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137 lines
3.5 KiB
C
137 lines
3.5 KiB
C
/* Return arc tangent of 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 "quadmath-imp.h"
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__complex128
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catanq (__complex128 x)
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{
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__complex128 res;
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int rcls = fpclassifyq (__real__ x);
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int icls = fpclassifyq (__imag__ x);
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if (__glibc_unlikely (rcls <= QUADFP_INFINITE || icls <= QUADFP_INFINITE))
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{
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if (rcls == QUADFP_INFINITE)
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{
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__real__ res = copysignq (M_PI_2q, __real__ x);
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__imag__ res = copysignq (0, __imag__ x);
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}
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else if (icls == QUADFP_INFINITE)
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{
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if (rcls >= QUADFP_ZERO)
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__real__ res = copysignq (M_PI_2q, __real__ x);
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else
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__real__ res = nanq ("");
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__imag__ res = copysignq (0, __imag__ x);
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}
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else if (icls == QUADFP_ZERO || icls == QUADFP_INFINITE)
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{
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__real__ res = nanq ("");
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__imag__ res = copysignq (0, __imag__ x);
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}
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else
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{
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__real__ res = nanq ("");
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__imag__ res = nanq ("");
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}
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}
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else if (__glibc_unlikely (rcls == QUADFP_ZERO && icls == QUADFP_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 (fabsq (__real__ x) >= 16 / FLT128_EPSILON
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|| fabsq (__imag__ x) >= 16 / FLT128_EPSILON)
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{
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__real__ res = copysignq (M_PI_2q, __real__ x);
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if (fabsq (__real__ x) <= 1)
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__imag__ res = 1 / __imag__ x;
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else if (fabsq (__imag__ x) <= 1)
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__imag__ res = __imag__ x / __real__ x / __real__ x;
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else
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{
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__float128 h = hypotq (__real__ x / 2, __imag__ x / 2);
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__imag__ res = __imag__ 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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__float128 den, absx, absy;
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absx = fabsq (__real__ x);
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absy = fabsq (__imag__ x);
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if (absx < absy)
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{
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__float128 t = absx;
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absx = absy;
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absy = t;
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}
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if (absy < FLT128_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 >= 0.75Q || absy >= 0.5Q)
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den = -__quadmath_x2y2m1q (absx, absy);
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else
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den = (1 - absx) * (1 + absx) - absy * absy;
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__real__ res = 0.5Q * atan2q (2 * __real__ x, den);
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if (fabsq (__imag__ x) == 1
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&& fabsq (__real__ x) < FLT128_EPSILON * FLT128_EPSILON)
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__imag__ res = (copysignq (0.5Q, __imag__ x)
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* ((__float128) M_LN2q
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- logq (fabsq (__real__ x))));
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else
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{
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__float128 r2 = 0, num, f;
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if (fabsq (__real__ x) >= FLT128_EPSILON * FLT128_EPSILON)
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r2 = __real__ x * __real__ x;
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num = __imag__ x + 1;
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num = r2 + num * num;
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den = __imag__ x - 1;
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den = r2 + den * den;
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f = num / den;
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if (f < 0.5Q)
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__imag__ res = 0.25Q * logq (f);
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else
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{
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num = 4 * __imag__ x;
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__imag__ res = 0.25Q * log1pq (num / den);
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}
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}
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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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