Newer milestone thread - Page 76

Aramis Wyler · 2013-08-13, 02:10

Quote:

Originally Posted by garo

I think that is more due to GPU72 holding everything from 61m upwards to make sure everything gets TFed to 74 bits before being handed out for LL testing. The thought process being it is better to hand out a 65M with TF to 74 bits than a 61M with TF done to 73 bits. If we find TF is lagging behind I think we could just throw back any 61M or 62M exponents into the LL pool and be fine. No need to mess with the What Makes Sense setting.

Yikes, I thought we were only holding 64M and higher to 74 bits, and < 64M was 73 bits? I've been using my card to factore the <64M ones to 73 bits, to sweep them out as it were, because I thought everyone was doing 64M+ to 74.

kladner · 2013-08-13, 02:36

Quote:

Originally Posted by Aramis Wyler

Yikes, I thought we were only holding 64M and higher to 74 bits, and < 64M was 73 bits? I've been using my card to factore the <64M ones to 73 bits, to sweep them out as it were, because I thought everyone was doing 64M+ to 74.

So THAT's where all those 73-74s are coming from! Argh!

(Just kidding. I tend to get a lot of Lowest Factored Level assignments, too, for my faster card. But I take everything to 74, no matter where it starts.)

Primeinator · 2013-08-13, 04:00

When is it desirable to go above 74 bits?

TheMawn · 2013-08-13, 04:09

Chris has been talking about starting up to 75 soon. I think it's a ways away and maybe borderline profitable. However, since from 74 to 75 takes the same amount of time as UP TO 74, and the trial factoring effort as we know isn't exactly doubling the LL pace, I don't think we can afford to move past 74 yet.

On the other hand, more knowledgeable people than I have probably thought this through. This is just what I've gathered over the last little while.

Aramis Wyler · 2013-08-13, 04:13

Quote:

Originally Posted by kladner

So THAT's where all those 73-74s are coming from! Argh!

(Just kidding. I tend to get a lot of Lowest Factored Level assignments, too, for my faster card. But I take everything to 74, no matter where it starts.)

lol, I'll release the rest of the 73s and take them all to 74. That must have changed while I was away and I missed it.

kladner · 2013-08-13, 04:25

Quote:

Originally Posted by Primeinator

When is it desirable to go above 74 bits?

This is a question of much discussion and dispute. AFIK, for the time being it is only recommended in the hundreds of millions exponent ranges. Also, at any level there is a break-even point, beyond which the TF does not save any time and effort versus an LL test.

This page gives current suggested guidelines, though these have been adjusted from time to time. Part of the calculus for GPU72 is how far we are staying ahead of LL assignments. When we pull ahead, there's time to take factoring to higher levels. If LL is catching up too quickly it may be better to drop back a level and complete more to lesser levels, instead of fewer to higher levels. (Please be aware that this is a crude explanation by one who has next to no grasp of the maths involved.) Chalsall monitors the assignment rates and can give a much better picture than I.

Primeinator · 2013-08-13, 04:56

Quote:

Originally Posted by kladner

This is a question of much discussion and dispute.

This page gives current suggested guidelines, though these have been adjusted from time to time. Part of the calculus for GPU72 is how far we are staying ahead of LL assignments. When we pull ahead, there's time to take factoring to higher levels. If LL is catching up too quickly it may be better to drop back a level and complete more to lesser levels, instead of fewer to higher levels. (Please be aware that this is a crude explanation by one who has next to no grasp of the maths involved.) Chalsall monitors the assignment rates and can give a much better picture than I.

Those videos are quite impressive. Kudos to the effort that must have taken!

blahpy · 2013-08-13, 06:12

Am I correct in saying that LL tests will get reassigned after 1 year if not manually extended? If so, we should be getting a lot of the low double-checks back this month, the lowest next week

http://mersenne.org/report_exponent/...&B1=Get+status

Chuck · 2013-08-13, 12:55

Quote:

Originally Posted by kladner

Chalsall monitors the assignment rates and can give a much better picture than I.

I just use "Let GPU72 decide" in MISFIT and I don't have to worry about changing requirements.

garo · 2013-08-13, 18:03

This page is what you are looking for:
http://www.mersenne.ca/cudalucas.php...ranularity=0.1

With a GTX570, you can start at 74 bits at 51M. But we simply do not have that kind of firepower.

kladner · 2013-08-13, 19:11

Quote:

Originally Posted by garo

This page is what you are looking for:
http://www.mersenne.ca/cudalucas.php...ranularity=0.1

With a GTX570, you can start at 74 bits at 51M. But we simply do not have that kind of firepower.

That's exactly the graph I was thinking of. Thanks very much, Garo!

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2013-08-13, 04:00	#828
Primeinator "Kyle" Feb 2005 Somewhere near M52.. 3×5×61 Posts	When is it desirable to go above 74 bits?

2013-08-13, 04:09	#829
TheMawn May 2013 East. Always East. 1727₁₀ Posts	Chris has been talking about starting up to 75 soon. I think it's a ways away and maybe borderline profitable. However, since from 74 to 75 takes the same amount of time as UP TO 74, and the trial factoring effort as we know isn't exactly doubling the LL pace, I don't think we can afford to move past 74 yet. On the other hand, more knowledgeable people than I have probably thought this through. This is just what I've gathered over the last little while.

2013-08-13, 06:12	#833
blahpy Jun 2013 107 Posts	Am I correct in saying that LL tests will get reassigned after 1 year if not manually extended? If so, we should be getting a lot of the low double-checks back this month, the lowest next week http://mersenne.org/report_exponent/...&B1=Get+status

2013-08-13, 18:03	#835
garo Aug 2002 Termonfeckin, IE ACC₁₆ Posts	This page is what you are looking for: http://www.mersenne.ca/cudalucas.php...ranularity=0.1 With a GTX570, you can start at 74 bits at 51M. But we simply do not have that kind of firepower.