Opened 13 years ago

Closed 12 years ago

Gap interface for number fields

Reported by: Owned by: Simon King William Stein major sage-4.6.2 interfaces gap interface number field sage-4.6.2.alpha2 Simon King Luis Felipe Tabera Alonso N/A

Description

Originally motivated by work on #5618, I found two bugs in the Gap interface for number fields, reported here.

#8909 has a positive review and seems partially relevant here, so, I started work with the patch from #8909 applied.

With the new patch, the following works (and is doctested):

```sage: L.<tau> = NumberField(x^3-2)
sage: gap(tau)^3  # note the exclamation mark used by GAP
!2
sage: L(gap(tau)^3) # this used to fail
2
```
```sage: P.<z> = QQ[]  # Note: The var'name is z, not x
sage: K.<zeta> = NumberField(z^2 - 2)
sage: k = gap(K)  # this used to fail, as only var'name x was accepted
```

Fixing the second problem, it is needed to avoid a conflict with an internal variable name of a GAP function, namely "E". This tests that the conflict is indeed avoided:

```sage: P.<E> = QQ[]
sage: L.<tau> = NumberField(E^3-2)
sage: gap(L)
<algebraic extension over the Rationals of degree 3>
```

Changed 13 years ago by Simon King

Fixing two bugs (doctested) in the GAP interface of number fields

comment:1 Changed 13 years ago by Simon King

Status: new → needs_review

comment:2 Changed 12 years ago by Luis Felipe Tabera Alonso

Reviewers: → Luis Felipe Tabera Alonso

The code corrects a couple of bugs in the gap interface of number fields. Since ! cannot be part of the name of a generator of a number field, then eliminating "!" from the gap representation is correct.

The solution to the "E" variable problem is correct, althought there should be a more system-wide solution to this kind of problems.

I will not give it a positive review until #5618 is also ready to merge, since this patch eliminates a doctest that after #5618 will be obsolete.

comment:3 Changed 12 years ago by Luis Felipe Tabera Alonso

Milestone: sage-4.6.1 → sage-4.6.2 needs_review → positive_review

Positive review, I have only updated the patch header to add the ticket number

Apply:

trac_9423_gap_for_numberfields.2.patch

Note to the release manager: ticket #5618 depends on this. This ticket should be merged together with #5618.

comment:4 Changed 12 years ago by Jeroen Demeyer

Merged in: → sage-4.6.2.alpha2 → fixed positive_review → closed
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