20200903, 02:50  #1 
1976 Toyota Corona years forever!
"Wayne"
Nov 2006
Saskatchewan, Canada
43·103 Posts 
Did the P1 percentage calculation program change recently?
About a year ago I tried to emulate prob.php with an Excel macro and was able to get to within about 0.04% of prob.php.
I rechecked lately and find I am now out by about 0.4% (10 times worse). I did not {intentionally} change my macro. Thanks 
20200903, 04:40  #2 
"Mihai Preda"
Apr 2015
514_{16} Posts 
Yes. One implementation of the new calculator is in gpuowl source code https://github.com/preda/gpuowl/tree/master/pm1 in python and C++.
The news is good, the new calculator returns higher percentages :) 
20200912, 19:51  #3  
1976 Toyota Corona years forever!
"Wayne"
Nov 2006
Saskatchewan, Canada
114D_{16} Posts 
FWIW ... this is still below what I am seeing.
Quote:
For no other reason than it worked and I like round numbers I mostly used a new B1/B2 of 1,000,000/20,000,000. The P1 Probability Calculator at mersenne.ca; and what is reported by Prime95 gave me a success rate back then of somewhere close to 4.25%. Most exponents had existing P1 with B1=B2 such that their expected success rate was about 1.75% The difference is 2.5% The new calculator has a success rate of about 4.35% with a difference of 2.6%. Over my 33,000 tests from the start and consistently continuing to the current date my success rate has been very close to, and often just above 3%. 

20200912, 22:03  #4  
"Mihai Preda"
Apr 2015
2^{2}×5^{2}×13 Posts 
Quote:
mprime uses BS (BrentSuyama extension) (when E>2, usually E==6), which may also bring a slight benefit, but not exactly known how large. If you have a big set of results, you could analyze them to filter segregate the cases:  P1 found a factor missed by TF (i.e. factoredto value was not correct, too large)  P1 found a BS factor (i.e. beyond B2) Last fiddled with by preda on 20200912 at 22:04 

20200912, 22:23  #5  
1976 Toyota Corona years forever!
"Wayne"
Nov 2006
Saskatchewan, Canada
43·103 Posts 
Quote:
BS has found very few for me (I don't have an exact count though) I like your idea of an analysis/filter; just a bit of work for me. Thx 

20200913, 00:01  #6  
Random Account
Aug 2009
U.S.A.
2×811 Posts 
Quote:


20200913, 00:14  #7  
P90 years forever!
Aug 2002
Yeehaw, FL
11^{2}·59 Posts 
Quote:
BS data from 33,000 tests would be very useful. If you can tell us, for each E value, how many P1 tests were run and how many factors would have been missed if BS was not used. 

20200913, 14:57  #8 
Jun 2003
126E_{16} Posts 
Does the p1 probability calculation account for the fact that k from 2kp+1 is more likely to have smaller factors compared to random number of the same size (because 2kp+1 is prime and does not have small factors)?
I had estimated that this is roughly equivalent to a 2bit reduction in size for k. 
20200913, 16:07  #9 
1976 Toyota Corona years forever!
"Wayne"
Nov 2006
Saskatchewan, Canada
43×103 Posts 

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