Double-check check?

[M0CZY]

I have just finished a double-check on an 18M exponent, and the result was not prime.
How can I check my residue against the residue of the original L-L test, so that I can be sure that my double-check was carried out correctly?

[TimSorbet]

Originally Posted by M0CZY

I have just finished a double-check on an 18M exponent, and the result was not prime.
How can I check my residue against the residue of the original L-L test, so that I can be sure that my double-check was carried out correctly?

I'm pretty sure that the only residues you can get have the last two (I think it's two) digits cut off, so you can't be 100% sure. I think that as long as you were assigned it as a DC by primenet, it will make sure the residues match and if they don't, will assign it again to a different DCing computer (although it will actually be triple-check).

[S485122]

You will find the residues of double checked exponents in the file ftp://mersenne.org/gimps/lucas_v.zip found on the status page of the GIMPS site. The file ftp://mersenne.org/gimps/hrf3.zip of single checked exponents does not contain the residues and this means that you will have to wait untill the lucas_v file is updated.

If there was a problem there will be a triple check and the faulty results would appear in the file ftp://mersenne.org/gimps/bad.zip

The updates of those files are done more or less every 2 weeks or every month depending on the schedule of the person who updates them.

[M0CZY]

I suppose with hindsight that I should have known that residues are kept secret to avoid cheating.
I have found my exponent in the primenet/cleared.txt list so this may suggest that my double-check result was valid.
I spent 3 months doing that DC, and I would hate to find out that the work I did turned out to be invalid.

[davieddy]

Originally Posted by M0CZY

I spent 3 months doing that DC, and I would hate to find out that the work I did turned out to be invalid.

I'm about to complete 6 months double checking 17,105,059.
I was hoping that the agreement or otherwise with the original
residue would be made clear on completion. Sounds like I might
have to try a bit harder to find out :(

[PhilF]

Originally Posted by M0CZY

I have found my exponent in the primenet/cleared.txt list so this may suggest that my double-check result was valid.

All completed tests go into the cleared .txt file, so you can not tell if your residues matched just by that. You will have to wait until the lucas_v.txt and hrf3.txt files get updated before you will know if your double-check results matched. As S485122 indicated, these files get updated approximately every 2 weeks.

If your results matched, your exponent will be in the lucas_v.txt file and the residue will be shown. If your results did not match, then your exponent will be in the hrf3.txt file, and the residue will not be shown.

[E_tron]

If ones results were different than the first LL test, then would one not get p90 credits for the test until triple check (assuming your results were correct)?

I say this, because i'm under the impression that if a PC returns incorrect results, it's p90 credits get revoked when triple checked.

[PhilF]

Originally Posted by E_tron

If ones results were different than the first LL test, then would one not get p90 credits for the test until triple check (assuming your results were correct)?

I say this, because i'm under the impression that if a PC returns incorrect results, it's p90 credits get revoked when triple checked.

You do get CPU credit when your computer reports the results, regardless of whether the residue matches. But you are correct in that the credit gets removed from your account later if a triple check shows your results were inaccurate.

[cheesehead]

Originally Posted by PhilF

You do get CPU credit when your computer reports the results, regardless of whether the residue matches.

... because (additional explanation), after all, GIMPS/PrimeNet doesn't know which result is correct! The later deletion of credit for non-matching results is (I think) human-moderated.

[davieddy]

Originally Posted by davieddy

I'm about to complete 6 months double checking 17,105,059.
I was hoping that the agreement or otherwise with the original
residue would be made clear on completion. Sounds like I might
have to try a bit harder to find out :(

I've made it to lucas_v.txt

17105059,Alfedenzo,C27F309E2,WX1,E04934BEF277CA71,12165283,00000000
17105059,davieddy,mycom,WZ1,E04934BEF277CA71,11505948,00000000

Could someone explain the fields I don't understand, please (?)

exponent,user,computer,?,residue,?,?

David

[Xyzzy]

Exponent
User ID
Computer Name
Software (Mprime, Prime95, etc.)
Residue
Can't remember
Error code