Re: Calculating powmod...

[David Cleaver <wraithx@morpheus.net>]

Bill Allombert wrote:
> On Sun, Oct 18, 2009 at 11:20:51AM -0500, David Cleaver wrote:
> > Hello,
> >
> > I'm interested in calculating "powmod"'s such as:
> > Mod(2^9182347891540, 9182347891541)
> > However, when I ran the function, it gave an error:
> >  ***   length (lg) overflow
>
> Of course because PARI cannot compute 2^9182347891540.
> You should compute with the class of 2 in in Z/9182347891541Z, i.e.
> Mod(2, 9182347891541).  In that case you get:
>
> ? Mod(2, 9182347891541)^9182347891540
> %1 = Mod(7569093976632, 9182347891541)
>
> Cheers,
> Bill.

Thank you very much for this answer.

Also, is there a way to print out timing information at the end of a program?  I 
know that when a "program" I've written finishes, I can do a ## to see how long 
it took to run.  But, I'd like to somehow put that command into the program. 
When I tried "##" or "##;", it said "unexpected character(s)" and pointed to 
right after the "##".

-David C.