# Calculation of maximal order fails even when using "maximize_at_primes"

I would like to calculate the maximal order of a field for which I already know at which primes we should maximize.

This means that the discriminant does not have to be factored, which is normally the bottleneck of this algorithm.

I did

```
d = [2,3,5,7,11,13,17,19]
K.<y> = NumberField([x^2 - di for di in d], maximize_at_primes=[2])
RR = K.maximal_order()
```

The last command did not finish overnight, but gave the following warning:

```
"*** Warning: MPQS: number too big to be factored with MPQS,
giving up."
```

Which seems to indicate that the program is indeed trying to perform a large factorization despite the command "maximize_at_primes=[2]"

Meanwhile, Magma has no problem performing this computation in a few hours:

```
R<x> := PolynomialRing(Integers());
K := NumberField([x^2 - 2,x^2 - 3 , x^2-5,x^2-7,x^2 - 11,x^2 - 13 , x^2 - 17 , x^2 - 19]:Abs);
O := MaximalOrder(K: Ramification := [2]);
```

Am I doing something wrong ?

JF Biasse

It works with

but...

and there are many other digits (totally 423).

Adding the 19 in the

`dList`

seems to be too much for the resources here.