Wrong conversion from algebraic to interval

[videlec]

sage: a = QuadraticField(5).gen()
sage: u = -573147844013817084101/2*a + 1281597540372340914251/2
sage: RealIntervalField(128)(u)
0
sage: RealIntervalField(128)(u).is_zero()
True

---

There is a related problem coming from the RealLazyField that we do not solve in this ticket

sage: v = RLF(u)
sage: v
0.?e6
sage: v.is_zero()
False
sage: RealIntervalField(128)(v)
0

CC: @sagetrac-tmonteil

Component: basic arithmetic

Author: Vincent Delecroix

Branch/Commit: 0953e11

Reviewer: Sébastien Labbé

Issue created by migration from https://trac.sagemath.org/ticket/21979

[videlec]

Commit: cd2828a

[videlec]

Author: Vincent Delecroix

[videlec]

Branch: u/vdelecroix/21979

[videlec]

New commits:

cd2828a

21979: fix conversion of algebraic quadratic to real interval

[seblabbe]

comment:6

Problem is fixed. Documentation builds fine. Positive review.

Vincent, do you want to create a ticket for the unsolved problem with RealLazyField ?

[seblabbe]

Reviewer: Sébastien Labbé

[videlec]

comment:7

Thanks.

I actually think that we should get rid of RealLazyField in any coercion involving number fields... I opened #21991.

[videlec]

comment:8

As patchbots say there is a broken doctest in polynomial_rational_flint.pyx

sage: R.<t> = QQ[]
sage: f = 1 + t/2
sage: f.reverse(I)

[sagetrac-git]

Changed commit from cd2828a to 0953e11

[sagetrac-git]

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

0953e11

21979: fix complex quadratic number conversion

[videlec]

comment:10

needs review again

[seblabbe]

comment:11

The patchbot says:

----------------------------------------------------------------------
sage -t --long src/sage/modular/modform/ambient.py  # Timed out
----------------------------------------------------------------------

I can not reproduce the problem. All other tests passed. Positive review.

[vbraun]

Changed branch from u/vdelecroix/21979 to 0953e11