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63551311 | 1 | /* Complex tangent function for double. |
3b6c37d4 | 2 | Copyright (C) 1997, 2005 Free Software Foundation, Inc. |
63551311 UD |
3 | This file is part of the GNU C Library. |
4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
7 | modify it under the terms of the GNU Lesser General Public |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
63551311 UD |
10 | |
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 14 | Lesser General Public License for more details. |
63551311 | 15 | |
41bdb6e2 AJ |
16 | You should have received a copy of the GNU Lesser General Public |
17 | License along with the GNU C Library; if not, write to the Free | |
18 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
19 | 02111-1307 USA. */ | |
63551311 UD |
20 | |
21 | #include <complex.h> | |
04be94a8 | 22 | #include <fenv.h> |
63551311 UD |
23 | #include <math.h> |
24 | ||
25 | #include "math_private.h" | |
26 | ||
27 | ||
28 | __complex__ double | |
29 | __ctan (__complex__ double x) | |
30 | { | |
31 | __complex__ double res; | |
32 | ||
b4012b75 | 33 | if (!isfinite (__real__ x) || !isfinite (__imag__ x)) |
63551311 UD |
34 | { |
35 | if (__isinf (__imag__ x)) | |
36 | { | |
37 | __real__ res = __copysign (0.0, __real__ x); | |
38 | __imag__ res = __copysign (1.0, __imag__ x); | |
39 | } | |
40 | else if (__real__ x == 0.0) | |
41 | { | |
42 | res = x; | |
43 | } | |
44 | else | |
45 | { | |
46 | __real__ res = __nan (""); | |
47 | __imag__ res = __nan (""); | |
04be94a8 UD |
48 | |
49 | #ifdef FE_INVALID | |
50 | if (__isinf (__real__ x)) | |
51 | feraiseexcept (FE_INVALID); | |
52 | #endif | |
63551311 UD |
53 | } |
54 | } | |
55 | else | |
56 | { | |
7799b7b3 UD |
57 | double sin2rx, cos2rx; |
58 | double den; | |
63551311 | 59 | |
7799b7b3 UD |
60 | __sincos (2.0 * __real__ x, &sin2rx, &cos2rx); |
61 | ||
62 | den = cos2rx + __ieee754_cosh (2.0 * __imag__ x); | |
63 | ||
3b6c37d4 UD |
64 | if (den == 0.0) |
65 | { | |
66 | __complex__ double ez = __cexp (1.0i * x); | |
67 | __complex__ double emz = __cexp (-1.0i * x); | |
68 | ||
69 | res = (ez - emz) / (ez + emz) * -1.0i; | |
70 | } | |
71 | else | |
72 | { | |
73 | __real__ res = sin2rx / den; | |
74 | __imag__ res = __ieee754_sinh (2.0 * __imag__ x) / den; | |
75 | } | |
63551311 UD |
76 | } |
77 | ||
78 | return res; | |
79 | } | |
80 | weak_alias (__ctan, ctan) | |
81 | #ifdef NO_LONG_DOUBLE | |
82 | strong_alias (__ctan, __ctanl) | |
83 | weak_alias (__ctan, ctanl) | |
84 | #endif |