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Old 2006-10-22, 20:18   #34
axn
 
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I am assuming you got this from this page: http://primes.utm.edu/top20/page.php?id=1

If so, the key sentence would be:
Quote:
Originally Posted by prime pages
Nice--too bad it is of virtually no practical value!
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Old 2006-10-24, 23:20   #35
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Quote:
I am assuming you got this from this page: http://primes.utm.edu/top20/page.php?id=1

If so, the key sentence would be:
Quote:
Quote:
Originally Posted by prime pages
Nice--too bad it is of virtually no practical value!
Didn't people once say the same thing about imaginary numbers?

Anyway, I just thought I'd throw it out there, just in case it was overlooked.

Never mind.
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Old 2006-11-14, 19:48   #36
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FYI, I started sieving 25G-50G. I'm planning to stop when p reaches 3T.
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Old 2006-11-14, 20:22   #37
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I don't think it is worthful. I can do that in 7-10 hours (or so I think) and the datafile will be quite large (> 300Mb) -- and thus not really transferrable.

Last fiddled with by gribozavr on 2006-11-14 at 20:24
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Old 2006-11-15, 14:52   #38
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Quote:
Originally Posted by gribozavr View Post
I don't think it is worthful. I can do that in 7-10 hours (or so I think) and the datafile will be quite large (> 300Mb) -- and thus not really transferrable.
Ok, then I'll keep testing numbers ;)
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Old 2006-11-26, 13:32   #39
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Splitting up horizontal sieving does not make sense, at all. (Of course, for the first G (before merging) this rule does not apply; here a bitmap instead of a hashtable is used due to the large number of candidates)
The sieving speed does not depend on the size of the range, therefore it is recommended, that the range is initially sized larger then necessary. We just need to take care that the computer has enough memory. (I do also some sieving on a 100G range and I have no impact on the sieving speed. The safe file is 750MBytes (but it can compressed down to 20% if the sieving is distributed) and NewPGen takes 320 Mbytes for the hashtable)

n=195000 does also follow this strategy; they chance of failing is only 1/6. In case we do not find a twin after the first 20G we can discuss our future plans. Either continuing from 25G or choosing a new N is an option. (I suggest to choose a N which is some 100 below a FFT change point (SSE2 and nonSSE2) in order to improve efficiency)
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Old 2006-11-26, 14:53   #40
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I think that we'll find a twin prime before 20G.
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Old 2006-11-29, 20:46   #41
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Quote:
Originally Posted by biwema View Post
n=195000 does also follow this strategy; they chance of failing is only 1/6. In case we do not find a twin after the first 20G we can discuss our future plans. Either continuing from 25G or choosing a new N is an option. (I suggest to choose a N which is some 100 below a FFT change point (SSE2 and nonSSE2) in order to improve efficiency)
I know it's a bit early, but shouldn't we start thinking about the next N already?
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Old 2006-11-30, 13:40   #42
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Range [1200e6; 25e9] is at p=930.0T, 8,397,809 k's left.
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Old 2006-11-30, 17:19   #43
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Quote:
Originally Posted by smh View Post
I know it's a bit early, but shouldn't we start thinking about the next N already?
Some time ago I did some testing and continued quite a bit.

My favourite is N=333333.
It has a little bit more than 100000 Digits and is just below a FFT change for SSE2.
So, I already started sieving on that number.
I have chosen a range of 100G (Has the same probability of finding a twin like a 34G Range at 195000).
At the moment I am somewhere beyond 150T and have less than 39 million candidtes left.

I will continue sieving that range and we can start with that N after finishing. N=195000. Maybe even distributes sieving is possible; the ideal sieving depth is between 50P and 100P depending architecture used.

How do you think about it?

Edit: Imagaine, we are working on than N, it is very likely that we find thousands of primes that are not a twin. These Primes will flood the top5000 page and have quite an inpact on the diversity of primes.

biwema

Last fiddled with by biwema on 2006-11-30 at 17:22
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Old 2006-12-02, 13:12   #44
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Looking at http://primes.utm.edu/primes/lists/all.txt I see that 17 primes have already been reported for n=333333.

Last fiddled with by gribozavr on 2006-12-02 at 13:12
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