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-   -   Merry Christmas and a prime! (M50 related) (https://www.mersenneforum.org/showthread.php?t=22837)

Prime95 2017-12-27 03:13

Merry Christmas and a prime! (M50 related)
 
A day after Christmas a computer has reported a new Mersenne prime. Unlike the numerous CudaLucas false positives we've had over the last few years, this one shows promise. It was assigned December 18, no errors during the run. This particular computer has reported 57 previous results including some successful double-checks.

Madpoo's running an LL test now. T-41 hours.

I'll reach out by email for the last save file, but with the holidays I may not get a response before Madpoo's run completes.

Fingers crossed!!

axn 2017-12-27 03:16

Nice! Here's hoping... *fingers crossed*

BTW, does the client itself do a quick selfcheck re-run from the last savefile in case of prime?

Prime95 2017-12-27 03:19

[QUOTE=axn;474944]BTW, does the client itself do a quick selfcheck re-run from the last savefile in case of prime?[/QUOTE]

No, its still in my long wish list.

axn 2017-12-27 03:22

[QUOTE=Prime95;474945]No, its still in my long wish list.[/QUOTE]

If Gerbicz error check becomes widespread, it will be a moot point.

Prime95 2017-12-27 03:28

Prime95 version 28.9 was used. Thus, no Jacobi checking during the run or at the end of the run.

gophne 2017-12-27 03:29

Wow...great news...All success.

Uncwilly 2017-12-27 05:16

Is a PRP being run on it too (in case it may finish first) as a check?

Did the e-mail system work? Did the residue masking work? (And is there a clue somewhere?) Can we assume that this is a WR or should we assume that this is a Double Check? Also, I would assume, based upon the times your are talking about, this is not in the 100M digit range.

Madpoo 2017-12-27 05:18

[QUOTE=Prime95;474943]...

Madpoo's running an LL test now. T-41 hours.
...[/QUOTE]

32 hours to go now (I setup that system to use 20 cores on it instead of the usual dual 14-core workers it runs).

I don't know if George has already reached out to anyone with a fast GPU system to get another verifying test going on it in parallel, just in case? What's the fastest GPU out there now for LL testing... Titan of some flavor? Anyone with one of those willing to lend some cycles for a couple days on the chance this is a new prime?

Otherwise, my verification won't technically count as a double-check since it's another Prime95 run and we'd still want one with another program (mprime, cudalucas, cllucas, etc). My run is just to know whether or not to go on to that next step. We've run into a lot of false positives over the past couple years, but this one has more confidence behind it. :smile:

Batalov 2017-12-27 05:22

Time to run mlucas on a C5 instance?

Madpoo 2017-12-27 06:09

[QUOTE=Uncwilly;474956]Is a PRP being run on it too (in case it may finish first) as a check?

Did the e-mail system work? Did the residue masking work? (And is there a clue somewhere?) Can we assume that this is a WR or should we assume that this is a Double Check? Also, I would assume, based upon the times your are talking about, this is not in the 100M digit range.[/QUOTE]

PRP... well, it raises an interesting question about how a new prime found via PRP would be handled. I'd guess that a pair of LL tests would be run since LL is deterministic and not "merely" probabilistic?

The email did successfully go out when the result was reported in, and fortunately I saw it pretty quick and started a verification run.

Since we have had those false positives lately (mostly from cudalucas, recently), what I've been doing when a "prime" comes in is to look at the age of the assignment. Most false reports (especially from cudalucas) were turning in results within hours of being assigned, so you could be pretty sure it was wrong.

There were the exceptions to that though, like the false positives from xolotl that were from Prime95, so the next thing I look at is the overall history of the machine that turned in the result, and of the user in general. How many double-check successes do they have, any bad results, etc. Are they a new user? Is the machine overclocked, etc?

So, yeah, everything in this case seems to be looking pretty good. It doesn't look like the machine is overclocked, it has a good history of matching DC's including some recent ones, in addition to the first-time checks it does. The user him or herself has been around for a while so this isn't some new person with a weird system...

In summary, fingers crossed, but it's looking good on the surface of it.

a1call 2017-12-27 06:23

Is it 22M dd+?
I'd like to let people I know, know before it makes the headline news.
Thanks in advance and good luck.:smile:


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