mersenneforum.org Reserved for MF - Sequence 4788
 Register FAQ Search Today's Posts Mark Forums Read

2009-03-23, 08:26   #12
10metreh

Nov 2008

2×33×43 Posts

Quote:
 Originally Posted by axn Currently, it is stuck on a c103 (which I'm not going to do), so it's up for grabs.
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
I don't particularly want to sieve this, but can you check whether this performs well against other C103 polys?

Last fiddled with by 10metreh on 2009-03-23 at 09:04

2009-03-23, 17:54   #13
mdettweiler
A Sunny Moo

Aug 2007
USA (GMT-5)

11000011010012 Posts

Quote:
 Originally Posted by 10metreh 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 I don't particularly want to sieve this, but can you check whether this performs well against other C103 polys?
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).

2009-03-23, 18:05   #14
10metreh

Nov 2008

2×33×43 Posts

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

2009-03-23, 18:16   #15
mdettweiler
A Sunny Moo

Aug 2007
USA (GMT-5)

3·2,083 Posts

Quote:
 Originally Posted by 10metreh BTW: I'd be happy to do the easy (i.e. computing iterations, doing small ECM etc.) work on this one.
Oh, I didn't mean I would take the whole sequence--just the C103. Sorry for any confusion there.

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.

2009-03-23, 18:23   #16
10metreh

Nov 2008

2·33·43 Posts

Quote:
 Originally Posted by mdettweiler Oh, I didn't mean I would take the whole sequence--just the C103. Sorry for any confusion there. 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.
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.

2009-03-23, 18:26   #17
mdettweiler
A Sunny Moo

Aug 2007
USA (GMT-5)

3×2,083 Posts

Quote:
 Originally Posted by 10metreh 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.
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.

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.

Last fiddled with by mdettweiler on 2009-03-23 at 18:27

2009-03-24, 05:00   #18
mdettweiler
A Sunny Moo

Aug 2007
USA (GMT-5)

3·2,083 Posts

Quote:
 Originally Posted by mdettweiler 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. 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.
Okay--the C103 has finished GNFS, and splits as follows:
Code:
prp37 factor: 6847689178574549212561159545722372429
prp66 factor: 980736539199553596521652049069316443450476568626535381565747233669
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 slightly 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.

 2009-03-24, 06:02 #19 mdettweiler A Sunny Moo     Aug 2007 USA (GMT-5) 3×2,083 Posts 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
2009-03-24, 07:21   #20
henryzz
Just call me Henry

"David"
Sep 2007
Cambridge (GMT/BST)

10111000110012 Posts

Quote:
 Originally Posted by mdettweiler Okay--the C103 has finished GNFS, and splits as follows: Code: prp37 factor: 6847689178574549212561159545722372429 prp66 factor: 980736539199553596521652049069316443450476568626535381565747233669 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 slightly 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.
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

2009-03-24, 07:28   #21
mdettweiler
A Sunny Moo

Aug 2007
USA (GMT-5)

3×2,083 Posts

Quote:
 Originally Posted by henryzz 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
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. I'll report back here with my results in a few minutes.

2009-03-24, 07:35   #22
mdettweiler
A Sunny Moo

Aug 2007
USA (GMT-5)

3·2,083 Posts

Quote:
 Originally Posted by mdettweiler 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. I'll report back here with my results in a few minutes.
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.

Edit: 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.

Last fiddled with by mdettweiler on 2009-03-24 at 07:36

 Similar Threads Thread Thread Starter Forum Replies Last Post kar_bon Aliquot Sequences 133 2021-10-16 17:21 RichD Aliquot Sequences 476 2021-10-04 20:47 RichD Aliquot Sequences 524 2021-09-06 21:00 prism019 GPU to 72 6 2020-09-21 22:11 petrw1 Lone Mersenne Hunters 82 2010-01-11 01:57

All times are UTC. The time now is 15:19.

Mon Oct 18 15:19:17 UTC 2021 up 87 days, 9:48, 0 users, load averages: 0.99, 1.20, 1.28