/* Return arc tangent of complex float type. Copyright (C) 1997-2018 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper , 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, see . */ #include "quadmath-imp.h" __complex128 catanq (__complex128 x) { __complex128 res; int rcls = fpclassifyq (__real__ x); int icls = fpclassifyq (__imag__ x); if (__glibc_unlikely (rcls <= QUADFP_INFINITE || icls <= QUADFP_INFINITE)) { if (rcls == QUADFP_INFINITE) { __real__ res = copysignq (M_PI_2q, __real__ x); __imag__ res = copysignq (0, __imag__ x); } else if (icls == QUADFP_INFINITE) { if (rcls >= QUADFP_ZERO) __real__ res = copysignq (M_PI_2q, __real__ x); else __real__ res = nanq (""); __imag__ res = copysignq (0, __imag__ x); } else if (icls == QUADFP_ZERO || icls == QUADFP_INFINITE) { __real__ res = nanq (""); __imag__ res = copysignq (0, __imag__ x); } else { __real__ res = nanq (""); __imag__ res = nanq (""); } } else if (__glibc_unlikely (rcls == QUADFP_ZERO && icls == QUADFP_ZERO)) { res = x; } else { if (fabsq (__real__ x) >= 16 / FLT128_EPSILON || fabsq (__imag__ x) >= 16 / FLT128_EPSILON) { __real__ res = copysignq (M_PI_2q, __real__ x); if (fabsq (__real__ x) <= 1) __imag__ res = 1 / __imag__ x; else if (fabsq (__imag__ x) <= 1) __imag__ res = __imag__ x / __real__ x / __real__ x; else { __float128 h = hypotq (__real__ x / 2, __imag__ x / 2); __imag__ res = __imag__ x / h / h / 4; } } else { __float128 den, absx, absy; absx = fabsq (__real__ x); absy = fabsq (__imag__ x); if (absx < absy) { __float128 t = absx; absx = absy; absy = t; } if (absy < FLT128_EPSILON / 2) { den = (1 - absx) * (1 + absx); if (den == 0) den = 0; } else if (absx >= 1) den = (1 - absx) * (1 + absx) - absy * absy; else if (absx >= 0.75Q || absy >= 0.5Q) den = -__quadmath_x2y2m1q (absx, absy); else den = (1 - absx) * (1 + absx) - absy * absy; __real__ res = 0.5Q * atan2q (2 * __real__ x, den); if (fabsq (__imag__ x) == 1 && fabsq (__real__ x) < FLT128_EPSILON * FLT128_EPSILON) __imag__ res = (copysignq (0.5Q, __imag__ x) * ((__float128) M_LN2q - logq (fabsq (__real__ x)))); else { __float128 r2 = 0, num, f; if (fabsq (__real__ x) >= FLT128_EPSILON * FLT128_EPSILON) r2 = __real__ x * __real__ x; num = __imag__ x + 1; num = r2 + num * num; den = __imag__ x - 1; den = r2 + den * den; f = num / den; if (f < 0.5Q) __imag__ res = 0.25Q * logq (f); else { num = 4 * __imag__ x; __imag__ res = 0.25Q * log1pq (num / den); } } } math_check_force_underflow_complex (res); } return res; }