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Diffstat (limited to 'math/s_cprojf.c')
-rw-r--r-- | math/s_cprojf.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/math/s_cprojf.c b/math/s_cprojf.c new file mode 100644 index 0000000..83df13c --- /dev/null +++ b/math/s_cprojf.c @@ -0,0 +1,49 @@ +/* Compute projection of complex float 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 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> + + +__complex__ float +__cprojf (__complex__ float x) +{ + __complex__ float res; + + if (isnan (__real__ x) && isnan (__imag__ x)) + return x; + else if (!isfinite (__real__ x) || !isfinite (__imag__ x)) + { + __real__ res = INFINITY; + __imag__ res = __copysignf (0.0, __imag__ x); + } + else + { + float 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; +} +#ifndef __cprojf +weak_alias (__cprojf, cprojf) +#endif |