1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
/* $NetBSD: catan.c,v 1.1 2007/08/20 16:01:32 drochner Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software written by Stephen L. Moshier.
* It is redistributed by the NetBSD Foundation by permission of the author.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* imported and modified include for newlib 2010/10/03
* Marco Atzeri <marco_atzeri@yahoo.it>
*/
/*
FUNCTION
<<catan>>, <<catanf>>---complex arc tangent
INDEX
catan
INDEX
catanf
ANSI_SYNOPSIS
#include <complex.h>
double complex catan(double complex <[z]>);
float complex catanf(float complex <[z]>);
DESCRIPTION
@ifnottex
These functions compute the complex arc tangent of <[z]>,
with branch cuts outside the interval [-i, +i] along the
imaginary axis.
@end ifnottex
@tex
These functions compute the complex arc tangent of <[z]>,
with branch cuts outside the interval [$-i$, $+i$] along the
imaginary axis.
@end tex
<<catanf>> is identical to <<catan>>, except that it performs
its calculations on <<floats complex>>.
RETURNS
@ifnottex
These functions return the complex arc tangent value, in the range
of a strip mathematically unbounded along the imaginary axis
and in the interval [-pi/2, +pi/2] along the real axis.
@end ifnottex
@tex
These functions return the complex arc tangent, in the range
of a strip mathematically unbounded along the imaginary axis
and in the interval [$-\pi/2$, $+\pi/2$] along the real axis.
@end tex
PORTABILITY
<<catan>> and <<catanf>> are ISO C99
QUICKREF
<<catan>> and <<catanf>> are ISO C99
*/
#include <complex.h>
#include <math.h>
#include "cephes_subr.h"
#ifdef __weak_alias
__weak_alias(catan, _catan)
#endif
double complex
catan(double complex z)
{
double complex w;
double a, t, x, x2, y;
x = creal(z);
y = cimag(z);
if ((x == 0.0) && (y > 1.0))
goto ovrf;
x2 = x * x;
a = 1.0 - x2 - (y * y);
if (a == 0.0)
goto ovrf;
t = 0.5 * atan2(2.0 * x, a);
w = __mlibc_redupi(t);
t = y - 1.0;
a = x2 + (t * t);
if (a == 0.0)
goto ovrf;
t = y + 1.0;
a = (x2 + (t * t))/a;
w = w + (0.25 * log(a)) * I;
return w;
ovrf:
#if 0
mtherr ("catan", OVERFLOW);
#endif
w = HUGE_VAL + HUGE_VAL * I;
return w;
}
|
