Lucas Wiman <[EMAIL PROTECTED]> writes
>[...]
>> when I found out than Curt Noll had started an attack on M(M(127)) with
>> superior hardware. I imagine that by now he has carried the search much
>> further.
>
>This is further evidence for why GIMPS is such a good idea! (as if we
>needed more)
Well, yes ... but in practice when you work on a problem with
considerably more powerful hardware than has previously been applied to
it, there is little cost in starting again from scratch, and it double-
checks the work that has already been done.
>If Curt Noll and you have been working together, your computer time would
>not have been wasted, nor would (presumably) much of his. This is the
>beauty of distributed computing projects, but this illistrates how *key*
>centrilization is.
Of course, soon after Curt started working on M_M_127 I collaborated
with him - by retiring!
>Now, I think that it might be a nifty (tm) idea if GIMPS/primenet
>were to start looking for factors of double Mersenne numbers. If I
>understand correctly, much of the code is already written (changes to
>the P-1 code, and the normal factoring code), and I'm sure that such things
>could interest mathematicians more than finding the next Mersenne prime.
The only feasible approach for M_M_61 and above is trial-division. I
recently blew the dust off by my program MFAC and gave it a run. For
M_M_61 it processes divisors N*M_61 + 1 on an AMD/400 at about 2.2
billion N's per hour. (6 billion/hour for M_M_31.) If people are
interested, and unless someone else can do better, after a bit of
tidying up I can make this program available.
Then we need a mechanism for handing out work. I am happy to volunteer,
but it will have to be done manually.
--
Tony
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