I agree, it seems odd that the OS/compiler has a 128 bit math library available. I certainly hope that your seemingly correct answer is not being corrupted when you compute a 64-bit sine of a 128 bit number...
I used GMP's arbitrary precision library (rational number arithmetic) for my thesis a few years back. It was very easy to implement, but not fast (better on x86 hardware than sun/sgi/power as I recall). I too am curious about the sort of algorithm that would require that much precision. (for me, it was inverting a probability distribution that was piecewise-defined, described here, http://arxiv.org/abs/cond-mat/0506786, sorry, nobody ever gets to talk about their thesis...). Nathan On Fri, Jun 25, 2010 at 10:54 AM, Nifty Tom Mitchell <niftyo...@niftyegg.com> wrote: > On Fri, Jun 25, 2010 at 10:28:15AM -0400, Prentice Bisbal wrote: >> >> Beowulfers, >> >> One of my Fortran programmers had to increase the precision of his >> program so he switched from REAL*8 to REAL*16 which changes the size of >> his variables from 64 bits to 128 bits. The program now takes 32x longer >> to run. >> > > I am surprised that it works as support in things like > the math lib, log and trig functions could be missing. > Which compiler is he using? > > > > > > -- > T o m M i t c h e l l > Found me a new hat, now what? > > _______________________________________________ > Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing > To change your subscription (digest mode or unsubscribe) visit > http://www.beowulf.org/mailman/listinfo/beowulf > -- - - - - - - - - - - - - - - - - - - - - - Nathan Moore Assistant Professor, Physics Winona State University AIM: nmoorewsu - - - - - - - - - - - - - - - - - - - - - _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
