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-rw-r--r--math/s_catan.c89
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diff --git a/math/s_catan.c b/math/s_catan.c
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+/* Return arc tangent of complex double value.
+ 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
+__catan (__complex__ double x)
+{
+ __complex__ double res;
+ int rcls = fpclassify (__real__ x);
+ int icls = fpclassify (__imag__ x);
+
+ if (rcls <= FP_INFINITE || icls <= FP_INFINITE)
+ {
+ if (rcls == FP_INFINITE)
+ {
+ __real__ res = __copysign (M_PI_2, __real__ x);
+ __imag__ res = __copysign (0.0, __imag__ x);
+ }
+ else if (icls == FP_INFINITE)
+ {
+ if (rcls >= FP_ZERO)
+ __real__ res = __copysign (M_PI_2, __real__ x);
+ else
+ __real__ res = __nan ("");
+ __imag__ res = __copysign (0.0, __imag__ x);
+ }
+ else if (icls == FP_ZERO || icls == FP_INFINITE)
+ {
+ __real__ res = __nan ("");
+ __imag__ res = __copysign (0.0, __imag__ x);
+ }
+ else
+ {
+ __real__ res = __nan ("");
+ __imag__ res = __nan ("");
+ }
+ }
+ else if (rcls == FP_ZERO && icls == FP_ZERO)
+ {
+ res = x;
+ }
+ else
+ {
+ double r2, num, den;
+
+ r2 = __real__ x * __real__ x;
+
+ den = 1 - r2 - __imag__ x * __imag__ x;
+
+ __real__ res = 0.5 * __ieee754_atan2 (2.0 * __real__ x, den);
+
+ num = __imag__ x + 1.0;
+ num = r2 + num * num;
+
+ den = __imag__ x - 1.0;
+ den = r2 + den * den;
+
+ __imag__ res = 0.25 * __ieee754_log (num / den);
+ }
+
+ return res;
+}
+weak_alias (__catan, catan)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__catan, __catanl)
+weak_alias (__catan, catanl)
+#endif