Re: TI-M: Re: TI-Math Digest V1 #22


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Re: TI-M: Re: TI-Math Digest V1 #22




> The point of the congruency list is to cut down on the number of
divisions,
> since it's the division (or the check for divisibility as a whole) that is
> the slowest process (from my experience).  Dividing each potential
> probable-prime would take the complete point out of wheeler algorithm,
whose
> purpose is to decrease the number of overall trial-divisions.  If you have
to
> trial-divide potential probable-primes, which, if determined to be not
> divisible by 2, 3, 5, 7, 11 (or whatever), would then be trial-divided
into
> the number, the whole process would be a hell of a lot slower.  The
"trouble"
> of the congruency list pays off in that probable primes are quickly
> calculated one after another, so most of the processing time is spent
finding
> factors of the inputted number, not determining the divisibility of
potential
> probable-primes.

Wait a sec, maybe I get it now - we _don't_ prove the primality of any other
those numbers, do we?  We trial divide the number to be factored by all the
PROABABLE primes, not just the PROVEN ones?  Or am I still way off? =)

> Oh, musta missed that...

I looked the name of that algorithm up on the net, too - didn't understand a
thing.  They're all written from a math perspective and not a programming
one =)

> So where's that Alg85 that I need...? ;)

Isn't that where this thread started?  Somebody suggested a z80 symbolic
CAS? =)

    -Scott




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