20120209, 14:41  #1 
P90 years forever!
Aug 2002
Yeehaw, FL
11×751 Posts 
P1 formula (help wanted)
For those that do a lot of P1, the Test/Status menu choice and sending expected completion dates are rather time consuming. This is because prime95 computes the optimal bounds every time.
My idea is to replace the optimal bounds calculation with a simple formula that's accurate within 10% or so for the most common cases. Would someone like to do a little research and if possible come up with a formula that takes in exponent, TF, and available mem and generates a reasonably accurate guess of B1 and B2? Thanks! 
20120209, 14:51  #2  
"Nathan"
Jul 2008
Maryland, USA
5×223 Posts 
Quote:


20120209, 15:03  #3 
P90 years forever!
Aug 2002
Yeehaw, FL
8261_{10} Posts 

20120209, 15:59  #4 
Jun 2003
43·127 Posts 
Sort the expos (well, find min/max expo per FFT). Calculate the bounds for the first and last expo for each FFT length. Interpolate linearly for the others. Should be very accurate at the expense of 24 bound calculations.
Last fiddled with by axn on 20120209 at 16:00 
20120209, 22:48  #5  
Account Deleted
"Tim Sorbera"
Aug 2006
San Antonio, TX USA
11×389 Posts 
If we were to see a table of the results of the current optimal bounds calculations, a bestfit formula would likely be easy to extrapolate.
Quote:


20120209, 22:59  #6 
Basketry That Evening!
"Bunslow the Bold"
Jun 2011
40<A<43 89<O<88
7221_{10} Posts 
Perhaps after calculating the bounds, just autoconvert a PFactor line to a Pminus1 line, except with the AID.
(And is there anything wrong with the way it is? Sure, it takes a few seconds, but so what?) Last fiddled with by Dubslow on 20120209 at 23:04 
20120210, 02:26  #7 
Sep 2010
Annapolis, MD, USA
2×3^{2}×11 Posts 

20120210, 02:37  #8  
"Bob Silverman"
Nov 2003
North of Boston
7558_{10} Posts 
Quote:
optimizing?? "Guess B1 and B2". Guess their values to achieve what goal? If you answer "maximize the probability of success", it is not a realistic goal, since you can always increase that probability up to 1 simply by taking B1 and B2 large enough..... If you want to (say) maximize the probability of success per unit time spent, you can get that data from my "Practical Analysis of ECM" paper. Running P1 is equivalent to running ECM with just one curve. If you want to select B1 and B2 to maximize the probability of success given a FIXED RUN TIME, then my paper shows how to do that as well. If the factor you seek is (say) 1 mod q for some value q, then simply adjust the size of factor being sought by the size of q. 

20120210, 02:53  #9  
Basketry That Evening!
"Bunslow the Bold"
Jun 2011
40<A<43 89<O<88
16065_{8} Posts 
Quote:
Personally, I don't see why the results would be different depending on when I run the algorithm. Why not just use the bounds in the save files (or put them in worktodo as MG and I have suggested), whenever they're requested? I have 29 P1 assignments currently, and it took 7 seconds to run (yes I did time it). That's just fine in my book. If I have 50 and it takes 10 seconds, it's still not that big a deal, IMO. (I'd rather George work on AVX/membandwidth than the ETA function, for they'll have greater long term impact on GIMPS, but then, it's his program and time.) Last fiddled with by Dubslow on 20120210 at 02:57 

20120210, 03:13  #10  
Oct 2011
679_{10} Posts 
Quote:


20120210, 03:38  #11 
Basketry That Evening!
"Bunslow the Bold"
Jun 2011
40<A<43 89<O<88
16065_{8} Posts 
Ah. 1700>>50. Point taken.

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