On Tue, Oct 02, 2007 at 09:56:07AM +0100, Brian Gough wrote: > At Sat, 29 Sep 2007 00:50:38 +0000 (GMT), > [EMAIL PROTECTED] wrote: > > > > I just got the GSL book today and immediately > > tried the sample program on page 9. > > > > I did not get the exact same answer shown in the book: > > JO(5) = -1.775967713143382920e-01 > > I got J)(5) = -1.775967713143382642e-01 > > ^^^ > > I'm running 64-bit AMD OpenBSD 4.1 on AM2 Athlon 64. > > Thanks for your email. The results vary in the final bit, 1ulp = > 2e-16. There are many factors which can affect the result at this > level (compiler options, order of rounding, etc) -- I've added a note > to the manual that this is normal. > > -- > Brian Gough
I tried computing J0(5) using the Bessel function in the gnu math library and I got the exact result listed in the book. So I'm wondering if the difference in the final 3 digits is the result of using double (64-bit xmm registers vs long double (80-bit temp real in 8087 registers). -- _______________________________________________ Help-gsl mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-gsl
