attachment:2not4Galoisapproachv2.sage of GaganSekhon

   1 x = QQ['x'].0
   2 for A in load("/sagedatafor2not4or4not8/li4"):
   3     E=EllipticCurve(A);
   4     rho=E.galois_representation();
   5     if E.has_cm()==False and  rho.is_surjective(2):
   6         F=factor(E.division_polynomial(4));
   7         l=len([p for p,e in F if p.degree()==6]);
   8         if l!=0:
   9             for p,e in F:
  10                 if p.degree()==6:
  11                     g(x)=p(x/2)*2^6;
  12                     f = gp(loads(g(x).dumps()))
  13                     h=f.polgalois();
  14                     if h[1] !=48:
  15                         print E.label(),":", h;
  16                     
  17         else:
  18            G=F/(E.division_polynomial(2));
  19            for p,e in G:
  20                                g(x)=p(x/2)*2^3;
  21                 f = gp(loads(g(x).dumps()))
  22                 h=f.polgalois();
  23                 if h[1] !=48:
  24                     print E.label(),":", h;
  25 print 'done';