{
__real__ res = __nanf ("");
__imag__ res = __copysignf (0.0, __imag__ x);
}
else
{
__real__ res = __nanf ("");
__imag__ res = __nanf ("");
}
}
else if (__builtin_expect (rcls == FP_ZERO && icls == FP_ZERO, 0))
{
res = x;
}
else
{
float r2, num, den;
r2 = __real__ x * __real__ x;
den = 1 - r2 - __imag__ x * __imag__ x;
__real__ res = 0.5 * __ieee754_atan2f (2.0 * __real__ x, den);
num = __imag__ x + 1.0;
num = r2 + num * num;
den = __imag__ x - 1.0;
den = r2 + den * den;
__imag__ res = 0.25 * __ieee754_logf (num / den);
}
return res;
}
#ifndef __catanf
weak_alias (__catanf, catanf)
#endif