On Thu, Jan 15, 2009 at 4:49 PM, Robert Bradshaw <[email protected]> wrote: > > On Jan 15, 2009, at 4:39 PM, William Stein wrote: > >> On Thu, Jan 15, 2009 at 4:21 PM, Robert Bradshaw >> <[email protected]> wrote: >>> >>> On Jan 15, 2009, at 4:10 PM, [email protected] wrote: >>> >>>> That's interesting because I calculated M37 = 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! >>> >>> Yeah, sagenb.org can get pretty loaded down some times. >> >> He was saying that "6 minutes" was very very fast, not slow. > > I was comparing it to what times I would have expected to see based > on my local timings. The online notebook sometimes felt sluggish to > me, but I do almost everything locally so it's not a fair comparison > (and I only occasionally use it, probably less than a dozen times > since we moved it off the old hardware). > >> [[his >> timing turns >> out to really have been of printing out the answer via the notebook. >> better would be to do >> sage: time s = 2^3021377-1 >> CPU time: 0.00 s, Wall time: 0.00 s >> sage: time open('output.txt','w').write(str(s)) >> CPU time: 0.70 s, Wall time: 0.70 s >> >> which gives a link to a file that you can download that contains >> the answer.]] > > Yep, that was my diagnosis of the 6 minutes too. Or perhaps as > mentioned it was a different Mersenne prime that we're talking about,
It wasn't. 2^3021377-1 is the third largest known and the next two larger are only slightly bigger. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
