factornf

Function: factornf
Section: number_fields
C-Name: polfnf
Prototype: GG
Obsolete: 2016-08-08
Help: factornf(x,t): this function is obsolete, use nffactor.
Doc: This function is obsolete, use \kbd{nffactor}.

 factorization of the univariate polynomial $x$
 over the number field defined by the (univariate) polynomial $t$. $x$ may
 have coefficients in $\Q$ or in the number field. The algorithm reduces to
 factorization over $\Q$ (\idx{Trager}'s trick). The direct approach of
 \tet{nffactor}, which uses \idx{van Hoeij}'s method in a relative setting, is
 in general faster.

 The main variable of $t$ must be of \emph{lower} priority than that of $x$
 (see \secref{se:priority}). However if nonrational number field elements
 occur (as polmods or polynomials) as coefficients of $x$, the variable of
 these polmods \emph{must} be the same as the main variable of $t$. For
 example

 \bprog
 ? factornf(x^2 + Mod(y, y^2+1), y^2+1);
 ? factornf(x^2 + y, y^2+1); \\@com these two are OK
 ? factornf(x^2 + Mod(z,z^2+1), y^2+1)
   ***   at top-level: factornf(x^2+Mod(z,z
   ***                 ^--------------------
   *** factornf: inconsistent data in rnf function.
 ? factornf(x^2 + z, y^2+1)
   ***   at top-level: factornf(x^2+z,y^2+1
   ***                 ^--------------------
   *** factornf: incorrect variable in rnf function.
 @eprog