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frmky 2012-12-06 05:35

[QUOTE=jasonp;320654]the more effective root sieve developed by Shi Bai[/QUOTE]
Steal it and put it in msieve? :devil:

frmky 2012-12-11 22:07

From my 1.3 million stage 1 hits, so far I've gotten a

# norm 4.371817e-20 alpha -11.383344 e 2.347e-19 rroots 4

The run continues...

jasonp 2012-12-12 01:49

I sent a batch of hits computed with a cutoff of 5e33 instead of the previous 1e33, and apparently the polynomials generated with the looser cutoff are similar in quality. So if you use 5e33 for the stage1_norm you'll generate hits about 5x faster.

pinhodecarlos 2012-12-12 09:17

[QUOTE=jasonp;318710]and then run

msieve -v -np1 "stage1_norm=[B]5[/B]e33 X,Y"

where X and Y is a range of numbers with magnitude 10^12 to 10^15. [/QUOTE]

So it's better to update first post.

bai 2012-12-13 23:52

[QUOTE=poily;320153]Here's my slightly better (according to msieve) polynomial
SKEW 28338177.70
R0 -3626941552197564826492128852700460060642852
R1 48957407582916194761589
A0 -26101732745933806144485280988037796254029367990700826499285
A1 -2408464141902741608017790242140644715688145388490381
A2 -174314770228113076791419006080421369720970639
A3 28697722660097589508721192118263624637
A4 1036456362256909021188219944324
A5 -21292410351587764080336
A6 181000001476800
skew 28338177.70, size 4.381e-20, alpha -12.189, combined = 2.348e-19 rroots = 2

jasonp, what score does CADO show for your or my polynomial?[/QUOTE]

Hi poily, in cado, it's
Y1: 48957407582916194761589
Y0: -3626941552197564826492128852700460060642852
c6: 181000001476800
c5: -21292410351587764080336
c4: 1036456362256909021188219944324
c3: 28697722660097589508721192118263624637
c2: -174314770228113076791419006080421369720970639
c1: -2408464141902741608017790242140644715688145388490381
c0: -26101732745933806144485280988037796254029367990700826499285
skew: 20504576.000
# lognorm: 83.45, alpha: -12.19 (proj: -3.18), E: 71.26, nr: 2
# MurphyE(Bf=10000000,Bg=5000000,area=1.00e+16)=3.39e-19

jasonp 2012-12-14 01:30

Msieve computes an E-value of 2.339e-19 when using the skew computed by CADO. Would it be worthwhile to find out what causes such big differences?

poily 2012-12-14 09:31

Ok, [URL=""]here[/URL] are about 1.8M hits for the new bound 5e33. It seems the tighter bound was better: with 1e33 as a bound on stage 1 after size optimizations I saw norms of about Xe32 whereas the new bound gives only Xe33 and worse. The best e for this pack was about 2.2e-19.

Bai, I used E.sage from the public CADO repository and got almost the same Murphy e values as msieve shows. Do you compute it somehow different now?

Dubslow 2012-12-14 16:13

[QUOTE=jasonp;321620]Would it be worthwhile to find out what causes such big differences?[/QUOTE]

As a bystander who has no knowledge of either how to go about such finding out or how much work it might be, I would be very interested in the results. :popcorn: (poily's post directly above this makes it all the more interesting!)

debrouxl 2012-12-14 16:26

1 Attachment(s)
For the purposes of generating several hits with CPUs (as I can't currently use my GPU...) more quickly, I resurrected poily's MPI polsel patch, from [url][/url] .
Mainline msieve changed somewhat since then (e.g. separation of the size optimization and the root sieve), so I started by upgrading and expanding the additions to the code; I also changed whitespace to follow the coding convention of the surrounding code more closely :smile:

That allowed the computer to produce a number of hits with:
$ mpirun -n 6 msieve -np1 "stage1_norm=2e33 1100000000000,1100010000000" -v

I think it would be great to see the MPI polsel patch integrated to mainline msieve. This way, every user of multi-threaded polsel (even on a single computer) would benefit without having to apply (and upgrade) an out of tree patch :smile:
However, AFAICS, the patch requires improvements before this can happen. Indeed, I noticed that when a child process has finished working ("polynomial selection complete"), it sticks its core to 100% usage. One of the processes found no suitable leading coefficient in its range and gave up on polsel immediately; after ~2h47 of CPU time wasted by that one, soon after another process had exhausted its range as well, I tried to kill one of the inactive processes... which killed all of its siblings, as I should have expected...
293 stage 1 hits generated in ~10h40 CPU time on Xeon E3-1230 @ 3.2 GHz.

I have zero MPI experience, and therefore, no clue how to make finished jobs not waste significant CPU power :wink:

jasonp 2012-12-14 18:01

The patch makes all the MPI processes wait at a barrier when poly selection is finishing, and my experience with OpenMPI is that this is a computationally expensive operation. I suspect that's what is burning up 100% CPU.

Unfortunately there's no real way around that, if you wanted processes to stop waiting on each other then you wouldn't be using barrier synchronization; put another way, MPI is a poor substitute for a distributed client-server architecture :)

firejuggler 2012-12-14 20:22

1 Attachment(s)
ran a 15 min 'search' on a 560, got 227 hit, best poly

Fri Dec 14 21:18:19 2012 Msieve v. 1.51 (SVN 766)
Fri Dec 14 21:18:19 2012 random seeds: ccf343ec 7dcd68de
Fri Dec 14 21:18:19 2012 factoring 412023436986659543855531365332575948179811699844327982845455626433876445565248426198098870423161841879261420247188869492560931776375033421130982397485150944909106910269861031862704114880866970564902903653658867433731720813104105190864254793282601391257624033946373269391 (270 digits)
Fri Dec 14 21:18:21 2012 no P-1/P+1/ECM available, skipping
Fri Dec 14 21:18:21 2012 commencing number field sieve (270-digit input)
Fri Dec 14 21:18:21 2012 commencing number field sieve polynomial selection
Fri Dec 14 21:18:21 2012 polynomial degree: 6
Fri Dec 14 21:18:21 2012 max stage 1 norm: 1.08e+035
Fri Dec 14 21:18:21 2012 max stage 2 norm: 1.05e+035
Fri Dec 14 21:18:21 2012 min E-value: 0.00e+000
Fri Dec 14 21:18:21 2012 poly select deadline: 1079999
Fri Dec 14 21:20:02 2012 polynomial selection complete
Fri Dec 14 21:20:02 2012 R0: -3334009071282816277832905784211277620964254
Fri Dec 14 21:20:02 2012 R1: 100281358245707420758237
Fri Dec 14 21:20:02 2012 A0: 372828901627475347894334652824133151170797461276260673
Fri Dec 14 21:20:02 2012 A1: 77826863799406908305447316219479205604506482315
Fri Dec 14 21:20:02 2012 A2: -8440449792077225990613216882014698768493181
Fri Dec 14 21:20:02 2012 A3: -434343399475320970345769932599595433
Fri Dec 14 21:20:02 2012 A4: 27102576369602076901509411656588
Fri Dec 14 21:20:02 2012 A5: 139702468047107462100798
Fri Dec 14 21:20:02 2012 A6: 300000002082000
Fri Dec 14 21:20:02 2012 skew 1498026.43, size 1.811e-020, alpha -8.436, combined = 1.092e-019 rroots = 4
(yeah I know, score is pretty bad, but thats a 15 min run)
and the msieve.dat.m file to be run in cado

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