From: Waldemar Schultz <schultz AT ma DOT tum DOT de>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: exp() doesn't work !
Date: Tue, 22 May 2001 16:59:11 +0200
Organization: [posted via] Leibniz-Rechenzentrum, Muenchen (Germany)
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Waldemar Schultz schrieb:
> 
> Scott Sinclair schrieb:
> >
> > Hi
> >
> > I hope I'm just being stupid :) but the following code:
> >
> > //////////////////////////////
> > double x, y;
> >
> > y = some_sensibly_small_number;
> >
> > x = exp(y);
> > /////////////////////////////
> >
> > does NOT set x equal to e^y ???? I am using the libraries suplied with DJGPP
> > version 2.03.
> > Unfortunately I can't follow the assembler code in the exp.s source file (is
> > this assembler ?), so I can't fix the error and rebuild my libraries.
> > Help ????:)
> >
> > cheers
> >
> > Scott
> 
> #include <stdio.h>
> #include <stdlib.h>
> #include <math.h>
> 
> int main() //int argc, char **argv)
> {
> double s;
> 
   s=exp(3e-15);
   ^^^^^^^^^^^^^
oops sorry, I was too eager cleaning the snippet
>  printf("%40.20g\n",s);
>  return EXIT_SUCCESS;
> }
> 
> prints                     1.0000000000000031086
> 
> what did you expect ? e^0.0 == 1.0 !
> 
> --
>  Gruss Waldemar Schultz.         schultz AT ma DOT tum DOT de
>  Technische Universität München, Zentrum Mathematik M1, D 80290 München
>  Tel: +49 (0)89 2892 8226        FAX: +49 (0)89 2892 8228


sorry for inconvenience.

-- 
 Gruss Waldemar Schultz.         schultz AT ma DOT tum DOT de
 Technische Universität München, Zentrum Mathematik M1, D 80290 München
 Tel: +49 (0)89 2892 8226        FAX: +49 (0)89 2892 8228