20210422, 00:19  #419 
"James Heinrich"
May 2004
exNorthern Ontario
110100011100_{2} Posts 
Easily done. P+1 has never found a Mersenne factor, therefore optimal effort to spend on it is zero.

20210422, 00:47  #420  
1976 Toyota Corona years forever!
"Wayne"
Nov 2006
Saskatchewan, Canada
41·113 Posts 
Quote:
There are only about 600 exponents left that I could still reasonably P1 with aggressive bounds for an expected success rate of about 1.5% (9 factors) for about 5,000 GhzDays; about 550 per factor. After that P1 becomes very expensive with the success rate dropping to about 0.5%; and 1,700+ GhzDays per factor. Comparatively to find the remaining 47 factors via TF would take about 800,000 GhzDays. So...the only actual comparison I can do is from my own farm: Option 1: If I do all the remaining with TF it would take 170 days for my 2080Ti. Option 2: If I first complete the above 600 P1 assignments that would take about 18 days on my 20 cores (5 PCs). 290 GhzDays/Day I then TF for the remaining 38 factors in 109 days. Option 2 total is 127 days. Option 3: If I complete the P1 in 18 days. Then I do the P+1 (6,731 GhzDays) that is another 23 days. Now if I do find 15 factors by P+/1 the remaining 32 TF factors would take about 400,000 GhzDays or 85 calendar days. The total in option 2 is 126 days. So personally the P+1 benefit seems minimal. However, if my farm had less CPUs or conversely if I had a 1080Ti instead of a 2080Ti the bottom lines would be quite different. Does anyone see it different? 

20210422, 02:31  #421 
"Curtis"
Feb 2005
Riverside, CA
2·7·11·31 Posts 
Seems your personal goals are limited by GPU time, so option 3 appears fastest you can run CPU tasks and GPU tasks at the same time and finish in 85 days. But then, you could also add 10% to remaining P1 bounds and maybe still find factors faster than TF, further reducing required GPU time.

20210422, 02:52  #422  
1976 Toyota Corona years forever!
"Wayne"
Nov 2006
Saskatchewan, Canada
1219_{16} Posts 
Quote:
At the present time there are more total contributions than CPU. In that state it is better to NOT go to extreme P+/1. If GPU resources diminish then I will lean to MORE P+/1. 

20210422, 04:16  #423 
"James Heinrich"
May 2004
exNorthern Ontario
2^{2}·839 Posts 

20210422, 07:01  #424  
Einyen
Dec 2003
Denmark
2^{2}×11×71 Posts 
Quote:
30 digits and 97.1 bits, nice. From the timestamps it was the 92nd reported curve, but he reported 52 more in the same batch after the factor, so really it was the first factor in 144 curves from all up to and including 20210422 06:48:xx. Last fiddled with by ATH on 20210422 at 07:15 

20210422, 10:08  #425 
Jun 2003
3^{2}·19·29 Posts 
Cunching the numbers on chalsall's GCE runs:
Code:
6532 0.321 0.176913655848132 7685 0.364 0.170513988288874 8956 0.401 0.161188030370701 9502 0.437 0.165565144180173 One thing that puzzles me is the fairly low B2/B1 ratio. Given how much slower stage 1 is compared to P1 stage 1, I would've expected it to be a lot higher. I would like to try out higher B2/B1 ratios (maybe 100x). Give me some time to get some probability estimates using the higher ratio. I have enough runtime data to accurately model Prob/Hr on that GCE machine  I just need the probability figures. 
20210422, 11:46  #426 
Jun 2003
11537_{8} Posts 
So after further crunching, I noticed that the GCE machines were producing inconsistent timings. After correcting for it, there was a much more pronounced loss of efficiency (prob/hr) as you go higher B1. So considering that, I think B1=600k is about as high as I would recommend.
The good news is that, I made a mistake in the previous assignment. I kept the TF depth as 75, when actual depth for 42.6 range should've been 74. That improves the probability a bit. Keeping that in mind, here are the updated assignments. I am still leaving B2 selection up to P95. There was no improvement going to larger B2. I have removed the 5 that were completed. The probability of success is about 1 factor in 500 hours of a 4 core GCE (give or take  there is natural variability in machine performance). It is up to you whether you consider this worthwhile. 
20210422, 14:24  #427  
Jul 2003
wear a mask
2·11·73 Posts 
Quote:
One more reminder about your estimates, although I'm sure you know this, each task is slightly parasitic to the other tasks in terms of lowering probabilities or number of factors found. For instance, TF will find factors that P+1 or P1 might find. Of course, each method will be the quickest way to find a certain factor; too bad we don't know in advance. Last fiddled with by masser on 20210422 at 19:12 

20210422, 14:35  #428 
If I May
"Chris Halsall"
Sep 2002
Barbados
22542_{8} Posts 
Thank you for your efforts. But for my ranges, I think doing deep P1'ing is more costeffective.

20210422, 17:14  #429 
Jun 2003
3^{2}×19×29 Posts 

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