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Old 2019-11-03, 11:39   #9
MrRepunit's Avatar
Mar 2011

97 Posts

Originally Posted by storm5510 View Post
I tried this on two machines. An older one running Windows 7 Pro x64 with a GTX 750Ti and a newer one running Windows 10 Pro x64, v1903, using a GTX 1080.

Using the version of mfaktc I had, the 1080 would run around 1050 GHz-d/day. This one was 730 GHz-d/day., more or less. This was with base 2.

It seems that specifying the base in the worktodo file would be problematic for PrimeNet and GPUto72. Perhaps it may be better to specify the base in the configuration file? I would not think many would be changing the base very often, or at all, given this projects goal of finding Mersenne prime numbers.

When I started the fork of mfaktc I was only considering base 10 repunits, so I had to 'deoptimize' some code. I removed the Barrett kernels as they seemed unsuited to fit the base 10 and also more general bases. I needed to generalize some methods that where using the better performant shl instruction (optional_mul). Also implementing the 64 bit kernel was for speeding up lower exponents. Mersenne numbers are already factored far beyond this point.That considered the current version is definitively not optimal for factoring Mersenne numbers, but tries to focus on other bases and smaller exponents.

Reading the default base from the configuration file is a good idea, will implement this soon.

However, I am not sure if gr-mfaktc should be a complete replacement for mfaktc (it is still the project from TheJudger), or if it should be thought as an orthogonal project that puts the focus on general repunits. I could certainly try to start from scratch againg and cherry-pick my changes while leaving the Mersenne & Wagstaff number stuff mainly untouched and just add more functionality. Maybe TheJudger has some thoughts about this...
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