primep matter



Greetings!

Wolfgang Jenkner <wjenkner@inode.at> writes:

> Andrei Zorine <zoav1@uic.nnov.ru> writes:
> 
> > 1) primep(2^31-1) hangs.
> 
> Not on SBCL or CLISP.
> 

Nor on my recent maxima 5.9.0 build atop gcl 2.6.1.

> > 2) (defun primep...) tries to factor its argument which is very slow.
> 
> Only if a pseudo-prime test (in a weak sense) is passed.  In the worst
> case (if the argument N is actually a prime) CFACTOR performs
> sqrt(N)/3+O(1) trial divisions.  There was a similar discussion some
> time ago in the thread starting with
> 
> http://www.math.utexas.edu/pipermail/maxima/2002/001979.html
> 
> But I think that Camm fixed that (GCL-) bug.
> 

Should be fixed to my knowledge.

Take care,

> > 3) faster algorithhm is easily introducible: just load primeq.lisp from
> > Prof. Fateman's MockMathematica, and add (define jacobi-symbol(p q)
> > (JacobiSymbol p q)) line.
> 
> Maxima has $JACOBI.
> 
> Wolfgang
> 
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> 
> 

-- 
Camm Maguire			     			camm@enhanced.com
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