Function: ellwp
Section: elliptic_curves
C-Name: ellwp0
Prototype: GDGD0,L,pP
Help: ellwp(E,{z=x},{flag=0}):
 computes the value at z of the Weierstrass P function attached to the
 elliptic curve E as given by ellinit (alternatively, E can be
 given as a lattice [om1,om2]). Optional flag means 0 (default), compute only
 P(z), 1 compute [P(z),P'(z)], 2 consider om as an elliptic curve and compute
 P(z) for that curve (identical to ellztopoint in that case). If z is omitted or
 is a simple variable, return formal expansion in z.
Doc: Computes the value at $z$ of the Weierstrass $\wp$ function attached to
 the elliptic curve $E$ as given by \kbd{ellinit} (alternatively, $E$ can be
 given as a lattice $[\omega_1,\omega_2]$).

 If $z$ is omitted or is a simple variable, computes the \emph{power series}
 expansion in $z$ (starting $z^{-2}+O(z^2)$). The number of terms to an
 \emph{even} power in the expansion is the default serieslength in \kbd{gp},
 and the second argument (C long integer) in library mode.

 Optional \fl\ is (for now) only taken into account when $z$ is numeric, and
 means 0: compute only $\wp(z)$, 1: compute $[\wp(z),\wp'(z)]$.

Variant: Also available is \fun{GEN}{weipell}{GEN E, long precdl} for the power
 series.
