Anyone factoring <5M?

[lorgix]

Originally Posted by markr

The reason the "worst" cases you saw had B2=200000 is that I selected exponents with B2<200000 (arbitrarily) when I went through doing P-1 ahead of TF. I used Pfactor, set up so B1 & B2 were at least about 100000 & 2000000. In the 3M range I changed to selecting with B2<180000 because there's a lot of them, and bumped up the target bounds a bit. I'm below 3060000 now.

Lucky for me I went through your area of interest before you - I found my largest low-exponent factor there!

Good luck with the ECM work!

I see, good for you! And us! :D

Between us we've gone through the interval pretty well then.

Yeah, like I said; for me Pfactor 3tests saved gave bounds around there.

That's a NICE factor!

My later work was more in the 4.4~4.48M range btw.

You (or anyone interested ofc) might wanna have a look as I have now unreserved all exponents in the range I was working on.

Maybe I left something behind for you (wasn't being super thorough, and didn't quite finish the "project"); the range I looked at was:

M4400131-M4519561

As of right now that range (only looking at TF 0-61) has [51exponents with B1=20k], [32 with B2<250k], and [13 with B1=20k B2=205k].

Probably more efficient with ECM now, but if anyone wants to have a go...


Live long and factor.

//L

p.s. 205 and 250 above are NOT typos.

[petrw1]

This is probably a silly question but what is to stop all of TF, P-1 and ECM from finding, reporting and getting credit for the very same factor?

Or is there some client or server code that ignores duplicate factors?

[garo]

Once a factor is found, no more credit is awarded for any further work on the exponent.

[petrw1]

Originally Posted by garo

Once a factor is found, no more credit is awarded for any further work on the exponent.

That makes sense, however, on the ECM Progress report one of the sections is "ECM on Mersenne numbers with known factors". Does this not mean there are still people doing ECM on the exponents? and if so, are they NOT getting credit but rather doing this for the "prize" of fully factoring?

Thanks

[lorgix]

I'd certainly like to finish the factoring of M929... even if it gave me negative "credit".

[petrw1]

Originally Posted by lorgix

I'd certainly like to finish the factoring of M929... even if it gave me negative "credit".

Well at 280 digits and factors so far equating 67 digits the remaining composite should be 213 digits.

If I assume that, since the largest factor found so far is 51 digits, that the remaining factors are larger than that then there could be a factor remaining up to about 160 digits.

Yes, that would be an amazing find.

[TimSorbet]

Originally Posted by petrw1

That makes sense, however, on the ECM Progress report one of the sections is "ECM on Mersenne numbers with known factors". Does this not mean there are still people doing ECM on the exponents? and if so, are they NOT getting credit but rather doing this for the "prize" of fully factoring?

Thanks

It won't give repeat credit for the same factor, but you can continue to find further factors. And I think it does keep giving credit...at least for ECM on small Mersenne numbers and on Fermat numbers. Maybe there are special exceptions so that ECM work still gives credit but other things don't, I don't know.

[lorgix]

Originally Posted by petrw1

Well at 280 digits and factors so far equating 67 digits the remaining composite should be 213 digits.

If I assume that, since the largest factor found so far is 51 digits, that the remaining factors are larger than that then there could be a factor remaining up to about 160 digits.

Yes, that would be an amazing find.

Yes, 214digits even.
11233987055329272412876331600598951897049736479775
75010718300556383281688180366350559792974172384557
07354841517981565066492488482182991795198282677373
04091777193052937545026022471107579402189543491305
99583977799817 to be more specific.
The largest smaller factor is
91238872988674526
30283577249393667
31341350831028977


GET TO IT PEOPLE!

[cheesehead]

Originally Posted by alpertron

a) These cases were software errors, not hardware errors, as recognized by Woltman, and the factors were found by rerunning all bit levels.

Yes, by rerunning TF.

BTW, exactly how did you determine that there have been, or not been, any hardware errors that prevented finding a factor, by any method?

[lorgix]

Originally Posted by chalsall

I occasionally have a few of my machines working in the <1M range, bring the exponents from 60 to 61.

Rather silly really, I know. Out of 3964 tested, only 5 factors found (0.1261%)....

Originally Posted by alpertron

...Also notice that after some bit level threshold which depend on the exponent, you will find more results per unit of time using ECM than using TF. For smaller exponents, that bit level is lower, so it is recommended not to use TF but ECM instead.

Just the other day I brought down (among the non-assigned) the number of the biggest exponent that still hadn't been factored to 61. Probably not very efficient. (mostly doing ECM on 5M+ now btw)

The biggest exponent available that hasn't been factored to 61 is 693967.

694277 has been assigned for ECM for about 6months.

[alpertron]

Originally Posted by lorgix

The biggest exponent available that hasn't been factored to 61 is 693967.

694277 has been assigned for ECM for about 6months.

Many of the assigned exponents were forgotten. According to http://www.mersenne.org/report_expon...&B1=Get+status there were other people that were doing ECM on that factor after being assigned to WileECoyote on April. This user has not returned any result on this exponent.