>> That is assuming the trial-factoring to 2^80 (~1.25 >> years) and the P-1 (stage 1 only where B1= 8,010,000 >> B2=8,010,00 (chosen by Prime) with FFT of 32M and >> 3.04% chance) of ~240 days didn't find any factors. [note: corrected days for P-1 shown above]
>If you had (or configured) enough memory then the B2 limit >should have been much higher - around 20x B1. And the run >time would be significantly bigger - around 1 year - though >the chance of finding a factor during P-1 would be nearer >6% than 3%. >The point here is that 32M FFT run length implies a >_minimum_ working set of 256M bytes for L-L and P-1 stage >1; P-1 stage 2 needs several times that amount, 4 GBytes >would seem reasonable. This _should_ be available on >systems with the power to handle 500M range exponents. Obviously, 2 GB of memory (1.5GB allowed for Prime95 on this test) is not enough for it to want to do stage 2 of the P-1, since B2 is equal to B1. I did guessimate that Prime95 would want a _minimum_ of 1.2GB to do stage 2, with a _desirable_ amount just under 3.6GB Out of curiousity, I just went and ran the test again, jacking it up to 1792MB allowed for Prime95 to do the test, and it decided it would do the P-1 stage 2 test now, with limits B1=4,835,000, B2=56,811,250, and a 4.54% chance. Estimated time for completion of P-1 goes from ~240 days to ~7.4 yrs. I'm sure using the _desirable_ amount of 3.6GB would of course increase the limits (and of course time and % chance) >Though I suppose someone with more avarice than common >sense is going to want to start working on exponents around >332.2 million as soon as the 10M digit prize is claimed.... More avarice than common sense? How kind of you Brian. I would have use the word stupidity, but that's just myself. lol. >there's still an enormous amount of work to do on exponents >under 79 million. I agree. Even on a 3Ghz P4D it takes ~50 days to L-L test a 42M exponent. Considering how many exponents under 79M still to be done, it will take years to do, even if every machine working on the project was a 3Ghz P4D. _______________________________________________ Prime mailing list [email protected] http://hogranch.com/mailman/listinfo/prime
