20140613, 19:17  #1 
I moo ablest echo power!
May 2013
1,741 Posts 
GPU GMPECM to higher input limit
I've been working on removing the 2^1018 limit on GMPECM's GPU implementation, and I think I've gotten it done. I'm not going to completely doublepost, but I've put more details about how I've been testing it in this thread: http://mersenneforum.org/showthread.php?t=16480&page=23 (specifically, posts #253, 254, and 255 starting at the bottom of page 23).
I would appreciate some of the more knowledgeable mathematicians and programmers on here trying out the file uploaded in post 253 and letting me know if you get similar results. At this point, it should be able to handle up to 2^40961 as an input. I've personally tried as high as 2^40001. Thanks. 
20140613, 23:22  #2 
I moo ablest echo power!
May 2013
1,741 Posts 
Not sure if anybody is actually interested or not, but I've got the limit to 2^81861 now. Still working alright.

20140613, 23:25  #3 
Sep 2008
Kansas
2×31×53 Posts 
Is there a 64bit Linux version available for trial?

20140613, 23:39  #4 
I moo ablest echo power!
May 2013
1,741 Posts 
If you're able to compile it yourself on Linux, I can tell you the (small) changes I made. Unfortunately, the only Linux box I have has a CC 1.3 Nvidia card in it, so I don't know if it's able to compile at CC 2.0 or higher.
Edit: Also, a question for those who understand ECM fair better than I do: the sigma in the GPU version is only randomly chosen as a starting point. Subsequent sigmas are incremented from this initial random value. Is that a problem in terms of the probability of finding factors of a given size? Last fiddled with by wombatman on 20140613 at 23:49 
20140614, 03:40  #5 
Romulan Interpreter
Jun 2011
Thailand
5^{2}·7·53 Posts 
It doesn't matter. Like when you play lottery and pick 10 numbers in a row, or 10 random numbers, your chances are the same, it is 10 over the total numbers possible. The random selection in the beginning helps to have different people run different curves therefore avoid duplication of work when more people are ECMing the same number, so it has to be kept.

20140614, 04:44  #6 
I moo ablest echo power!
May 2013
6CD_{16} Posts 
Just what I needed to know. Thanks!

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