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Old 2013-01-11, 14:14   #1
lycorn
 
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Default What a (TF) factor!!...

Man, is this real?

From the Primenet Progress Report (Cleared exponents):

dbaugh Manual testing 2268941 F Jan 10 2013 9:11PM 0.0 7265.6046 79710277416868001845009

The figures seem correct. That´s a ~76bit factor for a 2.2M exponent. But... are you really TFing exponents so small this high, or was it just a lucky strike?
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Old 2013-01-11, 15:10   #2
axn
 
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How did you determine that this was TF? More probable is ECM. How does an ECM factor report look like?
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Old 2013-01-11, 18:51   #3
bcp19
 
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Quote:
Originally Posted by axn View Post
How did you determine that this was TF? More probable is ECM. How does an ECM factor report look like?
It does say Manual Testing... how many people run a manual ecm program? Either way, doubtful TF... 3,557 days, poss P-1? 10.4 days.

Last fiddled with by bcp19 on 2013-01-11 at 18:53
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Old 2013-01-11, 20:42   #4
TObject
 
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k = 17565524492895144 = 2^3 * 3^2 * 121661 * 2005290257
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Old 2013-01-11, 20:47   #5
lycorn
 
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Quote:
Originally Posted by axn View Post
How did you determine that this was TF? More probable is ECM. How does an ECM factor report look like?
The amount of credit given matches the one expected for TFing a 2.2M exponent to ~76 bits (the length of the factor is 76.077 bits).
Moreover, factors found through TF are identified by the server with an "F", which is the current case. ECM factors are identified by "F-ECM".
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Old 2013-01-11, 20:54   #6
petrw1
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Quote:
Originally Posted by lycorn View Post
Man, is this real? But... are you really TFing exponents so small this high, or was it just a lucky strike?
He is.
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Old 2013-01-11, 21:47   #7
Dubslow
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The k that TObject mentions is a feasible P-1 Brent-Suyama hit.

I find it more likely that it was an ECM hit that got misreported than doing TF.
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Old 2013-01-11, 21:50   #8
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It is possible to be a TF result, since dbaugh once trial factored M4025501 to 77 bits without finding a factor and then found a 77.127 bits factor. In that case, it's not so clear if the factor was found using TF or ECM, but the "no factor found" results should be valid I think.

Last fiddled with by dabaichi on 2013-01-11 at 21:52
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Old 2013-01-12, 06:31   #9
dbaugh
 
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I do a lot of ECM and also a lot of TF. The ECM keeps the processor busy while I use mfakto and mfaktc to do TF. I lost credit for the first several hundred exponents I LL'ed over 15 years ago when Primenet migrated. I am revisiting those exponents and others in the vicinity to re-earn that credit and more doing high TF. I also like finding small missed exponents of numbers whose history was cleared by someone finding a larger factor using ECM. I keep my own records of bit levels TFed because I cannot get this information when a factor is known. The best ones are where there is no factor known. The others are a lot of work for no credit other than my own knowledge that they have been exhaustively searched up to a high bit level. Occasionally an exponent catches my interest. At the moment I especially like ones with long histories like 1000003. I have been running a 79 to 80 TF on one machine and a 80 to 81 TF on another for the last several months of the exponent 9007753.
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Old 2013-01-12, 06:53   #10
ixfd64
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Now that's what I call dedication!

However, I couldn't help but mention that the effort required to factor M9007753 to 81 bits is approximately equivalent to TF'ing 1,000 exponents in the 60M range from 70 to 73 bits. The latter would be much more beneficial to GIMPS. Heck, even searching for a factor of MM127 would be greatly welcomed.

Last fiddled with by ixfd64 on 2013-01-12 at 07:01
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Old 2013-01-12, 07:00   #11
dbaugh
 
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I split my efforts between satisfying my narrow interests and helping the larger project. If someone finds a factor of 9007753 by any means, I pledge to drop it and work on taking 1,000 60M exponents from 71 to 73 instead. 4025501 factoring method is muddied because although I reported my TF result, Primenet recorded it as an ECM result. I contacted George with all the details and he resubmitted it for me as TF.

Last fiddled with by dbaugh on 2013-01-12 at 07:08 Reason: more info
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