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 2013-07-08, 18:28 #12 VBCurtis     "Curtis" Feb 2005 Riverside, CA 28·19 Posts 5 days on a 460M for Lorgix' second C157 has produced no strong polys. Here's the best, with msieve suggesting 2.01 to 2.31 as the expected range: Code: # norm 2.916149e-015 alpha -7.119644 e 1.883e-012 rroots 5 skew: 1639936.64 c0: 8532868550138516311046827336336400640 c1: 70998128199694820805749331912482 c2: -52696319235656576134337513 c3: -75162003432935559781 c4: 19930163724423 c5: 8036784 Y0: -860303108391035434159057424509 Y1: 44662544129823973 I'm starting 39^158+1, the second of Chris' C155s. I'll let it run while I'm in Vegas the next 4 days, and report a poly Saturday for it. Once that's done I'll return to the rest of Lorgix' numbers. In the meantime, could someone beat this poly please?
 2013-07-08, 18:35 #13 lorgix     Sep 2010 Scandinavia 3·5·41 Posts Thanks for the polynomials! I haven't gotten around to poly selection on GPU yet, so this saves days of CPU-time. Hopefully someone will improve on the second one. You seem to know your way around the parameters, so I guess this is what's called 'bad luck'. I might get a used GTX560Ti or something like that (ideas?) so that I have some GPU-power to experiment with.
 2013-07-08, 18:49 #14 VBCurtis     "Curtis" Feb 2005 Riverside, CA 28×19 Posts You're quite welcome. Now that I know you don't have a GPU, I volunteer to find you at least decent polys for the next few months of your factoring. They may not hit msieve's GPU-target range every time, but doing your poly selects beats LLR-cuda as a good use of my GPU. Repeated searches in the C155+ region give me some incentive to learn how to test-sieve, which leads to fiddling with the knobs as Jason puts it. All useful knowledge, and possibly heading for a beginner-guide mid-level GNFS entry. GPU ideas: Go cheap, just get anything that supports the right flavor of CUDA. Even a low-end current card will be 50-100x faster for stage 1, while using fewer watts than a $100+ card. Last fiddled with by VBCurtis on 2013-07-08 at 18:51 Reason: GPU opinion  2013-07-08, 18:55 #15 firejuggler Apr 2010 Over the rainbow 2·1,301 Posts The GTX5xx are 2 generation behind. It might be hard to get "new" one. I guess a GTX 650 or 640 (if they are not only for laptop) might work for you. 2013-07-08, 19:31 #16 lorgix Sep 2010 Scandinavia 3·5·41 Posts Quote:  Originally Posted by VBCurtis You're quite welcome. Now that I know you don't have a GPU, I volunteer to find you at least decent polys for the next few months of your factoring. They may not hit msieve's GPU-target range every time, but doing your poly selects beats LLR-cuda as a good use of my GPU. Repeated searches in the C155+ region give me some incentive to learn how to test-sieve, which leads to fiddling with the knobs as Jason puts it. All useful knowledge, and possibly heading for a beginner-guide mid-level GNFS entry. GPU ideas: Go cheap, just get anything that supports the right flavor of CUDA. Even a low-end current card will be 50-100x faster for stage 1, while using fewer watts than a$100+ card.
Well, I actually have a CUDA-capable GPU. But it is weak, and has few cores. And it is hooked up to my main screen.
There are currently five p^q-1-GNFS-candidates in the range 154-156. I could pretest some above 160 as well. I also have my eyes on a HP-number in the low 160s. So there's no shortage of candidates, if you're up for it.
I really should be getting a new GPU some time soon (in a few moths, at least). More powerful ones should be very useful for ECM. Does poly select saturate any GPU? (can it use any number of cores?)
Maybe I'll opt for a cheaper one; a GT630 based on GK208 (meaning 28nm) was released fairly recently.
Should I look for the latest Compute Capability? (I don't really know the significance of that)
Quote:
 Originally Posted by firejuggler The GTX5xx are 2 generation behind. It might be hard to get "new" one. I guess a GTX 650 or 640 (if they are not only for laptop) might work for you.
I was under the impression that the Fermi architecture was still very competitive in GPGPU. I'm not sure though.
The GTX650 should be close to peak performance/$(in the sense of MHz*cores/$), in the 600-series, and so should be a good choice I suppose.
The 6- & 700-series use an entirely different architecture than the 4- & 500, so I don't really know how to compare them.
Specifically I'd like to know what correction factor I need in order to compare MHz*cores between Fermi and Kepler. In terms of poly select performance (and ECM performance).

 2013-07-08, 19:38 #17 firejuggler     Apr 2010 Over the rainbow 2×1,301 Posts VBcurtis, what msieve version did you use to find that poly? it seems that Msieve150 and below sur-evaluate the poly score a bit.
 2013-07-08, 20:55 #18 VBCurtis     "Curtis" Feb 2005 Riverside, CA 28×19 Posts 1.51, svn 845 (I think). April 2013 download, premade binary. It should be the newer/lower E-values. My GPU also drives my main screen, and the only time response has slowed was on the C210 sextic search. I've run cuda-LLR for 12 months straight, and now poly select, with no apparent effect on the screen. I suggest you get CUDA drivers installed and test things out- if nothing else, you can see how many hits you get overnight on the card. My mobile-GPU part isn't all that fast, and still can produce 8 hrs' worth of -nps work in just an hour or two. So, just overnight GPU -np1 runs might produce more than enough data for stage 2 needs. Yes, I am game for at least a half-dozen candidates after those already posted by you and Chris. Last fiddled with by VBCurtis on 2013-07-08 at 21:00 Reason: GPU commentary
 2013-07-09, 02:10 #19 firejuggler     Apr 2010 Over the rainbow 50528 Posts For now I have one *good* hit , score is equivalent to VBCurtis but skew is a bit lower Code: Tue Jul 09 02:19:43 2013 factoring 3787388118933512063249259173231597770049112435945032094640277541632460519045009491164974276597271170346757143570242916437315466248541421375702840232794402591 (157 digits) Tue Jul 09 02:37:40 2013 R0: -1063466059487867106617472794654 Tue Jul 09 02:37:40 2013 R1: 64668823176851 Tue Jul 09 02:37:40 2013 A0: -3962907102148251811365883799925121155 Tue Jul 09 02:37:40 2013 A1: -989212107945990307577657150068 Tue Jul 09 02:37:40 2013 A2: 6390045909351316737980130 Tue Jul 09 02:37:40 2013 A3: -9592336224573633921 Tue Jul 09 02:37:40 2013 A4: 5859137926178 Tue Jul 09 02:37:40 2013 A5: 2784336 Tue Jul 09 02:37:40 2013 skew 1408059.13, size 2.287e-015, alpha -6.085, combined = 1.833e-012 rroots = 3 Last fiddled with by firejuggler on 2013-07-09 at 02:10
 2013-07-09, 02:14 #20 wombatman I moo ablest echo power!     May 2013 22×443 Posts For the 1st C155 listed, this is the best I've gotten thus far. It's a bit below the expected range, but not by too much: Code: expecting poly E from 2.62e-012 to > 3.02e-012 R0: -1982277912715175423679197808784 R1: 69837075648803257 A0: -44322257284138334787861242542456972633815 A1: 9286106559194619360096878548752378 A2: 108520072080442627462348267 A3: -10202649139317912268 A4: -61572653402 A5: 1740 skew 45960569.14, size 4.023e-015, alpha -7.466, combined = 2.541e-012 rroots = 5
 2013-07-09, 06:34 #21 firejuggler     Apr 2010 Over the rainbow 2×1,301 Posts Code: factoring 3787388118933512063249259173231597770049112435945032094640277541632460519045009491164974276597271170346757143570242916437315466248541421375702840232794402591 (157 digits) R0: -1378574698621825663558022013546 R1: 214052541470369 A0: -175040708004969558266567903993405593325 A1: -220312394373520757850174317763772 A2: 49282988466830844032614321 A3: 25532977516064005444 A4: -3884830113524 A5: 760656 skew 3526801.51, size 2.601e-015, alpha -7.664, combined = 1.978e-012 rroots = 3 Last fiddled with by firejuggler on 2013-07-09 at 06:47
 2013-07-13, 17:19 #22 VBCurtis     "Curtis" Feb 2005 Riverside, CA 130016 Posts Here is the poly for 39^158+1: Code:  # norm 5.644615e-015 alpha -7.931357 e 2.775e-012 rroots 3 skew: 1813413.83 c0: -26576343119721934097475724487682275175 c1: 58618135712883968651879051388681 c2: -21402685978619238283492841 c3: -24030041819615310289 c4: 13579142843224 c5: 4598160 Y0: -415948918490177005559476926358 Y1: 30809158838486467 I am now working on the third of Chris' numbers. Or was it already done? Edit: Ah, seems post 121 refers to this third number. I'll stop my search now, run npr on the overnight data, and report if I found a better poly. Edit2: Nothing of use. I am now working on the 3rd number from post #85. Firejuggler, the 4th number from post 85 has had no work yet. Last fiddled with by VBCurtis on 2013-07-13 at 17:52

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