ecmprob.magma

SetVerbose("MPQS",false); // disable MPQS messages (if any)

FindGroupOrder := function (p, sigma)
   K := GF(p);
   v := K ! (4*sigma);
   u := K ! (sigma^2-5);
   x := u^3;
   b := 4*x*v;
   a := (v-u)^3*(3*u+v);
   A := a/b-2;
   x := x/v^3;
   b := x^3 + A*x^2 + x;
   E := EllipticCurve([0,b*A,0,b^2,0]);
   return FactoredOrder(E);
end function;

// ecmprob(20, 11000, 1583400, 1000, 6);
// sigma=6: n= 1000 e2= 3.269 e3= 1.696 e5= 0.281 success= 13/1000
// sigma=7: n= 1000 e2= 3.304 e3= 1.656 e5= 0.29 success= 11/1000
// sigma=1/4: n= 1000 e2= 3.327 e3= 1.687 e5= 0.298 success= 3/200
// ecmprob(25, 50000, 14201460, 1000, 6);
// sigma=6: n= 1000 e2= 3.353 e3= 1.665 e5= 0.319 success= 3/1000
// sigma=7: n= 1000 e2= 3.293 e3= 1.662 e5= 0.299 success= 1/250
// sigma=1/4: n= 1000 e2= 3.374 e3= 1.646 e5= 0.291 success= 3/500
// ecmprob(30, 250000, 173213040, 1000, 6);
// sigma=6: n= 1000 e2= 3.369 e3= 1.655 e5= 0.314 success= 1/250
// sigma=7: n= 1000 e2= 3.219 e3= 1.676 e5= 0.308 success= 1/500
// sigma=1/4: n= 1000 e2= 3.373 e3= 1.678 e5= 0.287 success= 3/1000
// ecmprob(35, 1000000, 975508380, 1000, 6);
// sigma=6: n= 1000 e2= 3.39 e3= 1.699 e5= 0.292 success= 3/1000
// sigma=7: n= 1000 e2= 3.292 e3= 1.665 e5= 0.329 success= 1/1000
// sigma=1/4: n= 1000 e2= 3.346 e3= 1.675 e5= 0.321 success= 1/1000
// ecmprob(40, 3000000, 4595040450, 1000, 6);
// sigma=6: n= 1000 e2= 3.391 e3= 1.667 e5= 0.298 success= 1/1000
// sigma=7: n= 1000 e2= 3.237 e3= 1.685 e5= 0.308 success= 1/1000
// sigma=1/4: n= 1000 e2= 3.335 e3= 1.657 e5= 0.251 success= 0
// ecmprob(45, 11000000, 30114892080, 1000, 6);
// sigma=6: n= 1000 e2= 3.244 e3= 1.721 e5= 0.317 success= 0
// sigma=7: n= 1000 e2= 3.334 e3= 1.668 e5= 0.295 success= 0
// sigma=1/4: n= 1000 e2= 3.295 e3= 1.647 e5= 0.305 success= 0
// ecmprob(50, 43000000, 198674155680, 1000, 6);
// sigma=1/4: n= 1000 e2= 3.396 e3= 1.655 e5= 0.267 success= 0
// ecmprob(55, 110000000, 729516567780, 1000, 6);
// sigma=1/4: n= 1000 e2= 3.217 e3= 1.629 e5= 0.301 success= 0
ecmprob := procedure (d, B1, B2, N, sigma)
local p, g, n, e2, e3, e5, i, success, l, S, T;
   T := RealField(d);
   p := Ceiling(Exp((T ! d - T ! 0.5) * Log(T ! 10.0)));
   S := RealField(8);
   e2 := S ! 0.0;
   e3 := S ! 0.0;
   e5 := S ! 0.0;
   n := 0; // number of primes
   success := 0;
   for n := 1 to N do
      p := NextPrime (p : Proof := false);
      g := FindGroupOrder (p, sigma);
      i := 1;
      l := #g;
      if l ge i and g[i][1] eq 2 then
         e2 := e2 + g[i][2];
         i := i + 1;
      end if;
      if l ge i and g[i][1] eq 3 then
         e3 := e3 + g[i][2];
         i := i + 1;
      end if;
      if l ge i and g[i][1] eq 5 then
         e5 := e5 + g[i][2];
         i := i + 1;
      end if;
      if g[l][1] le B2 and (l eq 1 or g[l-1][1] le B1) then
         success := success + 1;
      end if;
      print "n=",n,"e2=",e2/n,"e3=",e3/n,"e5=",e5/n,"success=",success/n;
   end for;
end procedure;