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
|
/* mpc_abs -- Absolute value of a complex number.
Copyright (C) 2002 Andreas Enge, Paul Zimmermann
This file is part of the MPC Library.
The MPC Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version.
The MPC 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 Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the MPC 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 "gmp.h"
#include "mpfr.h"
#include "mpc.h"
#include "mpc-impl.h"
int
mpc_abs (mpfr_ptr a, mpc_srcptr b, mp_rnd_t rnd)
{
mpfr_t u, v;
mp_prec_t prec;
int inexact;
prec = MPFR_PREC(a);
mpfr_init (u);
mpfr_init (v);
do
{
prec += _mpfr_ceil_log2 ((double) prec) + 3;
mpfr_set_prec (u, prec);
mpfr_set_prec (v, prec);
/* first compute norm(b)^2 */
inexact = mpfr_mul (u, MPC_RE(b), MPC_RE(b), GMP_RNDD); /* err<=1ulp */
inexact |= mpfr_mul (v, MPC_IM(b), MPC_IM(b), GMP_RNDD); /* err<=1ulp*/
inexact |= mpfr_add (u, u, v, GMP_RNDD); /* err <= 3 ulps */
inexact |= mpfr_sqrt (u, u, GMP_RNDD); /* err <= 4 ulps */
}
while (inexact != 0 &&
mpfr_can_round (u, prec - 2, GMP_RNDD, rnd, MPFR_PREC(a)) == 0);
inexact |= mpfr_set (a, u, rnd);
mpfr_clear (u);
mpfr_clear (v);
return inexact;
}
|
