20161005, 06:32  #1 
Feb 2012
3^{2}·7 Posts 
msieve 1.52 with GPU polynomial selection
I have been using yafu to do nfs on inputs around 150 digits and would like to to now use a gpu to help speed up polynomial selection on inputs larger than 150 digits (I have read a numerous places that it isn't practical to use poly selection for inputs less than 140 digits with a gpu). Anyways, since I have never used msieve directly and the readme doesn't say much about what kind of line command to use for stage 1 gpu polynomial selection, I looked around on this form and am using the following command:
>msieve.exe v g 0 np1 Msieve v. 1.52 (SVN unknown) Wed Oct 05 02:23:33 2016 random seeds: fbb158e0 8b921750 factoring 14983833053669267073388859640749386761592128691535474632716887403740027331275486495085918514582693799340373342068801035123016311177538173489337402480577483 (155 digits) searching for 15digit factors commencing number field sieve (155digit input) commencing number field sieve polynomial selection polynomial degree: 5 max stage 1 norm: 8.32e+023 max stage 2 norm: 5.19e+021 min Evalue: 2.32e012 poly select deadline: 1020287 time limit set to 283.41 CPUhours expecting poly E from 2.83e012 to > 3.26e012 searching leading coefficients from 1 to 17047468 using GPU 0 (GeForce GTX 980) selected card has CUDA arch 5.2 cannot load library 'sort_engine_sm20.dll', error 126 error: failed to load GPU sorting engine Although it doesn't say the SVN number, I downloaded the latest version I could find, which is 942 which claims to have gpu support. Obviously, I don't want to spend 280 hours searching for a polynomial, and thus I am going to have to play around with the parameters (no doubt I will have some questions on this), but as a first step I would like to get things working on the gpu. It claims that a file "sort_engine_sm20.dll" can't be loaded, but its in my directory: Directory of C:\Users\Documents\Factoring\msieve_gpu 10/05/2016 02:29 AM <DIR> . 10/05/2016 02:29 AM <DIR> .. 08/25/2013 08:25 PM 1,570 AUTHORS.GMPECM 08/25/2013 08:25 PM 3,795 AUTHORS.MPIR 08/25/2013 08:25 PM 96,586 Changes 08/25/2013 08:25 PM 35,147 COPYING.GMPECM 08/25/2013 08:25 PM 35,147 COPYING.MPIR 10/05/2016 02:07 AM 0 msieve.dat.m 08/17/2013 02:26 PM 1,307,136 msieve.exe 10/05/2016 02:29 AM 1,182 msieve.log 11/14/2014 11:54 AM 119,888 pthreadGC2.dll 08/25/2013 08:25 PM 25,290 Readme 08/25/2013 08:25 PM 34,686 README.GMPECM 08/25/2013 08:25 PM 3,889 README.MPIR 08/25/2013 08:25 PM 57,203 Readme.nfs 08/25/2013 08:25 PM 7,987 Readme.qs 08/17/2013 02:26 PM 380,928 sort_engine_sm11.dll 08/17/2013 02:27 PM 458,752 sort_engine_sm13.dll 08/17/2013 02:26 PM 459,776 sort_engine_sm20.dll 08/17/2013 02:26 PM 134,747 stage1_core_sm11.ptx 08/17/2013 02:27 PM 134,731 stage1_core_sm13.ptx 08/17/2013 02:27 PM 129,841 stage1_core_sm20.ptx 10/05/2016 02:23 AM 155 worktodo.ini 10/05/2016 02:23 AM 155 worktodo.txt 22 File(s) 3,428,591 bytes 2 Dir(s) 388,388,360,192 bytes free I tried to do cpu only poly selection using svn 942 but it fails for the same reason. Using svn 958, cpu poly selection works: msieve152.exe v np1 Msieve v. 1.52 (SVN 958) Wed Oct 05 02:29:48 2016 random seeds: e7c648cc 2929e0a1 factoring 453900508707227117088044239531189329962427502081603308969082793654958205298131757286256493811103457282903828743904586118273728781849349264159173919 (147 digits) searching for 15digit factors commencing number field sieve (147digit input) commencing number field sieve polynomial selection polynomial degree: 5 max stage 1 norm: 2.96e+022 max stage 2 norm: 4.52e+020 min Evalue: 6.73e012 poly select deadline: 478041 time limit set to 132.79 CPUhours expecting poly E from 7.05e012 to > 8.10e012 searching leading coefficients from 1 to 7173428 deadline: 400 CPUseconds per coefficient coeff 12 specialq 1  642311 other 42546  102110 aprogs: 6679 entries, 8791 roots 12 30473492865977 130483586313074599578258471154 12 391108512956581 130483586313428536359648699855 12 190036387843211 130483586313104264552255614163 12 497903426792239 130483586312969950410530939056 12 99555052674679 130483586313102856028358736905 12 600506580821749 130483586312706903525049241402 12 1221048763726757 130483586318845356291945943661 12 2148660442996951 130483586300814908091187560627 12 87480910558181 130483586313063800465946947163 12 1436859739291417 130483586321040833931721147487 12 1213171586284541 130483586318594367511176389436 12 131262263274587 130483586312817142862671690680 12 565369239538831 130483586312326311257545617485 12 16429244447641 130483586313059619825238059161 12 211253239565317 130483586313016451909772556149 12 16020807683731 130483586313059861562225900477 12 92548280928131 130483586313079469319119183091 12 1817425292632033 130483586321008646147001995250 12 1367724755956723 130483586309277352903604946221 received signal 2; shutting down hashtable: 8192 entries, 0.13 MB polynomial selection complete error generating or reading NFS polynomials elapsed time 00:00:05 any ideas about what is going wrong or how to fix this. Thanks... Last fiddled with by cgy606 on 20161005 at 06:37 
20161005, 07:20  #2  
May 2008
Worcester, United Kingdom
1000011011_{2} Posts 
Quote:


20161005, 07:36  #3 
Feb 2012
63_{10} Posts 
That's not it. I didn't build this using VS2015. I downloaded the zip from http://gilchrist.ca/jeff/factoring/ (the 1.52dev SVN 942 (compiled by Brian Gladman)) and simple unpacked it and put it into a folder.

20161005, 08:35  #4  
May 2008
Worcester, United Kingdom
7^{2}·11 Posts 
Quote:


20161005, 17:18  #5  
Feb 2012
3^{2}·7 Posts 
Quote:
C:\Users\Documents\Factoring\msieve>dir Volume in drive C has no label. Volume Serial Number is 588F04AB Directory of C:\Users\Documents\Factoring\msieve 10/05/2016 01:15 PM <DIR> . 10/05/2016 01:15 PM <DIR> .. 08/25/2013 08:25 PM 1,570 AUTHORS.GMPECM 08/25/2013 08:25 PM 3,795 AUTHORS.MPIR 08/25/2013 08:25 PM 96,586 Changes 08/25/2013 08:25 PM 35,147 COPYING.GMPECM 08/25/2013 08:25 PM 35,147 COPYING.MPIR 10/05/2016 01:13 PM <DIR> cub 10/05/2016 02:07 AM 0 msieve.dat.m 08/17/2013 02:26 PM 1,307,136 msieve.exe 10/05/2016 01:15 PM 5,910 msieve.log 08/19/2016 02:11 AM 1,363,644 msieve152.exe 10/04/2016 09:25 AM <DIR> pthreadgc2 11/14/2014 11:54 AM 119,888 pthreadGC2.dll 08/25/2013 08:25 PM 25,290 Readme 08/25/2013 08:25 PM 34,686 README.GMPECM 08/25/2013 08:25 PM 3,889 README.MPIR 08/25/2013 08:25 PM 57,203 Readme.nfs 08/25/2013 08:25 PM 7,987 Readme.qs 08/17/2013 02:26 PM 134,747 stage1_core_sm11.ptx 08/17/2013 02:27 PM 134,731 stage1_core_sm13.ptx 08/17/2013 02:27 PM 129,841 stage1_core_sm20.ptx 10/05/2016 02:23 AM 155 worktodo.ini 10/05/2016 02:23 AM 155 worktodo.txt 20 File(s) 3,497,507 bytes 4 Dir(s) 388,363,792,384 bytes free I tried to rerun gpu msieve and I am still getting the same error: C:\Users\Documents\Factoring\msieve>msieve.exe v np1 Msieve v. 1.52 (SVN unknown) Wed Oct 05 13:15:37 2016 random seeds: 45ee0db8 6bfdcdd7 factoring 14983833053669267073388859640749386761592128691535474632716887403740027331275486495085918514582693799340373342068801035123016311177538173489337402480577483 (155 digits) searching for 15digit factors commencing number field sieve (155digit input) commencing number field sieve polynomial selection polynomial degree: 5 max stage 1 norm: 8.32e+023 max stage 2 norm: 5.19e+021 min Evalue: 2.32e012 poly select deadline: 1020287 time limit set to 283.41 CPUhours expecting poly E from 2.83e012 to > 3.26e012 searching leading coefficients from 1 to 17047468 using GPU 0 (GeForce GTX 980) selected card has CUDA arch 5.2 cannot load library 'sort_engine_sm20.dll', error 126 error: failed to load GPU sorting engine 

20161005, 17:24  #6 
"Carlos Pinho"
Oct 2011
Milton Keynes, UK
3×5×11×31 Posts 
Please try these binaries:
http://www.mersenneforum.org/showpos...0&postcount=45 http://www.mersenneforum.org/showpos...3&postcount=50 
20161005, 17:33  #7  
Feb 2012
3^{2}×7 Posts 
Quote:


20161005, 18:26  #8 
Tribal Bullet
Oct 2004
2×5^{2}×71 Posts 
GPU poly selection works for degree 4, 5, or 6. For a 150digit input anything other than degree 5 is a waste of effort. I'll leave it to others who have much more practice than I do to help with parameter selection; most of the time you make the stage 1 bound more and more stringent until hits arrive at a rate of just a few per second. Then you can do size optimization at the same rate that stage 1 hits are produced. Buffer up a few thousand to a few million of those, then run the root optimization on the 10010000 sizeoptimized results whose size is best.

20161005, 18:46  #9 
Feb 2012
77_{8} Posts 
I have a quick question. I am running a stage 1 polynomial selection on a 155 digit number. I set a deadline for searching of 100 seconds ("poly_deadline=100"), while not changing anything else. msieve appears to be running, however it took about 16 minutes. Why doesn't it enforce the deadline I specified? Furthermore, I get the following message at the end:
156 13734560102344961 2491722452247316394300991682441 156 28347894540434953 2491722449832725012667605005815 156 38998963368318367 2491722449473816650196253487469 156 17772432379479701 2491722451500964249800099105531 polynomial selection complete error generating or reading NFS polynomials elapsed time 00:16:09 Any ideas on what went wrong (or if something is wrong?) Last fiddled with by cgy606 on 20161005 at 18:51 
20161005, 20:52  #10 
Tribal Bullet
Oct 2004
2·5^{2}·71 Posts 
The error message is just because you didn't produce any complete polynomials, only stage 1 hits. If you ran size or root optimization as well then you would get a best polynomial that would get saved to file.
The time limit stuff has not been well tested; the limit is on CPU time, which is zero while the GPU is running. Experience has shown that nothing I can put in code will satisfy everyone who wants to limit by time. CPU or wall clock time? Does time in lowpower or sleep mode count differently? How does GPU time contribute to that? 
20161005, 22:21  #11  
Feb 2012
3^{2}·7 Posts 
Quote:
In regards to timing, I guess I would like to know how many stage 1 hits are enough (based on the size of the number being factored) such that I have reasonable confidence that a satisfactory polynomial can be found in the remaining stages. I produced 760K stage 1 hits in 970 seconds which subsequently lead to a polynomial being found after the other two stages in a little less than 2 hours (20 min for size and 95 min for root opt). Do you think this is enough effort for a c155 gnfs? What benefit would I get if I were to let it spend more time doing polynomial search. I know these are tough questions to answer (and many of you are performing 'alpha' research in these areas), but in order to do a differential analysis, usually one has to quantify the marginal benefits from continuing their efforts beyond the point they are at and compare to what they have already achieved. On a technical note, I read in the readme that np1 and nps can be done at the same time. If I do this, will msieve do np1 on the GPU and than nps on the CPU (once np1 has finished) in series, or will it do then in parallel as hits are being generated from stage 1? 

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