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 2010-10-05, 16:55 #386 jasonp Tribal Bullet     Oct 2004 2×3×19×31 Posts Maybe flip rlim and alim? The rational norms will probably be larger for this input...
2010-10-05, 17:43   #387
axn

Jun 2003

3·5·17·19 Posts

Quote:
 Originally Posted by jasonp Maybe flip rlim and alim? The rational norms will probably be larger for this input...
Considering that too large an FB is more benign than too small, I'd suggest to bump both of them to 2^24-1. And probably start sieving from lower special-q (say 3 mil?). Siever 13e or 14e -- at this size, it's probably a wash.

Last fiddled with by axn on 2010-10-05 at 17:46

 2010-10-05, 19:37 #388 chris2be8     Sep 2009 2·3·331 Posts The alim of 8000000 was because factMsieve.pl lowers alim to the start of the range it is sieving from. I've restarted with alim and rlim just under 2^24 from q0: 3e6 and I'm getting a better yield even though alim gets lowered to 3e6. Hopefully the yield will rise further as alim rises. The numbers with exponent 16 seem the hardest to handle. I'm almost wondering what an inverted octic would yield (at a guess even worse though). But I don't plan to try it, I'm more limited by human time than CPU time. Thanks for the advice though! Chris K
 2010-10-08, 16:20 #389 chris2be8     Sep 2009 2·3·331 Posts A result from my other system doing SNFS: sigma(15428908531^16) r1=14626378603026637440876935345110752326808617649740543443295899 (pp62) r2=348735520870862164578134010988731594775521012539225570516087953133011785002062963 (pp81) And two more ECM results: Code: sigma(141785047417170330875956138182105901767368657881^10) ********** Factor found in step 1: 8349872936935826450829882263387 Found probable prime factor of 31 digits: 8349872936935826450829882263387 Composite cofactor 40866985545846521048453193355520513526503240765554925877353723400485544483604953923826252458151948382470863922759727058989786327240642768290326542226332321865881692141018216421787423442300724000665825199595659330779350921450136560086140658305570640678959955814433678115192087305648210585291332471320245185635679498732804767101607334727832647486861621247079329135407136244608771259695022713694923620212185008598968345925618935356337653 has 434 digits sigma(1631164874282493956886307^22) ********** Factor found in step 2: 169857056796434447746180363 Found probable prime factor of 27 digits: 169857056796434447746180363 Composite cofactor 1320467393510333024063211346076966466841344987176326750859641480884859799715831190718922798242061399416850605702085108236324986714042557397410124477729323138456022508589978108810244870449688608291500588432566165553552080036035942805450939317070299207327690658843986018600930517027023290324882482769797573657266419012869498740082495472091303138026148957934947790768632964871414242387818077191548080621282553735011441988430478473037832933580692517198691579992539673491431 has 469 digits Chris K
2010-10-12, 04:43   #390
apocalypse

Feb 2003

2·3·29 Posts

Quote:
 Originally Posted by chris2be8 The alim of 8000000 was because factMsieve.pl lowers alim to the start of the range it is sieving from. I've restarted with alim and rlim just under 2^24 from q0: 3e6 and I'm getting a better yield even though alim gets lowered to 3e6. Hopefully the yield will rise further as alim rises. The numbers with exponent 16 seem the hardest to handle. I'm almost wondering what an inverted octic would yield (at a guess even worse though). But I don't plan to try it, I'm more limited by human time than CPU time. Thanks for the advice though! Chris K
I was working on a polynomial chooser for SNFS factorizations (specifically for the odd perfect project) about 6 months ago. I'm attaching it here in case you or someone else finds it useful. The metrics are only half-baked, but it tries to estimate the (log of the) effort required for various polynomials. I ran out of time before I could finish it. I'm sure lots of folks on the forum could recommend improved estimates.
Attached Files
 snfs_poly_chooser.pl.gz (2.5 KB, 53 views)

 2010-10-14, 17:23 #391 chris2be8     Sep 2009 2×3×331 Posts One more result: sigma(18041^42): r1=846126399222253639420487670576156969521047338120896029474041329110013 (pp69) r2=135426587507029610408100819035371891457760142878407814770672813795782498399 (pp75) No more ECM results, I've finished 1 curve at 3E6 against everything in t1200.txt. How much p-1, p+1 and ECM have been run against them, I'm wondering if p-1 or p+1 would be more cost effective than ECM? Chris K
 2010-10-17, 21:59 #392 wblipp     "William" May 2003 New Haven 23×5×59 Posts ECM towards p50 by yoyo@home found this p49, saving the NFS factorization Code: sigma(3221,58) = P49 * P104 P49: 4187411465746443851965730786432472142030602773179 P104: 11578859994289585962788903706727722276478611473383633819079738873056500991287941273954277589513036337893
 2010-10-18, 21:23 #393 chris2be8     Sep 2009 198610 Posts Another result: sigma(217081^30): r1=132883127965541779603133141099647960961486176894560469 (pp54) r2=5317613337469178892564229124327778444553412665772353373089326643138525852814621227771 (pp85) I would have posted it earlier, but mersenneforum.org locked up on me. Chris K
 2010-10-19, 16:57 #394 chris2be8     Sep 2009 2·3·331 Posts And another: sigma(926659^28) r1=7892247161280771044859798190887909435039422985794643101 (pp55) r2=36096359295529807517688919847790933188120139266525047350948270612809255451089225056386069689 (pp92) Chris K
 2010-10-22, 16:55 #395 chris2be8     Sep 2009 2×3×331 Posts One more: sigma(30941^40): r1=71241324717871904734237072306645377856814262516307521318979646514277 (pp68) r2=446507703883500494604423145413264927598208355225624679133946196988827605251701927 (pp81) Chris K
 2010-10-24, 16:04 #396 wblipp     "William" May 2003 New Haven 23·5·59 Posts From Pascal's t600.txt, sigma(571^72) = P50 * P57 * P90 ECM to t50 by yoyo@home SNFS sieving by RSALS Post Processing by Lionel Debroux Code: sigma(571^72) = P50 * P57 * P90 P50: 26386891018759314236196466940037349919451259404889 P57: 591872886509135249796335715865365136847433393908176875571 P90: 657774081749910492615766542057725047742640115655851832517033424113696223608856837236143399 For more background see Pascal's web site. Composites from t600.txt are "first composites" encountered in the factor chain proof that there is no odd perfect number less than 10^600. These factors are desired because they will always be used even at higher bounds - the later discovery of other factorizations will never cause these factorizations to disappear from the factor chain.

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