Steve Harris wrote: >-----Original Message----- >From: [EMAIL PROTECTED] <[EMAIL PROTECTED]> >To: [EMAIL PROTECTED] <[EMAIL PROTECTED]> >Date: Tuesday, October 02, 2001 3:44 PM >Subject: Re: FW: Mersenne: Re: Factoring Failure? > ><snip> >> > Either way, GIMPS >> > has never considered missing a factor as a big deal. It >> > only means some wasted effort running a LL test that could >> > have been avoided. > >>True enough - though I'm concerned that the "no factors below 2^N" >>database may be seriously flawed, from the point of view of GIMPS >>it would seem to be a waste of time to go round redoing trial >>factoring just to fix this problem. > >Yes, from the point of view of GIMPS (that is, searching for >Mersenne primes) it's not a huge deal... but there also exists >an effort to fully factor the candidates that are not prime, >and this throws a big problem into that project. Someone could >be trial factoring an exponent from 2^59 to 2^65 and find a >factor in that range after a smaller factor had been missed, >and it will go into the database as the smallest factor when >it actually is not. Might be decades before the smaller factor >is discovered.
Actually... IIRC... George noted once that the database of smallest KNOWN factors was just that... and did NOT necessarily mean that it contained the smallest factors of any given exponent... There was a bug in a previous version (v19??) which caused Prime95 to not continue trial-factoring to find a smaller factor after one had been found and it had been stopped (or went to sleep)... There was also the advent of P-1 factoring which does not necessarily find the smallest factor, but instead finds factors comprised of lots of small factors, and can therefore miss smaller factors which does not have lots of small factors... In this case... the database would not necessarily have the smallest factor for every exponent with a factor found... but instead the smallest KNOWN factor... which is not necessarily the smallest factor for that exponent... Eric _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
