/* Compute complex natural logarithm. Copyright (C) 1997 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, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #include <complex.h> #include <math.h> #include "math_private.h" __complex__ double __clog (__complex__ double x) { __complex__ double result; int rcls = fpclassify (__real__ x); int icls = fpclassify (__imag__ x); if (rcls == FP_ZERO && icls == FP_ZERO) { /* Real and imaginary part are 0.0. */ __imag__ result = signbit (__real__ x) ? M_PI : 0.0; __imag__ result = __copysign (__imag__ result, __imag__ x); /* Yes, the following line raises an exception. */ __real__ result = -1.0 / fabs (__real__ x); } else if (rcls != FP_NAN && icls != FP_NAN) { /* Neither real nor imaginary part is NaN. */ __real__ result = __ieee754_log (__ieee754_hypot (__real__ x, __imag__ x)); __imag__ result = __ieee754_atan2 (__imag__ x, __real__ x); } else { __imag__ result = __nan (""); if (rcls == FP_INFINITE || icls == FP_INFINITE) /* Real or imaginary part is infinite. */ __real__ result = HUGE_VAL; else __real__ result = __nan (""); } return result; } weak_alias (__clog, clog) #ifdef NO_LONG_DOUBLE strong_alias (__clog, __clogl) weak_alias (__clog, clogl) #endif