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Old 2012-05-29, 02:16   #23
ATH
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George should make a Prime95 version for BOINC and give people lots of credits so we get thousands of new contributors
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Old 2012-05-29, 02:47   #24
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It would be like Newegg getting new customers by opening an ebay storefront. Seems utterly redundant... only it isn't!
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Old 2012-05-29, 03:06   #25
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Quote:
Originally Posted by davieddy View Post
George has the definitive(?) database re the state of the art.
State of the art database? Well... I'll give him state of the art software
(Awesome software, hands down.)
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Old 2012-05-29, 03:14   #26
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Quote:
Originally Posted by ATH View Post
George should make a Prime95 version for BOINC and give people lots of credits so we get thousands of new contributors
What are "they" on?

Re "credit", all I care about is maximizing the probability of finding another MP before I die.
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Old 2012-05-29, 11:52   #27
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Default Two new factors, but there are probably many others

They have two factors for small exponents on their webpage (http://mersenneathome.net/), which are not in the GIMPS database:

Quote:
For p=2100451, M(p) is divisible by 63923221582748657. The divisor found by:For p=2102207, M(p) is divisible by 124414352434216087. The divisor found by:
How to deal with that. Should we submit them to GIMPS or those factors are not "ours"?

Last fiddled with by bloodIce on 2012-05-29 at 11:53
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Old 2012-05-29, 12:14   #28
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Quote:
Originally Posted by bloodIce View Post
They have two factors for small exponents on their webpage (http://mersenneathome.net/), which are not in the GIMPS database:

How to deal with that. Should we submit them to GIMPS or those factors are not "ours"?
Surely the appropriate way would be to send a polite request that they be added into the GIMPS database, with the offer for one of the GIMPS team to submit them if the finders' prefer, and that GIMPS credit be given to the finders.

Paul
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Old 2012-05-29, 13:49   #29
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Although, it takes about 0.00913267 GHz days to produce those factors (which are around 56-57 bits). I thought that the factorization to 2^60 was already done for those two exponents (2102207 and 2100451), but obviously not.
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Old 2012-05-29, 15:41   #30
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Well guys, I got this reply from Bobrecki:
----------------------------------------------------------------------------
Hello KEP,

Hello Sebastian
...
1. Is all candidates previously factored by GIMPs removed from testing?

The majority of it. But probably an insignificant percentage of the work may overlap.
----------------------------------------------------------------------------

It was given to me as a reply to a PM. I'm really not understanding if George should fail to get a reply if he sends a PM at the mersenneathome.net website, since I got reply in less than 8 hours. But as you can see it appears that all candidates previously factored by GIMPs has been removed from the database. However it appears that the remaining candidates were left for further TF without concern to previous TF depths. So maybe a consideration should be to convince Bobrecki to do 1 of following suggestions:

1. Give people the possibility of only doing TF of candidates for n>1G (All 3 phases)
2. Only to do TF that has not allready been done by GIMPs (thereby also consider current TF bit depth)
3. To coordinate the future workload with George or other people at GIMPs such that new discoveries are made by both projects. Discoveries wich can then be exported to one anothers different database.

Well that's my thoughts. I'm unfortunantly not able to speak Polish, but with todays recent findings of 2 unknown factors, it actually shows that there may be something to look for afterall, despite those different TF ranges has already been extensively tested previously.

Take care

Kenneth
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Old 2012-05-29, 16:02   #31
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Quote:
Originally Posted by KEP View Post
...but with todays recent findings of 2 unknown factors, it actually shows that there may be something to look for afterall, despite those different TF ranges has already been extensively tested previously.
In Science, independent work is welcomed, not discouraged.
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Old 2012-05-29, 17:52   #32
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Quote:
Originally Posted by bloodIce View Post
Although, it takes about 0.00913267 GHz days to produce those factors (which are around 56-57 bits). I thought that the factorization to 2^60 was already done for those two exponents (2102207 and 2100451), but obviously not.
We've found that if bad hardware is used, sometimes factors are missed, when they should have been found. A few members of this forum like to go back to low exponents that have already been double-LLed and rerun P-1, if it was skipped or done poorly the first time; occasionally they find factors that should have been found the first time, but due to hardware errors were not found. James Heinrich maintains a list of such exponents here.

Neither trial factoring nor P-1 factoring are double checked by GIMPS, because the effort/value ratio is far too high compared to just running two LL tests. As far as I know, there isn't anybody that is redoing TF on very low exponents. The nature of the P-1 algorithm means that extending the bounds will find smaller factors anyways, whereas doing TF from 2^60 to 2^61 will not find any missed factors <2^60.

Addendum: Here's some discussion of should-have-been-found-the-first-time P-1 factors.

Last fiddled with by Dubslow on 2012-05-29 at 18:02
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Old 2012-05-29, 17:58   #33
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Quote:
Originally Posted by Dubslow View Post
We've found that if bad hardware is used, sometimes factors are missed, when they should have been found.
We've also found that the software provided by GIMPS did not always find the factors which should have been found....
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