1 /* Return arc hyperbole tangent for float value. 2 Copyright (C) 1997 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. 5 6 The GNU C Library is free software; you can redistribute it and/or 7 modify it under the terms of the GNU Lesser General Public 8 License as published by the Free Software Foundation; either 9 version 2.1 of the License, or (at your option) any later version. 10 11 The GNU C Library is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 Lesser General Public License for more details. 15 16 You should have received a copy of the GNU Lesser General Public 17 License along with the GNU C Library; if not, write to the Free 18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 19 02111-1307 USA. */ 20 21 #include <complex.h> 22 #include <math.h> 23 24 #include "math_private.h" 25 26 27 __complex__ float 28 __catanhf (__complex__ float x) 29 { 30 __complex__ float res; 31 int rcls = fpclassify (__real__ x); 32 int icls = fpclassify (__imag__ x); 33 34 if (rcls <= FP_INFINITE || icls <= FP_INFINITE) 35 { 36 if (icls == FP_INFINITE) 37 { 38 __real__ res = copysignf (0.0, __real__ x); 39 __imag__ res = copysignf (M_PI_2, __imag__ x); 40 } 41 else if (rcls == FP_INFINITE || rcls == FP_ZERO) 42 { 43 __real__ res = copysignf (0.0, __real__ x); 44 if (icls >= FP_ZERO) 45 __imag__ res = copysignf (M_PI_2, __imag__ x); 46 else 47 __imag__ res = nanf (""); 48 } 49 else 50 { 51 __real__ res = nanf (""); 52 __imag__ res = nanf (""); 53 } 54 } 55 else if (rcls == FP_ZERO && icls == FP_ZERO) 56 { 57 res = x; 58 } 59 else 60 { 61 float i2, num, den; 62 63 i2 = __imag__ x * __imag__ x; 64 65 num = 1.0 + __real__ x; 66 num = i2 + num * num; 67 68 den = 1.0 - __real__ x; 69 den = i2 + den * den; 70 71 __real__ res = 0.25 * (logf (num) - logf (den)); 72 73 den = 1 - __real__ x * __real__ x - i2; 74 75 __imag__ res = 0.5 * atan2f (2.0 * __imag__ x, den); 76 } 77 78 return res; 79 } 80 #ifndef __catanhf 81 weak_alias (__catanhf, catanhf) 82 #endif 83