]>
Commit | Line | Data |
---|---|---|
e4d82761 UD |
1 | /* |
2 | * IBM Accurate Mathematical Library | |
aeb25823 AJ |
3 | * written by International Business Machines Corp. |
4 | * Copyright (C) 2001 Free Software Foundation | |
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 | |
50944bca | 8 | * the Free Software Foundation; either version 2 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 | |
17 | * along with this program; if not, write to the Free Software | |
50944bca | 18 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
e4d82761 UD |
19 | */ |
20 | /**************************************************************************/ | |
21 | /* MODULE_NAME:slowexp.c */ | |
22 | /* */ | |
50944bca | 23 | /* FUNCTION:slowexp */ |
e4d82761 UD |
24 | /* */ |
25 | /* FILES NEEDED:mpa.h */ | |
26 | /* mpa.c mpexp.c */ | |
27 | /* */ | |
28 | /*Converting from double precision to Multi-precision and calculating */ | |
29 | /* e^x */ | |
30 | /**************************************************************************/ | |
31 | #include "mpa.h" | |
15b3c029 | 32 | #include "math_private.h" |
e4d82761 | 33 | |
ca58f1db | 34 | void __mpexp(mp_no *x, mp_no *y, int p); |
e4d82761 UD |
35 | |
36 | /*Converting from double precision to Multi-precision and calculating e^x */ | |
ca58f1db | 37 | double __slowexp(double x) { |
50944bca UD |
38 | double w,z,res,eps=3.0e-26; |
39 | #if 0 | |
40 | double y; | |
41 | #endif | |
42 | int p; | |
43 | #if 0 | |
44 | int orig,i; | |
45 | #endif | |
e4d82761 | 46 | mp_no mpx, mpy, mpz,mpw,mpeps,mpcor; |
50944bca | 47 | |
e4d82761 | 48 | p=6; |
ca58f1db | 49 | __dbl_mp(x,&mpx,p); /* Convert a double precision number x */ |
e4d82761 | 50 | /* into a multiple precision number mpx with prec. p. */ |
ca58f1db UD |
51 | __mpexp(&mpx, &mpy, p); /* Multi-Precision exponential function */ |
52 | __dbl_mp(eps,&mpeps,p); | |
53 | __mul(&mpeps,&mpy,&mpcor,p); | |
54 | __add(&mpy,&mpcor,&mpw,p); | |
55 | __sub(&mpy,&mpcor,&mpz,p); | |
50944bca UD |
56 | __mp_dbl(&mpw, &w, p); |
57 | __mp_dbl(&mpz, &z, p); | |
e4d82761 UD |
58 | if (w == z) return w; |
59 | else { /* if calculating is not exactly */ | |
60 | p = 32; | |
ca58f1db UD |
61 | __dbl_mp(x,&mpx,p); |
62 | __mpexp(&mpx, &mpy, p); | |
50944bca | 63 | __mp_dbl(&mpy, &res, p); |
e4d82761 UD |
64 | return res; |
65 | } | |
66 | } |