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-   -   Reserved for MF - Sequence 4788 (https://www.mersenneforum.org/showthread.php?t=11615)

10metreh 2009-03-23 08:26

[quote=axn;166346]Currently, it is stuck on a c103 (which I'm not going to do), so it's up for grabs.[/quote]

I'll run the poly search.

Edit: very odd - msieve only found one poly! (And this is v1.40!)

[code]n: 6715778986509437351659355479537317503862077567628701560157424823155957703109875481494795372990506112001
c0: 28509115761858954126279375
c1: -5610188709933878015066
c2: -299245357257746597
c3: 8739030406140
c4: 111593376
c5: 1320
Y0: -87357695058887796682
Y1: 39569762047
skew: 36124.47[/code]

I don't particularly want to sieve this, but can you check whether this performs well against other C103 polys?

mdettweiler 2009-03-23 17:54

[quote=10metreh;166349]I'll run the poly search.

Edit: very odd - msieve only found one poly! (And this is v1.40!)

[code]n: 6715778986509437351659355479537317503862077567628701560157424823155957703109875481494795372990506112001
c0: 28509115761858954126279375
c1: -5610188709933878015066
c2: -299245357257746597
c3: 8739030406140
c4: 111593376
c5: 1320
Y0: -87357695058887796682
Y1: 39569762047
skew: 36124.47[/code]I don't particularly want to sieve this, but can you check whether this performs well against other C103 polys?[/quote]
If you'd rather not do the sieving, I'll take it (though of course I won't start until someone's verified that the polynomial is OK). :smile:

10metreh 2009-03-23 18:05

[quote=mdettweiler;166390]If you'd rather not do the sieving, I'll take it (though of course I won't start until someone's verified that the polynomial is OK). :smile:[/quote]

BTW: I'd be happy to do the easy (i.e. computing iterations, doing small ECM etc.) work on this one.

mdettweiler 2009-03-23 18:16

[quote=10metreh;166391]BTW: I'd be happy to do the easy (i.e. computing iterations, doing small ECM etc.) work on this one.[/quote]
Oh, I didn't mean I would take the whole sequence--just the C103. Sorry for any confusion there. :smile:

Though, of course, since it sounds like 4788 is going to be done as a group effort, that would be great if you'd like to do the ECM/computing iterations/etc. portion of the work for it. :smile:

10metreh 2009-03-23 18:23

[quote=mdettweiler;166394]Oh, I didn't mean I would take the whole sequence--just the C103. Sorry for any confusion there. :smile:

Though, of course, since it sounds like 4788 is going to be done as a group effort, that would be great if you'd like to do the ECM/computing iterations/etc. portion of the work for it. :smile:[/quote]

The poly works fine, it's only its speed I was wondering about. You have done GNFSs in the C103 range (I think), so you should be able to check whether the poly is good and start now. Otherwise I'll get pol51 to find a poly.

mdettweiler 2009-03-23 18:26

[quote=10metreh;166396]The poly works fine, it's only its speed I was wondering about. You have done GNFSs in the C103 range (I think), so you should be able to check whether the poly is good and start now. Otherwise I'll get pol51 to find a poly.[/quote]
Yes, I've done a number of C103 GNFSs; however, I never did remember to save the sec./rel numbers for any of them so I'm afraid that won't do much good. :rolleyes:

Nonetheless, OK, I'll go ahead and give it a try. I should be able to get started on it sometime within the next few hours. I'll post the sec./rel amount here as soon as I get started, so others can do an approximate comparison with their figures.

mdettweiler 2009-03-24 05:00

[quote=mdettweiler;166397]Yes, I've done a number of C103 GNFSs; however, I never did remember to save the sec./rel numbers for any of them so I'm afraid that won't do much good. :rolleyes:

Nonetheless, OK, I'll go ahead and give it a try. I should be able to get started on it sometime within the next few hours. I'll post the sec./rel amount here as soon as I get started, so others can do an approximate comparison with their figures.[/quote]
Okay--the C103 has finished GNFS, and splits as follows:
[code]prp37 factor: 6847689178574549212561159545722372429
prp66 factor: 980736539199553596521652049069316443450476568626535381565747233669[/code]
Here's a sec./rel readout taken from the end of the last q-range that was done:
total yield: 278800, q=1900009 (0.00686 sec/rel)
I presume that's within a reasonably normal range for an Intel Core 2 Duo E4500 (2.2Ghz)? (Note: it may be [i]slightly[/i] slower than normal for this CPU, since there were some other programs stealing a small amount of CPU cycles. Nonetheless, it shouldn't be too far out of normal range.)

I'll submit the factors to Syd's database shortly, and crank as many further lines as possible using the workers. I'll report back here as soon as I run into one that survives full ECM. :smile:

mdettweiler 2009-03-24 06:02

The next line (2358) has a C92 that survived full ECM. My resources are completely tied up for tonight, so if anyone else wants to do QS on this, go ahead. If nobody's grabbed it by the time I get on tomorrow (probably late morning) I'll do it myself since things should be freed up a bit by then.

The number is:
[code]23815769543009537132187278752799013868767385674615392411879275450950012601757447373080004859[/code]

henryzz 2009-03-24 07:21

[quote=mdettweiler;166437]Okay--the C103 has finished GNFS, and splits as follows:
[code]prp37 factor: 6847689178574549212561159545722372429
prp66 factor: 980736539199553596521652049069316443450476568626535381565747233669[/code]Here's a sec./rel readout taken from the end of the last q-range that was done:
total yield: 278800, q=1900009 (0.00686 sec/rel)
I presume that's within a reasonably normal range for an Intel Core 2 Duo E4500 (2.2Ghz)? (Note: it may be [I]slightly[/I] slower than normal for this CPU, since there were some other programs stealing a small amount of CPU cycles. Nonetheless, it shouldn't be too far out of normal range.)

I'll submit the factors to Syd's database shortly, and crank as many further lines as possible using the workers. I'll report back here as soon as I run into one that survives full ECM. :smile:[/quote]
i did a comparison with a pol51m0b poly that i generated in about 30 secs and i got about 0.0038 sec/rel for both although the pol51m0b seemed to be slightly slower if anything
how did you get such a bad time? i ran on a Q6600 overclocked to 3Ghz
i suspect you underestimated the amount the other program slowed it down

mdettweiler 2009-03-24 07:28

[quote=henryzz;166448]i did a comparison with a pol51m0b poly that i generated in about 30 secs and i got about 0.0038 sec/rel for both although the pol51m0b seemed to be slightly slower if anything
how did you get such a bad time? i ran on a Q6600 overclocked to 3Ghz
i suspect you underestimated the amount the other program slowed it down[/quote]
Well, the other program (mprime, which I have doing TF on both cores at lowest priority to soak up any otherwise-wasted CPU cycles between factorization jobs) that was running normally doesn't take any more than 7-10% of the CPU at a time, so it couldn't have been nearly that much. Something seems a little fishy there...

Here, I've got an idea. I'll try again with the same polynomial as before, in approximately a similar q-range, but this time set to a nice value of -20. That should ensure that nothing else gets in its way. :smile: I'll report back here with my results in a few minutes.

mdettweiler 2009-03-24 07:35

[quote=mdettweiler;166450]Here, I've got an idea. I'll try again with the same polynomial as before, in approximately a similar q-range, but this time set to a nice value of -20. That should ensure that nothing else gets in its way. :smile: I'll report back here with my results in a few minutes.[/quote]
Okay, I've tried that, with no other applications running, and got the exact same thing:

total yield: 2149, q=1900511 (0.00638 sec/rel)

BTW--I've got a taskbar gadget that reads out my CPU temperatures continuously and they're well below the throttle limit, so thermal throttling can be ruled out as the cause of any problems.

[B]Edit[/B]: Oh, wait! I just realized what's going on. henryzz, are you by chance using the 64-bit version of gnfs-lasieve4I12e? I'm using the 32-bit version, which of course is about half as fast--so that would explain the discrepancy perfectly. :smile:


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