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136 lines
3.5 KiB
C
136 lines
3.5 KiB
C
/* Return arc hyperbolic tangent for a complex float type.
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Copyright (C) 1997-2018 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 <math.h>
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#include <math_private.h>
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#include <float.h>
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CFLOAT
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M_DECL_FUNC (__catanh) (CFLOAT x)
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{
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CFLOAT res;
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int rcls = fpclassify (__real__ x);
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int icls = fpclassify (__imag__ x);
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if (__glibc_unlikely (rcls <= FP_INFINITE || icls <= FP_INFINITE))
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{
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if (icls == FP_INFINITE)
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{
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__real__ res = M_COPYSIGN (0, __real__ x);
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__imag__ res = M_COPYSIGN (M_MLIT (M_PI_2), __imag__ x);
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}
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else if (rcls == FP_INFINITE || rcls == FP_ZERO)
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{
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__real__ res = M_COPYSIGN (0, __real__ x);
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if (icls >= FP_ZERO)
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__imag__ res = M_COPYSIGN (M_MLIT (M_PI_2), __imag__ x);
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else
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__imag__ res = M_NAN;
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}
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else
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{
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__real__ res = M_NAN;
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__imag__ res = M_NAN;
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}
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}
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else if (__glibc_unlikely (rcls == FP_ZERO && icls == FP_ZERO))
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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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if (M_FABS (__real__ x) >= 16 / M_EPSILON
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|| M_FABS (__imag__ x) >= 16 / M_EPSILON)
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{
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__imag__ res = M_COPYSIGN (M_MLIT (M_PI_2), __imag__ x);
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if (M_FABS (__imag__ x) <= 1)
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__real__ res = 1 / __real__ x;
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else if (M_FABS (__real__ x) <= 1)
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__real__ res = __real__ x / __imag__ x / __imag__ x;
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else
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{
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FLOAT h = M_HYPOT (__real__ x / 2, __imag__ x / 2);
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__real__ res = __real__ x / h / h / 4;
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}
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}
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else
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{
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if (M_FABS (__real__ x) == 1
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&& M_FABS (__imag__ x) < M_EPSILON * M_EPSILON)
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__real__ res = (M_COPYSIGN (M_LIT (0.5), __real__ x)
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* ((FLOAT) M_MLIT (M_LN2)
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- M_LOG (M_FABS (__imag__ x))));
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else
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{
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FLOAT i2 = 0;
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if (M_FABS (__imag__ x) >= M_EPSILON * M_EPSILON)
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i2 = __imag__ x * __imag__ x;
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FLOAT num = 1 + __real__ x;
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num = i2 + num * num;
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FLOAT den = 1 - __real__ x;
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den = i2 + den * den;
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FLOAT f = num / den;
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if (f < M_LIT (0.5))
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__real__ res = M_LIT (0.25) * M_LOG (f);
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else
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{
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num = 4 * __real__ x;
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__real__ res = M_LIT (0.25) * M_LOG1P (num / den);
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}
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}
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FLOAT absx, absy, den;
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absx = M_FABS (__real__ x);
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absy = M_FABS (__imag__ x);
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if (absx < absy)
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{
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FLOAT t = absx;
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absx = absy;
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absy = t;
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}
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if (absy < M_EPSILON / 2)
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{
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den = (1 - absx) * (1 + absx);
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if (den == 0)
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den = 0;
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}
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else if (absx >= 1)
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den = (1 - absx) * (1 + absx) - absy * absy;
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else if (absx >= M_LIT (0.75) || absy >= M_LIT (0.5))
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den = -M_SUF (__x2y2m1) (absx, absy);
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else
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den = (1 - absx) * (1 + absx) - absy * absy;
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__imag__ res = M_LIT (0.5) * M_ATAN2 (2 * __imag__ x, den);
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}
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math_check_force_underflow_complex (res);
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}
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return res;
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}
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declare_mgen_alias (__catanh, catanh)
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