#20330: hyperbolic_geodesic midpoint bugfix
-------------------------------------+-------------------------------------
Reporter: jhonrubia6 | Owner:
Type: defect | Status: needs_review
Priority: major | Milestone: sage-7.2
Component: geometry | Resolution:
Keywords: hyperbolic | Merged in:
geometry, geodesic | Reviewers: Vincent Delecroix
Authors: Javier Honrubia | Work issues:
González | Commit:
Report Upstream: N/A | 2ba1c96e25d7e128adc832bc4c4e4c51e8835b98
Branch: | Stopgaps:
u/jhonrubia6/hyperbolic_geodesic_midpoint_bugfix|
Dependencies: |
-------------------------------------+-------------------------------------
Comment (by jhonrubia6):
Replying to [comment:45 nbruin]:
> Once you've established which parent P to work over, you need a way to
find `I` in there. Just as getting 0, 1, -1 into P is to construct them in
the simplest parent (ZZ in this case) and converting them into P via
`P(0),P(1),P(-1)`, constructing `I` in P should be a similar procedure.
There is one solution that works most of the time via cyclotomic fields:
`P(CyclotomicField(4).0)`
> In a way, if that fails for `P` then `P` is probably not a good parent
for this kind of computations.
>
> There are some numerical noise problems with `CC(CyclotomicField(4),0)`
which mightbe worth fixing.
>
> Currently, `GF(5)(CyclotomicField(4).0)` doesn't work.
>
> Code along these lines could be a lot more robust for new parents than
the special-casing approach taken now. I'm not quite sure we have suitable
infrastructure for it to use it now, but perhaps we should (the main issue
is of course that the choice of I isn't unique, whereas the integers
convert uniquely into any integral domain)
I am out of my field here, but if I understand you right, are you
proposing to replace the elif block proposed by Vincent by something based
on the CyclotomicField? Why is it more robust? aside of the problems you
mention of {{{CC(CyclotomicField(4).0)}}} which may be should be
accomplished on a different ticket
--
Ticket URL: <http://trac.sagemath.org/ticket/20330#comment:46>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/sage-trac.
For more options, visit https://groups.google.com/d/optout.
