Marc Getty wrote:
>
>How does the CPU time contributed get calculated? I would assume
>that there is a standard credit for each FFT size, but I can't
>find what that credit is anywhere on mersenne.org.
Actually, the formula isn't based on FFT size. To get a good
estimate of how much time you'll get credited for any given
exponent, you'll need to multiply the exponent minus 1 by the
average time it takes to do each iteration. Then multiply
by the number of times faster the PC is than a P-90. Finally
the % of a year you get is the approx. amount of time credited.
For example:
On the exponent 5,593,943...
Multiply 5,593,942 by .275 to get 1,538,334 seconds.
Multiply 1,538,334 by 3.5 (for a PII-266) to get 5,384,169 secs.
5,384,169 seconds is 17.073% of a year...
So you'll get approx 0.171 P-90 years credit
>I doubt that anyone out there is using more then a 1792 K FFT.
Well.... There are actually a few of us brave souls out there
who are QA'ing exponents in FFT sizes all the way up to 4096K!!
Based on my estimates, the exponent I'm QA'ing will provide me
with ~36.348 P-90 years of credit when completed.
Eric
_________________________________________________________________________
Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
Mersenne Prime FAQ -- http://www.exu.ilstu.edu/mersenne/faq-mers.txt
