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Thread: Small n factoring

  1. #121
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    Originally posted by vjs
    I always thought the txt was simpley overwritten and the >> was an append?
    That's correct - but it all depends on the granularity. The overwrite event only takes place at the start of gmp-ecm, not at the start of a curve (when using the -c parameter - without, it's the same, of course).
    Thus, the information of curve results within a single gmp-ecm run gets appended to the output file, whereas a new start of gmp-ecm naturally erases all data when using > instead of >>.

  2. #122
    Moderator vjs's Avatar
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    O.K. so using > instead of >>

    Basically using > and the -c curves option, reports the last curve done. Either containg the factor if it stoped early or the final curve of a run. However you have no idea howmany curves were completed in the event of a crash etc.

    Thanks for clearing this up.

  3. #123
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    Actually, it seems like I didn't express myself clearly.

    According to my tests, > and -c saves all output of a single gmp-ecm run.

    Example:
    echo 2^^^^1061-1 | ecm -c 5 1e4 > results.txt

    Contents of results.txt
    GMP-ECM 6.0.1 [powered by GMP 4.1.4] [ECM]
    Input number is 2^1061-1 (320 digits)
    Using B1=10000, B2=1186831, polynomial x^1, sigma=2999931604
    Step 1 took 783ms
    Step 2 took 844ms
    Run 2 out of 5:
    Using B1=10000, B2=1186831, polynomial x^1, sigma=3364805730
    Step 1 took 901ms
    Step 2 took 876ms
    Run 3 out of 5:
    Using B1=10000, B2=1186831, polynomial x^1, sigma=4143695723
    Step 1 took 1020ms
    Step 2 took 841ms
    Run 4 out of 5:
    Using B1=10000, B2=1186831, polynomial x^1, sigma=2441763206
    Step 1 took 885ms
    Step 2 took 879ms
    Run 5 out of 5:
    Using B1=10000, B2=1186831, polynomial x^1, sigma=523117962
    Step 1 took 870ms
    Step 2 took 811ms

    When you restart gmp-ecm, the contents is lost, of course.

  4. #124
    That's because > explictly means 'redirect stdout to this filename after truncating to zero length'. As opposed to >> which means 'redirect stdout and append to this filename'. Neither of these are options/flags to the program itself. They are instructions to the shell (which is used to launch the program) to connect certain file descriptors to the file rather than to your tty/terminal/screen/whatever.

  5. #125
    i have started experimenting with p95 but on the irst factoring run it chose b1 bounds that are so large it'll take my athalon 2000+ over 13 days to complete stage one and B@ equals stage ones value. Is there something i can do to set bounds manually?

  6. #126
    The way to chose the bounds manually is:
    Pminus1=K,2,N,1,B1,B2,0

    There is the max B1=B2 value possible somewhere at mersenneforum, but I don't remember it.

    But there are reasons, (don't ask me) to use ECM for so large factors. And I wonder if somebody didn't run P-1 already for these small N, with quite impressive bounds.
    H.

  7. #127
    when doing stage 1 with P95 and P-1 how doyou have save files created and stored s othat you can use greater bounds later?

  8. #128
    Originally posted by Keroberts1
    when doing stage 1 with P95 and P-1 how doyou have save files created and stored s othat you can use greater bounds later?
    With Pminus1=...

    Doing this, the save file is not deleted. But you have to keep track of the bounds, because continue on a savefile with the wrong bounds works, but gives bogus, I got the impression.
    I don't know either if you can extend B1 from say 1000000 to 2000000. There are commands like
    Pminus1=K,2,N,1,B1old-B1new, B2,0

    or

    Pminus1=K,2,N,1,B1new-B1old, B2,0
    I don't know. The same seems to work with B2.
    Try it out and keep us informed, please.
    Have fun, H.

  9. #129
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    From what I know/remember...

    First the max B1 is something like 4G what every 2^n is for 4G anyways.

    I'm pretty sure you can extend B1 easiely, simply don't erase the intermediate file and run the same worktodo.ini and specify a larger bound. Don't get confused with the B2New-B2old. Increasing B1 on a second run actually extends the existing file were running B2'-B2 simply checks a different range of B2 between B2' and B2. I hope this makes sence.

    The idea behind running prime95 for stage1 is it's faster, however it does start to take quite a bit of disk space if you want to do 1000 curves for example.

  10. #130
    where does p95 putput factors? Can i have them placed into a specific file?

  11. #131
    Originally posted by Keroberts1
    where does p95 putput factors? Can i have them placed into a specific file?
    Isn't it results.txt?
    And you can put e.g. the line

    results.txt=fact.txt

    into your prime.ini.
    There you get residues and eventual factors. H.

  12. #132
    ok i have an interesting error. I have set up P95 to start on eveer 67607 test through 15-16 million. for starters i set it to P-1 them all with bounds of B1=1000 and no stage 2. I just checked it and it has found a factor for almost everyone of the tests adn the factor is 1. For some of thetests it says it has found a factor and then itsays error factor doesn't divide N. Is that because i used such low bounds or is there somethingelse going on? the lines in my prime.ini are like this.

    Pminus1=67607,2,15001691,1,1000,1000

    Is that wrong?

    I already have my worktodo.ini populkated so that it will go through all of the tests with this bounds and then do them all again up to 5000 and then 20000 and then 50000. Will this work? Will not work? Any ideas? Just to explain some people have been working o ngetting 9-10 Million to have fewer than 1000 tests for 67607 and I'm just trying to see if i can d oit with 14-15 mil. first. Races are always fun ya know.

  13. #133
    Originally posted by Keroberts1
    the lines in my prime.ini are like this.

    Pminus1=67607,2,15001691,1,1000,1000

    Is that wrong?
    PRIME.INI??? You mean worktodo.ini.

    And can you try to put the line

    Pminus1=67607,2,15001691,1,1000,1000,0

    with a final useless parameter 0? That's the way I did it back then.
    Don't know if this helps...
    H.

  14. #134
    yes imeant worktodo.ini and i have tried adding the 0 i will let you know how it works.

  15. #135
    ok well it worked fine for several hours and then went back to giving the same errorsand 1 as a factor. Its a mighty weird error even if it is hardware. my guess is it has something ot do with such low bounds or a syntax error somewhere in my command line.

  16. #136
    You say it worked fine for a few hours. Does this mean in your results.txt (or whatever it is called) you've got residues and all? With such small bounds, there must be dozens.
    And then it startts to mess up again, right?

    If you think it's a hardware error, you can run a stress test, a memory test ( you find information on this forum) and stuff, you know all this I guess.
    Also, you can post at mersenneforum.org. There you will find qualified support, probably more helpful than me.
    It could have to do with a FFT length related bug, too, who knows?
    I would like to try it out but don't have time. Perhaps this evening.
    Meanwhile, you can post more specific output, like from results.txt, screen (I think you need to make a screenshot) and so on.
    Not for me, but others might recognize something.
    Good luck, Yours H.

  17. #137
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    New status:

    Code:
    		25	30	35	40			
    
    21181,1148	ok	ok	ok	ok
    21181,1172	ok	ok	ok	ok
    10223,1181	ok	ok	ok	ok
    21181,1268	ok	ok	ok	reserved (24.6%)
    10223,1517	ok	ok	ok
    24737,1567	ok	ok	ok	reserved (26.5%)
    55459,1666	ok	ok	ok
    55459,1894	ok	ok	ok	reserved (69.8%)

  18. #138
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    Keroberts, is it working properly now?

    If not, would you consider a copy-paste of the contents of your prime.ini file, some sample rows of the working pairs from the worktodo.ini and fact.txt, and some sample rows of the non working pairs from the worktodo.ini and fact.txt files?

    May be somebody can guess what's going wrong (if it's not hardware related, of course).

    BTW, you should note that if you're using only one or two PCs, expect it to take at least a year to slim down 15m-16m to 999.
    Last edited by Nuri; 12-12-2005 at 07:30 PM.

  19. #139
    [Mon Dec 12 21:50:04 2005]
    67607*2^15051627+1 stage 1 is 34.69% complete.
    [Mon Dec 12 22:15:00 2005]
    67607*2^15051627+1 stage 1 is 69.39% complete.
    [Mon Dec 12 22:38:25 2005]
    P-1 found a factor in stage #1, B1=20000.
    ERROR: Factor doesn't divide N!
    67607*2^15051627+1 completed P-1, B1=20000, B2=20005, Wc1: 8573DA75
    [Mon Dec 12 23:06:32 2005]
    67607*2^15052451+1 stage 1 is 34.69% complete.
    [Mon Dec 12 23:35:26 2005]
    67607*2^15052451+1 stage 1 is 69.39% complete.
    [Tue Dec 13 00:03:36 2005]
    P-1 found a factor in stage #1, B1=20000.
    67607*2^15052451+1 has a factor: 1
    67607*2^15052451+1 completed P-1, B1=20000, B2=20005, Wc1: 8592DA6A

  20. #140
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    here's what I get...

    [Tue Dec 13 10:02:14 2005]
    67607*2^15051627+1 completed P-1, B1=20000, B2=20005, Wc1: 8573DA75
    [Tue Dec 13 11:13:55 2005]
    67607*2^15052451+1 completed P-1, B1=20000, B2=20005, Wc1: 8592DA6A

  21. #141
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    I had similar 'problems' when I was using sbfactor on one of my P4s.

    More than likely you have a duff bit of memory, it kept on reporting that 2 (or some other very small number) was a factor of a specific number (which is impossible).

    If you can, run the Prime95 binary in the stress test mode to see if it fails. Or you could run some sort of memory testing program.
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  22. #142
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    ... with prime95, version 24.14.1.0

    Other than that, I would also suggest a stress testing of your hardware.

  23. #143
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    New status:

    Code:
    		25	30	35	40			
    
    21181,1148	ok	ok	ok	ok
    21181,1172	ok	ok	ok	ok
    10223,1181	ok	ok	ok	ok
    21181,1268	ok	ok	ok	ok
    10223,1517	ok	ok	ok	reserved
    24737,1567	ok	ok	ok	reserved (44.8%)
    55459,1666	ok	ok	ok	reserved
    55459,1894	ok	ok	ok	reserved (69.8%)

  24. #144
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    I see Mike_H found a bunch of small n factors between 30K and 60K...

    Looks good mike were those P-1 and what bounds were you using just wondering.

  25. #145
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    Quote Originally Posted by vjs
    Looks good mike were those P-1 and what bounds were you using just wondering.
    Most of those recent successes were with ECM (using B1, B2 and curves which equate to 18 digits).

    I had been P-1ing, but I seem to have hit a bit of a drought, thus the switch to ECM. I'll probably be back on P-1 again soon.

  26. #146
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    Do you have a status update of your ECM work (like here)?

  27. #147
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    Quote Originally Posted by Mystwalker
    Do you have a status update of your ECM work (like here)?
    Code:
    Complete
    [Mon 02-Jan-2006 22:10:14]  ECM: Range    30000-50000    (20000), 18,       375 candidates 
    [Sat 21-Jan-2006 14:56:17]  ECM: Range    50000-70000    (20000), 18,       393 candidates 
    
    In progress
    [Sun 22-Jan-2006 17:54:07]  ECM: Range   100000-200000   (100000), 18,      K=67607,    124 candidates 
    [Wed 01-Feb-2006 22:19:55]  ECM: Range    70000-80000    (10000), 18,       189 candidates

  28. #148
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    What B1 and B2 are you using for 18 digits? At a guess I'd say:-

    B1 = 10000 B2 = 1500000 ?

    And how many curves max?

    What about B1 and B2 for P-1? The same?
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  29. #149
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    66 ECM curves, B1=7400, B2=740000

    Need to review where I'm at with the P-1 stuff, but I've been working with B1=B2, then when I get bored I'll do a B2=B1*100 then call it a day (probably).

    EDIT:

    Current status of P-1 testing is:

    Complete:
    Code:
    P-1: Range      991-   5000    B1=100000000, B2=100000000
    P-1: Range     5000-  20000    B1=15000000, B2=15000000
    P-1: Range    20000- 100000    B1=1000000, B2=1000000
    P-1: Range   100000-1000000    B1=600000, B2=600000, K=67607
    Last edited by MikeH; 02-06-2006 at 12:55 PM.

  30. #150
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    Well I'm doing 200000 to 210000 for all kwith B1=600000 and B2 will probably go to 100*B1 (just getting B1 there on all of them first).

    Found 5 so far, most notably:-

    111430207063079 | 2^202471+1

    That's only 111T for a very low n! Was this previously missed?

    p-1 = 2 * 17 * 19 * 360953 * 477881
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  31. #151
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    We don't have k=1...

  32. #152
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    Sorry, cut and paste error.

    111430207063079 | 24737*2^202471+1

    A sorted and cleaned results_duplicates_excluded_marked.txt has:-

    111371229538703 21181 11665988 3259 0
    111381585663619 19249 3462386 3259 0
    111388239468763 10223 10494725 3259 0
    111457721737709 21181 16796180 3259 0
    111460132600447 10223 8997581 3259 0
    111461408850647 24737 15021727 3259 0
    111469919309137 10223 5272421 3259 0

    I'm checking the gap between 111388239468763 and 111457721737709 now.

    I know how easy it is to forget to submit factors. I failed to submit a couple before I started using Sobistrator. It's quite easy to miss off the first digit when cutting and pasting into the factor submission box.

    When I went back to collect all the information to send to factrange@yahoo.com I checked each and every factor had been submitted and that's where I noticed the two I'd missed.

    Speaking of which I have about 8T worth of ranges to send to factrange@yahoo.com now the emails aren't bouncing :-).
    Last edited by Greenbank; 02-08-2006 at 09:07 AM.
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  33. #153
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    Most n<300k has been missed since the orginal sieve dat was 300K<n<3M followed by 1M<n<20M then finally 991<n<50M.

  34. #154
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    Aha, that explains it.
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  35. #155
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    I'm planning to throw some ECM cycles for my range at k=67607, 9m<n<10m to see if I can get faster results when compared to P-1 alone. If I stick to P-1 only, it looks like it'll take at least two more years before I reach 999 (compared to initial projection of 18 months).

    I've scanned through a couple of pages and got confused on how to run the program. It'd be very hepful if anyone could provide some help. Thanks in advance.

  36. #156
    it was my understanding that with such high N values it is muhc more efficient to P-1. I could be wrong however. I don't know taht much about ECM.

  37. #157
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    Well, running an ECM with a comparable chance of success takes longer than P-1 factoring. Hence, as long as there are enough candidates, it's best to stay at P-1. ECM comes in handy when a particular candidate has to be factored, especially when looking for a 40+ digit factor. In this range, P-1 factoring gets less efficient...

    If you want to try ECM factoring nevertheless, there are basically two (well, three) options to do it:

    1a. Use Prime95
    This should be the easiest one. Just use the command "ECM2=" in the worktodo.ini. The syntax is
    ECM2=k,b,n,c,B1,B2,curves_to_do[,specific_sigma]
    1b. Use gmp-ecm
    I haven't tested this program with numbers that high, though. And I think that it will be slower, because base 2 factoring attempts are pretty optimized in Prime95. Maybe the better stage2 implementation can gain some performance points again, but this usually levels the playing field at high digit searches (guesstimate: 35+ digits) only.
    Syntax:
    ecm <number> <B1> [<B2>]

    You can also add parameters such as -c <curveCount>.

    2. Mix: Prime95 for stage1, gmp-ecm for stage2
    The most efficient, but also most complex way. I don't go into further details, as knowing how to do 1a and 1b is recommended...

  38. #158
    any news on the factoring of 991? anyone still trying this?

  39. #159
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    Quote Originally Posted by Keroberts1
    any news on the factoring of 991? anyone still trying this?
    I do some work from time to time. If Joe O did no new curves since June 15th, we're at ~20% now.

  40. #160
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    Another update on ECM
    Code:
    In progress
    [Thu 09-Feb-2006 23:11:03]  ECM: Range     6000-25000    (19000), 25,       294 candidates 
    [Wed 01-Feb-2006 22:19:55]  ECM: Range    70000-80000    (10000), 18,       189 candidates 
    [Sat 04-Feb-2006 16:02:40]  ECM: Range    80000-100000   (20000), 18,       415 candidates 
    [Sun 22-Jan-2006 17:54:07]  ECM: Range   100000-200000   (100000), 18,      K=67607,    124 candidates

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