82 lines
2.0 KiB
C
82 lines
2.0 KiB
C
/* Complex tangent function for double.
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Copyright (C) 1997, 2005, 2011 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, see
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<http://www.gnu.org/licenses/>. */
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#include <complex.h>
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#include <fenv.h>
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#include <math.h>
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#include <math_private.h>
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__complex__ double
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__ctan (__complex__ double x)
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{
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__complex__ double res;
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if (__builtin_expect (!isfinite (__real__ x) || !isfinite (__imag__ x), 0))
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{
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if (__isinf_ns (__imag__ x))
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{
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__real__ res = __copysign (0.0, __real__ x);
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__imag__ res = __copysign (1.0, __imag__ x);
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}
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else if (__real__ x == 0.0)
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{
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res = x;
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}
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else
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{
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__real__ res = __nan ("");
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__imag__ res = __nan ("");
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if (__isinf_ns (__real__ x))
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feraiseexcept (FE_INVALID);
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}
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}
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else
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{
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double sin2rx, cos2rx;
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double den;
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__sincos (2.0 * __real__ x, &sin2rx, &cos2rx);
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den = cos2rx + __ieee754_cosh (2.0 * __imag__ x);
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if (den == 0.0)
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{
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__complex__ double ez = __cexp (1.0i * x);
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__complex__ double emz = __cexp (-1.0i * x);
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res = (ez - emz) / (ez + emz) * -1.0i;
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}
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else
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{
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__real__ res = sin2rx / den;
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__imag__ res = __ieee754_sinh (2.0 * __imag__ x) / den;
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}
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}
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return res;
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}
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weak_alias (__ctan, ctan)
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#ifdef NO_LONG_DOUBLE
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strong_alias (__ctan, __ctanl)
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weak_alias (__ctan, ctanl)
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#endif
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