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Unregistered 2011-07-26 13:30

ECM question
 
Hi, I have a quadcore running ECM factoring and I always make 6 curves of the same exponent on all the 4 CPU but I haven't find a factor yet. I wanted to know if it's useful make 24 curves using only a CPU instead of what I'm doing. Thanks

R.D. Silverman 2011-07-26 16:02

[QUOTE=Unregistered;267572]Hi, I have a quadcore running ECM factoring and I always make 6 curves of the same exponent on all the 4 CPU but I haven't find a factor yet. I wanted to know if it's useful make 24 curves using only a CPU instead of what I'm doing. Thanks[/QUOTE]

What do you mean by "useful"?? 24 curves will give a higher probability
of success than 6.

I do not understand what you mean by "using only a CPU". Do you mean
"only using a single CPU"? Using more than one CPU allows one to run
more curves in a fixed amount of time.

Unregistered 2011-07-26 16:45

Sorry, I wrote my question bad. I wanted to say 24 curves using one CPU instead of 6 curves per haed to the 4 CPU (a single ECM of 24 curves or 4 ECM of 6 curves). Thanks

cheesehead 2011-07-26 18:53

[QUOTE=Unregistered;267591]Sorry, I wrote my question bad. I wanted to say 24 curves using one CPU instead of 6 curves per haed to the 4 CPU (a single ECM of 24 curves or 4 ECM of 6 curves). Thanks[/QUOTE]For results reported to GIMPS, it'll be the same either way.

24 curves are 24 curves (all with the same B1/B2, that is) regardless of how you divide them among your CPUs.

Do whichever is more convenient for you.

R.D. Silverman 2011-07-26 19:47

[QUOTE=Unregistered;267591]Sorry, I wrote my question bad. I wanted to say 24 curves using one CPU instead of 6 curves per haed to the 4 CPU (a single ECM of 24 curves or 4 ECM of 6 curves). Thanks[/QUOTE]

The probability of success will be the same in either case. One CPU
will take a bit longer :smile:


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