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Old 2021-09-12, 11:18   #382
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Mar 2017
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Default MM127 is on its last mmff kernel & 3 bits

Originally Posted by Prime95 View Post
Today I'm releasing a beta version of a GPU factoring program for the double-Mersennes (MM61, MM89, MM107, MM127) and small Fermat numbers (F26 to F157). Sources attached. Nvidia cards with 2.0 compute capability is required.
Originally Posted by Uncwilly View Post
I would love for this to be the end of the "MM127 is prime" speculation!
Originally Posted by Gary View Post
With these changes, all 43 known factors within the range of mmff can be verified
Here is source with these changes and a CUDA 10.1 Linux binary that will hopefully run on Kepler or later (--gpu-architecture=compute_30). I included Serge's patch to print factors found in K*2^N+1 form. If you want factors in the old format, use output.c from the 0.28 release. I also fixed a few other misc things, and changed the version to 0.28.1 to identify this binary. I am not sure who the current owner of mmff is, but if I changed anything in a "bad" way please feel free to fix it and re-post.
If I read the v0.28 source correctly, TF on MM127 is supported up to factors 2188. MM127 has been trial factored to slightly over 2185. A rough estimate of time to complete TF up to the limit of v0.28 is 5 RTX2080-years. That limit could be reached within 2 years by application of multiple GPUs on different blocks in parallel.

2185 / 2 /(2127-1) is ~257 which is 144,115,188,075,855,872: going to 288.23E15 (186 bits) would be roughly 6 x 144.12 = 865 days = 2.37 years on a single GTX1650.
To go to 187, 4.74 years more; to 188, 9.5 years more; total 14.24 GTX1650-years, or about 5 RTX2080-years.
Four GTX1650 plus 2 RTX2080 could get there in ~1.5 years, if no factor is found before then. (I estimate factor odds from 185 through 188 as 1.6%.)

Other supported double mersennes have a little more bits margin remaining in mmff v0.28.
MMp        URL                                  k max done   ~bits   kernels’ max bits    bits left
MM31    450.E15    90.64    89, 96                5.36    
MM61    230.E15   119.67    108, 120, 128         8.33    
MM89     54.E15   145.58    128, 140, 152, 160   14.42    
MM107    10.E15   161.15    152, 160, 172        10.85    
MM127   145.E15   185.01    183, 185, 188         2.99
Of these, MM31 has known factors.

Last fiddled with by kriesel on 2021-09-12 at 11:20
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