Igor Schein on Tue, 21 Jul 1998 16:00:57 -0400


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ispseudoprime behavior


Hi, consider the following function

f(n)=while(1,print(ispseudoprime(n)))

Now let n be a negative integer whose absolute
value is an odd composite integer.  For example
let n=-9.  In a few iterations you'll see the
following:
***   impossible inverse modulo: Mod(3, 9).

I was trying to figure out what's going on in
the code, I noticed that negative sign gets
stripped out by the time millerrabin() is called,
but couldn't figure out where.

I looked at the manual, and didn't see any
mentioning of having to restrict arguments
to ispseudoprime() to positive integers.  So,
if ispseudoprime() is supposed to work on negative
integers, than the behavior described above is a bug.
If it's not supposed to work on negative integers,
then I'd like that to be mentioned in the manual
on in online help.  

Thanks

Igor