New code for primality testing
Torbjörn Granlund
tg at gmplib.org
Wed Nov 21 15:33:34 UTC 2018
Paul Leyland <paul.leyland at gmail.com> writes:
I table of known exponents, and then just a lookup there? Cute idea.
For larger exponents, we might just execute a sleep(999999999) in an
infinite loop as the computation will be too slow to terminate anyway.
:-)
I note the smiley but you never know, someone might want to heat their
house for a few years and then contribute a check result to GIMPS.
(As for MR repeats mentioned in your other mail, I've long argued that
running more than one test to a randomly chosen base is a complete
waste of time. If the test says it's composite, game over. If it
claims it may be prime you either want a slow deterministic proof or
it is good enough for all practical purposes, including crypto.)
I agree 99%.
If the source of the random number is not under one's own control,
running more M-R rounds does make sense. There exists numbers for which
1/4 of M-R bases are false prime witnessess.
But this is largely moot with BPSW, IIUC.
--
Torbjörn
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