Function:ellmaninconstant
Section: elliptic_curves
C-Name: ellmaninconstant
Prototype: G
Help: ellmaninconstant(E): let E be an elliptic curve over Q given by
 ellinit or a rational isogeny class given by ellisomat. Return the
 Manin constant of the curve, see ellweilcurve.
 The algorithm is slow but unconditional.
Doc: let $E$ be an elliptic curve over $Q$ given by
 \kbd{ellinit} or a rational isogeny class given by ellisomat. Return the
 Manin constant of the curve, see \kbd{ellweilcurve}.
 The algorithm is slow but unconditional.
 The function also accepts the output of \kbd{ellisomat} and returns the list
 of Manin constants for all the isogeny class.
 \bprog
 ? E = ellinit("11a3");
 ? ellmaninconstant(E)
 %2 = 5
 ? L=ellisomat(E,,1);
 ? ellmaninconstant(L)
 %4 = [5,1,1]
 @eprog
