Here are some ideas:
1) You don't need to mail back all the intermediate residues to see if
they are matching - you only need to send a checksum, which could be
as small as a few hundred bytes!
2) Users could elect how often to save the residue, by % or by
iteration #, depending on their free hard drive space.
3) Users would send an intermediate residue -if- a checksum mismatch
is found during a double check. (This only adds one additional
mailing of a residual to the total net-traffic since work on that
iteration would halt on the double check machine until a
triple-checking of the exponent reaches the iteration in question.
Then the residue [if any] matches one of the other two, then the
testing or double-checking would continue - depending on which residue
matched which.
4) In the future, local groups who manage exponents with local servers
could be improved & optimized assuming local groups are connected with
a network, and the server has plenty of hard drive space. The idea
would be for the local groups to self-coordinate the factoring, LL &
double-checking of exponents or groups of exponents, making use of
intermediate residues (which will be fraught with more & more errors
as exponents get larger). The local server would assign work
according to speed & reliability, and would be able to pull a machine
off a job to expedite double or triple checking. It would also be
able to take additional work on other exponents, and would know what
type of work can best be added into its work group based on it's total
speed & reliability.
I believe the total average savings (in my 3rd point) would be
substantial - especially for large exponents. Note that this SLOWS
the completion of an exponent, since it requires a wait for an
assignment of a triple check to point X iteration of an exponent, and
for results to be received back, until it's known if double checking
(or the original LL test - or neither) is able to restart). However -
the savings comes in efficiently using people's machines - machines
would continue to work on other assignments in the meantime, and there
is where the savings comes in.
The savings from my 4th point works into this idea - it would
eliminate the delay in assigning & starting the mid-point triple-check
(assuming the work group had a free / almost-free machine), so total
time for completed exponents wouldn't be hurt too much.
This process could help save work from mid-point gimp quitters, by
letting them at least send in their mid-point residue. (Or is this
already done - I've never quit!)
Comments?
-Kevin Moore
PS. someone just sent out a note with a similar comment, so I'll
leave it at that. :)
_________________________________________________________________
Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
