| /* Return arc hyperbolic tangent for a complex float type. |
| Copyright (C) 1997-2018 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, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "quadmath-imp.h" |
| |
| __complex128 |
| catanhq (__complex128 x) |
| { |
| __complex128 res; |
| int rcls = fpclassifyq (__real__ x); |
| int icls = fpclassifyq (__imag__ x); |
| |
| if (__glibc_unlikely (rcls <= QUADFP_INFINITE || icls <= QUADFP_INFINITE)) |
| { |
| if (icls == QUADFP_INFINITE) |
| { |
| __real__ res = copysignq (0, __real__ x); |
| __imag__ res = copysignq (M_PI_2q, __imag__ x); |
| } |
| else if (rcls == QUADFP_INFINITE || rcls == QUADFP_ZERO) |
| { |
| __real__ res = copysignq (0, __real__ x); |
| if (icls >= QUADFP_ZERO) |
| __imag__ res = copysignq (M_PI_2q, __imag__ x); |
| else |
| __imag__ res = nanq (""); |
| } |
| 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) |
| { |
| __imag__ res = copysignq (M_PI_2q, __imag__ x); |
| if (fabsq (__imag__ x) <= 1) |
| __real__ res = 1 / __real__ x; |
| else if (fabsq (__real__ x) <= 1) |
| __real__ res = __real__ x / __imag__ x / __imag__ x; |
| else |
| { |
| __float128 h = hypotq (__real__ x / 2, __imag__ x / 2); |
| __real__ res = __real__ x / h / h / 4; |
| } |
| } |
| else |
| { |
| if (fabsq (__real__ x) == 1 |
| && fabsq (__imag__ x) < FLT128_EPSILON * FLT128_EPSILON) |
| __real__ res = (copysignq (0.5Q, __real__ x) |
| * ((__float128) M_LN2q |
| - logq (fabsq (__imag__ x)))); |
| else |
| { |
| __float128 i2 = 0; |
| if (fabsq (__imag__ x) >= FLT128_EPSILON * FLT128_EPSILON) |
| i2 = __imag__ x * __imag__ x; |
| |
| __float128 num = 1 + __real__ x; |
| num = i2 + num * num; |
| |
| __float128 den = 1 - __real__ x; |
| den = i2 + den * den; |
| |
| __float128 f = num / den; |
| if (f < 0.5Q) |
| __real__ res = 0.25Q * logq (f); |
| else |
| { |
| num = 4 * __real__ x; |
| __real__ res = 0.25Q * log1pq (num / den); |
| } |
| } |
| |
| __float128 absx, absy, den; |
| |
| 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; |
| |
| __imag__ res = 0.5Q * atan2q (2 * __imag__ x, den); |
| } |
| |
| math_check_force_underflow_complex (res); |
| } |
| |
| return res; |
| } |