On Tue, 12 Oct 1999, George Woltman wrote:
> I admire your patience!
Thank you :)
> > I think it said 1 in 250,000 chance if finding
> >a prime. So.. on average, it would probably take that one computer, by
> >itself, 241,250 years to find a 10m digit prime. Right ?
>
> Define "probably". 241,250 years gives you a 50% chance. Actually it will
> take longer since the exponents get bigger and bigger.
Mathmatical probability... on average, it'll take 50% of the whole thing.
At the time I didn't know it took longer toward the end.
> >it'd be good to break up
> >primes into like, 1 month chunks, & distribute them.
>
> A good idea but the Lucas-Lehmer primality test is a "serial" algorithm.
> That is, I can't have 33 machines each do a million iterations and get the
> answer in a month. The second million iterations can't start until the
> first million complete.
I see. Well, we need more people involved either way :)
Other thing I gotta calculate... how long it would probably take us if we
converted everyone from distributed.net to GIMPS. This is actually the
biggest reason why I wanna calculate prize/probability ratio of the 2.
> >I also think it would have been better to award $5k per new prime, of any
> >length. But that's just my opinion.
>
> The prize fund was set up by the EFF and the anonymous donor. I agree with
> you and have tried to encourage an orderly progression by awarding $5,000
> to all smaller Mersenne primes (but only if we also find the 10 million
> digit prime).
I understand the contest was not set up by you, but it's good to hear
you're trying to incourage $5k/prime. I doubt there are many people who's
input could be more valued for this.
> >And how is the probability of finding a prime calculated ?
>
> It is roughly how-far-factored-in-bits * 2 / exponent
Okay.. what's "how-far-factored-in-bits" mean ?
> >I wanna do a comparison of the prize money to probability ratio between
> >distributed.net's rc5-64 project ($2k prize), & GIMPS 10m digit prime
> >($55k prize). But it'll take me a chunk of time. Any estimates ?
>
> There is now a prize for factoring Fermat numbers too.
Neat. Where's the info ?
Also, the link pertaining to the EFF $100k award on the GIMPS page goes
directly to the EFF rules page, instead of
http://www.mersenne.org/prize.htm. I think it'd be nice to have a link
from the main GIMPS page to something w/ info on all prizes which could be
won with GIMPS. You were probably planning on doing that though...
> However, the best investment is probably to turn off your computer
> and pocket the $30 you save in electricity! Of course, that's no fun.
> So pick whichever project gives you the biggest thrill.
Alright then, it's a gamble, not an invenstment.
Wait, no, I'd leave my computer on all the time anyway. It's still an
investment. Yeah yeah, so if I didn't run one of these, the CPU would be
off less & draw less power. It doesn't matter, I like distributed
processing. I'm not in it for the money.
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