I assume, possibly incorrectly, that scientists know what level of tolerance/accuracy they need. While we can all dream about the futures or past - the present day needs are useful to know. In general a certain field may need A and another field will tolerate B...
I guess this is a NaN... if(signal/noise>0) On Sun, May 1, 2016 at 3:29 AM, Peter St. John <peter.st.j...@gmail.com> wrote: > I'm betting the answer to that will be "any" (i.e. "it depends"). > > In cryptography, we used to think of 128 bits for a PGP key as a lot, but > some folks have started using 4096 bits. Of course in exact arithmetic it's > much easier to deal with arbitrary precision than in quantitative analysis > of measurements with error intervals. > > Peter > > On Sat, Apr 30, 2016 at 3:09 PM, C Bergström <cbergst...@pathscale.com> > wrote: >> >> I was hoping for feedback, from scientists, about what level of >> accuracy their codes or fields of study typically require. Maybe the >> weekend wasn't the best time to post.. hmm.. >> >> On Sun, May 1, 2016 at 1:31 AM, Peter St. John <peter.st.j...@gmail.com> >> wrote: >> > A bit off the wall, and not much help for what you are doing now, but >> > sooner >> > or later we won't be hand-crating ruthlessly optimal code; we'll be >> > training >> > neural nets. You could do this now if you wanted: the objective function >> > is >> > just accurate answers (which you get from sub-optimal but mathematically >> > correct existing code) and the wall clock (faster is better), and you >> > train >> > with the target hardware. So in principle it's easy, and if you look at >> > how >> > fast Deep Mind trained AlphaGo it begins to sound feasible to train for >> > fast >> > fourier transforms or whatever. >> > Peter >> > >> > On Fri, Apr 29, 2016 at 9:06 PM, William Johnson >> > <meatheadmer...@gmail.com> >> > wrote: >> >> >> >> Due to the finite nature of number representation on computers, >> >> any answer will be an approximation to some degree. >> >> To me, it looks to be a non-issue to some 15 significant digits. >> >> I would say it depends how accurate you need. >> >> You could do long-hand general calculations that track percent error, >> >> and see how it gets compounded in a particular series of calculations. >> >> >> >> If you got right into the nuts and bolts of writing optimized >> >> functions, >> >> there are many clever ways to calculate common functions >> >> that you can find in certain math or algorithms & data structures >> >> texts. >> >> You would also need intimate knowledge of the target chipset. >> >> But it seems that would be way too much time in >> >> research and development to reinvent the wheel. >> >> >> >> >> >> On Fri, Apr 29, 2016 at 7:28 PM, Greg Lindahl <lind...@pbm.com> wrote: >> >>> >> >>> On Sat, Apr 30, 2016 at 02:23:31AM +0800, C Bergström wrote: >> >>> >> >>> > Surprisingly, glibc does a pretty respectable job in terms of >> >>> > accuracy, but alas it's certainly not the fastest. >> >>> >> >>> If you go look in the source comments I believe it says which paper's >> >>> algorithm it is using... doing range reduction for sin(6e5) is >> >>> expensive to do accurately. Which is why the x86 sin() hardware >> >>> instruction does it inaccurately but quickly, and most people/codes >> >>> don't care. >> >>> >> >>> -- greg >> >>> >> >>> >> >>> >> >>> _______________________________________________ >> >>> 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 >> >> >> >> >> >> >> >> _______________________________________________ >> >> 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 >> >> >> > >> > >> > _______________________________________________ >> > 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 >> > > > _______________________________________________ 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
