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50 lines
1.5 KiB
C
50 lines
1.5 KiB
C
/* Compute projection of complex float value to Riemann sphere.
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Copyright (C) 1997, 1999 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <complex.h>
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#include <math.h>
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__complex__ float
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__cprojf (__complex__ float x)
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{
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__complex__ float res;
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if (isnan (__real__ x) && isnan (__imag__ x))
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return x;
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else if (!isfinite (__real__ x) || !isfinite (__imag__ x))
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{
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__real__ res = INFINITY;
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__imag__ res = __copysignf (0.0, __imag__ x);
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}
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else
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{
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float den = __real__ x * __real__ x + __imag__ x * __imag__ x + 1.0;
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__real__ res = (2.0 * __real__ x) / den;
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__imag__ res = (2.0 * __imag__ x) / den;
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}
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return res;
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}
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#ifndef __cprojf
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weak_alias (__cprojf, cprojf)
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#endif
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