Two versions of QQ(sqrt{-1}) upon startup

[nbruin]

We have two copies upon startup:

sage: import gc
sage: Ks=[K for K in gc.get_objects() if
....: isinstance(K,sage.rings.number_field.number_field.NumberField_quadratic)]
sage: [latex(k.0) for k in Ks]
[i, \sqrt{-1}]

I suspect they are coming from
symbolic/pynac.pyx:2046 (in init_pynac_I)

    K = QuadraticField(-1, 'I', embedding=CC.gen(), latex_name='i')

and from rings/qqbar.py:7699 (in _init_qqbar)

    QQbar_I_nf = QuadraticField(-1, 'I', embedding=CC.gen())

Should we perhaps both give them the same latex name so that these can be the same field?

Component: interfaces

Author: Frédéric Chapoton

Branch/Commit: 5aa64be

Reviewer: Ralf Stephan

Issue created by migration from https://trac.sagemath.org/ticket/15298

[nbruin]

comment:1

A preliminary test shows that changing rings/qqbar.py:7699 to

QQbar_I_nf = QuadraticField(-1, 'I', embedding=CC.gen(), latex_name='i')

works fine and ensures that there's only one field created upon startup.
Note that:

sage: latex(QQbar.0)
\text{\texttt{1*I}}

so it looks like the latex printing will not be affected by this change either.

[fchapoton]

comment:6

done

---

New commits:

8aee254

trac 15298 only one field for I

[fchapoton]

Author: Frédéric Chapoton

[fchapoton]

Branch: u/chapoton/15298

[fchapoton]

Commit: 8aee254

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

cf4d4f8

trac 15298 only one field for I

[sagetrac-git]

Changed commit from 8aee254 to cf4d4f8

[rwst]

comment:8

Doctest fails in qqbar.py which are logical. You can set to positive after adaptation.

[rwst]

Reviewer: Ralf Stephan

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

5aa64be

trac 15928 fixing doctests

[sagetrac-git]

Changed commit from cf4d4f8 to 5aa64be

[fchapoton]

comment:10

Thanks. This introduces a non-uniform behaviour for the latex of QQbar elements. Sometimes "i" will still be displayed as sqrt{-1}. I propose to keep that issue for another ticket. Objection ?

[rwst]

comment:11

Replying to @fchapoton:

Objection ?

None. Please go ahead.

[fchapoton]

comment:12

then let it be positive

[vbraun]

Changed branch from u/chapoton/15298 to 5aa64be