#15996: Allow general base rings for WeierstrassForm
-------------------------------------+-------------------------------------
Reporter: jkeitel | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.2
Component: algebraic geometry | Keywords: toric,
Merged in: | weierstrass
Reviewers: | Authors: Jan Keitel
Work issues: | Report Upstream: N/A
Commit: | Branch:
b2fb5cc9f20201d167d9bac0c787220c7d96b70f| u/jkeitel/weierstrass_general_rings
Stopgaps: | Dependencies:
-------------------------------------+-------------------------------------
Currently, one method in {{{sage.rings.invariant_theory}}} and another one
in {{{sage.schemes.toric.weierstrass}}} make use of {{{__floordiv__}}}.
More precisely, if p and m are elements in a ring R with base ring B, then
one needs
{{{p // m}}},
where {{{m}}} always has a unit coefficient. However, {{{__floordiv__}}}
is only implemented if B is a field and therefore doing something like
{{{
sage: P.<a> = QQ[]
sage: R.<x,y,z> = P[]
sage: cubic = x^3 + a*y^3 + a^2*z^3
sage: WeierstrassForm(cubic)
}}}
does not work because
{{{
sage: cubic // x^3
}}}
fails. However, since the coefficients of {{{m}}} are always in {{{QQ}}},
we can work around that and I've written a short patch that does so.
It might not be very pretty (if someone has a nicer idea, that would be
great), but it works and actually speeds up long calculations.
Best,
Jan
--
Ticket URL: <http://trac.sagemath.org/ticket/15996>
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