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-rw-r--r--math/s_ctan_template.c129
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diff --git a/math/s_ctan_template.c b/math/s_ctan_template.c
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+/* Complex tangent function for double.
+ Copyright (C) 1997-2016 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 <complex.h>
+#include <fenv.h>
+#include <math.h>
+#include <math_private.h>
+#include <float.h>
+
+__complex__ double
+__ctan (__complex__ double x)
+{
+ __complex__ double res;
+
+ if (__glibc_unlikely (!isfinite (__real__ x) || !isfinite (__imag__ x)))
+ {
+ if (isinf (__imag__ x))
+ {
+ if (isfinite (__real__ x) && fabs (__real__ x) > 1.0)
+ {
+ double sinrx, cosrx;
+ __sincos (__real__ x, &sinrx, &cosrx);
+ __real__ res = __copysign (0.0, sinrx * cosrx);
+ }
+ else
+ __real__ res = __copysign (0.0, __real__ x);
+ __imag__ res = __copysign (1.0, __imag__ x);
+ }
+ else if (__real__ x == 0.0)
+ {
+ res = x;
+ }
+ else
+ {
+ __real__ res = __nan ("");
+ __imag__ res = __nan ("");
+
+ if (isinf (__real__ x))
+ feraiseexcept (FE_INVALID);
+ }
+ }
+ else
+ {
+ double sinrx, cosrx;
+ double den;
+ const int t = (int) ((DBL_MAX_EXP - 1) * M_LN2 / 2);
+
+ /* tan(x+iy) = (sin(2x) + i*sinh(2y))/(cos(2x) + cosh(2y))
+ = (sin(x)*cos(x) + i*sinh(y)*cosh(y)/(cos(x)^2 + sinh(y)^2). */
+
+ if (__glibc_likely (fabs (__real__ x) > DBL_MIN))
+ {
+ __sincos (__real__ x, &sinrx, &cosrx);
+ }
+ else
+ {
+ sinrx = __real__ x;
+ cosrx = 1.0;
+ }
+
+ if (fabs (__imag__ x) > t)
+ {
+ /* Avoid intermediate overflow when the real part of the
+ result may be subnormal. Ignoring negligible terms, the
+ imaginary part is +/- 1, the real part is
+ sin(x)*cos(x)/sinh(y)^2 = 4*sin(x)*cos(x)/exp(2y). */
+ double exp_2t = __ieee754_exp (2 * t);
+
+ __imag__ res = __copysign (1.0, __imag__ x);
+ __real__ res = 4 * sinrx * cosrx;
+ __imag__ x = fabs (__imag__ x);
+ __imag__ x -= t;
+ __real__ res /= exp_2t;
+ if (__imag__ x > t)
+ {
+ /* Underflow (original imaginary part of x has absolute
+ value > 2t). */
+ __real__ res /= exp_2t;
+ }
+ else
+ __real__ res /= __ieee754_exp (2 * __imag__ x);
+ }
+ else
+ {
+ double sinhix, coshix;
+ if (fabs (__imag__ x) > DBL_MIN)
+ {
+ sinhix = __ieee754_sinh (__imag__ x);
+ coshix = __ieee754_cosh (__imag__ x);
+ }
+ else
+ {
+ sinhix = __imag__ x;
+ coshix = 1.0;
+ }
+
+ if (fabs (sinhix) > fabs (cosrx) * DBL_EPSILON)
+ den = cosrx * cosrx + sinhix * sinhix;
+ else
+ den = cosrx * cosrx;
+ __real__ res = sinrx * cosrx / den;
+ __imag__ res = sinhix * coshix / den;
+ }
+ math_check_force_underflow_complex (res);
+ }
+
+ return res;
+}
+weak_alias (__ctan, ctan)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__ctan, __ctanl)
+weak_alias (__ctan, ctanl)
+#endif