nth root

[casevh]

On Jan 31, 9:36 pm, "Tim Roberts" <t.robe... at cqu.edu.au> wrote:
> Actually, all I'm interested in is whether the 100 digit numbers have an exact integral root, or not.  At the moment, because of accuracy concerns, I'm doing something like
>
>                     for root in powersp:
>                             nroot = round(bignum**(1.0/root))
>                             if bignum==long(nroot)**root:
>                                                              .........
> which is probably very inefficient, but I can't see anything better.....
>
> Tim

Take a look at gmpy and the is_power function. I think it will do
exactly what you want.

http://code.google.com/p/gmpy/

casevh