Programming and factoring problem - Page 4

lavalamp · 2010-04-20, 19:14

OK, well that took longer than expected. I was somewhat wide of the mark when I estimated the time to run stage 2 in ECM-GMP.

However, I've now run 2351 curves at B1=3000000 and B2=4592487916 on 10^999+13 without finding a factor. Moving on, I'll now do 4,482 curves at B1=11000000 and B2=30114149530.

axn · 2010-04-20, 19:16

Quote:

Originally Posted by lavalamp

OK, well that took longer than expected. I was somewhat wide of the mark when I estimated the time to run stage 2 in ECM-GMP.

However, I've now run 2351 curves at B1=3000000 and B2=4592487916 on 10^999+13 without finding a factor. Moving on, I'll now do 4,482 curves at B1=11000000 and B2=30114149530.

Quote:

Originally Posted by axn

If anybody is planning to do ECM on this number, be sure to use Prime95 (v25.11) for stage 1 and gmp-ecm for stage2

Are you using this?

lavalamp · 2010-04-20, 20:43

Yup, and the performance improvement is quite large. I think it's around 4.5 times faster in stage 1.

I was using 8 instances last time, but I'm using 4 this time. There was a slight performance benefit to 8 threads (hyperthreading on quad core i7), but it made the computer less responsive so I'm back to 4.

Can you help with my earlier queries by any chance?

Quote:

Originally Posted by lavalamp

Does anyone know how to reduce the screen outputs of Prime95 while running ECM? They scroll by far too fast to be of any use and I fear they may be draining some performance (every little helps right?).

To be honest, I'd be happy for it not to display any progress at all and just show a start and end line. Maybe with the time that curve took or a timestamp accurate to the second so I can see how things are progressing (currently the timestamps are only accurate to the minute).

I don't know if any of this is possible of course, all of the GUI settings appear to be geared for the mersenne stuff. I just wonder if anyone knows a setting I can add to prime.txt or similar that can alter the screen outputs.

frmky · 2010-04-20, 21:04

Quote:

Originally Posted by lavalamp

Can you help with my earlier queries by any chance?

Increase the number of iterations between outputs in the GUI options.

lavalamp · 2010-04-20, 21:14

Ah, that was already set to 100,000, I figured there was no way it was doing 100,000 iterations in 0.14 seconds. I guess it was. Anyway, now it's set to 10 million.

It does seem to have had a positive effect on iteration times, throughput increased nearly 1%. Every little helps.

Also, I can actually see what's going on now, so that's nice too.

frmky · 2010-04-20, 22:00

Code:

 d   |       k
 200  |  103

10^199 + 49 = P47 * P70 * P84

axn · 2010-04-20, 23:21

Quote:

Originally Posted by frmky

Code:

 d   |       k
 200  |  103

10^199 + 49 = P47 * P70 * P84

If anyone has the factor(s) for 10^199+91, could you update it, please?

lavalamp · 2010-04-21, 05:37

Quote:

Originally Posted by frmky

Code:

 d   |       k
 200  |  103

10^199 + 49 = P47 * P70 * P84

Ooh, those are pretty big factors, did you use ECM? If so the P70 could go on here:
http://www.loria.fr/~zimmerma/records/top50.html

Unless you found the P84 first, in which case I shall swoon.

Anyway, here's an updated table:

Code:

  d   |       k
 100  |  9
 200  |  103
 300  |  59
 400  |  31
 500  |  21, 51, 187, 217, 247, 267
 600  |  19, 81, 109, 631, 861, 939
 700  |  63
 800  |  79, 167
 900  |  69, 153
1000  |  13, 139
1100  |  51
1200  |  211

frmky · 2010-04-21, 05:50

Quote:

Originally Posted by lavalamp

Ooh, those are pretty big factors, did you use ECM?

Started with ECM, but it didn't yield anything. Used SNFS to get the factors.

lavalamp · 2010-04-21, 06:13

Ah, that looks tailor made for solving this problem. Do you know a good SNFS factoring utility for Windows?

Also, how long do you estimate it took to break up 10^199 + 49, and on what CPU?

frmky · 2010-04-21, 07:38

Quote:

Originally Posted by lavalamp

Ah, that looks tailor made for solving this problem. Do you know a good SNFS factoring utility for Windows?

Also, how long do you estimate it took to break up 10^199 + 49, and on what CPU?

For NFS instructions, see http://gilchrist.ca/jeff/factoring/n...ers_guide.html. This one took about 1200 CPU-hours to do. I used an 8-way quad-core 2 GHz Opteron system (32 cores). Unfortunately, this is the last one NFS can solve. 500 digits is much too large.

2010-04-20, 22:00	#39
frmky Jul 2003 So Cal 2·3⁴·13 Posts	Code: d \| k 200 \| 103 10^199 + 49 = P47 * P70 * P84

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2010-04-20, 19:14	#34
lavalamp Oct 2007 Manchester, UK 5·271 Posts	OK, well that took longer than expected. I was somewhat wide of the mark when I estimated the time to run stage 2 in ECM-GMP. However, I've now run 2351 curves at B1=3000000 and B2=4592487916 on 10^999+13 without finding a factor. Moving on, I'll now do 4,482 curves at B1=11000000 and B2=30114149530.

2010-04-20, 21:14	#38
lavalamp Oct 2007 Manchester, UK 1355₁₀ Posts	Ah, that was already set to 100,000, I figured there was no way it was doing 100,000 iterations in 0.14 seconds. I guess it was. Anyway, now it's set to 10 million. It does seem to have had a positive effect on iteration times, throughput increased nearly 1%. Every little helps. Also, I can actually see what's going on now, so that's nice too.

2010-04-21, 06:13	#43
lavalamp Oct 2007 Manchester, UK 54B₁₆ Posts	Ah, that looks tailor made for solving this problem. Do you know a good SNFS factoring utility for Windows? Also, how long do you estimate it took to break up 10^199 + 49, and on what CPU?