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Old 2013-08-27, 08:43   #144
Lennart
 
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At the rate at which primes have been added to this list in the past, the 307855 digit prime "2217*2^1022660-1" may only be on the list for about 4 weeks.


2217*2^1022660-1 is Prime


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Old 2013-08-27, 10:40   #145
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Quote:
Originally Posted by Kosmaj View Post
Although, frankly speaking, with my limited resources I'm not that interested in searching for primes that will last only a few weeks on Top-5000.
Me too.
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Old 2013-08-27, 11:45   #146
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I think it is best to leave this range or cut it down to 2000<k<2100.

I have 100 core on it now and it will keep it on the list now, but we need at least 200 core to make any progress ( to get higher on the list).

What do you think ?


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Old 2013-08-27, 11:49   #147
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I think this drive should be shut down. Leave the numbers to NPLB. Let's concentrate on k's<300.

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Old 2013-08-27, 12:24   #148
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Quote:
Originally Posted by Lennart View Post
I think it is best to leave this range or cut it down to 2000<k<2100.
A cut down to a smaller number of k might be a good option (instead of abandoning the whole drive). But maybe 2000<k<2100 is still too large. We could also consider to pick just the high weights, or (alternatively) the k's which had been primeless so far.
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Old 2013-08-27, 12:38   #149
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Let's look at our Top 5000 primes. The first prime with k 2xxx appears in position 184, the second in position 2110, and so on, so we are wasting time with this drive.
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Old 2013-08-27, 13:07   #150
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Quote:
Originally Posted by pinhodecarlos View Post
Let's look at our Top 5000 primes. The first prime with k 2xxx appears in position 184, the second in position 2110, and so on, so we are wasting time with this drive.
Carlos, I agree with you that the most economic search would be to concentrate on the smallest k's only (let's say k<300). But shall we therefore drop all other drives?

Of course, we currently have quite a few drives - maybe just too many.
If we are about to abandon any, the 11th drive would be the first to consider.

But as long as there is interest in this drive, we should keep it alive, but without jeopardizing the other drives by drawing too much computing power...
(There might also be individuals who don't care about their Top5000 score and who crunch "their" numbers just for fun.)

Regarding a cut down to a smaller number of k's:
I checked the 7th drive (which covers the range k=2000-3000). The average Nash weight is 2901, with individual weights ranging from 1659 (k=2265) to 3883 (k=2835).
In comparison, the 11th drive contains quite a few k's with even larger weights. Here are the largest ones with weight>3000:
Code:
 k  weight
----------
2289 3107
2061 3124
2271 3180
2079 3221
2085 3345
2127 3437
2259 3437
2253 3507
2205 3532
2103 3935
2043 4049
2211 4509
So, how about picking just those 12 k's, driving them to n=1290k and merging them into the 7th drive?
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Old 2013-08-27, 13:27   #151
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Quote:
Originally Posted by Thomas11 View Post
Carlos, I agree with you that the most economic search would be to concentrate on the smallest k's only (let's say k<300). But shall we therefore drop all other drives?
Yes, drop all drives above k>300. That's my opinion.
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Old 2013-08-27, 14:39   #152
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I was planning on alternating between the 8th and 11th drives to help advance both drives.

My thinking is we only needed to get both drives to n=1.20M to stay ahead of PrimeGrid's Proth search which is producing many more primes than their SG search. Proth is the one we need to worry about. The SG search could go on for years and will never increase in digits so we can catch up and pass at some point down the road.

The 8th drive once ahead of the proth search can be easily be maintained with just a few machines active. Pulling ahead should only take a couple of weeks at current rate.

The 11th drive is a bit more problematic due to the number k's involved. Per Lennart's post with his 100 cores engaged it will be a long slog to reach our goal of overtaking the proth search. I could bring 50+ cores to the effort, more once the summer is over, but when Lennart's and my interest wains we would be stuck losing ground again.

So, I would vote to cut the number of k's to a more manageable level, but what that level should be?
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Old 2013-08-27, 14:57   #153
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Quote:
Originally Posted by Thomas11 View Post
So, how about picking just those 12 k's, driving them to n=1290k and merging them into the 7th drive?
From counting the number of candidates in the sieve file it turns out that picking just those 12 high weight k's from the original 126 k's would reduce the work load to about 20% (19.05%).

Picking the range k=2000-2100 would be roughly 33%. Quite comparable...

I would vote for one of those options.

BTW.: I could also bring a few cores (about 20) into this effort.

Last fiddled with by Thomas11 on 2013-08-27 at 15:00
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Old 2013-08-27, 23:09   #154
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1021-1025k complete 2 Primes

2171*2^1023034-1 is Prime


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