>"Brian J. Beesley" wrote:
> > There was a problem with some versions which resulted in this error
> > message appearing constantly. I think the problem was related to a
> > factor which was already known being found again - this happens
> > constantly but should be resolved by reference to the low?.txt file.
I am running v20.4.1, so I suspect I'm okay in that regard.
>I got the same error in a F14 curve (I jumped out of my seat).
George told me
>that it
>was a bug in v20.1 where the GCD routine sometimes returned bogus factors,
>which
>were then trapped in a sanity check. That error was fixed in 20.3 . I dont
>know
>about
>errors by faulty low[mp].txt files, but that sure was not the reason in my
>case,
>as F14 has
>no known factors and the error occurred only once out of hundreds of
>curves.
The exponent that I was running also has no known factors.
> > BTW from George's ECM status pages it seems that either factors have
> > become _very_ hard to find recently. Anyone have any views on this?
>
>I think the 2^p+1 list still offers a few good candidates. There have been
>much
>fewer curves
>run on them than on their "2 less" counterparts.
>I'm focusing on F14 right now, while Richard Crandall's challenge still is
>on,
>but predictably,
>nothing much happened so far.
>
>Ciao,
> Alex.
I deliberately run ECM on exponents that
1) are relatively large and do not appear to be "immortal". For example, I
wouldn't devote a large chuck of time to, say, M727, which has occupied the
"hot seat" since I have joined GIMPS. I wonder how long it's been there...
-or-
2) have had much less ECM run than their immediate neighbors. Examples
would be M751 and F13.
I have 250 curves on M751 queued to run, simply because I feel that the
larger thrill connected with cracking such a nearly "immortal" exponent is
worth the reduced chance, and because that exponent is currently less
factored than its neighbors, making this a good opportunity to run a low
unfactored exponent.
Nathan
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