id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,work_issues,upstream,reviewer,author,merged,dependencies,stopgaps
4749,[with patch; with positive review] improve coercion of points between elliptic curves and reduction of points mod p,was,cswiercz,"If I have a point P on an elliptic curve E and F is another curve, then F(P) should work if possible.  It doesn't.   For example:
{{{
E = EllipticCurve([1,-1,0,94,9]) 
R = E([0,3]) + 5*E([8,31])      # big denom's
E11 = E.change_ring(GF(11))
E11(R) 
 BOOM!
}}}
But it should clear denominators and coerce in the triple like so:
{{{
def reduce(R, p):
    x, y = R.xy()
    d = LCM(x.denominator(), y.denominator())
    return R.curve().change_ring(GF(p))([x*d,y*d,d])
}}}
",enhancement,closed,major,sage-3.2.3,number theory,fixed,elliptic curves,cswiercz,,,,,,,