20090111, 02:48  #34 
Mar 2003
New Zealand
13×89 Posts 

20090111, 02:52  #35  
Mar 2003
New Zealand
13·89 Posts 
Quote:
Quote:


20090130, 21:29  #36 
Mar 2003
New Zealand
13·89 Posts 
For best performance upgrade to sr2sieve version 1.8.8: Versions 1.8.6  1.8.7 in particular will be slow with the latest sieve file unless the switch Q720 is added to the command line.
With the sieve file reduced to 3 sequences, here are the times to complete a 1T range with sr2sieve version 1.8.8 on my machines: 2.66GHz Core 2 Duo: (64 bit, 1 core): 2 days 8 hr (32 bit, 1 core): 4 days 6 hr 2.9GHz Pentium 4 HT: (32 bit, 1 thread): 8 days 7 hr (32 bit, 2 threads): 6 days 2 hr 
20090131, 04:01  #37 
May 2007
11^{2} Posts 
geoff,
Thanks for the update. I replaced the sr2sieve to 1.8.8 ver from 1.8.3 and saw an immediate 1mil p/sec increase on my q6600 running x64 ubuntu. Can't beat that with a stick. 
20090202, 04:57  #38  
Mar 2003
New Zealand
1157_{10} Posts 
From another thread:
Quote:
5 sequences (87 subsequences mod 720), 3.82M p/sec 4 sequences (69 subsequences mod 720), 4.41M p/sec (15.4% faster, expected sqrt(87/69)= 12.3%) 3 sequences (57 subsequences mod 720), 5.01M p/sec (13.6% faster, expected sqrt(69/57)= 10.0%) The expected gain is just for the discrete logarithm part of the algorithm, which usually accounts for the vast majority of the time taken. But now that the number of sequences is getting very small some other factors start to play a bigger part. One is that the chance of all the terms in the sieve simultaneously being quadratic nonresidues is 1 in 2^x where x is the number of sequences*. When this happens, 12.5% of the time now, the algorithm shortcircuits before the discrete logarithm code is even started. I think this is that main reason that it can sometimes be faster to sieve the sequences separately when there are only 2 left. (*) sequences which have both odd and even terms count as two, but there are none of those in this project. 

20090210, 16:42  #39 
Jun 2003
Ottawa, Canada
10010010100_{2} Posts 
How do you compile the sr2sieve code for 64bit Windows, is that using MinGW as? I wasn`t aware they figured out a way to get gcc to compile 64bit Windows code yet, do you have any link to instructions on how to do that?
Thanks, Jeff. 
20090211, 03:33  #40  
Mar 2003
New Zealand
13·89 Posts 
Quote:
I cross compile sr2sieve from Linux using this command, but it should work the same in Windows provided you have GNU make installed: make ARCH=x8664gcc430 CC=x86_64pcmingw32gcc Remember to change the definition of BASE to zero in sr5sieve.h, and rename the resulting sr5sieve executable to sr2sieve. The version of the mingww64 compiler I use has some bugs (which I think all early gcc 4.3.0 versions had), and the ARCH=x8664gcc430 option works around them by reducing the optimisation level to O1. If you have a later version the bugs might be fixed and you could instead use ARCH=x8664. 

20090211, 10:31  #41  
Jun 2003
Ottawa, Canada
2^{2}·293 Posts 
Quote:
Hopefully cygwin will also get to 64bit support some day as well. 

20090212, 02:10  #42 
Mar 2003
New Zealand
13·89 Posts 
MinGW uses the printf/scanf etc. functions from the Windows system libraries (MSVCRT.DLL I think), so blame Bill for that one.

20090218, 00:30  #43 
"Phil"
Sep 2002
Tracktown, U.S.A.
1119_{10} Posts 
Can you believe this?
100691806065289  2^2969687+41693 and also: 111228322245563  2^2969687+41693 The first was reported by Geoff on the 12th, and I eliminated it from the work file. Then I received the second from Kent (Kman1293) on the 15th, the only factor of a number in the range 2.93 million to 3.20 million, out of the 2500 or so entries in the currently unclaimed workfiles. Struck me as rather improbable, but then again, primes can be a bit spooky. 
20090910, 00:23  #44 
Jun 2008
Wollongong, .au
3×61 Posts 
With the sieving having received a significant boost recently (thanks Lennart! Continuing thanks to Kman, Zuzu and geoff for his excellent program too!) and with the removal of the 3rd sequence, are there some benchmark numbers on the speed increase seen?
There are ... 315557 candidates left in the sieve file (thank you line count in WinEdt!) 
Thread Tools  
Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
S9 and general sieving discussion  Lennart  Conjectures 'R Us  31  20140914 15:14 
Sieving discussion thread  jasong  Twin Prime Search  311  20101022 18:41 
Combined sieving discussion  ltd  Prime Sierpinski Project  76  20080725 11:44 
Sieving Discussion  ltd  Prime Sierpinski Project  26  20051101 07:45 
Sieving Discussion  R.D. Silverman  Factoring  7  20050930 12:57 