Date: Sat, 14 Jul 2001 13:23:41 -0500 From: Stephen Montgomery-Smith <stephen@math.missouri.edu> To: Jim.Pirzyk@disney.com Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: math library difference between linux emulation and native freebsd (and native linux) Message-ID: <3B508E2D.41FAC546@math.missouri.edu> References: <200107141809.f6EI9M809946@snoopy.fan.fa.disney.com>
next in thread | previous in thread | raw e-mail | index | archive | help
The correct answer to the level of accuracy you quote is: 137581029243568295877658.36934931 Both are correct to about 15 sig figs, which is about what the precision of IEEE double precision arithmetic is supposed to be. Jim.Pirzyk@disney.com wrote: > > So I have stumbled across a linux emulation bug in freebsd. Below > is the program that returns different results based on FreeBSD, > Linux or Linux emulation under FreeBSD. > > Running natively under FreeBSD: > > x = 53.27850000 > exp(x) = 137581029243568449912832.00000000 > > Running natively under Linux: > > x = 53.278500 > exp(x) = 137581029243568449912832.000000 > > Running under FreeBSD in Linux emulation mode: > > x = 53.27850000 > exp(x) = 137581029243567812378624.00000000 > > #include <stdio.h> > #include <math.h> > #include <stdlib.h> > > int main (int argc, char **argv) { > double x = 53.278500; > > printf ("x = %8lf\n", x); > printf ("exp(x) = %8lf\n", exp(x)); > > exit (0); > } > > There are only two shared libaries in common (libc and libm) and > both are the same on FreeBSD (in /compat/linux) and Linux. > > So any ideas on where the program is going wrong? > > - JimP > -- > --- @(#) $Id: dot.signature,v 1.10 2001/05/17 23:38:49 Jim.Pirzyk Exp $ > __o Jim.Pirzyk@disney.com ------------- pirzyk@freebsd.org > _'\<,_ Senior Systems Engineer, Walt Disney Feature Animation > (*)/ (*) > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message -- Stephen Montgomery-Smith stephen@math.missouri.edu http://www.math.missouri.edu/~stephen To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3B508E2D.41FAC546>