lowest 10M exponents available - pick your choice

[Knappo]

Thanks ckdo,

I've updated my worktodo file including your factoring limit.

[ckdo]

I've taken another four exponents:

Test=34201081,68,0 - ckdo - October 2008
Test=34201177,68,0 - ckdo - August 2008
Test=34201333,68,0 - ckdo - August 2008
Test=34201417,68,0 - ckdo - August 2008

These run unattended on the V5 server.

[jrk]

I'll take the last two:

Test=34201883,68,0 - jrk - September 2008
Test=34201987,68,0 - jrk - October 2008

[markr]

M34200709 is not prime

[ckdo]

M34400651 has a factor: 375855982335783868679

[tha]

Originally Posted by ckdo

M34400651 has a factor: 375855982335783868679

OK, good too know. Did you test the exponent or did you look it up somewhere? If so, where?

[ckdo]

I have a machine P-1 test the new exponents while I'm away, via V5. I'll let you know once they're done.

[ckdo]

M34400389 has a factor: 9541285631068389553

[S485122]

Originally Posted by ckdo

M34400389 has a factor: 9541285631068389553

There is a problem somewhere : this is a 63 bits factor for an exponent that was supposed to be factored to 68 bits...

Test=34400389,68,0

The Prime V5 server does not give any data for that exponent. This means it might be a good idea to check the factoring limits of all exponents that are still in test (and even the already completed exponents ? *) and to change the "how far trial factored" parameter to 0 (or 26 = int(2 * log₂(33602077))) if they have no factoring limits or to the factoring limits indicated by the server otherwise.

Jacob

* In my opinion GIMP should get ALL exponents lower than the trial factoring limit for their range.

[ckdo]

I agree that there is a problem. I didn't verify whether this (or any other) factor is actually correct, but mprime segfaulted when finishing the exponent. Konsole snippet follows:

[Worker #1 Aug 14 01:16] Stage 2 GCD complete. Time: 246.293 sec.                                                       
[Worker #1 Aug 14 01:16] P-1 found a factor in stage #2, B1=410000, B2=11070000.                                        
[Worker #1 Aug 14 01:16] M34400389 has a factor: 9541285631068389553                                                    
Segmentation fault (core dumped)    
kossy@leela:~/leela$ ./__start                                                                                          
[Main thread Aug 16 13:28] Mersenne number primality test program version 25.6                                          
[Comm thread Aug 16 13:28] Sending result to server: UID: ckdo/leela, M34400389 has a factor: 9541285631068389553, AID: 5678875EA392BC568ED714947B23CE86
[Comm thread Aug 16 13:28]
[Main thread Aug 16 13:28] Starting worker threads.
[Worker #1 Aug 16 13:28] Work thread starting
[Worker #3 Aug 16 13:28] Work thread starting
[Worker #4 Aug 16 13:28] Work thread starting
[Worker #2 Aug 16 13:28] Work thread starting
[Worker #4 Aug 16 13:28] Optimal P-1 factoring of M34401967 using up to 1792MB of memory.
[Worker #1 Aug 16 13:28] Optimal P-1 factoring of M34400389 using up to 1792MB of memory.
[Worker #1 Aug 16 13:28] Assuming no factors below 2^68 and 2 primality tests saved if a factor is found.
[Worker #2 Aug 16 13:28] Optimal P-1 factoring of M34400603 using up to 1792MB of memory.
[Worker #2 Aug 16 13:28] Assuming no factors below 2^68 and 2 primality tests saved if a factor is found.
[Worker #4 Aug 16 13:28] Assuming no factors below 2^68 and 2 primality tests saved if a factor is found.
[Worker #3 Aug 16 13:28] Optimal P-1 factoring of M34401827 using up to 1792MB of memory.
[Worker #3 Aug 16 13:28] Assuming no factors below 2^68 and 2 primality tests saved if a factor is found.
[Comm thread Aug 16 13:28] PrimeNet success code with additional info:
[Comm thread Aug 16 13:28] CPU credit is 1.382725 GHz-days.

Notice that it did in fact start the same exponent again (which I happened to notice only hours later, duh!)...

[S485122]

The factor is correct (I checked it by trial factoring from 63 bits onwards...) The segfault is not related to the bad factoring limits in the assignments. It might be a Prime95 bug or a coincidence.

Jacob