]>
Commit | Line | Data |
---|---|---|
e4d82761 UD |
1 | /* |
2 | * IBM Accurate Mathematical Library | |
aeb25823 | 3 | * written by International Business Machines Corp. |
f4cf5f2d | 4 | * Copyright (C) 2001-2012 Free Software Foundation, Inc. |
e4d82761 UD |
5 | * |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU Lesser General Public License as published by | |
cc7375ce | 8 | * the Free Software Foundation; either version 2.1 of the License, or |
e4d82761 | 9 | * (at your option) any later version. |
50944bca | 10 | * |
e4d82761 UD |
11 | * This program 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 | |
c6c6dd48 | 14 | * GNU Lesser General Public License for more details. |
e4d82761 UD |
15 | * |
16 | * You should have received a copy of the GNU Lesser General Public License | |
59ba27a6 | 17 | * along with this program; if not, see <http://www.gnu.org/licenses/>. |
e4d82761 UD |
18 | */ |
19 | /**************************************************************************/ | |
20 | /* MODULE_NAME:slowexp.c */ | |
21 | /* */ | |
50944bca | 22 | /* FUNCTION:slowexp */ |
e4d82761 UD |
23 | /* */ |
24 | /* FILES NEEDED:mpa.h */ | |
25 | /* mpa.c mpexp.c */ | |
26 | /* */ | |
27 | /*Converting from double precision to Multi-precision and calculating */ | |
28 | /* e^x */ | |
29 | /**************************************************************************/ | |
30 | #include "mpa.h" | |
1ed0291c | 31 | #include <math_private.h> |
e4d82761 | 32 | |
31d3cc00 UD |
33 | #ifndef SECTION |
34 | # define SECTION | |
35 | #endif | |
36 | ||
ca58f1db | 37 | void __mpexp(mp_no *x, mp_no *y, int p); |
e4d82761 UD |
38 | |
39 | /*Converting from double precision to Multi-precision and calculating e^x */ | |
31d3cc00 UD |
40 | double |
41 | SECTION | |
42 | __slowexp(double x) { | |
50944bca UD |
43 | double w,z,res,eps=3.0e-26; |
44 | #if 0 | |
45 | double y; | |
46 | #endif | |
47 | int p; | |
48 | #if 0 | |
49 | int orig,i; | |
50 | #endif | |
e4d82761 | 51 | mp_no mpx, mpy, mpz,mpw,mpeps,mpcor; |
50944bca | 52 | |
e4d82761 | 53 | p=6; |
ca58f1db | 54 | __dbl_mp(x,&mpx,p); /* Convert a double precision number x */ |
31d3cc00 | 55 | /* into a multiple precision number mpx with prec. p. */ |
ca58f1db UD |
56 | __mpexp(&mpx, &mpy, p); /* Multi-Precision exponential function */ |
57 | __dbl_mp(eps,&mpeps,p); | |
58 | __mul(&mpeps,&mpy,&mpcor,p); | |
59 | __add(&mpy,&mpcor,&mpw,p); | |
60 | __sub(&mpy,&mpcor,&mpz,p); | |
50944bca UD |
61 | __mp_dbl(&mpw, &w, p); |
62 | __mp_dbl(&mpz, &z, p); | |
e4d82761 UD |
63 | if (w == z) return w; |
64 | else { /* if calculating is not exactly */ | |
65 | p = 32; | |
ca58f1db UD |
66 | __dbl_mp(x,&mpx,p); |
67 | __mpexp(&mpx, &mpy, p); | |
50944bca | 68 | __mp_dbl(&mpy, &res, p); |
e4d82761 UD |
69 | return res; |
70 | } | |
71 | } |