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Diffstat (limited to 'REORG.TODO/math/s_ctanh_template.c')
| -rw-r--r-- | REORG.TODO/math/s_ctanh_template.c | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/REORG.TODO/math/s_ctanh_template.c b/REORG.TODO/math/s_ctanh_template.c new file mode 100644 index 0000000000..1c00d14428 --- /dev/null +++ b/REORG.TODO/math/s_ctanh_template.c @@ -0,0 +1,130 @@ +/* Complex hyperbolic tangent for float types. + Copyright (C) 1997-2017 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> + +CFLOAT +M_DECL_FUNC (__ctanh) (CFLOAT x) +{ + CFLOAT res; + + if (__glibc_unlikely (!isfinite (__real__ x) || !isfinite (__imag__ x))) + { + if (isinf (__real__ x)) + { + __real__ res = M_COPYSIGN (1, __real__ x); + if (isfinite (__imag__ x) && M_FABS (__imag__ x) > 1) + { + FLOAT sinix, cosix; + M_SINCOS (__imag__ x, &sinix, &cosix); + __imag__ res = M_COPYSIGN (0, sinix * cosix); + } + else + __imag__ res = M_COPYSIGN (0, __imag__ x); + } + else if (__imag__ x == 0) + { + res = x; + } + else + { + __real__ res = M_NAN; + __imag__ res = M_NAN; + + if (isinf (__imag__ x)) + feraiseexcept (FE_INVALID); + } + } + else + { + FLOAT sinix, cosix; + FLOAT den; + const int t = (int) ((M_MAX_EXP - 1) * M_MLIT (M_LN2) / 2); + + /* tanh(x+iy) = (sinh(2x) + i*sin(2y))/(cosh(2x) + cos(2y)) + = (sinh(x)*cosh(x) + i*sin(y)*cos(y))/(sinh(x)^2 + cos(y)^2). */ + + if (__glibc_likely (M_FABS (__imag__ x) > M_MIN)) + { + M_SINCOS (__imag__ x, &sinix, &cosix); + } + else + { + sinix = __imag__ x; + cosix = 1; + } + + if (M_FABS (__real__ x) > t) + { + /* Avoid intermediate overflow when the imaginary part of + the result may be subnormal. Ignoring negligible terms, + the real part is +/- 1, the imaginary part is + sin(y)*cos(y)/sinh(x)^2 = 4*sin(y)*cos(y)/exp(2x). */ + FLOAT exp_2t = M_EXP (2 * t); + + __real__ res = M_COPYSIGN (1, __real__ x); + __imag__ res = 4 * sinix * cosix; + __real__ x = M_FABS (__real__ x); + __real__ x -= t; + __imag__ res /= exp_2t; + if (__real__ x > t) + { + /* Underflow (original real part of x has absolute value + > 2t). */ + __imag__ res /= exp_2t; + } + else + __imag__ res /= M_EXP (2 * __real__ x); + } + else + { + FLOAT sinhrx, coshrx; + if (M_FABS (__real__ x) > M_MIN) + { + sinhrx = M_SINH (__real__ x); + coshrx = M_COSH (__real__ x); + } + else + { + sinhrx = __real__ x; + coshrx = 1; + } + + if (M_FABS (sinhrx) > M_FABS (cosix) * M_EPSILON) + den = sinhrx * sinhrx + cosix * cosix; + else + den = cosix * cosix; + __real__ res = sinhrx * coshrx / den; + __imag__ res = sinix * cosix / den; + } + math_check_force_underflow_complex (res); + } + + return res; +} + +declare_mgen_alias (__ctanh, ctanh) + +#if M_LIBM_NEED_COMPAT (ctanh) +declare_mgen_libm_compat (__ctanh, ctanh) +#endif |