mersenneforum.org LLR Version 3.8.23 released
 User Name Remember Me? Password
 Register FAQ Search Today's Posts Mark Forums Read

2019-05-22, 22:32   #12
AG5BPilot

Dec 2011
New York, U.S.A.

97 Posts

Quote:
 Originally Posted by ATH You can probably add: CpuSupportsAVX512F=0 to LLR.ini, or use the -oCpuSupportsAVX512F=0 in the command line. I cannot test this since I do not have an AVX512 cpu, but for me using -oCpuSupportsFMA3=0 turns off AVX2 and uses AVX instead.
That was the first thing we tried. (See my message right before yours.)

Then we looked in the LLR source code. It's not there.

 2019-05-23, 05:41 #13 Darkclown   Jun 2007 Seattle, WA 5 Posts That flag does not work w/ the 3.8.23 release of LLR.
 2019-07-08, 13:39 #14 ATH Einyen     Dec 2003 Denmark 22×733 Posts Error with ForcePRP=1 in the ini file: https://mersenneforum.org/showthread.php?t=22981
 2019-09-20, 06:56 #15 stream   May 2015 3 Posts What happens if LLR cannot factorize 'b' ? It may happen with big GFN numbers, having very high 'b'. Probably aprcl.exe should help with factorization, but we don't include it in Boinc setups. Without aprcl, internal factorization fails and a warning is printed: >cllr64.3.8.23.exe -d -q"1814570322897374^65536+1" Error 2 while trying to create new process Error 2 while trying to create new process Base factorized as : 2*7*67*1934509939123*1 Base cofactor : 1934509939123, 1 (Must be proven prime or factorized externally) In the example above, 1934509939123 is prime. But what happens in theoretical case if LLR accepts composite cofactor? Will the prime test itself work correctly?
2020-05-19, 02:37   #16
Batalov

"Serge"
Mar 2008
Phi(4,2^7658614+1)/2

22×2,281 Posts

I am posting a patch to LLR that allows to run the "Proth.exe" -like test for k*b^n+1 dividing some large cyclotomic Phi(b^m,2).

The input file should have the following magic header:
Code:
ABC DivPhi($a*$b^$c+1) 2 3 822 2 3 897 2 3 1252 2 3 1454 2 3 4217 The output will be: Code: 2*3^822+1 does not divide 2^3^822-1 Time : 263.342 ms. 2*3^897+1 Divides 2^3^897-1 Time : 116.718 ms. 2*3^897+1 Divides 2^3^896-1 Time : 103.216 ms. 2*3^897+1 does not divide 2^3^895-1 Time : 101.769 ms. Conclusion: 2*3^897+1 Divides Phi(3^896,2) 2*3^1252+1 does not divide 2^3^1252-1 Time : 97.786 ms. 2*3^1454+1 does not divide 2^3^1454-1 Time : 109.374 ms. 2*3^4217+1 Divides 2^3^4217-1 Time : 37.989 ms. 2*3^4217+1 does not divide 2^3^4216-1 Time : 50.651 ms. Conclusion: 2*3^4217+1 Divides Phi(3^4217,2) Attached Files  Llr_DivPhi.zip (2.2 KB, 56 views) 2020-05-21, 13:53 #17 Jean Penné May 2004 FRANCE 24·5·7 Posts Thank you Serge! Quote:  Originally Posted by Batalov I am posting a patch to LLR that allows to run the "Proth.exe" -like test for k*b^n+1 dividing some large cyclotomic Phi(b^m,2). The input file should have the following magic header: Code: ABC DivPhi($a*$b^$c+1) 2 3 822 2 3 897 2 3 1252 2 3 1454 2 3 4217 The output will be: Code: 2*3^822+1 does not divide 2^3^822-1 Time : 263.342 ms. 2*3^897+1 Divides 2^3^897-1 Time : 116.718 ms. 2*3^897+1 Divides 2^3^896-1 Time : 103.216 ms. 2*3^897+1 does not divide 2^3^895-1 Time : 101.769 ms. Conclusion: 2*3^897+1 Divides Phi(3^896,2) 2*3^1252+1 does not divide 2^3^1252-1 Time : 97.786 ms. 2*3^1454+1 does not divide 2^3^1454-1 Time : 109.374 ms. 2*3^4217+1 Divides 2^3^4217-1 Time : 37.989 ms. 2*3^4217+1 does not divide 2^3^4216-1 Time : 50.651 ms. Conclusion: 2*3^4217+1 Divides Phi(3^4217,2)
Thank you, Serge, for this code ; in included it in my new Llr.c file and tested it locally. So, it will be included in the future LLR 3.8.24 release I hope to upload soon. Also, this release will include the Gerbicz tests for base two numbers, and also the -oCpuSupportsAVX512F=0 option that was required for a while...
I hope you are well and take care of you by these times...
Best Regards,
Jean

 2020-05-21, 16:06 #18 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 22×2,281 Posts Thank you Jean! This code is 5-6 years old so it passed a lot of internal testing (though this time I restored it from memory from scratch and of course, with modern LLR, one can now use m/t). I have extensively used it previously and I have already tested all known "Divides Phi numbers" (not just visible top 20; all such numbers including tiny ones can be found by UTM search, using option "all"). All past Proth.exe-based results are reproduced. There are additional checks that I can provide later -- so that we can quit this test very early; if by Euler's criterion we can immediately check that 2^b^n-1 will not be zero without computation.

 Similar Threads Thread Thread Starter Forum Replies Last Post Jean Penné Software 26 2019-07-08 16:54 Jean Penné Software 51 2019-04-10 06:04 Jean Penné Software 30 2018-08-13 20:00 Jean Penné Software 11 2017-02-23 08:52 opyrt Prime Sierpinski Project 11 2010-11-18 18:24

All times are UTC. The time now is 18:30.

Sun Sep 20 18:30:31 UTC 2020 up 10 days, 15:41, 0 users, load averages: 1.40, 1.41, 1.42