nffactor vs factornf

[Luis Felipe Tabera Alonso <taberalf@unican.es>]

Hello all,

I have a newbie question about how pari deals with factorization with 
algebraic numbers.

According to the documentation, factornf uses Trager's trick to perform a 
factorization over the rationals and nffactor uses Van Hoeij's method, which 
is preferable in many cases, but it needs a nf structure.

I have some complicated number fields where I would like to factor 
polynomials. If I already have the nf structure, I can use nffactor without 
problems. But for these fields nf is very expensive, so factornf is faster (I 
will not factor so many polynomials to do the effort).

But, as I understand Van Hoeij method, one does not need the nf structure, it 
may increase performance though. I am correct? Is there a way to use Van 
Hoeij's method without computing nf of the number field?

Thanks for this good piece of software.

Luis