On Wed, 07 Jun 2000 08:06:47 PDT,
Robert Braunwart <[EMAIL PROTECTED]> asked:
>Can anyone give me the formula for computing P90 CPU hours of work from a
>Mersenne exponent, for LL tests and for factoring?
IIRC, there is no easy formula for factoring, since smaller exponents
actually take longer to factor to a specific depth (there's more candidate
factors; see George's math pages). If you have a Pentium Pro or above, you
can get a rough idea by taking the time needed by your machine and
multiplying it by the clock speed; then divide by about 60 to 70 since
PPro-archetecture CPU's are much better at factoring relative to their clock
speed. This is my own rule-of-thumb formula, and may have nothing to do
with the ones Entropia uses for factoring credit; I suggest that you ask
them for that info.
For LL testing, head over to the official benchmark page at
http://www.mersenne.org/bench.htm and get the per-iteration time for a P90
for the exponent range, or 'runlength', that you are testing. His times
are per second, so multiply by the exponent and divide by 3600 for CPU
hours, or some large number for CPU years (I don't have a calculator here at
school). George's page doesn't presently list a P90, so you might try
linear interpolation or use the handy java applet.
Happy testing,
Nathan Russell
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