OFFICIAL "SERVER PROBLEMS" THREAD - Page 230

S485122 · 2023-03-14, 09:11

Quote:

Originally Posted by S485122

I believe I have identified the problem, looking at 14M PRP Results Page it is easy to verify that 6 of the "Verified PRP test results" should be in the "Factored PRP test results" section".

The wrongly classified PRP tests concern the following exponents in the 5 (indeed) ranges :

M2014997
M8833439
M9999991
M10000019
M14357429
M14357459
M14357489
M14357507
M14357527
M14357579

They were perhaps malformed attempts at cofactor PRP tests on exponents with factors ? But the result seems to be that the exponents status changed from factored to factored AND verified, and thus being counted twice.

One more in the 2M range :M2356597 counted on the PRP results as a PRP and "Factored PRP" (strange title : how can a PRP test result be factored ? ; - )
Part of the problem is that PrimeNet applies the status of Mersenne numbers to the LL and PRP tests : a verified LL or PRP test, a certified PRP test do not change because the Mersenne has been factored.

Only the Bad tests keep their status : - (
On the bright side it means that there is a separate record of the status of some tests at least.

Each time a factor is found for a Mersenne number that has been verified composite by LL or PRP, information is lost : those tests are no more "verified", they enter a vague category : tests that are not Bad on a factored Mersenne number.
Once all Mersennes of a range have been factored that range has 100% bad primality tests since the others are not in the verified category any more.

Andrew Usher · 2023-03-20, 12:38

And doing a correct PRP on such exponents does not fix their status; all those now have had (one was a self-DC but that doesn't affect the server). Clearly tests without all known factors need to be ignored for determining the status; and I note that the new 'automatic PRP' feature makes them easy to generate (see M41413) though misclassification happens only if the exponent was verified before being factored.

Of course I agree completely with the last point, but I suspect that's another legacy issue.

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2023-03-20, 12:38	#2521
Andrew Usher Dec 2022 312₁₀ Posts	And doing a correct PRP on such exponents does not fix their status; all those now have had (one was a self-DC but that doesn't affect the server). Clearly tests without all known factors need to be ignored for determining the status; and I note that the new 'automatic PRP' feature makes them easy to generate (see M41413) though misclassification happens only if the exponent was verified before being factored. Of course I agree completely with the last point, but I suspect that's another legacy issue.