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
131
132
133
134
|
/* mpfr_cosh -- hyperbolic cosine
Copyright (C) 1999-2001 Free Software Foundation.
This file is part of the MPFR Library.
The MPFR Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Library General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
The MPFR 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 Library General Public
License for more details.
You should have received a copy of the GNU Library General Public License
along with the MPFR Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
#include <stdio.h>
#include "gmp.h"
#include "gmp-impl.h"
#include "mpfr.h"
#include "mpfr-impl.h"
/* The computation of cosh is done by
cosh= 1/2[e^(x)+e^(-x)]
*/
int mpfr_cosh _PROTO((mpfr_ptr, mpfr_srcptr, mp_rnd_t));
int
#if __STDC__
mpfr_cosh (mpfr_ptr y, mpfr_srcptr x , mp_rnd_t rnd_mode)
#else
mpfr_cosh (y, x, rnd_mode)
mpfr_ptr y;
mpfr_srcptr x;
mp_rnd_t rnd_mode;
#endif
{
/****** Declaration ******/
/* Variable of Intermediary Calculation*/
mpfr_t t;
/* Variable of Intermediary Calculation*/
mpfr_t te,ti;
int round, inexact = 0;
int boucle = 1;
mp_prec_t Nx; /* Precision of input variable */
mp_prec_t Ny; /* Precision of output variable */
mp_prec_t Nt; /* Precision of Intermediary Calculation variable */
mp_prec_t err; /* Precision of error */
if (MPFR_IS_NAN(x))
{
MPFR_SET_NAN(y);
return 1;
}
MPFR_CLEAR_NAN(y);
if (MPFR_IS_INF(x))
{
MPFR_SET_INF(y);
if (MPFR_SIGN(y) < 0)
MPFR_CHANGE_SIGN(y);
return 0;
}
MPFR_CLEAR_INF(y);
if(!MPFR_NOTZERO(x))
{
mpfr_set_ui (y, 1, GMP_RNDN); /* cosh(0) = 1 */
return 0;
}
/* Initialisation of the Precision */
Nx=MPFR_PREC(x);
Ny=MPFR_PREC(y);
/* compute the size of intermediary variable */
if (Ny >= Nx)
Nt = Ny + 2 * BITS_PER_CHAR;
else
Nt = Nx + 2 * BITS_PER_CHAR;
/* initialize intermediary variables */
mpfr_init2 (t, Nt);
mpfr_init2 (te, Nt);
mpfr_init2 (ti, Nt);
while (boucle)
{
/* compute cosh */
mpfr_exp (te, x, GMP_RNDN); /* exp(x) */
mpfr_ui_div (ti, 1, te, GMP_RNDN); /* 1/exp(x) */
mpfr_add (t, te, ti, GMP_RNDN); /* exp(x) + 1/exp(x)*/
mpfr_div_2exp (t, t, 1, GMP_RNDN); /* 1/2(exp(x) + 1/exp(x))*/
err = Nt - 1;
round = mpfr_can_round (t, err, GMP_RNDN, rnd_mode, Ny);
if (round)
{
inexact = mpfr_set (y, t, rnd_mode);
boucle=0;
}
else
{
Nt += 10;
/* re-initialize intermediary variables */
mpfr_set_prec (t, Nt);
mpfr_set_prec (te, Nt);
mpfr_set_prec (ti, Nt);
}
}
mpfr_clear (t);
mpfr_clear (ti);
mpfr_clear (te);
return inexact;
}
|
