Function: quadregulator
Section: number_theoretical
C-Name: quadregulator
Prototype: Gp
Help: quadregulator(D): regulator of the real quadratic field of
 discriminant D.
Doc: regulator of the quadratic order of positive discriminant $D$ in time
 $\tilde{O}(D^{1/2})$ using the continued fraction algorithm. Raise
 an error if $D$ is not a discriminant (fundamental or not) or if $D$ is a
 square. The function \kbd{quadclassunit} is asymptotically faster (and also
 in practice for $D > 10^{10}$ or so) but depends on the GRH.
