About M1277 - Page 6

Prime95 · 2022-06-14, 00:41

Quote:

Originally Posted by BigNumberGuy

unfortunately whenever i set b2 to anything more than about 8 billion my process ends with "segmentation fault". wtf does that mean?

Means there is a bug in prime95.

Look for instructions on the forum as to how to run stage1 in prime95, stage 2 in GMP-ECM. You'll be glad you did (~3x more throughput).

BigNumberGuy · 2022-06-14, 03:28

Alright, In that case, I'm abandoning my ECM task and just going with whatever prime95 assigns for me then.

storm5510 · 2022-06-14, 15:37

Quote:

Originally Posted by kruoli

This does not apply if one is using GMP-ECM for stage 2 (which is basically a must for such a small exponent). It will also not apply to Prime95/mprime if/when George implements a GMP-ECM-like ECM stage 2. You (general "you") can do stage 1 in Prime95 and export it to GMP-ECM or build GMP-ECM with gwnum or run GMP-ECM directly. Use the suggested B1 for ECM in this thread, select a maximum memory and GMP-ECM will find a good B2 for this settings.

I have been using the current B1 level shown in the "ECM Progress" page on mersenne.org for my experiments with M4363. It is 110e6. For M1277, it would need to be beyond 800e6. I do not know of a practical way of determining what it should be. A guess, 12e8, or more.

VBCurtis · 2022-06-14, 16:56

Quote:

Originally Posted by storm5510

I do not know of a practical way of determining what it should be. A guess, 12e8, or more.

You could read this thread... I mean, you quoted a post that literally said "use the suggested B1 for ECM in this thread", to say you don't know where to find B1. Read the thread.

If that's not good enough for you, try the readme that comes with GMP-ECM. You'll find a suggested B1 for T70 of 29e8. We've discussed that T70 has been finished for M1277 already, so you should pick a B1 appropriate for T75. The list of B1s in the readme roughly triple every 5-digit level, e.g. 110M for T55 to 260M for T60 to 850M for T65 to 2900M for T70; you can guess from that list that a B1 around 8e9 for T75 is good enough. When in doubt, a little too big is better than a little too small.

Or you can read this thread.

swellman · 2022-06-14, 17:28

There’s more information here.

mathwiz · 2022-06-14, 21:55

Quote:

Originally Posted by storm5510

I have been using the current B1 level shown in the "ECM Progress" page on mersenne.org for my experiments with M4363. It is 110e6. For M1277, it would need to be beyond 800e6. I do not know of a practical way of determining what it should be. A guess, 12e8, or more.

B1=76e8.

Use GMP-ECM. Let it do its thing.

Done.

storm5510 · 2022-06-15, 13:16

Quote:

Originally Posted by mathwiz

B1=76e8.

Use GMP-ECM. Let it do its thing.

Done.

I won't be running M1277 myself. Others with much newer hardware can run it. What I have is long-in-the-tooth and there may not ever be anything newer.

Off-topic: I've been experimenting with M4363. I might as well stop with the experiments and set it up and let it run.

mrk74 · 2022-07-09, 23:28

So from what I've read even messing with M1277 is pretty much useless only using Prime95?

Side note: Before looking at much of this I thought I'd try a P-1 and I upped both bounds just a bit. It was ONLY going to take about 50 YEARS to do it. Hmmmm think I'll pass on trying that!

storm5510 · 2022-07-10, 17:25

FWIW. Several years ago, someone mentioned the best shot at M1277 would be with NFS, (Number Field Sieve). These are used with YAFU as add-ons. M1277 is 385 digits in length. Could YAFU handle a number of this size? I do not know. There is YAFU 2.0. It might be able to. Even if it could, there would be a lot of time involved.

bsquared · 2022-07-10, 18:34

Quote:

Originally Posted by storm5510

FWIW. Several years ago, someone mentioned the best shot at M1277 would be with NFS, (Number Field Sieve). These are used with YAFU as add-ons. M1277 is 385 digits in length. Could YAFU handle a number of this size?

No.

Longer answer:
Only CADO really has a chance at it, and it would still need a monumental effort.

storm5510 · 2022-07-10, 23:00

Quote:

Originally Posted by bsquared

No.

Longer answer:
Only CADO really has a chance at it, and it would still need a monumental effort.

CADO? That's a new one on me. A Google search is not revealing in this context.

As I wrote, a long time.

2022-06-14, 03:28	#57
BigNumberGuy May 2022 3×7 Posts	Alright, In that case, I'm abandoning my ECM task and just going with whatever prime95 assigns for me then. Last fiddled with by BigNumberGuy on 2022-06-14 at 03:34

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storm5510 Random Account Aug 2009 Not U. + S.A. 2·5·227 Posts	FWIW. Several years ago, someone mentioned the best shot at M1277 would be with NFS, (Number Field Sieve). These are used with YAFU as add-ons. M1277 is 385 digits in length. Could YAFU handle a number of this size? I do not know. There is YAFU 2.0. It might be able to. Even if it could, there would be a lot of time involved.