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Diffstat (limited to 'math/s_catan_template.c')
| -rw-r--r-- | math/s_catan_template.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/math/s_catan_template.c b/math/s_catan_template.c new file mode 100644 index 0000000000..5ab4c0d635 --- /dev/null +++ b/math/s_catan_template.c @@ -0,0 +1,143 @@ +/* Return arc tangent of complex double value. + 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 <math.h> +#include <math_private.h> +#include <float.h> + +__complex__ double +__catan (__complex__ double x) +{ + __complex__ double res; + int rcls = fpclassify (__real__ x); + int icls = fpclassify (__imag__ x); + + if (__glibc_unlikely (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 (__glibc_unlikely (rcls == FP_ZERO && icls == FP_ZERO)) + { + res = x; + } + else + { + if (fabs (__real__ x) >= 16.0 / DBL_EPSILON + || fabs (__imag__ x) >= 16.0 / DBL_EPSILON) + { + __real__ res = __copysign (M_PI_2, __real__ x); + if (fabs (__real__ x) <= 1.0) + __imag__ res = 1.0 / __imag__ x; + else if (fabs (__imag__ x) <= 1.0) + __imag__ res = __imag__ x / __real__ x / __real__ x; + else + { + double h = __ieee754_hypot (__real__ x / 2.0, __imag__ x / 2.0); + __imag__ res = __imag__ x / h / h / 4.0; + } + } + else + { + double den, absx, absy; + + absx = fabs (__real__ x); + absy = fabs (__imag__ x); + if (absx < absy) + { + double t = absx; + absx = absy; + absy = t; + } + + if (absy < DBL_EPSILON / 2.0) + { + den = (1.0 - absx) * (1.0 + absx); + if (den == -0.0) + den = 0.0; + } + else if (absx >= 1.0) + den = (1.0 - absx) * (1.0 + absx) - absy * absy; + else if (absx >= 0.75 || absy >= 0.5) + den = -__x2y2m1 (absx, absy); + else + den = (1.0 - absx) * (1.0 + absx) - absy * absy; + + __real__ res = 0.5 * __ieee754_atan2 (2.0 * __real__ x, den); + + if (fabs (__imag__ x) == 1.0 + && fabs (__real__ x) < DBL_EPSILON * DBL_EPSILON) + __imag__ res = (__copysign (0.5, __imag__ x) + * (M_LN2 - __ieee754_log (fabs (__real__ x)))); + else + { + double r2 = 0.0, num, f; + + if (fabs (__real__ x) >= DBL_EPSILON * DBL_EPSILON) + r2 = __real__ x * __real__ x; + + num = __imag__ x + 1.0; + num = r2 + num * num; + + den = __imag__ x - 1.0; + den = r2 + den * den; + + f = num / den; + if (f < 0.5) + __imag__ res = 0.25 * __ieee754_log (f); + else + { + num = 4.0 * __imag__ x; + __imag__ res = 0.25 * __log1p (num / den); + } + } + } + + math_check_force_underflow_complex (res); + } + + return res; +} +weak_alias (__catan, catan) +#ifdef NO_LONG_DOUBLE +strong_alias (__catan, __catanl) +weak_alias (__catan, catanl) +#endif |