Silly iota bug

[jvoight]

> _<x> := PolynomialRing(Rationals());
> f := x^5 - 3*x^4 + 5*x^3 + 27*x^2 + 18*x;
> K := SplittingField(f);
> X := HyperellipticCurve(f);
> geoendorep := GeometricEndomorphismRepresentation(X);

GeometricEndomorphismRepresentation(
    X: X
)
PeriodMatrix(
    X: X
)
In file "/Users/jvoight/Dropbox/github/CHIMP/endomorphisms/endomorphisms/magma/\
heuristic/Periods.m", line 100, column 33:
>> F := BaseRing(X); CC := Parent(F`iota);
                                   ^
Runtime error in `: Attribute 'iota' for this structure is valid but not 
assigned

I think we just need to assign the default complex numbers when the base ring is the rationals.

[edgarcosta]

geoendorep := HeuristicEndomorphismRepresentation(X : Geometric := true);

is the "Button".

Alternatively,

> _<x> := PolynomialRing(RationalsExtra(100));
> X := HyperellipticCurve(f);
> geoendorep := GeometricEndomorphismRepresentation(X);

I aim to " fix" the *Extra world at some point, but for now, it's not a high priority for me.

[jvoight]

Yes, not a high priority.

I also love heuristic buttons, but I think this should still work.