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/* Compute projection of complex double value to Riemann sphere.
Copyright (C) 1997, 1999 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 <math.h>
__complex__ double
__cproj (__complex__ double x)
{
__complex__ double res;
if (isnan (__real__ x) && isnan (__imag__ x))
return x;
else if (!isfinite (__real__ x) || !isfinite (__imag__ x))
{
__real__ res = INFINITY;
__imag__ res = __copysign (0.0, __imag__ x);
}
else
{
double den = __real__ x * __real__ x + __imag__ x * __imag__ x + 1.0;
__real__ res = (2.0 * __real__ x) / den;
__imag__ res = (2.0 * __imag__ x) / den;
}
return res;
}
weak_alias (__cproj, cproj)
#ifdef NO_LONG_DOUBLE
strong_alias (__cproj, __cprojl)
weak_alias (__cproj, cprojl)
#endif
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