20050313, 14:57  #1 
"Richard B. Woods"
Aug 2002
Wisconsin USA
2^{2}×3×641 Posts 
What about the ",30,4000000" P1s ?
679 of the exponents in the latest PMINUS1.TXT file have been P1 factored to B1,B2 limits of 30,4000000. The exponents are clumped in ranges 1647564716480001, 2589034925898239, 3059758730607201, 4001225340024763 and 4471957344721137. (Some exponents in those ranges have had P1 done to higher limits.)
According to a utility I wrote to calculate probabilities of finding factors at given B1,B2 for a given exponent (following the corresponding calculation code in Prime95), those limits (B1=30, B2=4000000) give a probability of less than 10^50 of finding a factor on any of those 679 exponents. That's less than 0.000000000000000000000000000000000000000000000001%. I suggest that all those 679 exponents be considered to have had practically no P1 done at all, and that the 58 such exponents in the 1647564716480001 range be immediately added to the current Marin's Mersennearies P1 project. 
20050313, 15:11  #2 
"Richard B. Woods"
Aug 2002
Wisconsin USA
2^{2}·3·641 Posts 
Pfactor lines for the 58 exponents in the first range are:
Pfactor=16475647,65,1 Pfactor=16475681,65,1 Pfactor=16475699,65,1 Pfactor=16475743,65,1 Pfactor=16475813,65,1 Pfactor=16475959,65,1 Pfactor=16475971,65,1 Pfactor=16475993,65,1 Pfactor=16476017,65,1 Pfactor=16476071,65,1 Pfactor=16476101,65,1 Pfactor=16476107,65,1 Pfactor=16476139,65,1 Pfactor=16476209,65,1 Pfactor=16476259,65,1 Pfactor=16476311,65,1 Pfactor=16476403,65,1 Pfactor=16476491,65,1 Pfactor=16476541,65,1 Pfactor=16476583,65,1 Pfactor=16476619,65,1 Pfactor=16476653,65,1 Pfactor=16476749,65,1 Pfactor=16476773,65,1 Pfactor=16476847,65,1 Pfactor=16476907,65,1 Pfactor=16476913,65,1 Pfactor=16476919,65,1 Pfactor=16476991,65,1 Pfactor=16477003,65,1 Pfactor=16477079,65,1 Pfactor=16477081,65,1 Pfactor=16477103,65,1 Pfactor=16477207,65,1 Pfactor=16477211,65,1 Pfactor=16477217,65,1 Pfactor=16477229,65,1 Pfactor=16477273,65,1 Pfactor=16477291,65,1 Pfactor=16477319,65,1 Pfactor=16477327,65,1 Pfactor=16477333,65,1 Pfactor=16477393,65,1 Pfactor=16477459,65,1 Pfactor=16477567,65,1 Pfactor=16477661,65,1 Pfactor=16477711,65,1 Pfactor=16477789,65,1 Pfactor=16478881,65,1 Pfactor=16478927,65,1 Pfactor=16478939,65,1 Pfactor=16478951,65,1 Pfactor=16478981,65,1 Pfactor=16479013,65,1 Pfactor=16479493,65,1 Pfactor=16479653,65,1 Pfactor=16479721,65,1 Pfactor=16480001,65,1 Last fiddled with by cheesehead on 20050313 at 15:16 
20050314, 12:54  #3 
Oct 2003
Australia, Brisbane
470_{10} Posts 
Aha.. claimed by me!!!! No, you may not have them....
Thanks for picking these up. I have wanted to go back and do further p1ing on many exponents that are currently in pminus1.txt. There are a fair few exponents have very little or no stage 2 done. The only reason that I haven't started doing this yet, is that there are still many exponents that have had NO p1 work done on them yet, so they are (at the moment) more important. However, these are effectively 0, so I will do these. Cheesehead, could you please send me that program that you wrote please?? Please??? The one that works out the probabilty of finding a factor given B1 and B2. I will use it to work out what exponents have such low B1 and B2 values that they should be rep1ed. (lol... prefix and suffix on "p1".... who would of thought??). Last fiddled with by dave_0273 on 20050314 at 12:56 
20050314, 13:20  #4 
Aug 2002
Termonfeckin, IE
2^{2}·691 Posts 
I'd be interested to see if you find any factors on these. It is quite possible that this is due to an error in reporting. I do not think there is any way Prime95 could have chosen these bounds. It is however possible that someone used a manual script and screwed up.

20050314, 16:12  #5  
"Richard B. Woods"
Aug 2002
Wisconsin USA
7692_{10} Posts 
Quote:
Quote:


20050314, 16:32  #6  
"Richard B. Woods"
Aug 2002
Wisconsin USA
7692_{10} Posts 
Quote:
Quote:
Quote:
Last fiddled with by cheesehead on 20050314 at 16:35 

20050314, 17:14  #7  
"James Heinrich"
May 2004
exNorthern Ontario
2^{2}·839 Posts 
Quote:


20050315, 00:44  #8 
"Richard B. Woods"
Aug 2002
Wisconsin USA
2^{2}×3×641 Posts 
Okay. Without documentation, support, or warranty (but with a couple of test input files and corresponding output), here it is.
Reminder 1: I derived it from code in Prime95. Reminder 2: It is a utility for calculating quantities associated with Prime95 P1 factoring such as estimated cost (time) of computation or probability of finding a factor, not a program for actually performing P1 factoring. Last fiddled with by cheesehead on 20050315 at 00:59 
20050315, 20:27  #9 
"James Heinrich"
May 2004
exNorthern Ontario
2^{2}·839 Posts 
I tried running it, without success. If I run it asis, I get "Bad file name or number" on line 388 (PRINT #7, "Unexpected error ="; ERR). If I comment that out, I get:
Code:
D:\PM1E\P95SF.DAT D:\PM1E\P95FFT.DAT D:\PM1E\P95FAC.DAT D:\PM1E\PM1IN.DAT Unexpected error = 53 
20050320, 15:49  #10 
"James Heinrich"
May 2004
exNorthern Ontario
3356_{10} Posts 
I've ported the B1/B2 probability code to PHP, with reasonable success (although for reasons unknown to me I've had to add a 1.15 "fudge factor" multiplier to get numbers that match Prime95)
http://mersennearies.sili.net/prob.php 
20050321, 11:48  #11  
"Richard B. Woods"
Aug 2002
Wisconsin USA
2^{2}×3×641 Posts 
Quote:


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