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192.168.1.100 / T106_DC / 79df1683c37bcbc2febebc9ed3671ea43a0960b2 / . / ap / libc / glibc / glibc-2.23 / math / s_catanhf.c
blob: fe43a518fb3dfa63c023effcf2bdd68146d8d2b5 [file] [log] [blame]
xf.libdd93d52023-05-12 07:10:14 -0700[diff] [blame]1/* Return arc hyperbole tangent for float value.
2 Copyright (C) 1997-2016 Free Software Foundation, Inc.
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
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.
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
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
19
20#include <complex.h>
21#include <math.h>
22#include <math_private.h>
23#include <float.h>
24
25__complex__ float
26__catanhf (__complex__ float x)
27{
28 __complex__ float res;
29 int rcls = fpclassify (__real__ x);
30 int icls = fpclassify (__imag__ x);
31
32 if (__glibc_unlikely (rcls <= FP_INFINITE || icls <= FP_INFINITE))
33 {
34 if (icls == FP_INFINITE)
35 {
36 __real__ res = __copysignf (0.0, __real__ x);
37 __imag__ res = __copysignf (M_PI_2, __imag__ x);
38 }
39 else if (rcls == FP_INFINITE || rcls == FP_ZERO)
40 {
41 __real__ res = __copysignf (0.0, __real__ x);
42 if (icls >= FP_ZERO)
43 __imag__ res = __copysignf (M_PI_2, __imag__ x);
44 else
45 __imag__ res = __nanf ("");
46 }
47 else
48 {
49 __real__ res = __nanf ("");
50 __imag__ res = __nanf ("");
51 }
52 }
53 else if (__glibc_unlikely (rcls == FP_ZERO && icls == FP_ZERO))
54 {
55 res = x;
56 }
57 else
58 {
59 if (fabsf (__real__ x) >= 16.0f / FLT_EPSILON
60 || fabsf (__imag__ x) >= 16.0f / FLT_EPSILON)
61 {
62 __imag__ res = __copysignf ((float) M_PI_2, __imag__ x);
63 if (fabsf (__imag__ x) <= 1.0f)
64 __real__ res = 1.0f / __real__ x;
65 else if (fabsf (__real__ x) <= 1.0f)
66 __real__ res = __real__ x / __imag__ x / __imag__ x;
67 else
68 {
69 float h = __ieee754_hypotf (__real__ x / 2.0f,
70 __imag__ x / 2.0f);
71 __real__ res = __real__ x / h / h / 4.0f;
72 }
73 }
74 else
75 {
76 if (fabsf (__real__ x) == 1.0f
77 && fabsf (__imag__ x) < FLT_EPSILON * FLT_EPSILON)
78 __real__ res = (__copysignf (0.5f, __real__ x)
79 * ((float) M_LN2
80 - __ieee754_logf (fabsf (__imag__ x))));
81 else
82 {
83 float i2 = 0.0f;
84 if (fabsf (__imag__ x) >= FLT_EPSILON * FLT_EPSILON)
85 i2 = __imag__ x * __imag__ x;
86
87 float num = 1.0f + __real__ x;
88 num = i2 + num * num;
89
90 float den = 1.0f - __real__ x;
91 den = i2 + den * den;
92
93 float f = num / den;
94 if (f < 0.5f)
95 __real__ res = 0.25f * __ieee754_logf (f);
96 else
97 {
98 num = 4.0f * __real__ x;
99 __real__ res = 0.25f * __log1pf (num / den);
100 }
101 }
102
103 float absx, absy, den;
104
105 absx = fabsf (__real__ x);
106 absy = fabsf (__imag__ x);
107 if (absx < absy)
108 {
109 float t = absx;
110 absx = absy;
111 absy = t;
112 }
113
114 if (absy < FLT_EPSILON / 2.0f)
115 {
116 den = (1.0f - absx) * (1.0f + absx);
117 if (den == -0.0f)
118 den = 0.0f;
119 }
120 else if (absx >= 1.0f)
121 den = (1.0f - absx) * (1.0f + absx) - absy * absy;
122 else if (absx >= 0.75f || absy >= 0.5f)
123 den = -__x2y2m1f (absx, absy);
124 else
125 den = (1.0f - absx) * (1.0f + absx) - absy * absy;
126
127 __imag__ res = 0.5f * __ieee754_atan2f (2.0f * __imag__ x, den);
128 }
129
130 math_check_force_underflow_complex (res);
131 }
132
133 return res;
134}
135#ifndef __catanhf
136weak_alias (__catanhf, catanhf)
137#endif