BTW, the 6 minutes included printing out the answer! HTH, A. Jorge Garcia
Teacher & Professor Applied Mathematics, Physics & Computer Science Baldwin Senior High School & Nassau Community College [email protected]_ (mailto:[email protected]) _http://calcpage.tripod.com_ (http://calcpage.tripod.com/) _ftp://centauri.baldwinschools.net_ (ftp://centauri.baldwinschools.net/) In a message dated 1/15/2009 7:18:53 P.M. Eastern Standard Time, [email protected] writes: On Thu, Jan 15, 2009 at 4:10 PM, <[email protected]> wrote: > That's interesting because I calculated M > 37 = 2^3021377-1 (909526 digits) on a 2.6 GHz pentium 4 using my own C++ > class to represent large ints and it about 2 hours. > > I calculated the same thing on www.sagenb.org and it took about 6 minutes! > > Well, I suppose 4 Xeon cores is a mini cluster of sorts. That doesn't matter, since Sage's code for doing integer arithmetic doesn't take advantage of multiple cores. It's only doing that using one core. When you write "my own C++ class to represent large ints", this suggests that you're using an entirely different algorithm than Sage to do arithmetic with large integers. Computing M with Sage takes less than *one second* for me on sagenb.org: sage: time s = 2^3021377-1 CPU time: 0.00 s, Wall time: 0.00 s sage: time k = str(s) CPU time: 0.67 s, Wall time: 0.67 s The same computation on some other new hardware I recently got from Sun with big caches is even faster: sage: time s = 2^3021377-1 CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s Wall time: 0.00 s sage: time k = str(s) CPU times: user 0.40 s, sys: 0.01 s, total: 0.41 s Wall time: 0.41 s sage: len(k) 909526 sage: timeit('s = 2^3021377-1') 625 loops, best of 3: 83.3 µs per loop Why don't you try using Sage on your 2.6Ghz Pentium 4 to do the computation? > > Regards, > A. Jorge Garcia > > Teacher & Professor > Applied Mathematics, Physics & Computer Science > Baldwin Senior High School & Nassau Community College > > [email protected] > http://calcpage.tripod.com > ftp://centauri.baldwinschools.net > > > > > ________________________________ > A Good Credit Score is 700 or Above. See yours in just 2 easy steps! > > > -- William Stein Associate Professor of Mathematics University of Washington http://wstein.org **************A Good Credit Score is 700 or Above. See yours in just 2 easy steps! (http://pr.atwola.com/promoclk/100000075x1215855013x1201028747/aol?redir=http://www.freecreditreport.com/pm/default.aspx?sc=668072%26hmpgID=62%26bcd=De cemailfooterNO62) --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sage-edu" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-edu?hl=en -~----------~----~----~----~------~----~------~--~---
