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Old 2003-09-15, 22:14   #3
GP2
 
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Sep 2003

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Default Re: Re: Error rate for LL tests

Quote:
Originally posted by NickGlover
I don't think we can assume the error rate is not increasing based on the data. We should only consider ranges where all exponents have been double-checked. For ranges where this is not the case (7M to 10M), the error rates could be either artificially low or artificially high, so I think it is difficult to make a conclusion about them.
Well, my calculations take into account only exponents that have had at least two LL tests done. As outlined in the first post in this thread, I believe we can draw fairly accurate conclusions about error rates for such exponents whether or not a matching residue was found.

In the range 7M-8M there are only 60 exponents that have never had at least two LL tests done. In the range 8M-9M, there are only 525 such exponents, and in the range 9M-10M, there are 5791 such exponents. So arguably, only the 9M-10M error rate could be expected to change much over time.


For higher exponents, the rates are artificially high because results returned with a nonzero error code get double-checked several years sooner than results returned with a zero error code. That is because the server immediately reassigns such nonzero-error-code results for another "first-time" LL test.

However, as soon as the leading edge of double-checking (currently around 10.1M) arrives, all those lagging double-checks of zero-error-code results finally end up getting done and the ratio gets back into proper balance.

For this reason, I'd argue that for anything below about 0.5M less than the leading edge of double-checking, we already have a fairly accurate estimate of error rate.


Quote:

Also I believe George significantly improved the error checking with one version of Prime95/mprime, so we would expect an improvement in the error rate for ranges that where checked more with newer version. This would not stop the error rate from continuing to go up for later ranges.
That's a valid point. And also Windows NT/2000/XP machines have much better protection from different processes overwriting each other's memory than older machines using Windows 3.1/95/98, which is another thing that affects error rates.


It's unfortunate that the server behavior which is optimized for detecting bad results as quickly as possible also makes it very difficult to estimate error rates for the leading edge of first-time LL tests.
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