Integer root extracting

[Hans Aberg]

On 3 Sep 2010, at 15:39, Paul Zimmermann wrote:

> you can restrict to prime exponent y. See Algorithm IsPower page 29  
> of [1],
> and the comment just below.

Yes, I posted that: I need to compute the value of the root, too. So  
iterate mpz_root() over primes 2, 3, ... In effect, it computes the  
gcd of the exponents in the prime factorization, without doing the  
factorization itself.