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 2010-05-30, 22:38 #1 Karl M Johnson     Mar 2010 3·137 Posts Which poly to use? Howdy, folks. So I decided to factor RSA-100.Again. I got 2 Polys using Msieve 1.45 with a CUDA GPU. Here's first: Code: N 1522605027922533360535618378132637429718068114961380688657908494580122963258952897654000350692006139 SKEW 554753.83 R0 -532756497435146513887571 R1 103288101097409 A0 6146189103866429094136080 A1 -308188141461002143706 A2 -28188889873255477 A3 2347896070 A4 18900 Second: Code: N 1522605027922533360535618378132637429718068114961380688657908494580122963258952897654000350692006139 SKEW 900108.23 R0 -635116372672313959258675 R1 91841463772921 A0 2510713546966177126893631144 A1 5674926898539175329782 A2 -10050582327235661 A3 -15172642638 A4 9360 Now, the question is, which one is better to use? And, how can I tell it's better? Karl.
 2010-05-31, 01:31 #2 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 2·11·421 Posts The first one is a bit better: it has larger norm, larger (in abs.value) alpha, and larger Murpy E score. p1: skew 554753.83, size 1.511335e-13, alpha -5.390549, combined = 1.409e-08 p2: skew 900108.23, size 1.389628e-13, alpha -5.127882, combined = 1.383e-08
 2010-05-31, 08:17 #3 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 2·11·421 Posts I found a slightly better poly: Code: # norm 1.472430e-013 alpha -5.486015 e 1.429e-008 skew: 894207.14 c0: 258649450348138371326825455 c1: 5399499758071374808669 c2: 11401030669362863 c3: -10289778325 c4: 3450 Y0: -815128765602942897511404 Y1: 86029790665901 (and yes, this c4 doesn't divide by 60 )
 2010-05-31, 09:53 #4 Karl M Johnson     Mar 2010 3×137 Posts I bet that poly was found using GGNFS. I wasnt able to get poly.exe running from that suite. It crashed right after initialization.
 2010-06-01, 15:26 #5 Karl M Johnson     Mar 2010 3·137 Posts What is a "degree" of a polynominal? GGNFS polyselector didnt want to start untill I specified the degree. I try to use GGNFS siever(gnfs-lasieve4I13e.exe) for sieving phase. Here's how rsa100.poly looks like: Code: name: rsa100 n: 1522605027922533360535618378132637429718068114961380688657908494580122963258952897654000350692006139 Y0: -532756497435146513887571 Y1: 103288101097409 c0: 6146189103866429094136080 c1: -308188141461002143706 c2: -28188889873255477 c3: 2347896070 c4: 18900 skew: 554753.83 type: gnfs Now, when I try to feed it to gnfs-lasieve4I13e.exe) , it says "Please set all bounds to reasonable values!" Now, why is that?How can I fix it?
2010-06-01, 16:17   #6
fivemack
(loop (#_fork))

Feb 2006
Cambridge, England

6,379 Posts

Quote:
 Originally Posted by Karl M Johnson Now, when I try to feed it to gnfs-lasieve4I13e.exe) , it says "Please set all bounds to reasonable values!" Now, why is that?How can I fix it?
You need to set the eight bounds: alim, rlim, lpbr, lpba, mfbr, mfba, alambda, rlambda. The factMsieve.pl script encodes a fair amount of the knowledge we have on how to set these bounds for numbers of different sizes; for 100 digits, alim=rlim=2000000, lpbr=lpba=24 should be about right. And in general alambda=rlambda=2.6 and mfbr=2*lpbr, mfba=2*lpba seem to work well.

 2010-06-01, 17:25 #7 Karl M Johnson     Mar 2010 6338 Posts Thanks Tom for the advice. Is there a way to feed a poly to factmsieve.py script? Last fiddled with by Karl M Johnson on 2010-06-01 at 17:30
 2010-06-01, 17:39 #8 henryzz Just call me Henry     "David" Sep 2007 Cambridge (GMT/BST) 2·2,897 Posts just put the stuff in post 5 into a file with extension .poly
 2010-06-01, 17:43 #9 Karl M Johnson     Mar 2010 3·137 Posts Results in Code: C:\Program Files (x86)\msieve\ggnfs\example>factmsieve.py example.poly -> ________________________________________________________________ -> | Running factmsieve.py, a Python driver for MSIEVE with GGNFS | -> | sieving support. It is Copyright, 2010, Brian Gladman and is | -> | a conversion of factmsieve.pl that is Copyright, 2004, Chris | -> | Monico. Version 0.68 (Python 2.6 or later) 24th April 2010. | -> |______________________________________________________________| -> This is client 1 of 1 -> Using 4 threads -> Working with NAME = example Could not find default parameter file ../def-par.txt! Last fiddled with by Karl M Johnson on 2010-06-01 at 17:43
2010-06-01, 18:32   #10
henryzz
Just call me Henry

"David"
Sep 2007
Cambridge (GMT/BST)

579410 Posts

Quote:
 Originally Posted by Karl M Johnson Results in Code: C:\Program Files (x86)\msieve\ggnfs\example>factmsieve.py example.poly -> ________________________________________________________________ -> | Running factmsieve.py, a Python driver for MSIEVE with GGNFS | -> | sieving support. It is Copyright, 2010, Brian Gladman and is | -> | a conversion of factmsieve.pl that is Copyright, 2004, Chris | -> | Monico. Version 0.68 (Python 2.6 or later) 24th April 2010. | -> |______________________________________________________________| -> This is client 1 of 1 -> Using 4 threads -> Working with NAME = example Could not find default parameter file ../def-par.txt!
is def-par.txt in the ggnfs directory?
also permissions probably wont be right in programfiles in either vista or windows 7
we have learnt to avoid it like the plague here

2010-06-01, 18:56   #11
Batalov

"Serge"
Mar 2008
Phi(4,2^7658614+1)/2

2×11×421 Posts

Quote:
 Originally Posted by Karl M Johnson I bet that poly was found using GGNFS. I wasnt able to get poly.exe running from that suite. It crashed right after initialization.
No, polyselect only searches a subspace with Y1=1, so it is not competitive here. Interesting historically, but otherwise now msieve is what you want to use for any degree. (Unless you have access to close-source software.)

Here's how the funny looking poly was found. I recompiled msieve_gpu with MULTIPLIER relaxed to 30, ...and later to 2 (and then I found a poly with c4=72, e=1.438e-08; this is probably as good a poly as it gets. Your standard polys were also reported, rank #3,4. This was done out of curiosity. Bottom line: this trick steals from the speed of search and the increment in the poly is insignificant. Also, with a difference in E so small, I won't be surprised if a test sieving would rerank these polys, anyway).

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