#9220: Unpredictable parent for polynomial evaluation
-----------------------------------------------+----------------------------
Reporter: nbruin | Owner: robertwb
Type: defect | Status: positive_review
Priority: major | Milestone: sage-5.7
Component: coercion | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers: Tom Boothby
Authors: Nils Bruin, Robert Bradshaw | Merged in:
Dependencies: | Stopgaps:
-----------------------------------------------+----------------------------
Changes (by tscrim):
* status: needs_review => positive_review
* work_issues: docstrings =>
Old description:
> I doubt that it is intended that the names of the variables of a
> polynomial ring can affect the parent of the result of evaluating such a
> polynomial:
>
> {{{
> sage: R=QQ['x']
> sage: S=QQ['x','y']
> sage: h=S.0^2
> sage: parent(h(R.0,0))
> Multivariate Polynomial Ring in x, y over Rational Field
>
> sage: R=QQ['x']
> sage: S=QQ['u','v']
> sage: h=S.0^2
> sage: parent(h(R.0,0))
> Univariate Polynomial Ring in x over Rational Field
> }}}
> I would expect the result of the second example in both cases.
>
> In
>
> http://groups.google.com/group/sage-
> devel/browse_thread/thread/4607f62126303ddd?pli=1
>
> John Cremona mentions #8502 as fixing a different but similar issue.
New description:
I doubt that it is intended that the names of the variables of a
polynomial ring can affect the parent of the result of evaluating such a
polynomial:
{{{
sage: R=QQ['x']
sage: S=QQ['x','y']
sage: h=S.0^2
sage: parent(h(R.0,0))
Multivariate Polynomial Ring in x, y over Rational Field
sage: R=QQ['x']
sage: S=QQ['u','v']
sage: h=S.0^2
sage: parent(h(R.0,0))
Univariate Polynomial Ring in x over Rational Field
}}}
I would expect the result of the second example in both cases.
In
http://groups.google.com/group/sage-
devel/browse_thread/thread/4607f62126303ddd?pli=1
John Cremona mentions #8502 as fixing a different but similar issue.
-----
Apply:
[attachment:9220-poly-evaluation-coerce-5.4.rebase.patch]
[attachment:trac_9220-poly_evaluation-review-ts.patch]
--
Comment:
The rebased version worked for me. I've attached a small reviewer patch
which just does the minor tweaks to the docstrings. Jeroen, I hope you
don't mind me setting this back to a positive review.
Best,[[BR]]
Travis
For patchbot:
Apply only: 9220-poly-evaluation-coerce-5.4.rebase.patch, trac_9220
-poly_evaluation-review-ts.patch
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9220#comment:16>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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