Hi all,
At 11:46 AM 6/13/99 -0500, several people wrote:
>The expiration policy is such-and-so...
Prime95 reports in with new expected completion dates as well as
next expected checkin date every N days where N is by default 28 days.
Your exponents are reassigned if you miss your next expected checkin date
by 60 days.
However, prime95 version 15 used a different algorithm. The program
reported an expected completion date when an exponent was reserved.
The exponent expired 60 days after the expected completion date is missed.
Exponents that are checked out by email do not follow a rigid
formula. Generally, progress must be reported every 4 or 5 months
and the range completed within a year. People I know such as Mr. Burge
and Mr. Sunde are given more slack than a name I do not recognize.
These exponents are usually recycled to people who cannot upgrade
from version 14 or are using Macs (which work a lot better on exponents
below 4.8M). Exponents above 5.2M are given to Primenet.
The "problem" exponents that started this thread almost assuredly came
from version 15 clients using the old expiration policy.
>Is "poaching" OK?
No. There's nothing I can do about it, but I certainly do not encourage it.
For the past two years it seems there has always been two or three people
testing the lowest available exponents. I don't think they have improved
their chances at all as they often report double-checks rather than first-time
checks.
>Oh great, I reported a result and got "exponent already tested" error.
Remember, you will get this error message when you retest an exponent
that was originally tested by buggy version 17. It is very likely that
you just completed the first CORRECT LL test.
That said, accidents happen. A manual tester can enter the wrong range,
an expired exponent can all of a sudden have its result reported, etc.
The system will never be perfect, but fortunately works as expected 99%
of the time.
>You should email the original person that reserved the exponent.
Well, my policy is not to give out email addresses.
>I'm not upgrading because I think my old P-whatever should run
>first time checks.
GIMPS does not mandate your computer do certain work. You can override
the defult behavior in the Test/Primenet dialog box. Remember, you are
here to have fun and if you don't mind waiting 6 months for an LL test,
that's fine by me. Your checkin every 28 days will let the server know
you are busy working on your exponent. (However, be reasonable. As this
thread shows if you grab an exponent that will take 4 years to test, you
can expect a "poacher" to finish it before you do. I would think one
year completion time would be OK though).
>Why do we care that these smaller exponents get tested in a timely manner?
The obvious answer is we want to make a relatively orderly determination
on the primality of every Mersenne number.
There is no sure-fire formula for detecting exponents that are no longer
being worked on. Once in a great while, I analyze the database and find
exponents that have "slipped through the cracks" or I think have been
abandoned and release them for reassignment. I do *not* email the affected
persons (I used to, but it was *way* too much work).
The good news is that the current prime95 expiration policy seems to
work very well. Thus, this problem should occur much less frequently
in the future.
Have fun,
George
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