2004-07-02, 08:40   #10
Matthias C. Noc

Dec 2003

23×3 Posts

Quote:
 Originally Posted by cheesehead Bob, Matthias, anyone else -- can you demonstrate actual real harm (not just an effect on someone's feelings) done by a slow-completer?
Hi,

you asked what harm slow-completer are causing. I have three points:

1.) The project is not only about finding isolated new Mersenne primes, but although about proving that these new found are the only ones in the range the current GIMPS is covering. We want to find all Mersenne primes in the data range and prove that they are the only ones. That means that we need to cover all exponents below a given new Mersenne prime to prove that this one is the number 36, 37 or 41. If it takes years to finish one small exponent, which under today’s normal performance would take only 4 of 5 days to calculate, it is holding up the whole process without need. That doesn’t help to get a better understanding of the distribution of those Mersenne primes.

2.) It makes a bad impression about the organisation of the project when we can’t finish a data range in an acceptable amount of time. We are crunching very large numbers, but fail to finish much smaller exponents. That doesn’t look good.

3.) We are doing a very abstract stuff here. To keep people motivated one needs to reach small and big milestones from time to time. As we don’t find a new Mersenne every month other milestones have to keep people interested. Like :

All exponents below 8,715,700 have been tested and double-checked.
All exponents below 12,441,900 have been tested at least once.
Countdown to testing all exponents below M(13466917) once: 4
Countdown to testing all exponents below M(20996011) once: 9,549
Countdown to testing all exponents below M(24036583) once: 42,739
Countdown to proving M(13466917) is the 39th Mersenne Prime: 39,154
Countdown to proving M(20996011) is the 40th Mersenne Prime: 204,395
Countdown to proving M(24036583) is the 41st Mersenne Prime: 271,351

If we loose one normal cruncher with an up-to-date PC due to frustration about no progress we are loosing much more power then when we loose 10 angry slow-crunchers because their exponents were reassigned in time to keep the project rolling.

It will close to be impossible to keep the project running in the much higher areas with only slow-completers. We need as much high-power as we can get now that we really working big numbers.

Best,

Matthias C. Noch