111 lines
2.9 KiB
C
111 lines
2.9 KiB
C
|
/* Complex square root of long double value.
|
||
|
|
Copyright (C) 1997, 1998 Free Software Foundation, Inc.
|
||
|
|
This file is part of the GNU C Library.
|
||
|
|
Based on an algorithm by Stephen L. Moshier <moshier@world.std.com>.
|
||
|
|
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, write to the Free
|
||
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
||
|
|
02111-1307 USA. */
|
||
|
|
|
||
|
|
#include <complex.h>
|
||
|
|
#include <math.h>
|
||
|
|
|
||
|
|
#include "math_private.h"
|
||
|
|
|
||
|
|
|
||
|
|
__complex__ long double
|
||
|
|
__csqrtl (__complex__ long double x)
|
||
|
|
{
|
||
|
|
__complex__ long double res;
|
||
|
|
int rcls = fpclassify (__real__ x);
|
||
|
|
int icls = fpclassify (__imag__ x);
|
||
|
|
|
||
|
|
if (rcls <= FP_INFINITE || icls <= FP_INFINITE)
|
||
|
|
{
|
||
|
|
if (icls == FP_INFINITE)
|
||
|
|
{
|
||
|
|
__real__ res = HUGE_VALL;
|
||
|
|
__imag__ res = __imag__ x;
|
||
|
|
}
|
||
|
|
else if (rcls == FP_INFINITE)
|
||
|
|
{
|
||
|
|
if (__real__ x < 0.0)
|
||
|
|
{
|
||
|
|
__real__ res = icls == FP_NAN ? __nanl ("") : 0;
|
||
|
|
__imag__ res = __copysignl (HUGE_VALL, __imag__ x);
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
__real__ res = __real__ x;
|
||
|
|
__imag__ res = (icls == FP_NAN
|
||
|
|
? __nanl ("") : __copysignl (0.0, __imag__ x));
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
__real__ res = __nanl ("");
|
||
|
|
__imag__ res = __nanl ("");
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
if (icls == FP_ZERO)
|
||
|
|
{
|
||
|
|
if (__real__ x < 0.0)
|
||
|
|
{
|
||
|
|
__real__ res = 0.0;
|
||
|
|
__imag__ res = __copysignl (__ieee754_sqrtl (-__real__ x),
|
||
|
|
__imag__ x);
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
__real__ res = fabsl (__ieee754_sqrtl (__real__ x));
|
||
|
|
__imag__ res = __copysignl (0.0, __imag__ x);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else if (rcls == FP_ZERO)
|
||
|
|
{
|
||
|
|
long double r = __ieee754_sqrtl (0.5 * fabsl (__imag__ x));
|
||
|
|
|
||
|
|
__real__ res = __copysignl (r, __imag__ x);
|
||
|
|
__imag__ res = r;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
long double d, r, s;
|
||
|
|
|
||
|
|
d = __ieee754_hypotl (__real__ x, __imag__ x);
|
||
|
|
/* Use the identity 2 Re res Im res = Im x
|
||
|
|
to avoid cancellation error in d +/- Re x. */
|
||
|
|
if (__real__ x > 0)
|
||
|
|
{
|
||
|
|
r = __ieee754_sqrtl (0.5L * d + 0.5L * __real__ x);
|
||
|
|
s = (0.5L * __imag__ x) / r;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
s = __ieee754_sqrtl (0.5L * d - 0.5L * __real__ x);
|
||
|
|
r = fabsl ((0.5L * __imag__ x) / s);
|
||
|
|
}
|
||
|
|
|
||
|
|
__real__ res = r;
|
||
|
|
__imag__ res = __copysignl (s, __imag__ x);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return res;
|
||
|
|
}
|
||
|
|
weak_alias (__csqrtl, csqrtl)
|