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comparison packages/language/c/libm/current/src/complex/cephes_subr.c @ 3337:77f9d3253c3e

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Add: Complex number header and library (single and double precision floating point), port from Newlib. Add: Single precision floating point library, port from Newlib. [ Bugzilla 1001539 ]
author vae
date Sun, 25 Aug 2013 14:38:57 +0000
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3336:8ecac279f33c 3337:77f9d3253c3e
1 /* $NetBSD: cephes_subr.c,v 1.1 2007/08/20 16:01:33 drochner Exp $ */
2
3 /*-
4 * Copyright (c) 2007 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software written by Stephen L. Moshier.
8 * It is redistributed by the NetBSD Foundation by permission of the author.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 *
31 * imported and modified include for newlib 2010/10/03
32 * Marco Atzeri <marco_atzeri@yahoo.it>
33 */
34
35 #include <complex.h>
36 #include <math.h>
37 #include "cephes_subr.h"
38
39 /* calculate cosh and sinh */
40
41 void
42 _cchsh(double x, double *c, double *s)
43 {
44 double e, ei;
45
46 if (fabs(x) <= 0.5) {
47 *c = cosh(x);
48 *s = sinh(x);
49 } else {
50 e = exp(x);
51 ei = 0.5 / e;
52 e = 0.5 * e;
53 *s = e - ei;
54 *c = e + ei;
55 }
56 }
57
58 /* Program to subtract nearest integer multiple of PI */
59
60 /* extended precision value of PI: */
61 static const double DP1 = 3.14159265160560607910E0;
62 static const double DP2 = 1.98418714791870343106E-9;
63 static const double DP3 = 1.14423774522196636802E-17;
64 #define MACHEP 1.1e-16
65
66 double
67 _redupi(double x)
68 {
69 double t;
70 long i;
71
72 t = x / M_PI;
73 if (t >= 0.0)
74 t += 0.5;
75 else
76 t -= 0.5;
77
78 i = t; /* the multiple */
79 t = i;
80 t = ((x - t * DP1) - t * DP2) - t * DP3;
81 return t;
82 }
83
84 /* Taylor series expansion for cosh(2y) - cos(2x) */
85
86 double
87 _ctans(double complex z)
88 {
89 double f, x, x2, y, y2, rn, t;
90 double d;
91
92 x = fabs(2.0 * creal(z));
93 y = fabs(2.0 * cimag(z));
94
95 x = _redupi(x);
96
97 x = x * x;
98 y = y * y;
99 x2 = 1.0;
100 y2 = 1.0;
101 f = 1.0;
102 rn = 0.0;
103 d = 0.0;
104 do {
105 rn += 1.0;
106 f *= rn;
107 rn += 1.0;
108 f *= rn;
109 x2 *= x;
110 y2 *= y;
111 t = y2 + x2;
112 t /= f;
113 d += t;
114
115 rn += 1.0;
116 f *= rn;
117 rn += 1.0;
118 f *= rn;
119 x2 *= x;
120 y2 *= y;
121 t = y2 - x2;
122 t /= f;
123 d += t;
124 } while (fabs(t/d) > MACHEP);
125 return d;
126 }