mersenneforum.org Factoring M7777171
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2020-10-19, 19:20   #12
gLauss

Nov 2014

3×13 Posts
Quote:
 Originally Posted by VBCurtis Curves at B1=50k could still find a factor, but B1=250k will have more than 5x the chance per curve (while taking about 5x as long, so odds-per-day improve).
I know. If you take a look, I did put more total effort into B1=250k curves than B1=50k. However, I ran only a few of them. According to the report_ecm, what I did in total is equivalent to 170 curves of t25. I think it is kind of unlikely for this number to have a factor less than 30 digits because of the very large P-1 bounds, too. And t35 is way beyond what I'm willing to spend on this stupid task

 2020-10-20, 08:50 #13 Viliam Furik     "Viliam Furík" Jul 2018 Martin, Slovakia 23·32·11 Posts TFed to 78bits I TFed the M20825573 to 78 bits, 79 is on the way. So far, no factor.
2020-10-20, 20:18   #14
gLauss

Nov 2014

1001112 Posts

Quote:
 Originally Posted by Viliam Furik I TFed the M20825573 to 78 bits, 79 is on the way. So far, no factor.
Hihi, thanks for that! My laptop GPU is too crappy for this bitlevels. However, I assume your chances for success are quite low because of the large P-1 and the ECM curves I already ran. I won't continue on this number for now, back to boring PRP testing...

 2021-10-29, 09:31 #15 Zhangrc   "University student" May 2021 Beijing, China 22×67 Posts Factoring M19491001 I'd like to factor M19491001, just because the way it looks. I did TF to 2^75 and dozens of ECM curves because I noticed that a prior P-1 has been done. So far, no factor was found. Should I do P+1 or try P-1 with larger bounds?
 2021-10-29, 14:24 #16 VBCurtis     "Curtis" Feb 2005 Riverside, CA 22×3×7×67 Posts I wouldn't do another P-1 until I'd finished the B1 = 50k ECM level. I'd do a few curves at B1=250k also before repeating P-1. If I did another P-1. I'd increase the bounds by 10x or so. You have to re-do all the work of the previous P-1, so increasing bounds just a little bit means you're mostly wasting work (and thus that there are better ways to use those cycles). P+1 seems like a reasonable choice- again, pick big bounds- big enough that you won't be tempted to try even-bigger ones later. How big to pick depends quite a bit on how much effort you want to spend on this factoring effort- completing the B1=50k level is non-trivial, but completing the B1=250k level is a pretty serious effort. If you intend to go that far, choose bigger P+1 (and maybe P-1) bounds than would normally be reasonable.
2021-10-29, 14:39   #17
Viliam Furik

"Viliam Furík"
Jul 2018
Martin, Slovakia

79210 Posts

Quote:
 Originally Posted by Zhangrc I'd like to factor M19491001, just because the way it looks. I did TF to 2^75 and dozens of ECM curves because I noticed that a prior P-1 has been done. So far, no factor was found. Should I do P+1 or try P-1 with larger bounds?
I wanted to go do TF on my new RTX 3080, but it seems I need a new version of mfaktc, compiled for CUDA runtime v11.40. So I'll do it on my RTX 2080Ti. 75 to 78 bits. See you tomorrow.

2021-11-25, 22:46   #18
gLauss

Nov 2014

2716 Posts

Quote:
 Originally Posted by VBCurtis If I did another P-1. I'd increase the bounds by 10x or so. You have to re-do all the work of the previous P-1, so increasing bounds just a little bit means you're mostly wasting work (and thus that there are better ways to use those cycles). P+1 seems like a reasonable choice- again, pick big bounds- big enough that you won't be tempted to try even-bigger ones later.
As I am stuck with "my number" and don't want to waste full t30 level, I will now run a P-1 with B1=15M and then two P+1 with B1=7.5M for 19491001. Let's see if I get lucky...

2021-11-25, 23:14   #19
Prime95
P90 years forever!

Aug 2002
Yeehaw, FL

23×1,019 Posts

Quote:
 Originally Posted by gLauss As I am stuck with "my number" and don't want to waste full t30 level, I will now run a P-1 with B1=15M and then two P+1 with B1=7.5M for 19491001. Let's see if I get lucky...
Stop! Investigate v30.8. Wait for a future version before trying P+1.

 2022-04-24, 00:30 #20 mrh   "mrh" Oct 2018 Temecula, ca 10110102 Posts I gave it some more P-1, but still it resists... https://www.mersenne.ca/exponent/7777171
2022-04-24, 02:18   #21
VBCurtis

"Curtis"
Feb 2005
Riverside, CA

22·3·7·67 Posts

Quote:
 Originally Posted by gLauss As I am stuck with "my number" and don't want to waste full t30 level, I will now run a P-1 with B1=15M and then two P+1 with B1=7.5M for 19491001. Let's see if I get lucky...
Why so small? For the time you've put into trial factoring, why not put a core-week or more into P-1?

Using 30.8 with a bunch of memory (16GB or more), I imagine B1 = 50M with the big B2 from 30.8 will give you something like 7-8% chance to find a factor. Again, don't do a calculation that you'll be tempted to redo later. Do P-1 once, so big you won't ever consider repeating it.

Last fiddled with by VBCurtis on 2022-04-24 at 02:19

2022-05-06, 05:10   #22
LaurV
Romulan Interpreter

"name field"
Jun 2011
Thailand

10,273 Posts

Quote:
 Originally Posted by VBCurtis Again, don't do a calculation that you'll be tempted to redo later. Do P-1 once, so big you won't ever consider repeating it.
+1

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