20081003, 18:16  #1 
Mar 2004
3×127 Posts 
Any news about Double Mersenne factor search?
Is there any news about the double Mersenne factor search?
There are no news on the Will Edgington’s pages for a long time. http://www.garlic.com/~wedgingt/MMPstats.txt MM13, MM17 and MM19 do not need a lot of coordination. Everyone can run ECM curves and report them to the primenet server. MM31. Thusfar there are 4 known factors. The last info I have is that Ernst Mayer is searching up to k=10^15. That means 82 bit fectors. That is about a 256 times higher k than used for exponent around 33M (68 bit). Is there any effort to go beyond? Prime95 is quite fast for that task, but difficult to split up the tasks. Maybe it is possible to split up the different passes when editing the factoring save file. http://www.mersenneforum.org/showpos...86&postcount=7 http://www.mersenneforum.org/showthread.php?t=4229 MM61: Tony Forbes is coordinating a search here. http://anthony.d.forbes.googlepages.com/mm61prog.htm Progress: 1bout 1.75*10^15 (Note that N=2k) MM89, M107: No news known. (k=3.5T; k=2T) MM127: Erst Mayer searched up to k=2^48 (176 bits). http://anthony.d.forbes.googlepages.com/mm61prog.htm Is there any further progress? It would be interesting to add some bits here. There are chances that we finally find a factor ( a bit more then 0.5% per bit). So we finally could stop all these Posts claiming that MM127 is prime… 
20081003, 18:46  #2  
Banned
"Luigi"
Aug 2002
Team Italia
2·29·83 Posts 
Quote:
I had the impression that ECM could be more efficient on these ranges, do you think I can be proven wrong? Luigi 

20081003, 23:49  #3 
Mar 2004
3×127 Posts 
Which ranges did you retest?
MM13, MM17 and MM19 are so small that trialfactor won't find any new factor. ECM is the clue here. Prime95, GMP ECM or a combination could be used. MM31: That number is so large that only trialfactor makes sense. Ernst's application and Prime95 are the most optimized programs. (Use Advanced Factor of the latest 24 Version, it is about 7 times faster than mfac) MM61, MM89, MM107, MM127 etc. These are too large for Prime95 I don't know Factor5 and how the performance is compared to Tony Forbes' mfac. 
20081004, 04:15  #4 
"Phil"
Sep 2002
Tracktown, U.S.A.
3·373 Posts 
Hopefully, Ernst may respond here. I understood that he was doing some searching on M61, M89, M107, and M127.
Higher iterated Mersennes, odds are low, but who knows? I've wondered about a coordinated search for some time. 
20081004, 10:17  #5  
Banned
"Luigi"
Aug 2002
Team Italia
2·29·83 Posts 
Quote:
I see now how to choose trialfactoring instead of ECM. Luigi 

20081004, 10:18  #6  
Banned
"Luigi"
Aug 2002
Team Italia
2·29·83 Posts 
Quote:
Luigi 

20081004, 13:34  #7  
Mar 2004
101111101_{2} Posts 
Quote:
According to the posts, Ernst did work on MM31 and MM127; Tony coordinates MM61; About the other exponents there is no new information since the update of Will's pages. I am sorry, but the last link in the first post should have been: http://www.mersenneforum.org/showthr...t=MM127&page=4 

20081007, 02:09  #8 
Dec 2003
Hopefully Near M48
11011011110_{2} Posts 
Bump.
Please Ernst Mayer? Last fiddled with by jinydu on 20081007 at 02:10 
20081009, 23:43  #9 
Mar 2003
New Zealand
13×89 Posts 
I am also interested in a coordinated search for factors of MM61 and higher.
Mark Rodenkirch has extended his gmpfermat program to work with double Mersenne numbers and I have added some x86_64specific assembly that makes it faster on MM61,MM89,MM107,MM127. I will post some Linux executables for testing if Mark is OK with releasing this version of his program. From the little testing I have done it seems to be significantly faster than the 32bit MFAC executable, but I don't know how it compares to other programs. 
20081010, 13:38  #10  
"Mark"
Apr 2003
Between here and the
1100010111011_{2} Posts 
Quote:


20081010, 23:44  #11 
Mar 2003
New Zealand
13×89 Posts 
gmpfermat21.zip contains Linux executables dm32 and dm64 to search for factors of double Mersenne numbers. Only dm64 has the assembler code to speed up MM61MM127. (fermat32 and fermat64 search for factors of Fermat numbers).
There isn't any documentation in the archive, but to run it just create a file fermat.ini like this one: kStart=2 kEnd=100000000 nStart=89 nEnd=89 FilterPrimes=50000 This would cause dm64 to search for factors k*(2^n1)+1 of the double Mersenne number 2^(2^n1)1 for k from 2 to 100000000 and n=89. I don't really know what the optimal value for FilterPrimes is, it will default to 500000 if not given. 
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