20160204, 21:41  #12 
Jun 2012
2^{3}·359 Posts 
No it is not an especially slow time for my computer but definitely on the high side for a SNFS ~240. Lots of scatter in the ETA vs. SNFS curve though.
Your results show that performance in Linux is better than in Windows. I don't disagree, but I eventually left Linux as I got tired of arm wrestling my machines everytime I wanted to use them... 
20160224, 09:54  #13 
Mar 2013
7_{8} Posts 
I am unable to reproduce the failure. Need more details on how to reproduce.
I tried Code:
D:\Factoring\lasieve4_ivybridge>gnfslasieve4I14e.exe v a f 24000000 c 2000 c189_147_41.txt gnfslasieve4I14e (with asm64): L1_BITS=15, SVN $Revision$ Warning: lowering FB_bound to 23999999. FBsize 1506969+0 (deg 6), 2888143+0 (deg 1) total yield: 3071, q=24002051 (0.09361 sec/rel) ETA 0h00m) 124 Special q, 762 reduction iterations reports: 34229068>499577>448037>350947>293902>293567 Number of relations with k rational and l algebraic primes for (k,l)=: Total yield: 3071 0/0 mpqs failures, 2240/2604 vain mpqs milliseconds total: Sieve 107431 Sched 0 medsched 41680 TD 19527 (Init 77, MPQS 2316) SieveChange 118852 TD side 0: init/small/medium/large/search: 2660 217 1398 3785 301 sieve: init/small/medium/large/search: 1248 15476 1039 35173 220 TD side 1: init/small/medium/large/search: 3041 393 1166 3743 383 sieve: init/small/medium/large/search: 1564 16673 942 32846 2250 Code:
n: 205451388964856467807686090421078666750691138189010020165236543387336128283211048921251478839880150378554118455189058228045898855699277369470472121604743428745579798048420314101101241961387 # 147^41+41^147, difficulty: 237.08, anorm: 6.37e+39, rnorm: 1.95e+45 # scaled difficulty: 237.08, suggest sieving algebraic side # size = 2.485e12, alpha = 0.188, combined = 2.415e13, rroots = 0 type: snfs size: 237 skew: 14.7100 c6: 1 c0: 10131387 Y1: 509111094534718962173411120845918138561 Y0: 1483273860320763 m: 44008401100288010210378427144625977757864842683924464711360809690583398911228987316128214321844953723667341332495287889981170421945600498539914605816457803581780075658984410989729763013655 alim: 48000000 rlim: 48000000 lpba: 31 lpbr: 31 mfba: 62 mfbr: 62 alambda: 2.5 rlambda: 2.5 
20160224, 14:42  #14 
Jun 2012
2872_{10} Posts 
Are you running on a Windows machine? The bug does not seem to occur in Linux.

20160224, 19:02  #15 
Basketry That Evening!
"Bunslow the Bold"
Jun 2011
40<A<43 89<O<88
3×2,399 Posts 
D:\Factoring\lasieve4_ivybridge>gnfslasieve4I14e.exe would certainly seem to indicate Windows

20160225, 00:38  #16 
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
23A3_{16} Posts 
Unsure about the Windoze port, but the original sievers long ago in the past had the childhood disease of sieving quite poorly when some unwritten rules were violated by a poly. (And it did happen with the automatically generated xyyx polys because of the specificity of the construction.) These unwritten rules were:
1. Y1 > 0 2. Y1 <= Y0 These are easily accommodated for  one by negating the rat'nl poly, and the other, by flipping both polyns on their heads (i.e. swap all poly indices c_{j}, Y_{i} :: i,j for deg _{side}i). You may want to try that. EDIT: another, unrelated hunch to try in parallel. Because 147 happens to be 3*7^{2}, one can try to lower the skew by leaving 7^{4} out (that is do overmultiply the algebraic poly by 3 but not by 7^{2}; leave coeffs as 7^4*x^6 + 3*41^3*y^6, and m=x/y (or y/x as the case may be, I haven't pulled out a napkin to play; this, here, is the napkin ...and its margins are too narrow). Or 3^5*x^6 + 41^3*7^2*y^6 (less likely to be useful) Last fiddled with by Batalov on 20160225 at 00:50 
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